Merge branch 'master' into ui-2

README.md

@@ -1,4 +1,4 @@
-# [Parity](https://parity.io/parity.html) - fast, light, and robust Ethereum client
+# [Parity](https://parity.io/) - fast, light, and robust Ethereum client
 
 [![build status](https://gitlab.parity.io/parity/parity/badges/master/build.svg)](https://gitlab.parity.io/parity/parity/commits/master)
 [![Snap Status](https://build.snapcraft.io/badge/paritytech/parity.svg)](https://build.snapcraft.io/user/paritytech/parity)

ethash/Cargo.toml

@@ -11,6 +11,8 @@ hash = { path = "../util/hash" }
 primal = "0.2.3"
 parking_lot = "0.4"
 crunchy = "0.1.0"
+memmap = "0.5.2"
+either = "1.0.0"
 
 [features]
 benches = []

ethash/src/cache.rs

@@ -0,0 +1,352 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+use compute::Light;
+use either::Either;
+use keccak::{H256, keccak_512};
+use memmap::{Mmap, Protection};
+use parking_lot::Mutex;
+use seed_compute::SeedHashCompute;
+
+use shared::{ETHASH_CACHE_ROUNDS, NODE_BYTES, NODE_DWORDS, Node, epoch, get_cache_size, to_hex};
+
+use std::borrow::Cow;
+use std::fs;
+use std::io::{self, Read, Write};
+use std::path::{Path, PathBuf};
+use std::slice;
+use std::sync::Arc;
+
+type Cache = Either<Vec<Node>, Mmap>;
+
+#[derive(PartialEq, Eq, Debug, Clone, Copy)]
+pub enum OptimizeFor {
+	Cpu,
+	Memory,
+}
+
+impl Default for OptimizeFor {
+	fn default() -> Self {
+		OptimizeFor::Cpu
+	}
+}
+
+fn byte_size(cache: &Cache) -> usize {
+	use self::Either::{Left, Right};
+
+	match *cache {
+		Left(ref vec) => vec.len() * NODE_BYTES,
+		Right(ref mmap) => mmap.len(),
+	}
+}
+
+fn new_buffer(path: &Path, num_nodes: usize, ident: &H256, optimize_for: OptimizeFor) -> Cache {
+	let memmap = match optimize_for {
+		OptimizeFor::Cpu => None,
+		OptimizeFor::Memory => make_memmapped_cache(path, num_nodes, ident).ok(),
+	};
+
+	memmap.map(Either::Right).unwrap_or_else(|| {
+		Either::Left(make_memory_cache(num_nodes, ident))
+	})
+}
+
+#[derive(Clone)]
+pub struct NodeCacheBuilder {
+	// TODO: Remove this locking and just use an `Rc`?
+	seedhash: Arc<Mutex<SeedHashCompute>>,
+	optimize_for: OptimizeFor,
+}
+
+// TODO: Abstract the "optimize for" logic
+pub struct NodeCache {
+	builder: NodeCacheBuilder,
+	cache_dir: Cow<'static, Path>,
+	cache_path: PathBuf,
+	epoch: u64,
+	cache: Cache,
+}
+
+impl NodeCacheBuilder {
+	pub fn light(&self, cache_dir: &Path, block_number: u64) -> Light {
+		Light::new_with_builder(self, cache_dir, block_number)
+	}
+
+	pub fn light_from_file(&self, cache_dir: &Path, block_number: u64) -> io::Result<Light> {
+		Light::from_file_with_builder(self, cache_dir, block_number)
+	}
+
+	pub fn new<T: Into<Option<OptimizeFor>>>(optimize_for: T) -> Self {
+		NodeCacheBuilder {
+			seedhash: Arc::new(Mutex::new(SeedHashCompute::new())),
+			optimize_for: optimize_for.into().unwrap_or_default(),
+		}
+	}
+
+	fn block_number_to_ident(&self, block_number: u64) -> H256 {
+		self.seedhash.lock().hash_block_number(block_number)
+	}
+
+	fn epoch_to_ident(&self, epoch: u64) -> H256 {
+		self.seedhash.lock().hash_epoch(epoch)
+	}
+
+	pub fn from_file<P: Into<Cow<'static, Path>>>(
+		&self,
+		cache_dir: P,
+		block_number: u64,
+	) -> io::Result<NodeCache> {
+		let cache_dir = cache_dir.into();
+		let ident = self.block_number_to_ident(block_number);
+
+		let path = cache_path(cache_dir.as_ref(), &ident);
+
+		let cache = cache_from_path(&path, self.optimize_for)?;
+		let expected_cache_size = get_cache_size(block_number);
+
+		if byte_size(&cache) == expected_cache_size {
+			Ok(NodeCache {
+				builder: self.clone(),
+				epoch: epoch(block_number),
+				cache_dir: cache_dir,
+				cache_path: path,
+				cache: cache,
+			})
+		} else {
+			Err(io::Error::new(
+				io::ErrorKind::InvalidData,
+				"Node cache is of incorrect size",
+			))
+		}
+	}
+
+	pub fn new_cache<P: Into<Cow<'static, Path>>>(
+		&self,
+		cache_dir: P,
+		block_number: u64,
+	) -> NodeCache {
+		let cache_dir = cache_dir.into();
+		let ident = self.block_number_to_ident(block_number);
+
+		let cache_size = get_cache_size(block_number);
+
+		// We use `debug_assert` since it is impossible for `get_cache_size` to return an unaligned
+		// value with the current implementation. If the implementation changes, CI will catch it.
+		debug_assert!(cache_size % NODE_BYTES == 0, "Unaligned cache size");
+		let num_nodes = cache_size / NODE_BYTES;
+
+		let path = cache_path(cache_dir.as_ref(), &ident);
+		let nodes = new_buffer(&path, num_nodes, &ident, self.optimize_for);
+
+		NodeCache {
+			builder: self.clone(),
+			epoch: epoch(block_number),
+			cache_dir: cache_dir.into(),
+			cache_path: path,
+			cache: nodes,
+		}
+	}
+}
+
+impl NodeCache {
+	pub fn cache_path(&self) -> &Path {
+		&self.cache_path
+	}
+
+	pub fn flush(&mut self) -> io::Result<()> {
+		if let Some(last) = self.epoch.checked_sub(2).map(|ep| {
+			cache_path(self.cache_dir.as_ref(), &self.builder.epoch_to_ident(ep))
+		})
+		{
+			fs::remove_file(last).unwrap_or_else(|error| match error.kind() {
+				io::ErrorKind::NotFound => (),
+				_ => warn!("Error removing stale DAG cache: {:?}", error),
+			});
+		}
+
+		consume_cache(&mut self.cache, &self.cache_path)
+	}
+}
+
+fn make_memmapped_cache(path: &Path, num_nodes: usize, ident: &H256) -> io::Result<Mmap> {
+	use std::fs::OpenOptions;
+
+	let file = OpenOptions::new()
+		.read(true)
+		.write(true)
+		.create(true)
+		.open(&path)?;
+	file.set_len((num_nodes * NODE_BYTES) as _)?;
+
+	let mut memmap = Mmap::open(&file, Protection::ReadWrite)?;
+
+	unsafe { initialize_memory(memmap.mut_ptr() as *mut Node, num_nodes, ident) };
+
+	Ok(memmap)
+}
+
+fn make_memory_cache(num_nodes: usize, ident: &H256) -> Vec<Node> {
+	let mut nodes: Vec<Node> = Vec::with_capacity(num_nodes);
+	// Use uninit instead of unnecessarily writing `size_of::<Node>() * num_nodes` 0s
+	unsafe {
+		initialize_memory(nodes.as_mut_ptr(), num_nodes, ident);
+		nodes.set_len(num_nodes);
+	}
+
+	nodes
+}
+
+fn cache_path<'a, P: Into<Cow<'a, Path>>>(path: P, ident: &H256) -> PathBuf {
+	let mut buf = path.into().into_owned();
+	buf.push(to_hex(ident));
+	buf
+}
+
+fn consume_cache(cache: &mut Cache, path: &Path) -> io::Result<()> {
+	use std::fs::OpenOptions;
+
+	match *cache {
+		Either::Left(ref mut vec) => {
+			let mut file = OpenOptions::new()
+				.read(true)
+				.write(true)
+				.create(true)
+				.open(&path)?;
+
+			let buf = unsafe {
+				slice::from_raw_parts_mut(vec.as_mut_ptr() as *mut u8, vec.len() * NODE_BYTES)
+			};
+
+			file.write_all(buf).map(|_| ())
+		}
+		Either::Right(ref mmap) => {
+			mmap.flush()
+		}
+	}
+}
+
+fn cache_from_path(path: &Path, optimize_for: OptimizeFor) -> io::Result<Cache> {
+	let memmap = match optimize_for {
+		OptimizeFor::Cpu => None,
+		OptimizeFor::Memory => Mmap::open_path(path, Protection::ReadWrite).ok(),
+	};
+
+	memmap.map(Either::Right).ok_or(()).or_else(|_| {
+		read_from_path(path).map(Either::Left)
+	})
+}
+
+fn read_from_path(path: &Path) -> io::Result<Vec<Node>> {
+	use std::fs::File;
+	use std::mem;
+
+	let mut file = File::open(path)?;
+
+	let mut nodes: Vec<u8> = Vec::with_capacity(file.metadata().map(|m| m.len() as _).unwrap_or(
+		NODE_BYTES * 1_000_000,
+	));
+	file.read_to_end(&mut nodes)?;
+
+	nodes.shrink_to_fit();
+
+	if nodes.len() % NODE_BYTES != 0 || nodes.capacity() % NODE_BYTES != 0 {
+		return Err(io::Error::new(
+			io::ErrorKind::Other,
+			"Node cache is not a multiple of node size",
+		));
+	}
+
+	let out: Vec<Node> = unsafe {
+		Vec::from_raw_parts(
+			nodes.as_mut_ptr() as *mut _,
+			nodes.len() / NODE_BYTES,
+			nodes.capacity() / NODE_BYTES,
+		)
+	};
+
+	mem::forget(nodes);
+
+	Ok(out)
+}
+
+impl AsRef<[Node]> for NodeCache {
+	fn as_ref(&self) -> &[Node] {
+		match self.cache {
+			Either::Left(ref vec) => vec,
+			Either::Right(ref mmap) => unsafe {
+				let bytes = mmap.ptr();
+				// This isn't a safety issue, so we can keep this a debug lint. We don't care about
+				// people manually messing with the files unless it can cause unsafety, but if we're
+				// generating incorrect files then we want to catch that in CI.
+				debug_assert_eq!(mmap.len() % NODE_BYTES, 0);
+				slice::from_raw_parts(bytes as _, mmap.len() / NODE_BYTES)
+			},
+		}
+	}
+}
+
+// This takes a raw pointer and a counter because `memory` may be uninitialized. `memory` _must_ be
+// a pointer to the beginning of an allocated but possibly-uninitialized block of
+// `num_nodes * NODE_BYTES` bytes
+//
+// We have to use raw pointers to read/write uninit, using "normal" indexing causes LLVM to freak
+// out. It counts as a read and causes all writes afterwards to be elided. Yes, really. I know, I
+// want to refactor this to use less `unsafe` as much as the next rustacean.
+unsafe fn initialize_memory(memory: *mut Node, num_nodes: usize, ident: &H256) {
+	let dst = memory as *mut u8;
+
+	debug_assert_eq!(ident.len(), 32);
+	keccak_512::unchecked(dst, NODE_BYTES, ident.as_ptr(), ident.len());
+
+	for i in 1..num_nodes {
+		// We use raw pointers here, see above
+		let dst = memory.offset(i as _) as *mut u8;
+		let src = memory.offset(i as isize - 1) as *mut u8;
+
+		keccak_512::unchecked(dst, NODE_BYTES, src, NODE_BYTES);
+	}
+
+	// Now this is initialized, we can treat it as a slice.
+	let nodes: &mut [Node] = slice::from_raw_parts_mut(memory, num_nodes);
+
+	// For `unroll!`, see below. If the literal in `unroll!` is not the same as the RHS here then
+	// these have got out of sync! Don't let this happen!
+	debug_assert_eq!(NODE_DWORDS, 8);
+
+	// This _should_ get unrolled by the compiler, since it's not using the loop variable.
+	for _ in 0..ETHASH_CACHE_ROUNDS {
+		for i in 0..num_nodes {
+			let data_idx = (num_nodes - 1 + i) % num_nodes;
+			let idx = nodes.get_unchecked_mut(i).as_words()[0] as usize % num_nodes;
+
+			let data = {
+				let mut data: Node = nodes.get_unchecked(data_idx).clone();
+				let rhs: &Node = nodes.get_unchecked(idx);
+
+				unroll! {
+					for w in 0..8 {
+						*data.as_dwords_mut().get_unchecked_mut(w) ^=
+							*rhs.as_dwords().get_unchecked(w);
+					}
+				}
+
+				data
+			};
+
+			keccak_512::write(&data.bytes, &mut nodes.get_unchecked_mut(i).bytes);
+		}
+	}
+}

ethash/src/compute.rs

@@ -19,30 +19,16 @@
 
 // TODO: fix endianess for big endian
 
-use primal::is_prime;
-use std::cell::Cell;
+use keccak::{keccak_512, keccak_256, H256};
+use cache::{NodeCache, NodeCacheBuilder};
+use seed_compute::SeedHashCompute;
+use shared::*;
+use std::io;
+
 use std::mem;
+use std::path::Path;
 use std::ptr;
-use hash;
-use std::slice;
-use std::path::{Path, PathBuf};
-use std::io::{self, Read, Write};
-use std::fs::{self, File};
 
-use parking_lot::Mutex;
-
-pub const ETHASH_EPOCH_LENGTH: u64 = 30000;
-pub const ETHASH_CACHE_ROUNDS: usize = 3;
-pub const ETHASH_MIX_BYTES: usize = 128;
-pub const ETHASH_ACCESSES: usize = 64;
-pub const ETHASH_DATASET_PARENTS: u32 = 256;
-
-const DATASET_BYTES_INIT: u64 = 1 << 30;
-const DATASET_BYTES_GROWTH: u64 = 1 << 23;
-const CACHE_BYTES_INIT: u64 = 1 << 24;
-const CACHE_BYTES_GROWTH: u64 = 1 << 17;
-const NODE_WORDS: usize = 64 / 4;
-const NODE_BYTES: usize = 64;
 const MIX_WORDS: usize = ETHASH_MIX_BYTES / 4;
 const MIX_NODES: usize = MIX_WORDS / NODE_WORDS;
 const FNV_PRIME: u32 = 0x01000193;
@@ -55,48 +41,24 @@ pub struct ProofOfWork {
 	pub mix_hash: H256,
 }
 
-struct Node {
-	bytes: [u8; NODE_BYTES],
-}
-
-impl Default for Node {
-	fn default() -> Self {
-		Node { bytes: [0u8; NODE_BYTES] }
-	}
-}
-
-impl Clone for Node {
-	fn clone(&self) -> Self {
-		Node { bytes: *&self.bytes }
-	}
-}
-
-impl Node {
-	#[inline]
-	fn as_words(&self) -> &[u32; NODE_WORDS] {
-		unsafe { mem::transmute(&self.bytes) }
-	}
-
-	#[inline]
-	fn as_words_mut(&mut self) -> &mut [u32; NODE_WORDS] {
-		unsafe { mem::transmute(&mut self.bytes) }
-	}
-}
-
-pub type H256 = [u8; 32];
-
 pub struct Light {
-	cache_dir: PathBuf,
 	block_number: u64,
-	cache: Vec<Node>,
-	seed_compute: Mutex<SeedHashCompute>,
+	cache: NodeCache,
 }
 
 /// Light cache structure
 impl Light {
-	/// Create a new light cache for a given block number
-	pub fn new<T: AsRef<Path>>(cache_dir: T, block_number: u64) -> Light {
-		light_new(cache_dir, block_number)
+	pub fn new_with_builder(
+		builder: &NodeCacheBuilder,
+		cache_dir: &Path,
+		block_number: u64,
+	) -> Self {
+		let cache = builder.new_cache(cache_dir.to_path_buf(), block_number);
+
+		Light {
+			block_number: block_number,
+			cache: cache,
+		}
 	}
 
 	/// Calculate the light boundary data
@@ -106,107 +68,25 @@ impl Light {
 		light_compute(self, header_hash, nonce)
 	}
 
-	pub fn file_path<T: AsRef<Path>>(cache_dir: T, seed_hash: H256) -> PathBuf {
-		let mut cache_dir = cache_dir.as_ref().to_path_buf();
-		cache_dir.push(to_hex(&seed_hash));
-		cache_dir
-	}
-
-	pub fn from_file<T: AsRef<Path>>(cache_dir: T, block_number: u64) -> io::Result<Light> {
-		let seed_compute = SeedHashCompute::new();
-		let path = Light::file_path(&cache_dir, seed_compute.get_seedhash(block_number));
-		let mut file = File::open(path)?;
-
-		let cache_size = get_cache_size(block_number);
-		if file.metadata()?.len() != cache_size as u64 {
-			return Err(io::Error::new(io::ErrorKind::Other, "Cache file size mismatch"));
-		}
-		let num_nodes = cache_size / NODE_BYTES;
-		let mut nodes: Vec<Node> = Vec::with_capacity(num_nodes);
-
-		unsafe { nodes.set_len(num_nodes) };
-
-		let buf = unsafe { slice::from_raw_parts_mut(nodes.as_mut_ptr() as *mut u8, cache_size) };
-		file.read_exact(buf)?;
+	pub fn from_file_with_builder(
+		builder: &NodeCacheBuilder,
+		cache_dir: &Path,
+		block_number: u64,
+	) -> io::Result<Self> {
+		let cache = builder.from_file(cache_dir.to_path_buf(), block_number)?;
 		Ok(Light {
-			block_number,
-			cache_dir: cache_dir.as_ref().to_path_buf(),
-			cache: nodes,
-			seed_compute: Mutex::new(seed_compute),
+			block_number: block_number,
+			cache: cache,
 		})
 	}
 
-	pub fn to_file(&self) -> io::Result<PathBuf> {
-		let seed_compute = self.seed_compute.lock();
-		let path = Light::file_path(&self.cache_dir, seed_compute.get_seedhash(self.block_number));
-
-		if self.block_number >= ETHASH_EPOCH_LENGTH * 2 {
-			let deprecated = Light::file_path(
-				&self.cache_dir,
-				seed_compute.get_seedhash(self.block_number - ETHASH_EPOCH_LENGTH * 2)
-			);
-
-			if deprecated.exists() {
-				debug!(target: "ethash", "removing: {:?}", &deprecated);
-				fs::remove_file(deprecated)?;
+	pub fn to_file(&mut self) -> io::Result<&Path> {
+		self.cache.flush()?;
+		Ok(self.cache.cache_path())
 	}
 }
 
-		fs::create_dir_all(path.parent().unwrap())?;
-		let mut file = File::create(&path)?;
-
-		let cache_size = self.cache.len() * NODE_BYTES;
-		let buf = unsafe { slice::from_raw_parts(self.cache.as_ptr() as *const u8, cache_size) };
-		file.write(buf)?;
-		Ok(path)
-	}
-}
-
-pub struct SeedHashCompute {
-	prev_epoch: Cell<u64>,
-	prev_seedhash: Cell<H256>,
-}
-
-impl SeedHashCompute {
-	#[inline]
-	pub fn new() -> SeedHashCompute {
-		SeedHashCompute {
-			prev_epoch: Cell::new(0),
-			prev_seedhash: Cell::new([0u8; 32]),
-		}
-	}
-
-	#[inline]
-	fn reset_cache(&self) {
-		self.prev_epoch.set(0);
-		self.prev_seedhash.set([0u8; 32]);
-	}
-
-	#[inline]
-	pub fn get_seedhash(&self, block_number: u64) -> H256 {
-		let epoch = block_number / ETHASH_EPOCH_LENGTH;
-		if epoch < self.prev_epoch.get() {
-			// can't build on previous hash if requesting an older block
-			self.reset_cache();
-		}
-		if epoch > self.prev_epoch.get() {
-			let seed_hash = SeedHashCompute::resume_compute_seedhash(self.prev_seedhash.get(), self.prev_epoch.get(), epoch);
-			self.prev_seedhash.set(seed_hash);
-			self.prev_epoch.set(epoch);
-		}
-		self.prev_seedhash.get()
-	}
-
-	#[inline]
-	pub fn resume_compute_seedhash(mut hash: H256, start_epoch: u64, end_epoch: u64) -> H256 {
-		for _ in start_epoch..end_epoch {
-			unsafe { hash::keccak_256(hash[..].as_mut_ptr(), 32, hash[..].as_ptr(), 32) };
-		}
-		hash
-	}
-}
-
-pub fn slow_get_seedhash(block_number: u64) -> H256 {
+pub fn slow_hash_block_number(block_number: u64) -> H256 {
 	SeedHashCompute::resume_compute_seedhash([0u8; 32], 0, block_number / ETHASH_EPOCH_LENGTH)
 }
 
@@ -214,34 +94,6 @@ fn fnv_hash(x: u32, y: u32) -> u32 {
 	return x.wrapping_mul(FNV_PRIME) ^ y;
 }
 
-fn keccak_512(input: &[u8], output: &mut [u8]) {
-	unsafe { hash::keccak_512(output.as_mut_ptr(), output.len(), input.as_ptr(), input.len()) };
-}
-
-fn keccak_512_inplace(input: &mut [u8]) {
-	// This is safe since `keccak_*` uses an internal buffer and copies the result to the output. This
-	// means that we can reuse the input buffer for both input and output.
-	unsafe { hash::keccak_512(input.as_mut_ptr(), input.len(), input.as_ptr(), input.len()) };
-}
-
-fn get_cache_size(block_number: u64) -> usize {
-	let mut sz: u64 = CACHE_BYTES_INIT + CACHE_BYTES_GROWTH * (block_number / ETHASH_EPOCH_LENGTH);
-	sz = sz - NODE_BYTES as u64;
-	while !is_prime(sz / NODE_BYTES as u64) {
-		sz = sz - 2 * NODE_BYTES as u64;
-	}
-	sz as usize
-}
-
-fn get_data_size(block_number: u64) -> usize {
-	let mut sz: u64 = DATASET_BYTES_INIT + DATASET_BYTES_GROWTH * (block_number / ETHASH_EPOCH_LENGTH);
-	sz = sz - ETHASH_MIX_BYTES as u64;
-	while !is_prime(sz / ETHASH_MIX_BYTES as u64) {
-		sz = sz - 2 * ETHASH_MIX_BYTES as u64;
-	}
-	sz as usize
-}
-
 /// Difficulty quick check for POW preverification
 ///
 /// `header_hash`      The hash of the header
@@ -261,12 +113,12 @@ pub fn quick_get_difficulty(header_hash: &H256, nonce: u64, mix_hash: &H256) ->
 		ptr::copy_nonoverlapping(header_hash.as_ptr(), buf.as_mut_ptr(), 32);
 		ptr::copy_nonoverlapping(mem::transmute(&nonce), buf[32..].as_mut_ptr(), 8);
 
-		hash::keccak_512(buf.as_mut_ptr(), 64, buf.as_ptr(), 40);
+		keccak_512::unchecked(buf.as_mut_ptr(), 64, buf.as_ptr(), 40);
 		ptr::copy_nonoverlapping(mix_hash.as_ptr(), buf[64..].as_mut_ptr(), 32);
 
 		// This is initialized in `keccak_256`
 		let mut hash: [u8; 32] = mem::uninitialized();
-		hash::keccak_256(hash.as_mut_ptr(), hash.len(), buf.as_ptr(), buf.len());
+		keccak_256::unchecked(hash.as_mut_ptr(), hash.len(), buf.as_ptr(), buf.len());
 
 		hash
 	}
@@ -324,11 +176,7 @@ fn hash_compute(light: &Light, full_size: usize, header_hash: &H256, nonce: u64)
 			// leaving it fully initialized.
 			let mut out: [u8; NODE_BYTES] = mem::uninitialized();
 
-			ptr::copy_nonoverlapping(
-				header_hash.as_ptr(),
-				out.as_mut_ptr(),
-				header_hash.len(),
-			);
+			ptr::copy_nonoverlapping(header_hash.as_ptr(), out.as_mut_ptr(), header_hash.len());
 			ptr::copy_nonoverlapping(
 				mem::transmute(&nonce),
 				out[header_hash.len()..].as_mut_ptr(),
@@ -336,11 +184,11 @@ fn hash_compute(light: &Light, full_size: usize, header_hash: &H256, nonce: u64)
 			);
 
 			// compute keccak-512 hash and replicate across mix
-			hash::keccak_512(
+			keccak_512::unchecked(
 				out.as_mut_ptr(),
 				NODE_BYTES,
 				out.as_ptr(),
-				header_hash.len() + mem::size_of::<u64>()
+				header_hash.len() + mem::size_of::<u64>(),
 			);
 
 			Node { bytes: out }
@@ -354,7 +202,7 @@ fn hash_compute(light: &Light, full_size: usize, header_hash: &H256, nonce: u64)
 	let page_size = 4 * MIX_WORDS;
 	let num_full_pages = (full_size / page_size) as u32;
 	// deref once for better performance
-	let cache: &[Node] = &light.cache;
+	let cache: &[Node] = light.cache.as_ref();
 	let first_val = buf.half_mix.as_words()[0];
 
 	debug_assert_eq!(MIX_NODES, 2);
@@ -364,14 +212,10 @@ fn hash_compute(light: &Light, full_size: usize, header_hash: &H256, nonce: u64)
 		let index = {
 			// This is trivially safe, but does not work on big-endian. The safety of this is
 			// asserted in debug builds (see the definition of `make_const_array!`).
-			let mix_words: &mut [u32; MIX_WORDS] = unsafe {
-				make_const_array!(MIX_WORDS, &mut mix)
-			};
+			let mix_words: &mut [u32; MIX_WORDS] =
+				unsafe { make_const_array!(MIX_WORDS, &mut mix) };
 
-			fnv_hash(
-				first_val ^ i,
-				mix_words[i as usize % MIX_WORDS]
-			) % num_full_pages
+			fnv_hash(first_val ^ i, mix_words[i as usize % MIX_WORDS]) % num_full_pages
 		};
 
 		unroll! {
@@ -403,9 +247,8 @@ fn hash_compute(light: &Light, full_size: usize, header_hash: &H256, nonce: u64)
 		// times and set each index, leaving the array fully initialized. THIS ONLY WORKS ON LITTLE-
 		// ENDIAN MACHINES. See a future PR to make this and the rest of the code work correctly on
 		// big-endian arches like mips.
-		let mut compress: &mut [u32; MIX_WORDS / 4] = unsafe {
-			make_const_array!(MIX_WORDS / 4, &mut buf.compress_bytes)
-		};
+		let compress: &mut [u32; MIX_WORDS / 4] =
+			unsafe { make_const_array!(MIX_WORDS / 4, &mut buf.compress_bytes) };
 
 		// Compress mix
 		debug_assert_eq!(MIX_WORDS / 4, 8);
@@ -430,7 +273,7 @@ fn hash_compute(light: &Light, full_size: usize, header_hash: &H256, nonce: u64)
 		// We overwrite the second half since `keccak_256` has an internal buffer and so allows
 		// overlapping arrays as input.
 		let write_ptr: *mut u8 = mem::transmute(&mut buf.compress_bytes);
-		hash::keccak_256(
+		keccak_256::unchecked(
 			write_ptr,
 			buf.compress_bytes.len(),
 			read_ptr,
@@ -439,25 +282,21 @@ fn hash_compute(light: &Light, full_size: usize, header_hash: &H256, nonce: u64)
 		buf.compress_bytes
 	};
 
-	ProofOfWork {
-		mix_hash: mix_hash,
-		value: value,
-	}
+	ProofOfWork { mix_hash: mix_hash, value: value }
 }
 
+// TODO: Use the `simd` crate
 fn calculate_dag_item(node_index: u32, cache: &[Node]) -> Node {
 	let num_parent_nodes = cache.len();
 	let mut ret = cache[node_index as usize % num_parent_nodes].clone();
 	ret.as_words_mut()[0] ^= node_index;
 
-	keccak_512_inplace(&mut ret.bytes);
+	keccak_512::inplace(ret.as_bytes_mut());
 
 	debug_assert_eq!(NODE_WORDS, 16);
 	for i in 0..ETHASH_DATASET_PARENTS as u32 {
-		let parent_index = fnv_hash(
-			node_index ^ i,
-			ret.as_words()[i as usize % NODE_WORDS],
-		) % num_parent_nodes as u32;
+		let parent_index = fnv_hash(node_index ^ i, ret.as_words()[i as usize % NODE_WORDS]) %
+			num_parent_nodes as u32;
 		let parent = &cache[parent_index as usize];
 
 		unroll! {
@@ -467,66 +306,15 @@ fn calculate_dag_item(node_index: u32, cache: &[Node]) -> Node {
 		}
 	}
 
-	keccak_512_inplace(&mut ret.bytes);
+	keccak_512::inplace(ret.as_bytes_mut());
 
 	ret
 }
 
-fn light_new<T: AsRef<Path>>(cache_dir: T, block_number: u64) -> Light {
-	let seed_compute = SeedHashCompute::new();
-	let seedhash = seed_compute.get_seedhash(block_number);
-	let cache_size = get_cache_size(block_number);
-
-	assert!(cache_size % NODE_BYTES == 0, "Unaligned cache size");
-	let num_nodes = cache_size / NODE_BYTES;
-
-	let mut nodes: Vec<Node> = Vec::with_capacity(num_nodes);
-	unsafe {
-		// Use uninit instead of unnecessarily writing `size_of::<Node>() * num_nodes` 0s
-		nodes.set_len(num_nodes);
-
-		keccak_512(&seedhash[0..32], &mut nodes.get_unchecked_mut(0).bytes);
-		for i in 1..num_nodes {
-			hash::keccak_512(nodes.get_unchecked_mut(i).bytes.as_mut_ptr(), NODE_BYTES, nodes.get_unchecked(i - 1).bytes.as_ptr(), NODE_BYTES);
-		}
-
-		debug_assert_eq!(NODE_WORDS, 16);
-
-		// This _should_ get unrolled by the compiler, since it's not using the loop variable.
-		for _ in 0..ETHASH_CACHE_ROUNDS {
-			for i in 0..num_nodes {
-				let idx = *nodes.get_unchecked_mut(i).as_words().get_unchecked(0) as usize % num_nodes;
-				let mut data = nodes.get_unchecked((num_nodes - 1 + i) % num_nodes).clone();
-
-				unroll! {
-					for w in 0..16 {
-						*data.as_words_mut().get_unchecked_mut(w) ^= *nodes.get_unchecked(idx).as_words().get_unchecked(w);
-					}
-				}
-
-				keccak_512(&data.bytes, &mut nodes.get_unchecked_mut(i).bytes);
-			}
-		}
-	}
-
-	Light {
-		block_number,
-		cache_dir: cache_dir.as_ref().to_path_buf(),
-		cache: nodes,
-		seed_compute: Mutex::new(seed_compute),
-	}
-}
-
-static CHARS: &'static [u8] = b"0123456789abcdef";
-fn to_hex(bytes: &[u8]) -> String {
-	let mut v = Vec::with_capacity(bytes.len() * 2);
-	for &byte in bytes.iter() {
-		v.push(CHARS[(byte >> 4) as usize]);
-		v.push(CHARS[(byte & 0xf) as usize]);
-	}
-
-	unsafe { String::from_utf8_unchecked(v) }
-}
+#[cfg(test)]
+mod test {
+	use super::*;
+	use std::fs;
 
 	#[test]
 	fn test_get_cache_size() {
@@ -555,71 +343,70 @@ fn test_get_data_size() {
 
 	#[test]
 	fn test_difficulty_test() {
-	let hash = [0xf5, 0x7e, 0x6f, 0x3a, 0xcf, 0xc0, 0xdd, 0x4b, 0x5b, 0xf2, 0xbe, 0xe4, 0x0a, 0xb3, 0x35, 0x8a, 0xa6, 0x87, 0x73, 0xa8, 0xd0, 0x9f, 0x5e, 0x59, 0x5e, 0xab, 0x55, 0x94, 0x05, 0x52, 0x7d, 0x72];
-	let mix_hash = [0x1f, 0xff, 0x04, 0xce, 0xc9, 0x41, 0x73, 0xfd, 0x59, 0x1e, 0x3d, 0x89, 0x60, 0xce, 0x6b, 0xdf, 0x8b, 0x19, 0x71, 0x04, 0x8c, 0x71, 0xff, 0x93, 0x7b, 0xb2, 0xd3, 0x2a, 0x64, 0x31, 0xab, 0x6d];
+		let hash = [
+			0xf5, 0x7e, 0x6f, 0x3a, 0xcf, 0xc0, 0xdd, 0x4b, 0x5b, 0xf2, 0xbe, 0xe4, 0x0a, 0xb3,
+			0x35, 0x8a, 0xa6, 0x87, 0x73, 0xa8, 0xd0, 0x9f, 0x5e, 0x59, 0x5e, 0xab, 0x55, 0x94,
+			0x05, 0x52, 0x7d, 0x72,
+		];
+		let mix_hash = [
+			0x1f, 0xff, 0x04, 0xce, 0xc9, 0x41, 0x73, 0xfd, 0x59, 0x1e, 0x3d, 0x89, 0x60, 0xce,
+			0x6b, 0xdf, 0x8b, 0x19, 0x71, 0x04, 0x8c, 0x71, 0xff, 0x93, 0x7b, 0xb2, 0xd3, 0x2a,
+			0x64, 0x31, 0xab, 0x6d,
+		];
 		let nonce = 0xd7b3ac70a301a249;
-	let boundary_good = [0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x3e, 0x9b, 0x6c, 0x69, 0xbc, 0x2c, 0xe2, 0xa2, 0x4a, 0x8e, 0x95, 0x69, 0xef, 0xc7, 0xd7, 0x1b, 0x33, 0x35, 0xdf, 0x36, 0x8c, 0x9a, 0xe9, 0x7e, 0x53, 0x84];
+		let boundary_good = [
+			0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x3e, 0x9b, 0x6c, 0x69, 0xbc, 0x2c, 0xe2, 0xa2,
+			0x4a, 0x8e, 0x95, 0x69, 0xef, 0xc7, 0xd7, 0x1b, 0x33, 0x35, 0xdf, 0x36, 0x8c, 0x9a,
+			0xe9, 0x7e, 0x53, 0x84,
+		];
 		assert_eq!(quick_get_difficulty(&hash, nonce, &mix_hash)[..], boundary_good[..]);
-	let boundary_bad = [0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x3a, 0x9b, 0x6c, 0x69, 0xbc, 0x2c, 0xe2, 0xa2, 0x4a, 0x8e, 0x95, 0x69, 0xef, 0xc7, 0xd7, 0x1b, 0x33, 0x35, 0xdf, 0x36, 0x8c, 0x9a, 0xe9, 0x7e, 0x53, 0x84];
+		let boundary_bad = [
+			0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x3a, 0x9b, 0x6c, 0x69, 0xbc, 0x2c, 0xe2, 0xa2,
+			0x4a, 0x8e, 0x95, 0x69, 0xef, 0xc7, 0xd7, 0x1b, 0x33, 0x35, 0xdf, 0x36, 0x8c, 0x9a,
+			0xe9, 0x7e, 0x53, 0x84,
+		];
 		assert!(quick_get_difficulty(&hash, nonce, &mix_hash)[..] != boundary_bad[..]);
 	}
 
 	#[test]
 	fn test_light_compute() {
-	let hash = [0xf5, 0x7e, 0x6f, 0x3a, 0xcf, 0xc0, 0xdd, 0x4b, 0x5b, 0xf2, 0xbe, 0xe4, 0x0a, 0xb3, 0x35, 0x8a, 0xa6, 0x87, 0x73, 0xa8, 0xd0, 0x9f, 0x5e, 0x59, 0x5e, 0xab, 0x55, 0x94, 0x05, 0x52, 0x7d, 0x72];
-	let mix_hash = [0x1f, 0xff, 0x04, 0xce, 0xc9, 0x41, 0x73, 0xfd, 0x59, 0x1e, 0x3d, 0x89, 0x60, 0xce, 0x6b, 0xdf, 0x8b, 0x19, 0x71, 0x04, 0x8c, 0x71, 0xff, 0x93, 0x7b, 0xb2, 0xd3, 0x2a, 0x64, 0x31, 0xab, 0x6d];
-	let boundary = [0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x3e, 0x9b, 0x6c, 0x69, 0xbc, 0x2c, 0xe2, 0xa2, 0x4a, 0x8e, 0x95, 0x69, 0xef, 0xc7, 0xd7, 0x1b, 0x33, 0x35, 0xdf, 0x36, 0x8c, 0x9a, 0xe9, 0x7e, 0x53, 0x84];
+		let hash = [
+			0xf5, 0x7e, 0x6f, 0x3a, 0xcf, 0xc0, 0xdd, 0x4b, 0x5b, 0xf2, 0xbe, 0xe4, 0x0a, 0xb3,
+			0x35, 0x8a, 0xa6, 0x87, 0x73, 0xa8, 0xd0, 0x9f, 0x5e, 0x59, 0x5e, 0xab, 0x55, 0x94,
+			0x05, 0x52, 0x7d, 0x72,
+		];
+		let mix_hash = [
+			0x1f, 0xff, 0x04, 0xce, 0xc9, 0x41, 0x73, 0xfd, 0x59, 0x1e, 0x3d, 0x89, 0x60, 0xce,
+			0x6b, 0xdf, 0x8b, 0x19, 0x71, 0x04, 0x8c, 0x71, 0xff, 0x93, 0x7b, 0xb2, 0xd3, 0x2a,
+			0x64, 0x31, 0xab, 0x6d,
+		];
+		let boundary = [
+			0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x3e, 0x9b, 0x6c, 0x69, 0xbc, 0x2c, 0xe2, 0xa2,
+			0x4a, 0x8e, 0x95, 0x69, 0xef, 0xc7, 0xd7, 0x1b, 0x33, 0x35, 0xdf, 0x36, 0x8c, 0x9a,
+			0xe9, 0x7e, 0x53, 0x84,
+		];
 		let nonce = 0xd7b3ac70a301a249;
 		// difficulty = 0x085657254bd9u64;
-	let light = Light::new(&::std::env::temp_dir(), 486382);
+		let light = NodeCacheBuilder::new(None).light(&::std::env::temp_dir(), 486382);
 		let result = light_compute(&light, &hash, nonce);
 		assert_eq!(result.mix_hash[..], mix_hash[..]);
 		assert_eq!(result.value[..], boundary[..]);
 	}
 
-#[test]
-fn test_seed_compute_once() {
-	let seed_compute = SeedHashCompute::new();
-	let hash = [241, 175, 44, 134, 39, 121, 245, 239, 228, 236, 43, 160, 195, 152, 46, 7, 199, 5, 253, 147, 241, 206, 98, 43, 3, 104, 17, 40, 192, 79, 106, 162];
-	assert_eq!(seed_compute.get_seedhash(486382), hash);
-}
-
-#[test]
-fn test_seed_compute_zero() {
-	let seed_compute = SeedHashCompute::new();
-	assert_eq!(seed_compute.get_seedhash(0), [0u8; 32]);
-}
-
-#[test]
-fn test_seed_compute_after_older() {
-	let seed_compute = SeedHashCompute::new();
-	// calculating an older value first shouldn't affect the result
-	let _ = seed_compute.get_seedhash(50000);
-	let hash = [241, 175, 44, 134, 39, 121, 245, 239, 228, 236, 43, 160, 195, 152, 46, 7, 199, 5, 253, 147, 241, 206, 98, 43, 3, 104, 17, 40, 192, 79, 106, 162];
-	assert_eq!(seed_compute.get_seedhash(486382), hash);
-}
-
-#[test]
-fn test_seed_compute_after_newer() {
-	let seed_compute = SeedHashCompute::new();
-	// calculating an newer value first shouldn't affect the result
-	let _ = seed_compute.get_seedhash(972764);
-	let hash = [241, 175, 44, 134, 39, 121, 245, 239, 228, 236, 43, 160, 195, 152, 46, 7, 199, 5, 253, 147, 241, 206, 98, 43, 3, 104, 17, 40, 192, 79, 106, 162];
-	assert_eq!(seed_compute.get_seedhash(486382), hash);
-}
-
 	#[test]
 	fn test_drop_old_data() {
 		let path = ::std::env::temp_dir();
-	let first = Light::new(&path, 0).to_file().unwrap();
+		let builder = NodeCacheBuilder::new(None);
+		let first = builder.light(&path, 0).to_file().unwrap().to_owned();
 
-	let second = Light::new(&path, ETHASH_EPOCH_LENGTH).to_file().unwrap();
+		let second = builder.light(&path, ETHASH_EPOCH_LENGTH).to_file().unwrap().to_owned();
 		assert!(fs::metadata(&first).is_ok());
 
-	let _ = Light::new(&path, ETHASH_EPOCH_LENGTH * 2).to_file();
+		let _ = builder.light(&path, ETHASH_EPOCH_LENGTH * 2).to_file();
 		assert!(fs::metadata(&first).is_err());
 		assert!(fs::metadata(&second).is_ok());
 
-	let _ = Light::new(&path, ETHASH_EPOCH_LENGTH * 3).to_file();
+		let _ = builder.light(&path, ETHASH_EPOCH_LENGTH * 3).to_file();
 		assert!(fs::metadata(&second).is_err());
 	}
+}

ethash/src/keccak.rs

@@ -0,0 +1,52 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+extern crate hash;
+
+pub type H256 = [u8; 32];
+
+pub mod keccak_512 {
+	use super::hash;
+
+	pub use self::hash::keccak_512 as unchecked;
+
+	pub fn write(input: &[u8], output: &mut [u8]) {
+		unsafe { hash::keccak_512(output.as_mut_ptr(), output.len(), input.as_ptr(), input.len()) };
+	}
+
+	pub fn inplace(input: &mut [u8]) {
+		// This is safe since `sha3_*` uses an internal buffer and copies the result to the output. This
+		// means that we can reuse the input buffer for both input and output.
+		unsafe { hash::keccak_512(input.as_mut_ptr(), input.len(), input.as_ptr(), input.len()) };
+	}
+}
+
+pub mod keccak_256 {
+	use super::hash;
+
+	pub use self::hash::keccak_256 as unchecked;
+
+	#[allow(dead_code)]
+	pub fn write(input: &[u8], output: &mut [u8]) {
+		unsafe { hash::keccak_256(output.as_mut_ptr(), output.len(), input.as_ptr(), input.len()) };
+	}
+
+	pub fn inplace(input: &mut [u8]) {
+		// This is safe since `sha3_*` uses an internal buffer and copies the result to the output. This
+		// means that we can reuse the input buffer for both input and output.
+		unsafe { hash::keccak_256(input.as_mut_ptr(), input.len(), input.as_ptr(), input.len()) };
+	}
+}

ethash/src/lib.rs

@@ -14,28 +14,35 @@
 // You should have received a copy of the GNU General Public License
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
-//! Ethash implementation
-//! See https://github.com/ethereum/wiki/wiki/Ethash
-
 #![cfg_attr(feature = "benches", feature(test))]
 
 extern crate primal;
-extern crate hash;
 extern crate parking_lot;
+extern crate either;
+extern crate memmap;
 
 #[macro_use]
 extern crate crunchy;
 #[macro_use]
 extern crate log;
-mod compute;
 
+mod compute;
+mod seed_compute;
+mod cache;
+mod keccak;
+mod shared;
+
+pub use cache::{NodeCacheBuilder, OptimizeFor};
+pub use compute::{ProofOfWork, quick_get_difficulty, slow_hash_block_number};
+use compute::Light;
+use keccak::H256;
+use parking_lot::Mutex;
+pub use seed_compute::SeedHashCompute;
+pub use shared::ETHASH_EPOCH_LENGTH;
 use std::mem;
 use std::path::{Path, PathBuf};
-use compute::Light;
-pub use compute::{ETHASH_EPOCH_LENGTH, H256, ProofOfWork, SeedHashCompute, quick_get_difficulty, slow_get_seedhash};
 
 use std::sync::Arc;
-use parking_lot::Mutex;
 
 struct LightCache {
 	recent_epoch: Option<u64>,
@@ -46,15 +53,17 @@ struct LightCache {
 
 /// Light/Full cache manager.
 pub struct EthashManager {
+	nodecache_builder: NodeCacheBuilder,
 	cache: Mutex<LightCache>,
 	cache_dir: PathBuf,
 }
 
 impl EthashManager {
 	/// Create a new new instance of ethash manager
-	pub fn new<T: AsRef<Path>>(cache_dir: T) -> EthashManager {
+	pub fn new<T: Into<Option<OptimizeFor>>>(cache_dir: &Path, optimize_for: T) -> EthashManager {
 		EthashManager {
-			cache_dir: cache_dir.as_ref().to_path_buf(),
+			cache_dir: cache_dir.to_path_buf(),
+			nodecache_builder: NodeCacheBuilder::new(optimize_for.into().unwrap_or_default()),
 			cache: Mutex::new(LightCache {
 				recent_epoch: None,
 				recent: None,
@@ -96,11 +105,19 @@ impl EthashManager {
 			};
 			match light {
 				None => {
-					let light = match Light::from_file(&self.cache_dir, block_number) {
+					let light = match Light::from_file_with_builder(
+						&self.nodecache_builder,
+						&self.cache_dir,
+						block_number,
+					) {
 						Ok(light) => Arc::new(light),
 						Err(e) => {
 							debug!("Light cache file not found for {}:{}", block_number, e);
-							let light = Light::new(&self.cache_dir, block_number);
+							let mut light = Light::new_with_builder(
+								&self.nodecache_builder,
+								&self.cache_dir,
+								block_number,
+							);
 							if let Err(e) = light.to_file() {
 								warn!("Light cache file write error: {}", e);
 							}
@@ -120,7 +137,7 @@ impl EthashManager {
 
 #[test]
 fn test_lru() {
-	let ethash = EthashManager::new(&::std::env::temp_dir());
+	let ethash = EthashManager::new(&::std::env::temp_dir(), None);
 	let hash = [0u8; 32];
 	ethash.compute_light(1, &hash, 1);
 	ethash.compute_light(50000, &hash, 1);
@@ -138,24 +155,89 @@ fn test_lru() {
 mod benchmarks {
 	extern crate test;
 
-	use compute::{Light, light_compute, SeedHashCompute};
 	use self::test::Bencher;
+	use cache::{NodeCacheBuilder, OptimizeFor};
+	use compute::{Light, light_compute};
+
+	const HASH: [u8; 32] = [0xf5, 0x7e, 0x6f, 0x3a, 0xcf, 0xc0, 0xdd, 0x4b, 0x5b, 0xf2, 0xbe,
+	                        0xe4, 0x0a, 0xb3, 0x35, 0x8a, 0xa6, 0x87, 0x73, 0xa8, 0xd0, 0x9f,
+	                        0x5e, 0x59, 0x5e, 0xab, 0x55, 0x94, 0x05, 0x52, 0x7d, 0x72];
+	const NONCE: u64 = 0xd7b3ac70a301a249;
 
 	#[bench]
-	fn bench_light_compute(b: &mut Bencher) {
-		use ::std::env;
+	fn bench_light_compute_memmap(b: &mut Bencher) {
+		use std::env;
 
-		let hash = [0xf5, 0x7e, 0x6f, 0x3a, 0xcf, 0xc0, 0xdd, 0x4b, 0x5b, 0xf2, 0xbe, 0xe4, 0x0a, 0xb3, 0x35, 0x8a, 0xa6, 0x87, 0x73, 0xa8, 0xd0, 0x9f, 0x5e, 0x59, 0x5e, 0xab, 0x55, 0x94, 0x05, 0x52, 0x7d, 0x72];
-		let nonce = 0xd7b3ac70a301a249;
-		let light = Light::new(env::temp_dir(), 486382);
+		let builder = NodeCacheBuilder::new(OptimizeFor::Memory);
+		let light = Light::new_with_builder(&builder, &env::temp_dir(), 486382);
 
-		b.iter(|| light_compute(&light, &hash, nonce));
+		b.iter(|| light_compute(&light, &HASH, NONCE));
 	}
 
 	#[bench]
-	fn bench_seedhash(b: &mut Bencher) {
-		let seed_compute = SeedHashCompute::new();
+	fn bench_light_compute_memory(b: &mut Bencher) {
+		use std::env;
 
-		b.iter(|| seed_compute.get_seedhash(486382));
+		let light = Light::new(&env::temp_dir(), 486382);
+
+		b.iter(|| light_compute(&light, &HASH, NONCE));
+	}
+
+	#[bench]
+	#[ignore]
+	fn bench_light_new_round_trip_memmap(b: &mut Bencher) {
+		use std::env;
+
+		b.iter(|| {
+			let builder = NodeCacheBuilder::new(OptimizeFor::Memory);
+			let light = Light::new_with_builder(&builder, &env::temp_dir(), 486382);
+			light_compute(&light, &HASH, NONCE);
+		});
+	}
+
+	#[bench]
+	#[ignore]
+	fn bench_light_new_round_trip_memory(b: &mut Bencher) {
+		use std::env;
+		b.iter(|| {
+			let light = Light::new(&env::temp_dir(), 486382);
+			light_compute(&light, &HASH, NONCE);
+		});
+	}
+
+	#[bench]
+	fn bench_light_from_file_round_trip_memory(b: &mut Bencher) {
+		use std::env;
+
+		let dir = env::temp_dir();
+		let height = 486382;
+		{
+			let mut dummy = Light::new(&dir, height);
+			dummy.to_file().unwrap();
+		}
+
+		b.iter(|| {
+			let light = Light::from_file(&dir, 486382).unwrap();
+			light_compute(&light, &HASH, NONCE);
+		});
+	}
+
+	#[bench]
+	fn bench_light_from_file_round_trip_memmap(b: &mut Bencher) {
+		use std::env;
+
+		let dir = env::temp_dir();
+		let height = 486382;
+		{
+			let builder = NodeCacheBuilder::new(OptimizeFor::Memory);
+			let mut dummy = Light::new_with_builder(&builder, &dir, height);
+			dummy.to_file().unwrap();
+		}
+
+		b.iter(|| {
+			let builder = NodeCacheBuilder::new(OptimizeFor::Memory);
+			let light = Light::from_file_with_builder(&builder, &dir, 486382).unwrap();
+			light_compute(&light, &HASH, NONCE);
+		});
 	}
 }

ethash/src/seed_compute.rs

@@ -0,0 +1,109 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+use shared;
+use keccak::{keccak_256, H256};
+
+use std::cell::Cell;
+
+pub struct SeedHashCompute {
+	prev_epoch: Cell<u64>,
+	prev_seedhash: Cell<H256>,
+}
+
+impl SeedHashCompute {
+	#[inline]
+	pub fn new() -> SeedHashCompute {
+		SeedHashCompute {
+			prev_epoch: Cell::new(0),
+			prev_seedhash: Cell::new([0u8; 32]),
+		}
+	}
+
+	#[inline]
+	fn reset_cache(&self) {
+		self.prev_epoch.set(0);
+		self.prev_seedhash.set([0u8; 32]);
+	}
+
+	#[inline]
+	pub fn hash_block_number(&self, block_number: u64) -> H256 {
+		self.hash_epoch(shared::epoch(block_number))
+	}
+
+	#[inline]
+	pub fn hash_epoch(&self, epoch: u64) -> H256 {
+		if epoch < self.prev_epoch.get() {
+			// can't build on previous hash if requesting an older block
+			self.reset_cache();
+		}
+		if epoch > self.prev_epoch.get() {
+			let seed_hash = SeedHashCompute::resume_compute_seedhash(
+				self.prev_seedhash.get(),
+				self.prev_epoch.get(),
+				epoch,
+			);
+			self.prev_seedhash.set(seed_hash);
+			self.prev_epoch.set(epoch);
+		}
+		self.prev_seedhash.get()
+	}
+
+	#[inline]
+	pub fn resume_compute_seedhash(mut hash: H256, start_epoch: u64, end_epoch: u64) -> H256 {
+		for _ in start_epoch..end_epoch {
+			keccak_256::inplace(&mut hash);
+		}
+		hash
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::SeedHashCompute;
+
+	#[test]
+	fn test_seed_compute_once() {
+		let seed_compute = SeedHashCompute::new();
+		let hash = [241, 175, 44, 134, 39, 121, 245, 239, 228, 236, 43, 160, 195, 152, 46, 7, 199, 5, 253, 147, 241, 206, 98, 43, 3, 104, 17, 40, 192, 79, 106, 162];
+		assert_eq!(seed_compute.hash_block_number(486382), hash);
+	}
+
+	#[test]
+	fn test_seed_compute_zero() {
+		let seed_compute = SeedHashCompute::new();
+		assert_eq!(seed_compute.hash_block_number(0), [0u8; 32]);
+	}
+
+	#[test]
+	fn test_seed_compute_after_older() {
+		let seed_compute = SeedHashCompute::new();
+		// calculating an older value first shouldn't affect the result
+		let _ = seed_compute.hash_block_number(50000);
+		let hash = [241, 175, 44, 134, 39, 121, 245, 239, 228, 236, 43, 160, 195, 152, 46, 7, 199, 5, 253, 147, 241, 206, 98, 43, 3, 104, 17, 40, 192, 79, 106, 162];
+		assert_eq!(seed_compute.hash_block_number(486382), hash);
+	}
+
+	#[test]
+	fn test_seed_compute_after_newer() {
+		let seed_compute = SeedHashCompute::new();
+		// calculating an newer value first shouldn't affect the result
+		let _ = seed_compute.hash_block_number(972764);
+		let hash = [241, 175, 44, 134, 39, 121, 245, 239, 228, 236, 43, 160, 195, 152, 46, 7, 199, 5, 253, 147, 241, 206, 98, 43, 3, 104, 17, 40, 192, 79, 106, 162];
+		assert_eq!(seed_compute.hash_block_number(486382), hash);
+	}
+
+}

ethash/src/shared.rs

@@ -0,0 +1,149 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+use primal::is_prime;
+
+pub const DATASET_BYTES_INIT: u64 = 1 << 30;
+pub const DATASET_BYTES_GROWTH: u64 = 1 << 23;
+pub const CACHE_BYTES_INIT: u64 = 1 << 24;
+pub const CACHE_BYTES_GROWTH: u64 = 1 << 17;
+
+pub const ETHASH_EPOCH_LENGTH: u64 = 30000;
+pub const ETHASH_CACHE_ROUNDS: usize = 3;
+pub const ETHASH_MIX_BYTES: usize = 128;
+pub const ETHASH_ACCESSES: usize = 64;
+pub const ETHASH_DATASET_PARENTS: u32 = 256;
+pub const NODE_DWORDS: usize = NODE_WORDS / 2;
+pub const NODE_WORDS: usize = NODE_BYTES / 4;
+pub const NODE_BYTES: usize = 64;
+
+pub fn epoch(block_number: u64) -> u64 {
+	block_number / ETHASH_EPOCH_LENGTH
+}
+
+static CHARS: &'static [u8] = b"0123456789abcdef";
+pub fn to_hex(bytes: &[u8]) -> String {
+	let mut v = Vec::with_capacity(bytes.len() * 2);
+	for &byte in bytes.iter() {
+		v.push(CHARS[(byte >> 4) as usize]);
+		v.push(CHARS[(byte & 0xf) as usize]);
+	}
+
+	unsafe { String::from_utf8_unchecked(v) }
+}
+
+pub fn get_cache_size(block_number: u64) -> usize {
+	// TODO: Memoise
+	let mut sz: u64 = CACHE_BYTES_INIT + CACHE_BYTES_GROWTH * (block_number / ETHASH_EPOCH_LENGTH);
+	sz = sz - NODE_BYTES as u64;
+	while !is_prime(sz / NODE_BYTES as u64) {
+		sz = sz - 2 * NODE_BYTES as u64;
+	}
+	sz as usize
+}
+
+pub fn get_data_size(block_number: u64) -> usize {
+	// TODO: Memoise
+	let mut sz: u64 = DATASET_BYTES_INIT + DATASET_BYTES_GROWTH * (block_number / ETHASH_EPOCH_LENGTH);
+	sz = sz - ETHASH_MIX_BYTES as u64;
+	while !is_prime(sz / ETHASH_MIX_BYTES as u64) {
+		sz = sz - 2 * ETHASH_MIX_BYTES as u64;
+	}
+	sz as usize
+}
+
+pub type NodeBytes = [u8; NODE_BYTES];
+pub type NodeWords = [u32; NODE_WORDS];
+pub type NodeDwords = [u64; NODE_DWORDS];
+
+macro_rules! static_assert_size_eq {
+	(@inner $a:ty, $b:ty, $($rest:ty),*) => {
+		fn first() {
+			static_assert_size_eq!($a, $b);
+		}
+
+		fn second() {
+			static_assert_size_eq!($b, $($rest),*);
+		}
+	};
+	(@inner $a:ty, $b:ty) => {
+		unsafe {
+			let val: $b = ::std::mem::uninitialized();
+			let _: $a = ::std::mem::transmute(val);
+		}
+	};
+	($($rest:ty),*) => {
+		static_assert_size_eq!(size_eq: $($rest),*);
+	};
+	($name:ident : $($rest:ty),*) => {
+		#[allow(dead_code)]
+		fn $name() {
+			static_assert_size_eq!(@inner $($rest),*);
+		}
+	};
+}
+
+static_assert_size_eq!(Node, NodeBytes, NodeWords, NodeDwords);
+
+#[repr(C)]
+pub union Node {
+	pub dwords: NodeDwords,
+	pub words: NodeWords,
+	pub bytes: NodeBytes,
+}
+
+impl Clone for Node {
+	fn clone(&self) -> Self {
+		unsafe { Node { bytes: *&self.bytes } }
+	}
+}
+
+// We use `inline(always)` because I was experiencing an 100% slowdown and `perf` showed that these
+// calls were taking up ~30% of the runtime. Adding these annotations fixes the issue. Remove at
+// your peril, if and only if you have benchmarks to prove that this doesn't reintroduce the
+// performance regression. It's not caused by the `debug_assert_eq!` either, your guess is as good
+// as mine.
+impl Node {
+	#[inline(always)]
+	pub fn as_bytes(&self) -> &NodeBytes {
+		unsafe { &self.bytes }
+	}
+
+	#[inline(always)]
+	pub fn as_bytes_mut(&mut self) -> &mut NodeBytes {
+		unsafe { &mut self.bytes }
+	}
+
+	#[inline(always)]
+	pub fn as_words(&self) -> &NodeWords {
+		unsafe { &self.words }
+	}
+
+	#[inline(always)]
+	pub fn as_words_mut(&mut self) -> &mut NodeWords {
+		unsafe { &mut self.words }
+	}
+
+	#[inline(always)]
+	pub fn as_dwords(&self) -> &NodeDwords {
+		unsafe { &self.dwords }
+	}
+
+	#[inline(always)]
+	pub fn as_dwords_mut(&mut self) -> &mut NodeDwords {
+		unsafe { &mut self.dwords }
+	}
+}

ethcore/Cargo.toml

@@ -51,6 +51,7 @@ lru-cache = "0.1.0"
 native-contracts = { path = "native_contracts" }
 num = "0.1"
 num_cpus = "1.2"
+parity-machine = { path = "../machine" }
 parking_lot = "0.4"
 price-info = { path = "../price-info" }
 rayon = "0.8"

ethcore/light/src/client/fetch.rs

@@ -19,7 +19,8 @@
 use std::sync::Arc;
 
 use ethcore::encoded;
-use ethcore::engines::{Engine, StateDependentProof};
+use ethcore::engines::{EthEngine, StateDependentProof};
+use ethcore::machine::EthereumMachine;
 use ethcore::header::Header;
 use ethcore::receipt::Receipt;
 use futures::future::IntoFuture;
@@ -44,7 +45,12 @@ pub trait ChainDataFetcher: Send + Sync + 'static {
 	fn block_receipts(&self, header: &Header) -> Self::Receipts;
 
 	/// Fetch epoch transition proof at given header.
-	fn epoch_transition(&self, hash: H256, engine: Arc<Engine>, checker: Arc<StateDependentProof>) -> Self::Transition;
+	fn epoch_transition(
+		&self,
+		_hash: H256,
+		_engine: Arc<EthEngine>,
+		_checker: Arc<StateDependentProof<EthereumMachine>>
+	) -> Self::Transition;
 }
 
 /// Fetcher implementation which cannot fetch anything.
@@ -68,7 +74,12 @@ impl ChainDataFetcher for Unavailable {
 		Err("fetching block receipts unavailable")
 	}
 
-	fn epoch_transition(&self, _h: H256, _e: Arc<Engine>, _check: Arc<StateDependentProof>) -> Self::Transition {
+	fn epoch_transition(
+		&self,
+		_hash: H256,
+		_engine: Arc<EthEngine>,
+		_checker: Arc<StateDependentProof<EthereumMachine>>
+	) -> Self::Transition {
 		Err("fetching epoch transition proofs unavailable")
 	}
 }

ethcore/light/src/client/mod.rs

@@ -20,7 +20,8 @@ use std::sync::{Weak, Arc};
 
 use ethcore::block_status::BlockStatus;
 use ethcore::client::{ClientReport, EnvInfo};
-use ethcore::engines::{epoch, Engine, EpochChange, EpochTransition, Proof, Unsure};
+use ethcore::engines::{epoch, EthEngine, EpochChange, EpochTransition, Proof};
+use ethcore::machine::EthereumMachine;
 use ethcore::error::BlockImportError;
 use ethcore::ids::BlockId;
 use ethcore::header::{BlockNumber, Header};
@@ -117,7 +118,7 @@ pub trait LightChainClient: Send + Sync {
 	fn env_info(&self, id: BlockId) -> Option<EnvInfo>;
 
 	/// Get a handle to the consensus engine.
-	fn engine(&self) -> &Arc<Engine>;
+	fn engine(&self) -> &Arc<EthEngine>;
 
 	/// Query whether a block is known.
 	fn is_known(&self, hash: &H256) -> bool;
@@ -165,7 +166,7 @@ impl<T: LightChainClient> AsLightClient for T {
 /// Light client implementation.
 pub struct Client<T> {
 	queue: HeaderQueue,
-	engine: Arc<Engine>,
+	engine: Arc<EthEngine>,
 	chain: HeaderChain,
 	report: RwLock<ClientReport>,
 	import_lock: Mutex<()>,
@@ -381,7 +382,7 @@ impl<T: ChainDataFetcher> Client<T> {
 	}
 
 	/// Get a handle to the verification engine.
-	pub fn engine(&self) -> &Arc<Engine> {
+	pub fn engine(&self) -> &Arc<EthEngine> {
 		&self.engine
 	}
 
@@ -444,7 +445,7 @@ impl<T: ChainDataFetcher> Client<T> {
 		};
 
 		// Verify Block Family
-		let verify_family_result = self.engine.verify_block_family(&verified_header, &parent_header.decode(), None);
+		let verify_family_result = self.engine.verify_block_family(&verified_header, &parent_header.decode());
 		if let Err(e) = verify_family_result {
 			warn!(target: "client", "Stage 3 block verification failed for #{} ({})\nError: {:?}",
 				verified_header.number(), verified_header.hash(), e);
@@ -453,7 +454,7 @@ impl<T: ChainDataFetcher> Client<T> {
 		};
 
 		// "external" verification.
-		let verify_external_result = self.engine.verify_block_external(&verified_header, None);
+		let verify_external_result = self.engine.verify_block_external(&verified_header);
 		if let Err(e) = verify_external_result {
 			warn!(target: "client", "Stage 4 block verification failed for #{} ({})\nError: {:?}",
 				verified_header.number(), verified_header.hash(), e);
@@ -465,20 +466,35 @@ impl<T: ChainDataFetcher> Client<T> {
 		true
 	}
 
-	fn check_epoch_signal(&self, verified_header: &Header) -> Result<Option<Proof>, T::Error> {
-		let (mut block, mut receipts) = (None, None);
+	fn check_epoch_signal(&self, verified_header: &Header) -> Result<Option<Proof<EthereumMachine>>, T::Error> {
+		use ethcore::machine::{AuxiliaryRequest, AuxiliaryData};
 
-		// First, check without providing auxiliary data.
-		match self.engine.signals_epoch_end(verified_header, None, None) {
+		let mut block: Option<Vec<u8>> = None;
+		let mut receipts: Option<Vec<_>> = None;
+
+		loop {
+
+
+			let is_signal = {
+				let auxiliary = AuxiliaryData {
+					bytes: block.as_ref().map(|x| &x[..]),
+					receipts: receipts.as_ref().map(|x| &x[..]),
+				};
+
+				self.engine.signals_epoch_end(verified_header, auxiliary)
+			};
+
+			// check with any auxiliary data fetched so far
+			match is_signal {
 				EpochChange::No => return Ok(None),
 				EpochChange::Yes(proof) => return Ok(Some(proof)),
 				EpochChange::Unsure(unsure) => {
 					let (b, r) = match unsure {
-					Unsure::NeedsBody =>
+						AuxiliaryRequest::Body =>
 							(Some(self.fetcher.block_body(verified_header)), None),
-					Unsure::NeedsReceipts =>
+						AuxiliaryRequest::Receipts =>
 							(None, Some(self.fetcher.block_receipts(verified_header))),
-					Unsure::NeedsBoth => (
+						AuxiliaryRequest::Both => (
 							Some(self.fetcher.block_body(verified_header)),
 							Some(self.fetcher.block_receipts(verified_header)),
 						),
@@ -493,22 +509,11 @@ impl<T: ChainDataFetcher> Client<T> {
 					}
 				}
 			}
-
-		let block = block.as_ref().map(|x| &x[..]);
-		let receipts = receipts.as_ref().map(|x| &x[..]);
-
-		// Check again now that required data has been fetched.
-		match self.engine.signals_epoch_end(verified_header, block, receipts) {
-			EpochChange::No => return Ok(None),
-			EpochChange::Yes(proof) => return Ok(Some(proof)),
-			EpochChange::Unsure(_) =>
-				panic!("Detected faulty engine implementation: requests additional \
-					data to check epoch end signal when everything necessary provided"),
 		}
 	}
 
 	// attempts to fetch the epoch proof from the network until successful.
-	fn write_pending_proof(&self, header: &Header, proof: Proof) -> Result<(), T::Error> {
+	fn write_pending_proof(&self, header: &Header, proof: Proof<EthereumMachine>) -> Result<(), T::Error> {
 		let proof = match proof {
 			Proof::Known(known) => known,
 			Proof::WithState(state_dependent) => {
@@ -568,7 +573,7 @@ impl<T: ChainDataFetcher> LightChainClient for Client<T> {
 		Client::env_info(self, id)
 	}
 
-	fn engine(&self) -> &Arc<Engine> {
+	fn engine(&self) -> &Arc<EthEngine> {
 		Client::engine(self)
 	}
 

ethcore/light/src/net/mod.rs

@@ -899,7 +899,7 @@ impl LightProtocol {
 		// the maximum amount of requests we'll fill in a single packet.
 		const MAX_REQUESTS: usize = 256;
 
-		use ::request::RequestBuilder;
+		use ::request::Builder;
 		use ::request::CompleteRequest;
 
 		let peers = self.peers.read();
@@ -914,7 +914,7 @@ impl LightProtocol {
 		let peer: &mut Peer = &mut *peer;
 
 		let req_id: u64 = raw.val_at(0)?;
-		let mut request_builder = RequestBuilder::default();
+		let mut request_builder = Builder::default();
 
 		trace!(target: "pip", "Received requests (id: {}) from peer {}", req_id, peer_id);
 

ethcore/light/src/net/request_set.rs

@@ -147,7 +147,7 @@ fn compute_timeout(reqs: &Requests) -> Duration {
 #[cfg(test)]
 mod tests {
 	use net::ReqId;
-	use request::RequestBuilder;
+	use request::Builder;
 	use time::{SteadyTime, Duration};
 	use super::{RequestSet, compute_timeout};
 
@@ -156,7 +156,7 @@ mod tests {
 		let test_begin = SteadyTime::now();
 		let mut req_set = RequestSet::default();
 
-		let the_req = RequestBuilder::default().build();
+		let the_req = Builder::default().build();
 		let req_time = compute_timeout(&the_req);
 		req_set.insert(ReqId(0), the_req.clone(), 0.into(), test_begin);
 		req_set.insert(ReqId(1), the_req, 0.into(), test_begin + Duration::seconds(1));
@@ -173,7 +173,7 @@ mod tests {
 
 	#[test]
 	fn cumulative_cost() {
-		let the_req = RequestBuilder::default().build();
+		let the_req = Builder::default().build();
 		let test_begin = SteadyTime::now();
 		let test_end = test_begin + Duration::seconds(1);
 		let mut req_set = RequestSet::default();

ethcore/light/src/net/tests/mod.rs

@@ -41,7 +41,7 @@ use std::sync::Arc;
 // helper for encoding a single request into a packet.
 // panics on bad backreference.
 fn encode_single(request: Request) -> NetworkRequests {
-	let mut builder = RequestBuilder::default();
+	let mut builder = Builder::default();
 	builder.push(request).unwrap();
 	builder.build()
 }
@@ -344,7 +344,7 @@ fn get_block_bodies() {
 		proto.handle_packet(&Expect::Nothing, &1, packet::STATUS, &my_status);
 	}
 
-	let mut builder = RequestBuilder::default();
+	let mut builder = Builder::default();
 	let mut bodies = Vec::new();
 
 	for i in 0..10 {
@@ -400,7 +400,7 @@ fn get_block_receipts() {
 		.take(10)
 		.collect();
 
-	let mut builder = RequestBuilder::default();
+	let mut builder = Builder::default();
 	let mut receipts = Vec::new();
 	for hash in block_hashes.iter().cloned() {
 		builder.push(Request::Receipts(IncompleteReceiptsRequest { hash: hash.into() })).unwrap();
@@ -448,7 +448,7 @@ fn get_state_proofs() {
 	let key1: H256 = U256::from(11223344).into();
 	let key2: H256 = U256::from(99988887).into();
 
-	let mut builder = RequestBuilder::default();
+	let mut builder = Builder::default();
 	builder.push(Request::Account(IncompleteAccountRequest {
 		block_hash: H256::default().into(),
 		address_hash: key1.into(),

ethcore/light/src/on_demand/mod.rs

@@ -74,8 +74,8 @@ impl Peer {
 
 // Attempted request info and sender to put received value.
 struct Pending {
-	requests: basic_request::Requests<CheckedRequest>,
-	net_requests: basic_request::Requests<NetworkRequest>,
+	requests: basic_request::Batch<CheckedRequest>,
+	net_requests: basic_request::Batch<NetworkRequest>,
 	required_capabilities: Capabilities,
 	responses: Vec<Response>,
 	sender: oneshot::Sender<Vec<Response>>,
@@ -151,7 +151,7 @@ impl Pending {
 	fn update_net_requests(&mut self) {
 		use request::IncompleteRequest;
 
-		let mut builder = basic_request::RequestBuilder::default();
+		let mut builder = basic_request::Builder::default();
 		let num_answered = self.requests.num_answered();
 		let mut mapping = move |idx| idx - num_answered;
 
@@ -281,7 +281,7 @@ impl OnDemand {
 			return Ok(receiver);
 		}
 
-		let mut builder = basic_request::RequestBuilder::default();
+		let mut builder = basic_request::Builder::default();
 
 		let responses = Vec::with_capacity(requests.len());
 

ethcore/light/src/on_demand/request.rs

@@ -20,8 +20,9 @@ use std::sync::Arc;
 
 use ethcore::basic_account::BasicAccount;
 use ethcore::encoded;
-use ethcore::engines::{Engine, StateDependentProof};
-use ethcore::receipt::{Receipt, TransactionOutcome};
+use ethcore::engines::{EthEngine, StateDependentProof};
+use ethcore::machine::EthereumMachine;
+use ethcore::receipt::Receipt;
 use ethcore::state::{self, ProvedExecution};
 use ethcore::transaction::SignedTransaction;
 use vm::EnvInfo;
@@ -843,7 +844,7 @@ pub struct TransactionProof {
 	// TODO: it's not really possible to provide this if the header is unknown.
 	pub env_info: EnvInfo,
 	/// Consensus engine.
-	pub engine: Arc<Engine>,
+	pub engine: Arc<EthEngine>,
 }
 
 impl TransactionProof {
@@ -858,7 +859,7 @@ impl TransactionProof {
 			state_items,
 			root,
 			&self.tx,
-			&*self.engine,
+			self.engine.machine(),
 			&self.env_info,
 		);
 
@@ -877,15 +878,15 @@ pub struct Signal {
 	/// Block hash and number to fetch proof for.
 	pub hash: H256,
 	/// Consensus engine, used to check the proof.
-	pub engine: Arc<Engine>,
+	pub engine: Arc<EthEngine>,
 	/// Special checker for the proof.
-	pub proof_check: Arc<StateDependentProof>,
+	pub proof_check: Arc<StateDependentProof<EthereumMachine>>,
 }
 
 impl Signal {
 	/// Check the signal, returning the signal or indicate that it's bad.
 	pub fn check_response(&self, _: &Mutex<::cache::Cache>, signal: &[u8]) -> Result<Vec<u8>, Error> {
-		self.proof_check.check_proof(&*self.engine, signal)
+		self.proof_check.check_proof(self.engine.machine(), signal)
 			.map(|_| signal.to_owned())
 			.map_err(|_| Error::BadProof)
 	}
@@ -904,7 +905,7 @@ mod tests {
 	use ethcore::client::{BlockChainClient, TestBlockChainClient, EachBlockWith};
 	use ethcore::header::Header;
 	use ethcore::encoded;
-	use ethcore::receipt::Receipt;
+	use ethcore::receipt::{Receipt, TransactionOutcome};
 
 	fn make_cache() -> ::cache::Cache {
 		::cache::Cache::new(Default::default(), ::time::Duration::seconds(1))

ethcore/light/src/types/request/batch.rs

@@ -25,23 +25,23 @@ use request::{
 };
 
 /// Build chained requests. Push them onto the series with `push`,
-/// and produce a `Requests` object with `build`. Outputs are checked for consistency.
+/// and produce a `Batch` object with `build`. Outputs are checked for consistency.
 #[derive(Debug, Clone, PartialEq, Eq)]
-pub struct RequestBuilder<T> {
+pub struct Builder<T> {
 	output_kinds: HashMap<(usize, usize), OutputKind>,
 	requests: Vec<T>,
 }
 
-impl<T> Default for RequestBuilder<T> {
+impl<T> Default for Builder<T> {
 	fn default() -> Self {
-		RequestBuilder {
+		Builder {
 			output_kinds: HashMap::new(),
 			requests: Vec::new(),
 		}
 	}
 }
 
-impl<T: IncompleteRequest> RequestBuilder<T> {
+impl<T: IncompleteRequest> Builder<T> {
 	/// Attempt to push a request onto the request chain. Fails if the request
 	/// references a non-existent output of a prior request.
 	pub fn push(&mut self, request: T) -> Result<(), NoSuchOutput> {
@@ -62,9 +62,9 @@ impl<T: IncompleteRequest> RequestBuilder<T> {
 		&self.output_kinds
 	}
 
-	/// Convert this into a "requests" object.
-	pub fn build(self) -> Requests<T> {
-		Requests {
+	/// Convert this into a "batch" object.
+	pub fn build(self) -> Batch<T> {
+		Batch {
 			outputs: HashMap::new(),
 			requests: self.requests,
 			answered: 0,
@@ -74,13 +74,13 @@ impl<T: IncompleteRequest> RequestBuilder<T> {
 
 /// Requests pending responses.
 #[derive(Debug, Clone, PartialEq, Eq)]
-pub struct Requests<T> {
+pub struct Batch<T> {
 	outputs: HashMap<(usize, usize), Output>,
 	requests: Vec<T>,
 	answered: usize,
 }
 
-impl<T> Requests<T> {
+impl<T> Batch<T> {
 	/// Get access to the underlying slice of requests.
 	// TODO: unimplemented -> Vec<Request>, // do we _have to_ allocate?
 	pub fn requests(&self) -> &[T] { &self.requests }
@@ -94,10 +94,10 @@ impl<T> Requests<T> {
 	}
 
 	/// Map requests from one type into another.
-	pub fn map_requests<F, U>(self, f: F) -> Requests<U>
+	pub fn map_requests<F, U>(self, f: F) -> Batch<U>
 		where F: FnMut(T) -> U, U: IncompleteRequest
 	{
-		Requests {
+		Batch {
 			outputs: self.outputs,
 			requests: self.requests.into_iter().map(f).collect(),
 			answered: self.answered,
@@ -105,7 +105,7 @@ impl<T> Requests<T> {
 	}
 }
 
-impl<T: IncompleteRequest + Clone> Requests<T> {
+impl<T: IncompleteRequest + Clone> Batch<T> {
 	/// Get the next request as a filled request. Returns `None` when all requests answered.
 	pub fn next_complete(&self) -> Option<T::Complete> {
 		if self.is_complete() {
@@ -113,7 +113,7 @@ impl<T: IncompleteRequest + Clone> Requests<T> {
 		} else {
 			Some(self.requests[self.answered].clone()
 				.complete()
-				.expect("All outputs checked as invariant of `Requests` object; qed"))
+				.expect("All outputs checked as invariant of `Batch` object; qed"))
 		}
 	}
 
@@ -149,7 +149,7 @@ impl<T: IncompleteRequest + Clone> Requests<T> {
 	}
 }
 
-impl<T: super::CheckedRequest + Clone> Requests<T> {
+impl<T: super::CheckedRequest + Clone> Batch<T> {
 	/// Supply a response for the next request.
 	/// Fails on: wrong request kind, all requests answered already.
 	pub fn supply_response(&mut self, env: &T::Environment, response: &T::Response)
@@ -170,7 +170,7 @@ impl<T: super::CheckedRequest + Clone> Requests<T> {
 	}
 }
 
-impl Requests<super::Request> {
+impl Batch<super::Request> {
 	/// For each request, produce a response.
 	/// The responses vector produced goes up to the point where the responder
 	/// first returns `None`, an invalid response, or until all requests have been responded to.
@@ -193,7 +193,7 @@ impl Requests<super::Request> {
 	}
 }
 
-impl<T: IncompleteRequest> Deref for Requests<T> {
+impl<T: IncompleteRequest> Deref for Batch<T> {
 	type Target = [T];
 
 	fn deref(&self) -> &[T] {
@@ -201,7 +201,7 @@ impl<T: IncompleteRequest> Deref for Requests<T> {
 	}
 }
 
-impl<T: IncompleteRequest> DerefMut for Requests<T> {
+impl<T: IncompleteRequest> DerefMut for Batch<T> {
 	fn deref_mut(&mut self) -> &mut [T] {
 		&mut self.requests[..]
 	}
@@ -210,12 +210,12 @@ impl<T: IncompleteRequest> DerefMut for Requests<T> {
 #[cfg(test)]
 mod tests {
 	use request::*;
-	use super::RequestBuilder;
+	use super::Builder;
 	use bigint::hash::H256;
 
 	#[test]
 	fn all_scalar() {
-		let mut builder = RequestBuilder::default();
+		let mut builder = Builder::default();
 		builder.push(Request::HeaderProof(IncompleteHeaderProofRequest {
 			num: 100.into(),
 		})).unwrap();
@@ -227,7 +227,7 @@ mod tests {
 	#[test]
 	#[should_panic]
 	fn missing_backref() {
-		let mut builder = RequestBuilder::default();
+		let mut builder = Builder::default();
 		builder.push(Request::HeaderProof(IncompleteHeaderProofRequest {
 			num: Field::BackReference(100, 3),
 		})).unwrap();
@@ -236,7 +236,7 @@ mod tests {
 	#[test]
 	#[should_panic]
 	fn wrong_kind() {
-		let mut builder = RequestBuilder::default();
+		let mut builder = Builder::default();
 		assert!(builder.push(Request::HeaderProof(IncompleteHeaderProofRequest {
 			num: 100.into(),
 		})).is_ok());
@@ -247,7 +247,7 @@ mod tests {
 
 	#[test]
 	fn good_backreference() {
-		let mut builder = RequestBuilder::default();
+		let mut builder = Builder::default();
 		builder.push(Request::HeaderProof(IncompleteHeaderProofRequest {
 			num: 100.into(), // header proof puts hash at output 0.
 		})).unwrap();

ethcore/light/src/types/request/mod.rs

@@ -19,7 +19,7 @@
 use rlp::{Encodable, Decodable, DecoderError, RlpStream, UntrustedRlp};
 use bigint::hash::H256;
 
-mod builder;
+mod batch;
 
 // re-exports of request types.
 pub use self::header::{
@@ -73,7 +73,7 @@ pub use self::epoch_signal::{
 	Response as SignalResponse,
 };
 
-pub use self::builder::{RequestBuilder, Requests};
+pub use self::batch::{Batch, Builder};
 
 /// Error indicating a reference to a non-existent or wrongly-typed output.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
@@ -241,7 +241,7 @@ impl Encodable for HashOrNumber {
 }
 
 /// Type alias for "network requests".
-pub type NetworkRequests = Requests<Request>;
+pub type NetworkRequests = Batch<Request>;
 
 /// All request types, as they're sent over the network.
 /// They may be incomplete, with back-references to outputs

ethcore/node_filter/src/lib.rs

@@ -133,7 +133,7 @@ mod test {
 	fn node_filter() {
 		let contract_addr = Address::from_str("0000000000000000000000000000000000000005").unwrap();
 		let data = include_bytes!("../res/node_filter.json");
-		let spec = Spec::load(::std::env::temp_dir(), &data[..]).unwrap();
+		let spec = Spec::load(&::std::env::temp_dir(), &data[..]).unwrap();
 		let client_db = Arc::new(::util::kvdb::in_memory(::ethcore::db::NUM_COLUMNS.unwrap_or(0)));
 
 		let client = Client::new(

ethcore/res/constructor.json

@@ -1,7 +1,9 @@
 {
 	"name": "GenesisConstructor",
 	"engine": {
-		"null": null
+		"null": {
+			"params": {}
+		}
 	},
 	"params": {
 		"gasLimitBoundDivisor": "0x0400",

ethcore/res/ethereum/byzantium_test.json

@@ -6,12 +6,12 @@
 				"minimumDifficulty": "0x020000",
 				"difficultyBoundDivisor": "0x0800",
 				"durationLimit": "0x0d",
+				"blockReward": "0x4563918244F40000",
 				"homesteadTransition": "0x0",
 				"eip150Transition": "0x0",
 				"eip160Transition": "0x0",
 				"eip161abcTransition": "0x0",
 				"eip161dTransition": "0x0",
-				"maxCodeSize": 24576,
 				"eip649Reward": "0x29A2241AF62C0000",
 				"eip100bTransition": "0x0",
 				"eip649Transition": "0x0"
@@ -20,12 +20,12 @@
 	},
 	"params": {
 		"gasLimitBoundDivisor": "0x0400",
-		"blockReward": "0x4563918244F40000",
 		"registrar" : "0xc6d9d2cd449a754c494264e1809c50e34d64562b",
 		"accountStartNonce": "0x00",
 		"maximumExtraDataSize": "0x20",
 		"minGasLimit": "0x1388",
 		"networkID" : "0x1",
+		"maxCodeSize": 24576,
 		"eip98Transition": "0xffffffffffffffff",
 		"eip140Transition": "0x0",
 		"eip211Transition": "0x0",

ethcore/res/ethereum/classic.json

@@ -7,6 +7,7 @@
 				"minimumDifficulty": "0x020000",
 				"difficultyBoundDivisor": "0x0800",
 				"durationLimit": "0x0d",
+				"blockReward": "0x4563918244F40000",
 				"homesteadTransition": 1150000,
 				"eip150Transition": 2500000,
 				"eip160Transition": 3000000,
@@ -21,7 +22,6 @@
 	},
 	"params": {
 		"gasLimitBoundDivisor": "0x0400",
-		"blockReward": "0x4563918244F40000",
 		"registrar" : "0xc6d9d2cd449a754c494264e1809c50e34d64562b",
 		"accountStartNonce": "0x00",
 		"maximumExtraDataSize": "0x20",

ethcore/res/ethereum/constantinople_test.json

@@ -6,12 +6,12 @@
 				"minimumDifficulty": "0x020000",
 				"difficultyBoundDivisor": "0x0800",
 				"durationLimit": "0x0d",
+				"blockReward": "0x4563918244F40000",
 				"homesteadTransition": "0x0",
 				"eip150Transition": "0x0",
 				"eip160Transition": "0x0",
 				"eip161abcTransition": "0x0",
 				"eip161dTransition": "0x0",
-				"maxCodeSize": 24576,
 				"eip649Reward": "0x29A2241AF62C0000",
 				"eip100bTransition": "0x0",
 				"eip649Transition": "0x0"
@@ -20,12 +20,12 @@
 	},
 	"params": {
 		"gasLimitBoundDivisor": "0x0400",
-		"blockReward": "0x4563918244F40000",
 		"registrar" : "0xc6d9d2cd449a754c494264e1809c50e34d64562b",
 		"accountStartNonce": "0x00",
 		"maximumExtraDataSize": "0x20",
 		"minGasLimit": "0x1388",
 		"networkID" : "0x1",
+		"maxCodeSize": 24576,
 		"eip98Transition": "0xffffffffffffffff",
 		"eip140Transition": "0x0",
 		"eip210Transition": "0x0",

ethcore/res/ethereum/eip150_test.json

@@ -6,18 +6,17 @@
 				"minimumDifficulty": "0x020000",
 				"difficultyBoundDivisor": "0x0800",
 				"durationLimit": "0x0d",
+				"blockReward": "0x4563918244F40000",
 				"homesteadTransition": "0x0",
 				"eip150Transition": "0x0",
 				"eip160Transition": "0x7fffffffffffffff",
 				"eip161abcTransition": "0x7fffffffffffffff",
-				"eip161dTransition": "0x7fffffffffffffff",
-				"maxCodeSize": 24576
+				"eip161dTransition": "0x7fffffffffffffff"
 			}
 		}
 	},
 	"params": {
 		"gasLimitBoundDivisor": "0x0400",
-		"blockReward": "0x4563918244F40000",
 		"registrar" : "0xc6d9d2cd449a754c494264e1809c50e34d64562b",
 		"accountStartNonce": "0x00",
 		"maximumExtraDataSize": "0x20",
@@ -25,7 +24,8 @@
 		"networkID" : "0x1",
 		"eip98Transition": "0x7fffffffffffffff",
 		"eip86Transition": "0x7fffffffffffffff",
-		"eip155Transition": "0x7fffffffffffffff"
+		"eip155Transition": "0x7fffffffffffffff",
+		"maxCodeSize": 24576
 	},
 	"genesis": {
 		"seal": {

ethcore/res/ethereum/eip161_test.json

@@ -6,18 +6,17 @@
 				"minimumDifficulty": "0x020000",
 				"difficultyBoundDivisor": "0x0800",
 				"durationLimit": "0x0d",
+				"blockReward": "0x4563918244F40000",
 				"homesteadTransition": "0x0",
 				"eip150Transition": "0x0",
 				"eip160Transition": "0x0",
 				"eip161abcTransition": "0x0",
-				"eip161dTransition": "0x0",
-				"maxCodeSize": 24576
+				"eip161dTransition": "0x0"
 			}
 		}
 	},
 	"params": {
 		"gasLimitBoundDivisor": "0x0400",
-		"blockReward": "0x4563918244F40000",
 		"registrar" : "0xc6d9d2cd449a754c494264e1809c50e34d64562b",
 		"accountStartNonce": "0x00",
 		"maximumExtraDataSize": "0x20",
@@ -25,7 +24,8 @@
 		"networkID" : "0x1",
 		"eip98Transition": "0x7fffffffffffffff",
 		"eip86Transition": "0x7fffffffffffffff",
-		"eip155Transition": "0x7fffffffffffffff"
+		"eip155Transition": "0x7fffffffffffffff",
+		"maxCodeSize": 24576
 	},
 	"genesis": {
 		"seal": {

ethcore/res/ethereum/expanse.json

@@ -8,6 +8,7 @@
 				"difficultyBoundDivisor": "0x0800",
 				"difficultyIncrementDivisor": "60",
 				"durationLimit": "0x3C",
+				"blockReward": "0x6f05b59d3b200000",
 				"homesteadTransition": "0x30d40",
 				"difficultyHardforkTransition": "0x59d9",
 				"difficultyHardforkBoundDivisor": "0x0200",
@@ -21,7 +22,6 @@
 	},
 	"params": {
 		"gasLimitBoundDivisor": "0x0400",
-		"blockReward": "0x6f05b59d3b200000",
 		"registrar" : "0x6c221ca53705f3497ec90ca7b84c59ae7382fc21",
 		"accountStartNonce": "0x00",
 		"maximumExtraDataSize": "0x20",

ethcore/res/ethereum/foundation.json

@@ -7,6 +7,7 @@
 				"minimumDifficulty": "0x020000",
 				"difficultyBoundDivisor": "0x0800",
 				"durationLimit": "0x0d",
+				"blockReward": "0x4563918244F40000",
 				"homesteadTransition": "0x118c30",
 				"daoHardforkTransition": "0x1d4c00",
 				"daoHardforkBeneficiary": "0xbf4ed7b27f1d666546e30d74d50d173d20bca754",
@@ -131,14 +132,12 @@
 				"eip150Transition": "0x259518",
 				"eip160Transition": 2675000,
 				"eip161abcTransition": 2675000,
-				"eip161dTransition": 2675000,
-				"maxCodeSize": 24576
+				"eip161dTransition": 2675000
 			}
 		}
 	},
 	"params": {
 		"gasLimitBoundDivisor": "0x0400",
-		"blockReward": "0x4563918244F40000",
 		"registrar" : "0xe3389675d0338462dC76C6f9A3e432550c36A142",
 		"accountStartNonce": "0x00",
 		"maximumExtraDataSize": "0x20",
@@ -149,7 +148,8 @@
 		"eip155Transition": 2675000,
 
 		"eip98Transition": "0x7fffffffffffff",
-		"eip86Transition": "0x7fffffffffffff"
+		"eip86Transition": "0x7fffffffffffff",
+		"maxCodeSize": 24576
 	},
 	"genesis": {
 		"seal": {

ethcore/res/ethereum/frontier_like_test.json

@@ -6,6 +6,7 @@
 				"minimumDifficulty": "0x020000",
 				"difficultyBoundDivisor": "0x0800",
 				"durationLimit": "0x0d",
+				"blockReward": "0x4563918244F40000",
 				"homesteadTransition": "0x118c30",
 				"daoHardforkTransition": "0x1d4c00",
 				"daoHardforkBeneficiary": "0xbf4ed7b27f1d666546e30d74d50d173d20bca754",
@@ -136,7 +137,6 @@
 	},
 	"params": {
 		"gasLimitBoundDivisor": "0x0400",
-		"blockReward": "0x4563918244F40000",
 		"registrar" : "0xc6d9d2cd449a754c494264e1809c50e34d64562b",
 		"accountStartNonce": "0x00",
 		"maximumExtraDataSize": "0x20",

ethcore/res/ethereum/frontier_test.json

@@ -6,6 +6,7 @@
 				"minimumDifficulty": "0x020000",
 				"difficultyBoundDivisor": "0x0800",
 				"durationLimit": "0x0d",
+				"blockReward": "0x4563918244F40000",
 				"homesteadTransition": "0x7fffffffffffffff",
 				"eip150Transition": "0x7fffffffffffffff",
 				"eip160Transition": "0x7fffffffffffffff",
@@ -16,7 +17,6 @@
 	},
 	"params": {
 		"gasLimitBoundDivisor": "0x0400",
-		"blockReward": "0x4563918244F40000",
 		"registrar" : "0xc6d9d2cd449a754c494264e1809c50e34d64562b",
 		"accountStartNonce": "0x00",
 		"maximumExtraDataSize": "0x20",

ethcore/res/ethereum/homestead_test.json

@@ -6,6 +6,7 @@
 				"minimumDifficulty": "0x020000",
 				"difficultyBoundDivisor": "0x0800",
 				"durationLimit": "0x0d",
+				"blockReward": "0x4563918244F40000",
 				"homesteadTransition": "0x0",
 				"eip150Transition": "0x7fffffffffffffff",
 				"eip160Transition": "0x7fffffffffffffff",
@@ -16,7 +17,6 @@
 	},
 	"params": {
 		"gasLimitBoundDivisor": "0x0400",
-		"blockReward": "0x4563918244F40000",
 		"registrar" : "0xc6d9d2cd449a754c494264e1809c50e34d64562b",
 		"accountStartNonce": "0x00",
 		"maximumExtraDataSize": "0x20",

ethcore/res/ethereum/kovan.json

@@ -5,6 +5,7 @@
 		"authorityRound": {
 			"params": {
 			"stepDuration": "4",
+			"blockReward": "0x4563918244F40000",
 				"validators" : {
 					"list": [
 						"0x00D6Cc1BA9cf89BD2e58009741f4F7325BAdc0ED",
@@ -29,7 +30,6 @@
 	"params": {
 		"gasLimitBoundDivisor": "0x400",
 		"registrar" : "0xfAb104398BBefbd47752E7702D9fE23047E1Bca3",
-    "blockReward": "0x4563918244F40000",
 	"maximumExtraDataSize": "0x20",
 		"minGasLimit": "0x1388",
 		"networkID" : "0x2A",

ethcore/res/ethereum/morden.json

@@ -7,6 +7,7 @@
 				"minimumDifficulty": "0x020000",
 				"difficultyBoundDivisor": "0x0800",
 				"durationLimit": "0x0d",
+				"blockReward": "0x4563918244F40000",
 				"homesteadTransition": 494000,
 				"eip150Transition": 1783000,
 				"eip160Transition": 1915000,
@@ -20,7 +21,6 @@
 	},
 	"params": {
 		"gasLimitBoundDivisor": "0x0400",
-		"blockReward": "0x4563918244F40000",
 		"registrar": "0x52dff57a8a1532e6afb3dc07e2af58bb9eb05b3d",
 		"accountStartNonce": "0x0100000",
 		"maximumExtraDataSize": "0x20",

ethcore/res/ethereum/olympic.json

@@ -6,6 +6,7 @@
 				"minimumDifficulty": "0x020000",
 				"difficultyBoundDivisor": "0x0800",
 				"durationLimit": "0x08",
+				"blockReward": "0x14D1120D7B160000",
 				"homesteadTransition": "0x7fffffffffffffff",
 				"eip150Transition": "0x7fffffffffffffff",
 				"eip160Transition": "0x7fffffffffffffff",
@@ -16,7 +17,6 @@
 	},
 	"params": {
 		"gasLimitBoundDivisor": "0x0400",
-		"blockReward": "0x14D1120D7B160000",
 		"registrar": "5e70c0bbcd5636e0f9f9316e9f8633feb64d4050",
 		"accountStartNonce": "0x00",
 		"maximumExtraDataSize": "0x0400",

ethcore/res/ethereum/ropsten.json

@@ -7,12 +7,12 @@
 				"minimumDifficulty": "0x020000",
 				"difficultyBoundDivisor": "0x0800",
 				"durationLimit": "0x0d",
+				"blockReward": "0x4563918244F40000",
 				"homesteadTransition": 0,
 				"eip150Transition": 0,
 				"eip160Transition": 10,
 				"eip161abcTransition": 10,
 				"eip161dTransition": 10,
-				"maxCodeSize": 24576,
 				"eip649Reward": "0x29A2241AF62C0000",
 				"eip100bTransition": 1700000,
 				"eip649Transition": 1700000
@@ -21,7 +21,6 @@
 	},
 	"params": {
 		"gasLimitBoundDivisor": "0x0400",
-		"blockReward": "0x4563918244F40000",
 		"registrar": "0x81a4b044831c4f12ba601adb9274516939e9b8a2",
 		"accountStartNonce": "0x0",
 		"maximumExtraDataSize": "0x20",
@@ -29,6 +28,7 @@
 		"networkID" : "0x3",
 		"forkBlock": 641350,
 		"forkCanonHash": "0x8033403e9fe5811a7b6d6b469905915de1c59207ce2172cbcf5d6ff14fa6a2eb",
+		"maxCodeSize": 24576,
 		"eip155Transition": 10,
 		"eip98Transition": "0x7fffffffffffff",
 		"eip86Transition": "0x7fffffffffffff",

ethcore/res/ethereum/transition_test.json

@@ -6,12 +6,12 @@
 				"minimumDifficulty": "0x020000",
 				"difficultyBoundDivisor": "0x0800",
 				"durationLimit": "0x0d",
+				"blockReward": "0x4563918244F40000",
 				"homesteadTransition": "0",
 				"eip150Transition": "0",
 				"eip160Transition": "0",
 				"eip161abcTransition": "0",
 				"eip161dTransition": "0",
-				"maxCodeSize": 24576,
 				"eip649Reward": "0x29A2241AF62C0000",
 				"eip100bTransition": "5",
 				"eip649Transition": "5"
@@ -20,12 +20,12 @@
 	},
 	"params": {
 		"gasLimitBoundDivisor": "0x0400",
-		"blockReward": "0x4563918244F40000",
 		"registrar" : "0xc6d9d2cd449a754c494264e1809c50e34d64562b",
 		"accountStartNonce": "0x00",
 		"maximumExtraDataSize": "0x20",
 		"minGasLimit": "0x1388",
 		"networkID" : "0x1",
+		"maxCodeSize": 24576,
 		"eip98Transition": "5",
 		"eip140Transition": "5",
 		"eip211Transition": "5",

ethcore/res/null.json

@@ -1,7 +1,9 @@
 {
 	"name": "Morden",
 	"engine": {
-		"null": null
+		"null": {
+			"params": {}
+		}
 	},
 	"params": {
 		"gasLimitBoundDivisor": "0x0400",

ethcore/res/null_morden.json

@@ -1,7 +1,9 @@
 {
 	"name": "Morden",
 	"engine": {
-		"null": null
+		"null": {
+			"params": {}
+		}
 	},
 	"params": {
 		"gasLimitBoundDivisor": "0x0400",

ethcore/res/null_morden_with_reward.json

@@ -1,15 +1,18 @@
 {
 	"name": "Morden",
 	"engine": {
-		"null": null
+		"null": {
+			"params": {
+				"blockReward": "0x4563918244F40000"
+			}
+		}
 	},
 	"params": {
 		"gasLimitBoundDivisor": "0x0400",
 		"accountStartNonce": "0x0",
 		"maximumExtraDataSize": "0x20",
 		"minGasLimit": "0x1388",
-		"networkID" : "0x2",
-		"blockReward": "0x4563918244F40000"
+		"networkID" : "0x2"
 	},
 	"genesis": {
 		"seal": {

ethcore/src/block.rs

@@ -31,7 +31,7 @@ use unexpected::{Mismatch, OutOfBounds};
 
 use basic_types::{LogBloom, Seal};
 use vm::{EnvInfo, LastHashes};
-use engines::Engine;
+use engines::EthEngine;
 use error::{Error, BlockError, TransactionError};
 use factory::Factories;
 use header::Header;
@@ -97,6 +97,7 @@ pub struct ExecutedBlock {
 	transactions_set: HashSet<H256>,
 	state: State<StateDB>,
 	traces: Option<Vec<Vec<FlatTrace>>>,
+	last_hashes: Arc<LastHashes>,
 }
 
 /// A set of references to `ExecutedBlock` fields that are publicly accessible.
@@ -115,6 +116,17 @@ pub struct BlockRefMut<'a> {
 	pub traces: &'a mut Option<Vec<Vec<FlatTrace>>>,
 }
 
+impl<'a> BlockRefMut<'a> {
+	/// Add traces if tracing is enabled.
+	pub fn push_traces(&mut self, tracer: ::trace::ExecutiveTracer) {
+		use trace::Tracer;
+
+		if let Some(ref mut traces) = self.traces.as_mut() {
+			traces.push(tracer.drain())
+		}
+	}
+}
+
 /// A set of immutable references to `ExecutedBlock` fields that are publicly accessible.
 pub struct BlockRef<'a> {
 	/// Block header.
@@ -133,7 +145,7 @@ pub struct BlockRef<'a> {
 
 impl ExecutedBlock {
 	/// Create a new block from the given `state`.
-	fn new(state: State<StateDB>, tracing: bool) -> ExecutedBlock {
+	fn new(state: State<StateDB>, last_hashes: Arc<LastHashes>, tracing: bool) -> ExecutedBlock {
 		ExecutedBlock {
 			header: Default::default(),
 			transactions: Default::default(),
@@ -142,6 +154,7 @@ impl ExecutedBlock {
 			transactions_set: Default::default(),
 			state: state,
 			traces: if tracing {Some(Vec::new())} else {None},
+			last_hashes: last_hashes,
 		}
 	}
 
@@ -168,6 +181,20 @@ impl ExecutedBlock {
 			traces: &self.traces,
 		}
 	}
+
+	/// Get the environment info concerning this block.
+	pub fn env_info(&self) -> EnvInfo {
+		// TODO: memoise.
+		EnvInfo {
+			number: self.header.number(),
+			author: self.header.author().clone(),
+			timestamp: self.header.timestamp(),
+			difficulty: self.header.difficulty().clone(),
+			last_hashes: self.last_hashes.clone(),
+			gas_used: self.receipts.last().map_or(U256::zero(), |r| r.gas_used),
+			gas_limit: self.header.gas_limit().clone(),
+		}
+	}
 }
 
 /// Trait for a object that is a `ExecutedBlock`.
@@ -216,14 +243,33 @@ impl IsBlock for ExecutedBlock {
 	fn block(&self) -> &ExecutedBlock { self }
 }
 
+impl ::parity_machine::LiveBlock for ExecutedBlock {
+	type Header = Header;
+
+	fn header(&self) -> &Header {
+		&self.header
+	}
+
+	fn uncles(&self) -> &[Header] {
+		&self.uncles
+	}
+}
+
+impl ::parity_machine::Transactions for ExecutedBlock {
+	type Transaction = SignedTransaction;
+
+	fn transactions(&self) -> &[SignedTransaction] {
+		&self.transactions
+	}
+}
+
 /// Block that is ready for transactions to be added.
 ///
 /// It's a bit like a Vec<Transaction>, except that whenever a transaction is pushed, we execute it and
 /// maintain the system `state()`. We also archive execution receipts in preparation for later block creation.
 pub struct OpenBlock<'x> {
 	block: ExecutedBlock,
-	engine: &'x Engine,
-	last_hashes: Arc<LastHashes>,
+	engine: &'x EthEngine,
 }
 
 /// Just like `OpenBlock`, except that we've applied `Engine::on_close_block`, finished up the non-seal header fields,
@@ -234,7 +280,6 @@ pub struct OpenBlock<'x> {
 pub struct ClosedBlock {
 	block: ExecutedBlock,
 	uncle_bytes: Bytes,
-	last_hashes: Arc<LastHashes>,
 	unclosed_state: State<StateDB>,
 }
 
@@ -259,7 +304,7 @@ impl<'x> OpenBlock<'x> {
 	#[cfg_attr(feature="dev", allow(too_many_arguments))]
 	/// Create a new `OpenBlock` ready for transaction pushing.
 	pub fn new(
-		engine: &'x Engine,
+		engine: &'x EthEngine,
 		factories: Factories,
 		tracing: bool,
 		db: StateDB,
@@ -273,9 +318,8 @@ impl<'x> OpenBlock<'x> {
 		let number = parent.number() + 1;
 		let state = State::from_existing(db, parent.state_root().clone(), engine.account_start_nonce(number), factories)?;
 		let mut r = OpenBlock {
-			block: ExecutedBlock::new(state, tracing),
+			block: ExecutedBlock::new(state, last_hashes, tracing),
 			engine: engine,
-			last_hashes: last_hashes.clone(),
 		};
 
 		r.block.header.set_parent_hash(parent.hash());
@@ -287,8 +331,12 @@ impl<'x> OpenBlock<'x> {
 
 		let gas_floor_target = cmp::max(gas_range_target.0, engine.params().min_gas_limit);
 		let gas_ceil_target = cmp::max(gas_range_target.1, gas_floor_target);
-		engine.populate_from_parent(&mut r.block.header, parent, gas_floor_target, gas_ceil_target);
-		engine.on_new_block(&mut r.block, last_hashes, is_epoch_begin)?;
+
+		engine.machine().populate_from_parent(&mut r.block.header, parent, gas_floor_target, gas_ceil_target);
+		engine.populate_from_parent(&mut r.block.header, parent);
+
+		engine.machine().on_new_block(&mut r.block)?;
+		engine.on_new_block(&mut r.block, is_epoch_begin)?;
 
 		Ok(r)
 	}
@@ -343,16 +391,7 @@ impl<'x> OpenBlock<'x> {
 
 	/// Get the environment info concerning this block.
 	pub fn env_info(&self) -> EnvInfo {
-		// TODO: memoise.
-		EnvInfo {
-			number: self.block.header.number(),
-			author: self.block.header.author().clone(),
-			timestamp: self.block.header.timestamp(),
-			difficulty: self.block.header.difficulty().clone(),
-			last_hashes: self.last_hashes.clone(),
-			gas_used: self.block.receipts.last().map_or(U256::zero(), |r| r.gas_used),
-			gas_limit: self.block.header.gas_limit().clone(),
-		}
+		self.block.env_info()
 	}
 
 	/// Push a transaction into the block.
@@ -365,7 +404,7 @@ impl<'x> OpenBlock<'x> {
 
 		let env_info = self.env_info();
 //		info!("env_info says gas_used={}", env_info.gas_used);
-		match self.block.state.apply(&env_info, self.engine, &t, self.block.traces.is_some()) {
+		match self.block.state.apply(&env_info, self.engine.machine(), &t, self.block.traces.is_some()) {
 			Ok(outcome) => {
 				self.block.transactions_set.insert(h.unwrap_or_else(||t.hash()));
 				self.block.transactions.push(t.into());
@@ -418,7 +457,6 @@ impl<'x> OpenBlock<'x> {
 		ClosedBlock {
 			block: s.block,
 			uncle_bytes: uncle_bytes,
-			last_hashes: s.last_hashes,
 			unclosed_state: unclosed_state,
 		}
 	}
@@ -485,14 +523,13 @@ impl ClosedBlock {
 	}
 
 	/// Given an engine reference, reopen the `ClosedBlock` into an `OpenBlock`.
-	pub fn reopen(self, engine: &Engine) -> OpenBlock {
+	pub fn reopen(self, engine: &EthEngine) -> OpenBlock {
 		// revert rewards (i.e. set state back at last transaction's state).
 		let mut block = self.block;
 		block.state = self.unclosed_state;
 		OpenBlock {
 			block: block,
 			engine: engine,
-			last_hashes: self.last_hashes,
 		}
 	}
 }
@@ -504,7 +541,7 @@ impl LockedBlock {
 	/// Provide a valid seal in order to turn this into a `SealedBlock`.
 	///
 	/// NOTE: This does not check the validity of `seal` with the engine.
-	pub fn seal(self, engine: &Engine, seal: Vec<Bytes>) -> Result<SealedBlock, BlockError> {
+	pub fn seal(self, engine: &EthEngine, seal: Vec<Bytes>) -> Result<SealedBlock, BlockError> {
 		let mut s = self;
 		if seal.len() != engine.seal_fields() {
 			return Err(BlockError::InvalidSealArity(Mismatch{expected: engine.seal_fields(), found: seal.len()}));
@@ -518,12 +555,14 @@ impl LockedBlock {
 	/// Returns the `ClosedBlock` back again if the seal is no good.
 	pub fn try_seal(
 		self,
-		engine: &Engine,
+		engine: &EthEngine,
 		seal: Vec<Bytes>,
 	) -> Result<SealedBlock, (Error, LockedBlock)> {
 		let mut s = self;
 		s.block.header.set_seal(seal);
-		match engine.verify_block_seal(&s.block.header) {
+
+		// TODO: passing state context to avoid engines owning it?
+		match engine.verify_local_seal(&s.block.header) {
 			Err(e) => Err((e, s)),
 			_ => Ok(SealedBlock { block: s.block, uncle_bytes: s.uncle_bytes }),
 		}
@@ -575,7 +614,7 @@ pub fn enact(
 	header: &Header,
 	transactions: &[SignedTransaction],
 	uncles: &[Header],
-	engine: &Engine,
+	engine: &EthEngine,
 	tracing: bool,
 	db: StateDB,
 	parent: &Header,
@@ -647,7 +686,7 @@ fn push_transactions(block: &mut OpenBlock, transactions: &[SignedTransaction])
 #[cfg_attr(feature="dev", allow(too_many_arguments))]
 pub fn enact_verified(
 	block: &PreverifiedBlock,
-	engine: &Engine,
+	engine: &EthEngine,
 	tracing: bool,
 	db: StateDB,
 	parent: &Header,
@@ -675,7 +714,7 @@ pub fn enact_verified(
 mod tests {
 	use tests::helpers::*;
 	use super::*;
-	use engines::Engine;
+	use engines::EthEngine;
 	use vm::LastHashes;
 	use error::Error;
 	use header::Header;
@@ -690,7 +729,7 @@ mod tests {
 	#[cfg_attr(feature="dev", allow(too_many_arguments))]
 	fn enact_bytes(
 		block_bytes: &[u8],
-		engine: &Engine,
+		engine: &EthEngine,
 		tracing: bool,
 		db: StateDB,
 		parent: &Header,
@@ -737,7 +776,7 @@ mod tests {
 	#[cfg_attr(feature="dev", allow(too_many_arguments))]
 	fn enact_and_seal(
 		block_bytes: &[u8],
-		engine: &Engine,
+		engine: &EthEngine,
 		tracing: bool,
 		db: StateDB,
 		parent: &Header,

ethcore/src/client/ancient_import.rs

@@ -19,8 +19,9 @@
 use std::sync::Arc;
 
 use blockchain::BlockChain;
-use engines::{Engine, EpochVerifier};
+use engines::{EthEngine, EpochVerifier};
 use header::Header;
+use machine::EthereumMachine;
 
 use rand::Rng;
 use parking_lot::RwLock;
@@ -31,13 +32,13 @@ const HEAVY_VERIFY_RATE: f32 = 0.02;
 /// Ancient block verifier: import an ancient sequence of blocks in order from a starting
 /// epoch.
 pub struct AncientVerifier {
-	cur_verifier: RwLock<Box<EpochVerifier>>,
-	engine: Arc<Engine>,
+	cur_verifier: RwLock<Box<EpochVerifier<EthereumMachine>>>,
+	engine: Arc<EthEngine>,
 }
 
 impl AncientVerifier {
 	/// Create a new ancient block verifier with the given engine and initial verifier.
-	pub fn new(engine: Arc<Engine>, start_verifier: Box<EpochVerifier>) -> Self {
+	pub fn new(engine: Arc<EthEngine>, start_verifier: Box<EpochVerifier<EthereumMachine>>) -> Self {
 		AncientVerifier {
 			cur_verifier: RwLock::new(start_verifier),
 			engine: engine,

ethcore/src/client/client.rs

@@ -46,7 +46,7 @@ use client::{
 	ChainNotify, PruningInfo, ProvingBlockChainClient,
 };
 use encoded;
-use engines::{Engine, EpochTransition};
+use engines::{EthEngine, EpochTransition};
 use error::{ImportError, ExecutionError, CallError, BlockError, ImportResult, Error as EthcoreError};
 use vm::{EnvInfo, LastHashes};
 use evm::{Factory as EvmFactory, Schedule};
@@ -147,7 +147,7 @@ pub struct Client {
 	mode: Mutex<Mode>,
 	chain: RwLock<Arc<BlockChain>>,
 	tracedb: RwLock<TraceDB<BlockChain>>,
-	engine: Arc<Engine>,
+	engine: Arc<EthEngine>,
 	config: ClientConfig,
 	pruning: journaldb::Algorithm,
 	db: RwLock<Arc<KeyValueDB>>,
@@ -332,7 +332,7 @@ impl Client {
 	}
 
 	/// Returns engine reference.
-	pub fn engine(&self) -> &Engine {
+	pub fn engine(&self) -> &EthEngine {
 		&*self.engine
 	}
 
@@ -421,22 +421,34 @@ impl Client {
 			return Err(());
 		}
 
+		// Check if parent is in chain
+		let parent = match chain.block_header(header.parent_hash()) {
+			Some(h) => h,
+			None => {
+				warn!(target: "client", "Block import failed for #{} ({}): Parent not found ({}) ", header.number(), header.hash(), header.parent_hash());
+				return Err(());
+			}
+		};
+
 		// Verify Block Family
-		let verify_family_result = self.verifier.verify_block_family(header, &block.bytes, engine, &**chain);
+		let verify_family_result = self.verifier.verify_block_family(
+			header,
+			&parent,
+			engine,
+			Some((&block.bytes, &block.transactions, &**chain, self)),
+		);
+
 		if let Err(e) = verify_family_result {
 			warn!(target: "client", "Stage 3 block verification failed for #{} ({})\nError: {:?}", header.number(), header.hash(), e);
 			return Err(());
 		};
 
-		let verify_external_result = self.verifier.verify_block_external(header, &block.bytes, engine);
+		let verify_external_result = self.verifier.verify_block_external(header, engine);
 		if let Err(e) = verify_external_result {
 			warn!(target: "client", "Stage 4 block verification failed for #{} ({})\nError: {:?}", header.number(), header.hash(), e);
 			return Err(());
 		};
 
-		// Check if Parent is in chain
-		let chain_has_parent = chain.block_header(header.parent_hash());
-		if let Some(parent) = chain_has_parent {
 		// Enact Verified Block
 		let last_hashes = self.build_last_hashes(header.parent_hash().clone());
 		let db = self.state_db.lock().boxed_clone_canon(header.parent_hash());
@@ -466,10 +478,6 @@ impl Client {
 		}
 
 		Ok(locked_block)
-		} else {
-			warn!(target: "client", "Block import failed for #{} ({}): Parent not found ({}) ", header.number(), header.hash(), header.parent_hash());
-			Err(())
-		}
 	}
 
 	fn calculate_enacted_retracted(&self, import_results: &[ImportRoute]) -> (Vec<H256>, Vec<H256>) {
@@ -721,7 +729,12 @@ impl Client {
 		use engines::EpochChange;
 
 		let hash = header.hash();
-		match self.engine.signals_epoch_end(header, Some(block_bytes), Some(&receipts)) {
+		let auxiliary = ::machine::AuxiliaryData {
+			bytes: Some(block_bytes),
+			receipts: Some(&receipts),
+		};
+
+		match self.engine.signals_epoch_end(header, auxiliary) {
 			EpochChange::Yes(proof) => {
 				use engines::epoch::PendingTransition;
 				use engines::Proof;
@@ -754,7 +767,7 @@ impl Client {
 							).expect("state known to be available for just-imported block; qed");
 
 							let options = TransactOptions::with_no_tracing().dont_check_nonce();
-							let res = Executive::new(&mut state, &env_info, &*self.engine)
+							let res = Executive::new(&mut state, &env_info, self.engine.machine())
 								.transact(&transaction, options);
 
 							let res = match res {
@@ -821,7 +834,7 @@ impl Client {
 
 	// use a state-proving closure for the given block.
 	fn with_proving_caller<F, T>(&self, id: BlockId, with_call: F) -> T
-		where F: FnOnce(&::engines::Call) -> T
+		where F: FnOnce(&::machine::Call) -> T
 	{
 		let call = |a, d| {
 			let tx = self.contract_call_tx(id, a, d);
@@ -1119,15 +1132,14 @@ impl Client {
 	}
 
 	fn do_virtual_call(&self, env_info: &EnvInfo, state: &mut State<StateDB>, t: &SignedTransaction, analytics: CallAnalytics) -> Result<Executed, CallError> {
-		fn call<E, V, T>(
+		fn call<V, T>(
 			state: &mut State<StateDB>,
 			env_info: &EnvInfo,
-			engine: &E,
+			machine: &::machine::EthereumMachine,
 			state_diff: bool,
 			transaction: &SignedTransaction,
 			options: TransactOptions<T, V>,
 		) -> Result<Executed, CallError> where
-			E: Engine + ?Sized,
 			T: trace::Tracer,
 			V: trace::VMTracer,
 		{
@@ -1136,7 +1148,7 @@ impl Client {
 				.save_output_from_contract();
 			let original_state = if state_diff { Some(state.clone()) } else { None };
 
-			let mut ret = Executive::new(state, env_info, engine).transact_virtual(transaction, options)?;
+			let mut ret = Executive::new(state, env_info, machine).transact_virtual(transaction, options)?;
 
 			if let Some(original) = original_state {
 				ret.state_diff = Some(state.diff_from(original).map_err(ExecutionError::from)?);
@@ -1145,13 +1157,13 @@ impl Client {
 		}
 
 		let state_diff = analytics.state_diffing;
-		let engine = &*self.engine;
+		let machine = self.engine.machine();
 
 		match (analytics.transaction_tracing, analytics.vm_tracing) {
-			(true, true) => call(state, env_info, engine, state_diff, t, TransactOptions::with_tracing_and_vm_tracing()),
-			(true, false) => call(state, env_info, engine, state_diff, t, TransactOptions::with_tracing()),
-			(false, true) => call(state, env_info, engine, state_diff, t, TransactOptions::with_vm_tracing()),
-			(false, false) => call(state, env_info, engine, state_diff, t, TransactOptions::with_no_tracing()),
+			(true, true) => call(state, env_info, machine, state_diff, t, TransactOptions::with_tracing_and_vm_tracing()),
+			(true, false) => call(state, env_info, machine, state_diff, t, TransactOptions::with_tracing()),
+			(false, true) => call(state, env_info, machine, state_diff, t, TransactOptions::with_vm_tracing()),
+			(false, false) => call(state, env_info, machine, state_diff, t, TransactOptions::with_no_tracing()),
 		}
 	}
 
@@ -1235,7 +1247,7 @@ impl BlockChainClient for Client {
 			let tx = tx.fake_sign(sender);
 
 			let mut state = original_state.clone();
-			Ok(Executive::new(&mut state, &env_info, &*self.engine)
+			Ok(Executive::new(&mut state, &env_info, self.engine.machine())
 				.transact_virtual(&tx, options())
 				.map(|r| r.exception.is_none())
 				.unwrap_or(false))
@@ -1296,7 +1308,7 @@ impl BlockChainClient for Client {
 		let rest = txs.split_off(address.index);
 		for t in txs {
 			let t = SignedTransaction::new(t).expect(PROOF);
-			let x = Executive::new(&mut state, &env_info, &*self.engine).transact(&t, TransactOptions::with_no_tracing())?;
+			let x = Executive::new(&mut state, &env_info, self.engine.machine()).transact(&t, TransactOptions::with_no_tracing())?;
 			env_info.gas_used = env_info.gas_used + x.gas_used;
 		}
 		let first = rest.into_iter().next().expect("We split off < `address.index`; Length is checked earlier; qed");
@@ -1575,7 +1587,7 @@ impl BlockChainClient for Client {
 					.collect();
 				match (transaction, previous_receipts) {
 					(Some(transaction), Some(previous_receipts)) => {
-						Some(transaction_receipt(self.engine(), transaction, previous_receipts))
+						Some(transaction_receipt(self.engine().machine(), transaction, previous_receipts))
 					},
 					_ => None,
 				}
@@ -1680,14 +1692,22 @@ impl BlockChainClient for Client {
 
 		match (start, end) {
 			(Some(s), Some(e)) => {
-				let filter = trace::Filter {
+				let db_filter = trace::Filter {
 					range: s as usize..e as usize,
 					from_address: From::from(filter.from_address),
 					to_address: From::from(filter.to_address),
 				};
 
-				let traces = self.tracedb.read().filter(&filter);
-				Some(traces)
+				let traces = self.tracedb.read().filter(&db_filter);
+				if traces.is_empty() {
+					return Some(vec![]);
+				}
+
+				let traces_iter = traces.into_iter().skip(filter.after.unwrap_or(0));
+				Some(match filter.count {
+					Some(count) => traces_iter.take(count).collect(),
+					None => traces_iter.collect(),
+				})
 			},
 			_ => None,
 		}
@@ -1995,7 +2015,7 @@ impl ProvingBlockChainClient for Client {
 			jdb.as_hashdb_mut(),
 			header.state_root().clone(),
 			&transaction,
-			&*self.engine,
+			self.engine.machine(),
 			&env_info,
 			self.factories.clone(),
 			false,
@@ -2018,7 +2038,7 @@ impl Drop for Client {
 
 /// Returns `LocalizedReceipt` given `LocalizedTransaction`
 /// and a vector of receipts from given block up to transaction index.
-fn transaction_receipt(engine: &Engine, mut tx: LocalizedTransaction, mut receipts: Vec<Receipt>) -> LocalizedReceipt {
+fn transaction_receipt(machine: &::machine::EthereumMachine, mut tx: LocalizedTransaction, mut receipts: Vec<Receipt>) -> LocalizedReceipt {
 	assert_eq!(receipts.len(), tx.transaction_index + 1, "All previous receipts are provided.");
 
 	let sender = tx.sender();
@@ -2042,7 +2062,7 @@ fn transaction_receipt(engine: &Engine, mut tx: LocalizedTransaction, mut receip
 		gas_used: receipt.gas_used - prior_gas_used,
 		contract_address: match tx.action {
 			Action::Call(_) => None,
-			Action::Create => Some(contract_address(engine.create_address_scheme(block_number), &sender, &tx.nonce, &tx.data).0)
+			Action::Create => Some(contract_address(machine.create_address_scheme(block_number), &sender, &tx.nonce, &tx.data).0)
 		},
 		logs: receipt.logs.into_iter().enumerate().map(|(i, log)| LocalizedLogEntry {
 			entry: log,
@@ -2102,12 +2122,11 @@ mod tests {
 		use log_entry::{LogEntry, LocalizedLogEntry};
 		use receipt::{Receipt, LocalizedReceipt, TransactionOutcome};
 		use transaction::{Transaction, LocalizedTransaction, Action};
-		use tests::helpers::TestEngine;
 
 		// given
 		let key = KeyPair::from_secret_slice(&keccak("test")).unwrap();
 		let secret = key.secret();
-		let engine = TestEngine::new(0);
+		let machine = ::ethereum::new_frontier_test_machine();
 
 		let block_number = 1;
 		let block_hash = 5.into();
@@ -2151,7 +2170,7 @@ mod tests {
 		}];
 
 		// when
-		let receipt = transaction_receipt(&engine, transaction, receipts);
+		let receipt = transaction_receipt(&machine, transaction, receipts);
 
 		// then
 		assert_eq!(receipt, LocalizedReceipt {

ethcore/src/client/evm_test_client.rs

@@ -181,7 +181,7 @@ impl<'a> EvmTestClient<'a> {
 		let mut substate = state::Substate::new();
 		let mut tracer = trace::NoopTracer;
 		let mut output = vec![];
-		let mut executive = executive::Executive::new(&mut self.state, &info, &*self.spec.engine);
+		let mut executive = executive::Executive::new(&mut self.state, &info, self.spec.engine.machine());
 		executive.call(
 			params,
 			&mut substate,
@@ -211,7 +211,7 @@ impl<'a> EvmTestClient<'a> {
 
 		// Apply transaction
 		let tracer = trace::NoopTracer;
-		let result = self.state.apply_with_tracing(&env_info, &*self.spec.engine, &transaction, tracer, vm_tracer);
+		let result = self.state.apply_with_tracing(&env_info, self.spec.engine.machine(), &transaction, tracer, vm_tracer);
 
 		match result {
 			Ok(result) => {

ethcore/src/engines/authority_round/mod.rs

@@ -19,19 +19,16 @@
 use std::sync::atomic::{AtomicUsize, AtomicBool, Ordering as AtomicOrdering};
 use std::sync::{Weak, Arc};
 use std::time::{UNIX_EPOCH, Duration};
-use std::collections::{BTreeMap, HashSet, HashMap};
-use std::cmp;
+use std::collections::{BTreeMap, HashSet};
 
 use account_provider::AccountProvider;
 use block::*;
-use builtin::Builtin;
 use client::EngineClient;
-use engines::{Call, Engine, Seal, EngineError, ConstructedVerifier};
-use error::{Error, TransactionError, BlockError};
+use engines::{Engine, Seal, EngineError, ConstructedVerifier};
+use error::{Error, BlockError};
 use ethjson;
+use machine::{AuxiliaryData, Call, EthereumMachine};
 use header::{Header, BlockNumber};
-use spec::CommonParams;
-use transaction::UnverifiedTransaction;
 
 use super::signer::EngineSigner;
 use super::validator_set::{ValidatorSet, SimpleList, new_validator_set};
@@ -66,6 +63,8 @@ pub struct AuthorityRoundParams {
 	pub validate_step_transition: u64,
 	/// Immediate transitions.
 	pub immediate_transitions: bool,
+	/// Block reward in base units.
+	pub block_reward: U256,
 }
 
 impl From<ethjson::spec::AuthorityRoundParams> for AuthorityRoundParams {
@@ -77,6 +76,7 @@ impl From<ethjson::spec::AuthorityRoundParams> for AuthorityRoundParams {
 			validate_score_transition: p.validate_score_transition.map_or(0, Into::into),
 			validate_step_transition: p.validate_step_transition.map_or(0, Into::into),
 			immediate_transitions: p.immediate_transitions.unwrap_or(false),
+			block_reward: p.block_reward.map_or_else(Default::default, Into::into),
 		}
 	}
 }
@@ -138,7 +138,7 @@ impl EpochManager {
 	}
 
 	// zoom to epoch for given header. returns true if succeeded, false otherwise.
-	fn zoom_to(&mut self, client: &EngineClient, engine: &Engine, validators: &ValidatorSet, header: &Header) -> bool {
+	fn zoom_to(&mut self, client: &EngineClient, machine: &EthereumMachine, validators: &ValidatorSet, header: &Header) -> bool {
 		let last_was_parent = self.finality_checker.subchain_head() == Some(header.parent_hash().clone());
 
 		// early exit for current target == chain head, but only if the epochs are
@@ -164,7 +164,6 @@ impl EpochManager {
 			}
 		};
 
-
 		// extract other epoch set if it's not the same as the last.
 		if last_transition.block_hash != self.epoch_transition_hash {
 			let (signal_number, set_proof, _) = destructure_proofs(&last_transition.proof)
@@ -176,7 +175,7 @@ impl EpochManager {
 			let first = signal_number == 0;
 			let epoch_set = validators.epoch_set(
 				first,
-				engine,
+				machine,
 				signal_number, // use signal number so multi-set first calculation is correct.
 				set_proof,
 			)
@@ -208,8 +207,6 @@ impl EpochManager {
 
 /// Engine using `AuthorityRound` proof-of-authority BFT consensus.
 pub struct AuthorityRound {
-	params: CommonParams,
-	builtins: BTreeMap<Address, Builtin>,
 	transition_service: IoService<()>,
 	step: Arc<Step>,
 	can_propose: AtomicBool,
@@ -220,6 +217,8 @@ pub struct AuthorityRound {
 	validate_step_transition: u64,
 	epoch_manager: Mutex<EpochManager>,
 	immediate_transitions: bool,
+	block_reward: U256,
+	machine: EthereumMachine,
 }
 
 // header-chain validator.
@@ -228,7 +227,7 @@ struct EpochVerifier {
 	subchain_validators: SimpleList,
 }
 
-impl super::EpochVerifier for EpochVerifier {
+impl super::EpochVerifier<EthereumMachine> for EpochVerifier {
 	fn verify_light(&self, header: &Header) -> Result<(), Error> {
 		// always check the seal since it's fast.
 		// nothing heavier to do.
@@ -250,7 +249,6 @@ impl super::EpochVerifier for EpochVerifier {
 
 		let headers: Vec<Header> = otry!(UntrustedRlp::new(proof).as_list().ok());
 
-
 		for header in &headers {
 			// ensure all headers have correct number of seal fields so we can `verify_external`
 			// without panic.
@@ -347,13 +345,11 @@ impl AsMillis for Duration {
 
 impl AuthorityRound {
 	/// Create a new instance of AuthorityRound engine.
-	pub fn new(params: CommonParams, our_params: AuthorityRoundParams, builtins: BTreeMap<Address, Builtin>) -> Result<Arc<Self>, Error> {
+	pub fn new(our_params: AuthorityRoundParams, machine: EthereumMachine) -> Result<Arc<Self>, Error> {
 		let should_timeout = our_params.start_step.is_none();
 		let initial_step = our_params.start_step.unwrap_or_else(|| (unix_now().as_secs() / our_params.step_duration.as_secs())) as usize;
 		let engine = Arc::new(
 			AuthorityRound {
-				params: params,
-				builtins: builtins,
 				transition_service: IoService::<()>::start()?,
 				step: Arc::new(Step {
 					inner: AtomicUsize::new(initial_step),
@@ -368,6 +364,8 @@ impl AuthorityRound {
 				validate_step_transition: our_params.validate_step_transition,
 				epoch_manager: Mutex::new(EpochManager::blank()),
 				immediate_transitions: our_params.immediate_transitions,
+				block_reward: our_params.block_reward,
+				machine: machine,
 			});
 
 		// Do not initialize timeouts for tests.
@@ -410,22 +408,16 @@ impl IoHandler<()> for TransitionHandler {
 	}
 }
 
-impl Engine for AuthorityRound {
+impl Engine<EthereumMachine> for AuthorityRound {
 	fn name(&self) -> &str { "AuthorityRound" }
 
 	fn version(&self) -> SemanticVersion { SemanticVersion::new(1, 0, 0) }
 
+	fn machine(&self) -> &EthereumMachine { &self.machine }
+
 	/// Two fields - consensus step and the corresponding proposer signature.
 	fn seal_fields(&self) -> usize { 2 }
 
-	fn params(&self) -> &CommonParams { &self.params }
-
-	fn additional_params(&self) -> HashMap<String, String> {
-		hash_map!["registrar".to_owned() => self.params().registrar.hex()]
-	}
-
-	fn builtins(&self) -> &BTreeMap<Address, Builtin> { &self.builtins }
-
 	fn step(&self) {
 		self.step.increment();
 		self.can_propose.store(true, AtomicOrdering::SeqCst);
@@ -444,19 +436,10 @@ impl Engine for AuthorityRound {
 		]
 	}
 
-	fn populate_from_parent(&self, header: &mut Header, parent: &Header, gas_floor_target: U256, _gas_ceil_target: U256) {
+	fn populate_from_parent(&self, header: &mut Header, parent: &Header) {
 		// Chain scoring: total weight is sqrt(U256::max_value())*height - step
 		let new_difficulty = U256::from(U128::max_value()) + header_step(parent).expect("Header has been verified; qed").into() - self.step.load().into();
 		header.set_difficulty(new_difficulty);
-		header.set_gas_limit({
-			let gas_limit = parent.gas_limit().clone();
-			let bound_divisor = self.params().gas_limit_bound_divisor;
-			if gas_limit < gas_floor_target {
-				cmp::min(gas_floor_target, gas_limit + gas_limit / bound_divisor - 1.into())
-			} else {
-				cmp::max(gas_floor_target, gas_limit - gas_limit / bound_divisor + 1.into())
-			}
-		});
 	}
 
 	fn seals_internally(&self) -> Option<bool> {
@@ -491,7 +474,7 @@ impl Engine for AuthorityRound {
 				}
 			};
 
-			if !epoch_manager.zoom_to(&*client, self, &*self.validators, header) {
+			if !epoch_manager.zoom_to(&*client, &self.machine, &*self.validators, header) {
 				debug!(target: "engine", "Unable to zoom to epoch.");
 				return Seal::None;
 			}
@@ -518,15 +501,15 @@ impl Engine for AuthorityRound {
 		Seal::None
 	}
 
+	fn verify_local_seal(&self, _header: &Header) -> Result<(), Error> {
+		Ok(())
+	}
+
 	fn on_new_block(
 		&self,
 		block: &mut ExecutedBlock,
-		last_hashes: Arc<::vm::LastHashes>,
 		epoch_begin: bool,
 	) -> Result<(), Error> {
-		let parent_hash = block.fields().header.parent_hash().clone();
-		::engines::common::push_last_hash(block, last_hashes.clone(), self, &parent_hash)?;
-
 		// with immediate transitions, we don't use the epoch mechanism anyway.
 		// the genesis is always considered an epoch, but we ignore it intentionally.
 		if self.immediate_transitions || !epoch_begin { return Ok(()) }
@@ -536,10 +519,8 @@ impl Engine for AuthorityRound {
 		let first = header.number() == 0;
 
 		let mut call = |to, data| {
-			let result = ::engines::common::execute_as_system(
+			let result = self.machine.execute_as_system(
 				block,
-				last_hashes.clone(),
-				self,
 				to,
 				U256::max_value(), // unbounded gas? maybe make configurable.
 				Some(data),
@@ -553,17 +534,13 @@ impl Engine for AuthorityRound {
 
 	/// Apply the block reward on finalisation of the block.
 	fn on_close_block(&self, block: &mut ExecutedBlock) -> Result<(), Error> {
-		::engines::common::bestow_block_reward(block, self)
+		// TODO: move to "machine::WithBalances" trait.
+		::engines::common::bestow_block_reward(block, self.block_reward)
 	}
 
 	/// Check the number of seal fields.
-	fn verify_block_basic(&self, header: &Header, _block: Option<&[u8]>) -> Result<(), Error> {
-		if header.seal().len() != self.seal_fields() {
-			trace!(target: "engine", "verify_block_basic: wrong number of seal fields");
-			Err(From::from(BlockError::InvalidSealArity(
-				Mismatch { expected: self.seal_fields(), found: header.seal().len() }
-			)))
-		} else if header.number() >= self.validate_score_transition && *header.difficulty() >= U256::from(U128::max_value()) {
+	fn verify_block_basic(&self, header: &Header,) -> Result<(), Error> {
+		if header.number() >= self.validate_score_transition && *header.difficulty() >= U256::from(U128::max_value()) {
 			Err(From::from(BlockError::DifficultyOutOfBounds(
 				OutOfBounds { min: None, max: Some(U256::from(U128::max_value())), found: *header.difficulty() }
 			)))
@@ -572,19 +549,10 @@ impl Engine for AuthorityRound {
 		}
 	}
 
-	fn verify_block_unordered(&self, _header: &Header, _block: Option<&[u8]>) -> Result<(), Error> {
-		Ok(())
-	}
-
 	/// Do the step and gas limit validation.
-	fn verify_block_family(&self, header: &Header, parent: &Header, _block: Option<&[u8]>) -> Result<(), Error> {
+	fn verify_block_family(&self, header: &Header, parent: &Header) -> Result<(), Error> {
 		let step = header_step(header)?;
 
-		// Do not calculate difficulty for genesis blocks.
-		if header.number() == 0 {
-			return Err(From::from(BlockError::RidiculousNumber(OutOfBounds { min: Some(1), max: None, found: header.number() })));
-		}
-
 		let parent_step = header_step(parent)?;
 
 		// Ensure header is from the step after parent.
@@ -595,6 +563,7 @@ impl Engine for AuthorityRound {
 			self.validators.report_malicious(header.author(), header.number(), header.number(), Default::default());
 			Err(EngineError::DoubleVote(header.author().clone()))?;
 		}
+
 		// Report skipped primaries.
 		if let (true, Some(me)) = (step > parent_step + 1, self.signer.read().address()) {
 			debug!(target: "engine", "Author {} built block with step gap. current step: {}, parent step: {}",
@@ -611,17 +580,11 @@ impl Engine for AuthorityRound {
 			}
 		}
 
-		let gas_limit_divisor = self.params().gas_limit_bound_divisor;
-		let min_gas = parent.gas_limit().clone() - parent.gas_limit().clone() / gas_limit_divisor;
-		let max_gas = parent.gas_limit().clone() + parent.gas_limit().clone() / gas_limit_divisor;
-		if header.gas_limit() <= &min_gas || header.gas_limit() >= &max_gas {
-			return Err(From::from(BlockError::InvalidGasLimit(OutOfBounds { min: Some(min_gas), max: Some(max_gas), found: header.gas_limit().clone() })));
-		}
 		Ok(())
 	}
 
 	// Check the validators.
-	fn verify_block_external(&self, header: &Header, _block: Option<&[u8]>) -> Result<(), Error> {
+	fn verify_block_external(&self, header: &Header) -> Result<(), Error> {
 		// fetch correct validator set for current epoch, taking into account
 		// finality of previous transitions.
 		let active_set;
@@ -639,7 +602,7 @@ impl Engine for AuthorityRound {
 			};
 
 			let mut epoch_manager = self.epoch_manager.lock();
-			if !epoch_manager.zoom_to(&*client, self, &*self.validators, header) {
+			if !epoch_manager.zoom_to(&*client, &self.machine, &*self.validators, header) {
 				debug!(target: "engine", "Unable to zoom to epoch.");
 				return Err(EngineError::RequiresClient.into())
 			}
@@ -667,19 +630,19 @@ impl Engine for AuthorityRound {
 			.map(|set_proof| combine_proofs(0, &set_proof, &[]))
 	}
 
-	fn signals_epoch_end(&self, header: &Header, block: Option<&[u8]>, receipts: Option<&[::receipt::Receipt]>)
-		-> super::EpochChange
+	fn signals_epoch_end(&self, header: &Header, aux: AuxiliaryData)
+		-> super::EpochChange<EthereumMachine>
 	{
 		if self.immediate_transitions { return super::EpochChange::No }
 
 		let first = header.number() == 0;
-		self.validators.signals_epoch_end(first, header, block, receipts)
+		self.validators.signals_epoch_end(first, header, aux)
 	}
 
 	fn is_epoch_end(
 		&self,
 		chain_head: &Header,
-		chain: &super::Headers,
+		chain: &super::Headers<Header>,
 		transition_store: &super::PendingTransitionStore,
 	) -> Option<Vec<u8>> {
 		// epochs only matter if we want to support light clients.
@@ -703,7 +666,7 @@ impl Engine for AuthorityRound {
 
 		// find most recently finalized blocks, then check transition store for pending transitions.
 		let mut epoch_manager = self.epoch_manager.lock();
-		if !epoch_manager.zoom_to(&*client, self, &*self.validators, chain_head) {
+		if !epoch_manager.zoom_to(&*client, &self.machine, &*self.validators, chain_head) {
 			return None;
 		}
 
@@ -782,14 +745,14 @@ impl Engine for AuthorityRound {
 		None
 	}
 
-	fn epoch_verifier<'a>(&self, _header: &Header, proof: &'a [u8]) -> ConstructedVerifier<'a> {
+	fn epoch_verifier<'a>(&self, _header: &Header, proof: &'a [u8]) -> ConstructedVerifier<'a, EthereumMachine> {
 		let (signal_number, set_proof, finality_proof) = match destructure_proofs(proof) {
 			Ok(x) => x,
 			Err(e) => return ConstructedVerifier::Err(e),
 		};
 
 		let first = signal_number == 0;
-		match self.validators.epoch_set(first, self, signal_number, set_proof) {
+		match self.validators.epoch_set(first, &self.machine, signal_number, set_proof) {
 			Ok((list, finalize)) => {
 				let verifier = Box::new(EpochVerifier {
 					step: self.step.clone(),
@@ -805,18 +768,6 @@ impl Engine for AuthorityRound {
 		}
 	}
 
-	fn verify_transaction_basic(&self, t: &UnverifiedTransaction, header: &Header) -> Result<(), Error> {
-		t.check_low_s()?;
-
-		if let Some(n) = t.chain_id() {
-			if header.number() >= self.params().eip155_transition && n != self.params().chain_id {
-				return Err(TransactionError::InvalidChainId.into());
-			}
-		}
-
-		Ok(())
-	}
-
 	fn register_client(&self, client: Weak<EngineClient>) {
 		*self.client.write() = Some(client.clone());
 		self.validators.register_client(client);
@@ -847,7 +798,6 @@ mod tests {
 	use bigint::prelude::U256;
 	use bigint::hash::H520;
 	use header::Header;
-	use error::{Error, BlockError};
 	use rlp::encode;
 	use block::*;
 	use tests::helpers::*;
@@ -872,27 +822,13 @@ mod tests {
 		assert!(schedule.stack_limit > 0);
 	}
 
-	#[test]
-	fn verification_fails_on_short_seal() {
-		let engine = Spec::new_test_round().engine;
-		let header: Header = Header::default();
-
-		let verify_result = engine.verify_block_basic(&header, None);
-
-		match verify_result {
-			Err(Error::Block(BlockError::InvalidSealArity(_))) => {},
-			Err(_) => { panic!("should be block seal-arity mismatch error (got {:?})", verify_result); },
-			_ => { panic!("Should be error, got Ok"); },
-		}
-	}
-
 	#[test]
 	fn can_do_signature_verification_fail() {
 		let engine = Spec::new_test_round().engine;
 		let mut header: Header = Header::default();
 		header.set_seal(vec![encode(&H520::default()).into_vec()]);
 
-		let verify_result = engine.verify_block_external(&header, None);
+		let verify_result = engine.verify_block_external(&header);
 		assert!(verify_result.is_err());
 	}
 
@@ -946,11 +882,11 @@ mod tests {
 		// Two validators.
 		// Spec starts with step 2.
 		header.set_seal(vec![encode(&2usize).into_vec(), encode(&(&*signature as &[u8])).into_vec()]);
-		assert!(engine.verify_block_family(&header, &parent_header, None).is_ok());
-		assert!(engine.verify_block_external(&header, None).is_err());
+		assert!(engine.verify_block_family(&header, &parent_header).is_ok());
+		assert!(engine.verify_block_external(&header).is_err());
 		header.set_seal(vec![encode(&1usize).into_vec(), encode(&(&*signature as &[u8])).into_vec()]);
-		assert!(engine.verify_block_family(&header, &parent_header, None).is_ok());
-		assert!(engine.verify_block_external(&header, None).is_ok());
+		assert!(engine.verify_block_family(&header, &parent_header).is_ok());
+		assert!(engine.verify_block_external(&header).is_ok());
 	}
 
 	#[test]
@@ -972,11 +908,11 @@ mod tests {
 		// Two validators.
 		// Spec starts with step 2.
 		header.set_seal(vec![encode(&1usize).into_vec(), encode(&(&*signature as &[u8])).into_vec()]);
-		assert!(engine.verify_block_family(&header, &parent_header, None).is_ok());
-		assert!(engine.verify_block_external(&header, None).is_ok());
+		assert!(engine.verify_block_family(&header, &parent_header).is_ok());
+		assert!(engine.verify_block_external(&header).is_ok());
 		header.set_seal(vec![encode(&5usize).into_vec(), encode(&(&*signature as &[u8])).into_vec()]);
-		assert!(engine.verify_block_family(&header, &parent_header, None).is_ok());
-		assert!(engine.verify_block_external(&header, None).is_err());
+		assert!(engine.verify_block_family(&header, &parent_header).is_ok());
+		assert!(engine.verify_block_external(&header).is_err());
 	}
 
 	#[test]
@@ -998,9 +934,9 @@ mod tests {
 		// Two validators.
 		// Spec starts with step 2.
 		header.set_seal(vec![encode(&5usize).into_vec(), encode(&(&*signature as &[u8])).into_vec()]);
-		assert!(engine.verify_block_family(&header, &parent_header, None).is_ok());
+		assert!(engine.verify_block_family(&header, &parent_header).is_ok());
 		header.set_seal(vec![encode(&3usize).into_vec(), encode(&(&*signature as &[u8])).into_vec()]);
-		assert!(engine.verify_block_family(&header, &parent_header, None).is_err());
+		assert!(engine.verify_block_family(&header, &parent_header).is_err());
 	}
 
 	#[test]
@@ -1013,12 +949,14 @@ mod tests {
 			validate_score_transition: 0,
 			validate_step_transition: 0,
 			immediate_transitions: true,
+			block_reward: Default::default(),
 		};
 
 		let aura = {
 			let mut c_params = ::spec::CommonParams::default();
 			c_params.gas_limit_bound_divisor = 5.into();
-			AuthorityRound::new(c_params, params, Default::default()).unwrap()
+			let machine = ::machine::EthereumMachine::regular(c_params, Default::default());
+			AuthorityRound::new(params, machine).unwrap()
 		};
 
 		let mut parent_header: Header = Header::default();
@@ -1030,12 +968,12 @@ mod tests {
 		header.set_seal(vec![encode(&3usize).into_vec()]);
 
 		// Do not report when signer not present.
-		assert!(aura.verify_block_family(&header, &parent_header, None).is_ok());
+		assert!(aura.verify_block_family(&header, &parent_header).is_ok());
 		assert_eq!(last_benign.load(AtomicOrdering::SeqCst), 0);
 
 		aura.set_signer(Arc::new(AccountProvider::transient_provider()), Default::default(), Default::default());
 
-		assert!(aura.verify_block_family(&header, &parent_header, None).is_ok());
+		assert!(aura.verify_block_family(&header, &parent_header).is_ok());
 		assert_eq!(last_benign.load(AtomicOrdering::SeqCst), 1);
 	}
 }

ethcore/src/engines/basic_authority.rs

@@ -17,24 +17,18 @@
 //! A blockchain engine that supports a basic, non-BFT proof-of-authority.
 
 use std::sync::{Weak, Arc};
-use std::collections::BTreeMap;
-use std::cmp;
-use bigint::prelude::U256;
 use bigint::hash::{H256, H520};
 use parking_lot::RwLock;
 use util::*;
-use unexpected::{Mismatch, OutOfBounds};
 use ethkey::{recover, public_to_address, Signature};
 use account_provider::AccountProvider;
 use block::*;
-use builtin::Builtin;
-use spec::CommonParams;
-use engines::{Engine, Seal, Call, ConstructedVerifier, EngineError};
+use engines::{Engine, Seal, ConstructedVerifier, EngineError};
 use error::{BlockError, Error};
-use evm::Schedule;
 use ethjson;
-use header::{Header, BlockNumber};
+use header::Header;
 use client::EngineClient;
+use machine::{AuxiliaryData, Call, EthereumMachine};
 use semantic_version::SemanticVersion;
 use super::signer::EngineSigner;
 use super::validator_set::{ValidatorSet, SimpleList, new_validator_set};
@@ -58,7 +52,7 @@ struct EpochVerifier {
 	list: SimpleList,
 }
 
-impl super::EpochVerifier for EpochVerifier {
+impl super::EpochVerifier<EthereumMachine> for EpochVerifier {
 	fn verify_light(&self, header: &Header) -> Result<(), Error> {
 		verify_external(header, &self.list)
 	}
@@ -83,53 +77,31 @@ fn verify_external(header: &Header, validators: &ValidatorSet) -> Result<(), Err
 
 /// Engine using `BasicAuthority`, trivial proof-of-authority consensus.
 pub struct BasicAuthority {
-	params: CommonParams,
-	builtins: BTreeMap<Address, Builtin>,
+	machine: EthereumMachine,
 	signer: RwLock<EngineSigner>,
 	validators: Box<ValidatorSet>,
 }
 
 impl BasicAuthority {
 	/// Create a new instance of BasicAuthority engine
-	pub fn new(params: CommonParams, our_params: BasicAuthorityParams, builtins: BTreeMap<Address, Builtin>) -> Self {
+	pub fn new(our_params: BasicAuthorityParams, machine: EthereumMachine) -> Self {
 		BasicAuthority {
-			params: params,
-			builtins: builtins,
-			validators: new_validator_set(our_params.validators),
+			machine: machine,
 			signer: Default::default(),
+			validators: new_validator_set(our_params.validators),
 		}
 	}
 }
 
-impl Engine for BasicAuthority {
+impl Engine<EthereumMachine> for BasicAuthority {
 	fn name(&self) -> &str { "BasicAuthority" }
 	fn version(&self) -> SemanticVersion { SemanticVersion::new(1, 0, 0) }
+
+	fn machine(&self) -> &EthereumMachine { &self.machine }
+
 	// One field - the signature
 	fn seal_fields(&self) -> usize { 1 }
 
-	fn params(&self) -> &CommonParams { &self.params }
-	fn builtins(&self) -> &BTreeMap<Address, Builtin> { &self.builtins }
-
-	/// Additional engine-specific information for the user/developer concerning `header`.
-	fn extra_info(&self, _header: &Header) -> BTreeMap<String, String> { map!["signature".to_owned() => "TODO".to_owned()] }
-
-	fn schedule(&self, _block_number: BlockNumber) -> Schedule {
-		Schedule::new_homestead()
-	}
-
-	fn populate_from_parent(&self, header: &mut Header, parent: &Header, gas_floor_target: U256, _gas_ceil_target: U256) {
-		header.set_difficulty(parent.difficulty().clone());
-		header.set_gas_limit({
-			let gas_limit = parent.gas_limit().clone();
-			let bound_divisor = self.params().gas_limit_bound_divisor;
-			if gas_limit < gas_floor_target {
-				cmp::min(gas_floor_target, gas_limit + gas_limit / bound_divisor - 1.into())
-			} else {
-				cmp::max(gas_floor_target, gas_limit - gas_limit / bound_divisor + 1.into())
-			}
-		});
-	}
-
 	fn seals_internally(&self) -> Option<bool> {
 		Some(self.signer.read().is_some())
 	}
@@ -149,41 +121,11 @@ impl Engine for BasicAuthority {
 		Seal::None
 	}
 
-	fn verify_block_basic(&self, header: &Header, _block: Option<&[u8]>) -> Result<(), Error> {
-		// check the seal fields.
-		// TODO: pull this out into common code.
-		if header.seal().len() != self.seal_fields() {
-			return Err(From::from(BlockError::InvalidSealArity(
-				Mismatch { expected: self.seal_fields(), found: header.seal().len() }
-			)));
-		}
+	fn verify_local_seal(&self, _header: &Header) -> Result<(), Error> {
 		Ok(())
 	}
 
-	fn verify_block_unordered(&self, _header: &Header, _block: Option<&[u8]>) -> Result<(), Error> {
-		Ok(())
-	}
-
-	fn verify_block_family(&self, header: &Header, parent: &Header, _block: Option<&[u8]>) -> Result<(), Error> {
-		// Do not calculate difficulty for genesis blocks.
-		if header.number() == 0 {
-			return Err(From::from(BlockError::RidiculousNumber(OutOfBounds { min: Some(1), max: None, found: header.number() })));
-		}
-
-		// Check difficulty is correct given the two timestamps.
-		if header.difficulty() != parent.difficulty() {
-			return Err(From::from(BlockError::InvalidDifficulty(Mismatch { expected: *parent.difficulty(), found: *header.difficulty() })))
-		}
-		let gas_limit_divisor = self.params().gas_limit_bound_divisor;
-		let min_gas = parent.gas_limit().clone() - parent.gas_limit().clone() / gas_limit_divisor;
-		let max_gas = parent.gas_limit().clone() + parent.gas_limit().clone() / gas_limit_divisor;
-		if header.gas_limit() <= &min_gas || header.gas_limit() >= &max_gas {
-			return Err(From::from(BlockError::InvalidGasLimit(OutOfBounds { min: Some(min_gas), max: Some(max_gas), found: header.gas_limit().clone() })));
-		}
-		Ok(())
-	}
-
-	fn verify_block_external(&self, header: &Header, _block: Option<&[u8]>) -> Result<(), Error> {
+	fn verify_block_external(&self, header: &Header) -> Result<(), Error> {
 		verify_external(header, &*self.validators)
 	}
 
@@ -192,26 +134,26 @@ impl Engine for BasicAuthority {
 	}
 
 	#[cfg(not(test))]
-	fn signals_epoch_end(&self, _header: &Header, _block: Option<&[u8]>, _receipts: Option<&[::receipt::Receipt]>)
-		-> super::EpochChange
+	fn signals_epoch_end(&self, _header: &Header, _auxiliary: AuxiliaryData)
+		-> super::EpochChange<EthereumMachine>
 	{
 		// don't bother signalling even though a contract might try.
 		super::EpochChange::No
 	}
 
 	#[cfg(test)]
-	fn signals_epoch_end(&self, header: &Header, block: Option<&[u8]>, receipts: Option<&[::receipt::Receipt]>)
-		-> super::EpochChange
+	fn signals_epoch_end(&self, header: &Header, auxiliary: AuxiliaryData)
+		-> super::EpochChange<EthereumMachine>
 	{
 		// in test mode, always signal even though they don't be finalized.
 		let first = header.number() == 0;
-		self.validators.signals_epoch_end(first, header, block, receipts)
+		self.validators.signals_epoch_end(first, header, auxiliary)
 	}
 
 	fn is_epoch_end(
 		&self,
 		chain_head: &Header,
-		_chain: &super::Headers,
+		_chain: &super::Headers<Header>,
 		_transition_store: &super::PendingTransitionStore,
 	) -> Option<Vec<u8>> {
 		let first = chain_head.number() == 0;
@@ -220,10 +162,10 @@ impl Engine for BasicAuthority {
 		self.validators.is_epoch_end(first, chain_head)
 	}
 
-	fn epoch_verifier<'a>(&self, header: &Header, proof: &'a [u8]) -> ConstructedVerifier<'a> {
+	fn epoch_verifier<'a>(&self, header: &Header, proof: &'a [u8]) -> ConstructedVerifier<'a, EthereumMachine> {
 		let first = header.number() == 0;
 
-		match self.validators.epoch_set(first, self, header.number(), proof) {
+		match self.validators.epoch_set(first, &self.machine, header.number(), proof) {
 			Ok((list, finalize)) => {
 				let verifier = Box::new(EpochVerifier { list: list });
 
@@ -260,7 +202,6 @@ mod tests {
 	use hash::keccak;
 	use bigint::hash::H520;
 	use block::*;
-	use error::{BlockError, Error};
 	use tests::helpers::*;
 	use account_provider::AccountProvider;
 	use header::Header;
@@ -270,7 +211,7 @@ mod tests {
 	/// Create a new test chain spec with `BasicAuthority` consensus engine.
 	fn new_test_authority() -> Spec {
 		let bytes: &[u8] = include_bytes!("../../res/basic_authority.json");
-		Spec::load(::std::env::temp_dir(), bytes).expect("invalid chain spec")
+		Spec::load(&::std::env::temp_dir(), bytes).expect("invalid chain spec")
 	}
 
 	#[test]
@@ -287,27 +228,13 @@ mod tests {
 		assert!(schedule.stack_limit > 0);
 	}
 
-	#[test]
-	fn can_do_seal_verification_fail() {
-		let engine = new_test_authority().engine;
-		let header: Header = Header::default();
-
-		let verify_result = engine.verify_block_basic(&header, None);
-
-		match verify_result {
-			Err(Error::Block(BlockError::InvalidSealArity(_))) => {},
-			Err(_) => { panic!("should be block seal-arity mismatch error (got {:?})", verify_result); },
-			_ => { panic!("Should be error, got Ok"); },
-		}
-	}
-
 	#[test]
 	fn can_do_signature_verification_fail() {
 		let engine = new_test_authority().engine;
 		let mut header: Header = Header::default();
 		header.set_seal(vec![::rlp::encode(&H520::default()).into_vec()]);
 
-		let verify_result = engine.verify_block_family(&header, &Default::default(), None);
+		let verify_result = engine.verify_block_external(&header);
 		assert!(verify_result.is_err());
 	}
 

ethcore/src/engines/epoch.rs

@@ -17,8 +17,6 @@
 //! Epoch verifiers and transitions.
 
 use bigint::hash::H256;
-use error::Error;
-use header::Header;
 
 /// A full epoch transition.
 #[derive(Debug, Clone, RlpEncodable, RlpDecodable)]
@@ -40,15 +38,13 @@ pub struct PendingTransition {
 }
 
 /// Verifier for all blocks within an epoch with self-contained state.
-///
-/// See docs on `Engine` relating to proving functions for more details.
-pub trait EpochVerifier: Send + Sync {
+pub trait EpochVerifier<M: ::parity_machine::Machine>: Send + Sync {
 	/// Lightly verify the next block header.
 	/// This may not be a header belonging to a different epoch.
-	fn verify_light(&self, header: &Header) -> Result<(), Error>;
+	fn verify_light(&self, header: &M::Header) -> Result<(), M::Error>;
 
 	/// Perform potentially heavier checks on the next block header.
-	fn verify_heavy(&self, header: &Header) -> Result<(), Error> {
+	fn verify_heavy(&self, header: &M::Header) -> Result<(), M::Error> {
 		self.verify_light(header)
 	}
 
@@ -63,6 +59,6 @@ pub trait EpochVerifier: Send + Sync {
 /// Special "no-op" verifier for stateless, epoch-less engines.
 pub struct NoOp;
 
-impl EpochVerifier for NoOp {
-	fn verify_light(&self, _header: &Header) -> Result<(), Error> { Ok(()) }
+impl<M: ::parity_machine::Machine> EpochVerifier<M> for NoOp {
+	fn verify_light(&self, _header: &M::Header) -> Result<(), M::Error> { Ok(()) }
 }

ethcore/src/engines/instant_seal.rs

@@ -14,51 +14,42 @@
 // You should have received a copy of the GNU General Public License
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
-use std::collections::{BTreeMap, HashMap};
-use util::Address;
-use builtin::Builtin;
 use engines::{Engine, Seal};
-use spec::CommonParams;
-use block::{ExecutedBlock, IsBlock};
+use parity_machine::{Machine, Transactions};
 
 /// An engine which does not provide any consensus mechanism, just seals blocks internally.
-pub struct InstantSeal {
-	params: CommonParams,
-	builtins: BTreeMap<Address, Builtin>,
+/// Only seals blocks which have transactions.
+pub struct InstantSeal<M> {
+	machine: M,
 }
 
-impl InstantSeal {
-	/// Returns new instance of InstantSeal with default VM Factory
-	pub fn new(params: CommonParams, builtins: BTreeMap<Address, Builtin>) -> Self {
+impl<M> InstantSeal<M> {
+	/// Returns new instance of InstantSeal over the given state machine.
+	pub fn new(machine: M) -> Self {
 		InstantSeal {
-			params: params,
-			builtins: builtins,
+			machine: machine,
 		}
 	}
 }
 
-impl Engine for InstantSeal {
+impl<M: Machine> Engine<M> for InstantSeal<M>
+	where M::LiveBlock: Transactions
+{
 	fn name(&self) -> &str {
 		"InstantSeal"
 	}
 
-	fn params(&self) -> &CommonParams {
-		&self.params
-	}
-
-	fn additional_params(&self) -> HashMap<String, String> {
-		hash_map!["registrar".to_owned() => self.params().registrar.hex()]
-	}
-
-	fn builtins(&self) -> &BTreeMap<Address, Builtin> {
-		&self.builtins
-	}
+	fn machine(&self) -> &M { &self.machine }
 
 	fn seals_internally(&self) -> Option<bool> { Some(true) }
 
-	fn generate_seal(&self, block: &ExecutedBlock) -> Seal {
+	fn generate_seal(&self, block: &M::LiveBlock) -> Seal {
 		if block.transactions().is_empty() { Seal::None } else { Seal::Regular(Vec::new()) }
 	}
+
+	fn verify_local_seal(&self, _header: &M::Header) -> Result<(), M::Error> {
+		Ok(())
+	}
 }
 
 #[cfg(test)]
@@ -91,10 +82,10 @@ mod tests {
 		let engine = Spec::new_instant().engine;
 		let mut header: Header = Header::default();
 
-		assert!(engine.verify_block_basic(&header, None).is_ok());
+		assert!(engine.verify_block_basic(&header).is_ok());
 
 		header.set_seal(vec![::rlp::encode(&H520::default()).into_vec()]);
 
-		assert!(engine.verify_block_unordered(&header, None).is_ok());
+		assert!(engine.verify_block_unordered(&header).is_ok());
 	}
 }

ethcore/src/engines/mod.rs

@@ -42,18 +42,16 @@ use std::fmt;
 use self::epoch::PendingTransition;
 
 use account_provider::AccountProvider;
-use block::ExecutedBlock;
 use builtin::Builtin;
-use client::EngineClient;
-use vm::{EnvInfo, LastHashes, Schedule, CreateContractAddress};
+use vm::{EnvInfo, Schedule, CreateContractAddress};
 use error::Error;
 use header::{Header, BlockNumber};
-use receipt::Receipt;
 use snapshot::SnapshotComponents;
 use spec::CommonParams;
 use transaction::{UnverifiedTransaction, SignedTransaction};
 
 use ethkey::Signature;
+use parity_machine::{Machine, LocalizedMachine as Localized};
 use bigint::prelude::U256;
 use bigint::hash::H256;
 use semantic_version::SemanticVersion;
@@ -82,6 +80,8 @@ pub enum EngineError {
 	InsufficientProof(String),
 	/// Failed system call.
 	FailedSystemCall(String),
+	/// Malformed consensus message.
+	MalformedMessage(String),
 	/// Requires client ref, but none registered.
 	RequiresClient,
 }
@@ -97,6 +97,7 @@ impl fmt::Display for EngineError {
 			BadSealFieldSize(ref oob) => format!("Seal field has an unexpected length: {}", oob),
 			InsufficientProof(ref msg) => format!("Insufficient validation proof: {}", msg),
 			FailedSystemCall(ref msg) => format!("Failed to make system call: {}", msg),
+			MalformedMessage(ref msg) => format!("Received malformed consensus message: {}", msg),
 			RequiresClient => format!("Call requires client but none registered"),
 		};
 
@@ -115,49 +116,46 @@ pub enum Seal {
 	None,
 }
 
-/// Type alias for a function we can make calls through synchronously.
-/// Returns the call result and state proof for each call.
-pub type Call<'a> = Fn(Address, Bytes) -> Result<(Bytes, Vec<Vec<u8>>), String> + 'a;
-
 /// Type alias for a function we can get headers by hash through.
-pub type Headers<'a> = Fn(H256) -> Option<Header> + 'a;
+pub type Headers<'a, H> = Fn(H256) -> Option<H> + 'a;
 
 /// Type alias for a function we can query pending transitions by block hash through.
 pub type PendingTransitionStore<'a> = Fn(H256) -> Option<PendingTransition> + 'a;
 
 /// Proof dependent on state.
-pub trait StateDependentProof: Send + Sync {
+pub trait StateDependentProof<M: Machine>: Send + Sync {
 	/// Generate a proof, given the state.
-	fn generate_proof(&self, caller: &Call) -> Result<Vec<u8>, String>;
+	// TODO: make this into an &M::StateContext
+	fn generate_proof<'a>(&self, state: &<M as Localized<'a>>::StateContext) -> Result<Vec<u8>, String>;
 	/// Check a proof generated elsewhere (potentially by a peer).
 	// `engine` needed to check state proofs, while really this should
 	// just be state machine params.
-	fn check_proof(&self, engine: &Engine, proof: &[u8]) -> Result<(), String>;
+	fn check_proof(&self, machine: &M, proof: &[u8]) -> Result<(), String>;
 }
 
 /// Proof generated on epoch change.
-pub enum Proof {
+pub enum Proof<M: Machine> {
 	/// Known proof (extracted from signal)
 	Known(Vec<u8>),
 	/// State dependent proof.
-	WithState(Arc<StateDependentProof>),
+	WithState(Arc<StateDependentProof<M>>),
 }
 
 /// Generated epoch verifier.
-pub enum ConstructedVerifier<'a> {
+pub enum ConstructedVerifier<'a, M: Machine> {
 	/// Fully trusted verifier.
-	Trusted(Box<EpochVerifier>),
+	Trusted(Box<EpochVerifier<M>>),
 	/// Verifier unconfirmed. Check whether given finality proof finalizes given hash
 	/// under previous epoch.
-	Unconfirmed(Box<EpochVerifier>, &'a [u8], H256),
+	Unconfirmed(Box<EpochVerifier<M>>, &'a [u8], H256),
 	/// Error constructing verifier.
 	Err(Error),
 }
 
-impl<'a> ConstructedVerifier<'a> {
+impl<'a, M: Machine> ConstructedVerifier<'a, M> {
 	/// Convert to a result, indicating that any necessary confirmation has been done
 	/// already.
-	pub fn known_confirmed(self) -> Result<Box<EpochVerifier>, Error> {
+	pub fn known_confirmed(self) -> Result<Box<EpochVerifier<M>>, Error> {
 		match self {
 			ConstructedVerifier::Trusted(v) | ConstructedVerifier::Unconfirmed(v, _, _) => Ok(v),
 			ConstructedVerifier::Err(e) => Err(e),
@@ -166,84 +164,53 @@ impl<'a> ConstructedVerifier<'a> {
 }
 
 /// Results of a query of whether an epoch change occurred at the given block.
-pub enum EpochChange {
+pub enum EpochChange<M: Machine> {
 	/// Cannot determine until more data is passed.
-	Unsure(Unsure),
+	Unsure(M::AuxiliaryRequest),
 	/// No epoch change.
 	No,
 	/// The epoch will change, with proof.
-	Yes(Proof),
-}
-
-/// More data required to determine if an epoch change occurred at a given block.
-#[derive(Debug, Clone, Copy, PartialEq)]
-pub enum Unsure {
-	/// Needs the body.
-	NeedsBody,
-	/// Needs the receipts.
-	NeedsReceipts,
-	/// Needs both body and receipts.
-	NeedsBoth,
+	Yes(Proof<M>),
 }
 
 /// A consensus mechanism for the chain. Generally either proof-of-work or proof-of-stake-based.
 /// Provides hooks into each of the major parts of block import.
-pub trait Engine : Sync + Send {
+pub trait Engine<M: Machine>: Sync + Send {
 	/// The name of this engine.
 	fn name(&self) -> &str;
 	/// The version of this engine. Should be of the form
 	fn version(&self) -> SemanticVersion { SemanticVersion::new(0, 0, 0) }
 
+	/// Get access to the underlying state machine.
+	// TODO: decouple.
+	fn machine(&self) -> &M;
+
 	/// The number of additional header fields required for this engine.
 	fn seal_fields(&self) -> usize { 0 }
 
 	/// Additional engine-specific information for the user/developer concerning `header`.
-	fn extra_info(&self, _header: &Header) -> BTreeMap<String, String> { BTreeMap::new() }
+	fn extra_info(&self, _header: &M::Header) -> BTreeMap<String, String> { BTreeMap::new() }
 
 	/// Additional information.
 	fn additional_params(&self) -> HashMap<String, String> { HashMap::new() }
 
-	/// Get the general parameters of the chain.
-	fn params(&self) -> &CommonParams;
-
-	/// Get the EVM schedule for the given `block_number`.
-	fn schedule(&self, block_number: BlockNumber) -> Schedule {
-		self.params().schedule(block_number)
-	}
-
-	/// Builtin-contracts we would like to see in the chain.
-	/// (In principle these are just hints for the engine since that has the last word on them.)
-	fn builtins(&self) -> &BTreeMap<Address, Builtin>;
-
-	/// Some intrinsic operation parameters; by default they take their value from the `spec()`'s `engine_params`.
-	fn maximum_extra_data_size(&self) -> usize { self.params().maximum_extra_data_size }
 	/// Maximum number of uncles a block is allowed to declare.
 	fn maximum_uncle_count(&self) -> usize { 2 }
 	/// The number of generations back that uncles can be.
 	fn maximum_uncle_age(&self) -> usize { 6 }
-	/// The nonce with which accounts begin at given block.
-	fn account_start_nonce(&self, block: u64) -> U256 {
-		if block >= self.params().dust_protection_transition {
-			U256::from(self.params().nonce_cap_increment) * U256::from(block)
-		} else {
-			self.params().account_start_nonce
-		}
-	}
 
 	/// Block transformation functions, before the transactions.
 	/// `epoch_begin` set to true if this block kicks off an epoch.
 	fn on_new_block(
 		&self,
-		block: &mut ExecutedBlock,
-		last_hashes: Arc<LastHashes>,
+		_block: &mut M::LiveBlock,
 		_epoch_begin: bool,
-	) -> Result<(), Error> {
-		let parent_hash = block.fields().header.parent_hash().clone();
-		common::push_last_hash(block, last_hashes, self, &parent_hash)
+	) -> Result<(), M::Error> {
+		Ok(())
 	}
 
 	/// Block transformation functions, after the transactions.
-	fn on_close_block(&self, _block: &mut ExecutedBlock) -> Result<(), Error> {
+	fn on_close_block(&self, _block: &mut M::LiveBlock) -> Result<(), M::Error> {
 		Ok(())
 	}
 
@@ -251,68 +218,57 @@ pub trait Engine : Sync + Send {
 	/// Some(true) means the engine is currently prime for seal generation (i.e. node is the current validator).
 	/// Some(false) means that the node might seal internally but is not qualified now.
 	fn seals_internally(&self) -> Option<bool> { None }
+
 	/// Attempt to seal the block internally.
 	///
 	/// If `Some` is returned, then you get a valid seal.
 	///
 	/// This operation is synchronous and may (quite reasonably) not be available, in which None will
 	/// be returned.
-	fn generate_seal(&self, _block: &ExecutedBlock) -> Seal { Seal::None }
+	///
+	/// It is fine to require access to state or a full client for this function, since
+	/// light clients do not generate seals.
+	fn generate_seal(&self, _block: &M::LiveBlock) -> Seal { Seal::None }
 
-	/// Phase 1 quick block verification. Only does checks that are cheap. `block` (the header's full block)
-	/// may be provided for additional checks. Returns either a null `Ok` or a general error detailing the problem with import.
-	fn verify_block_basic(&self, _header: &Header,  _block: Option<&[u8]>) -> Result<(), Error> { Ok(()) }
+	/// Verify a locally-generated seal of a header.
+	///
+	/// If this engine seals internally,
+	/// no checks have to be done here, since all internally generated seals
+	/// should be valid.
+	///
+	/// Externally-generated seals (e.g. PoW) will need to be checked for validity.
+	///
+	/// It is fine to require access to state or a full client for this function, since
+	/// light clients do not generate seals.
+	fn verify_local_seal(&self, header: &M::Header) -> Result<(), M::Error>;
 
-	/// Phase 2 verification. Perform costly checks such as transaction signatures. `block` (the header's full block)
-	/// may be provided for additional checks. Returns either a null `Ok` or a general error detailing the problem with import.
-	fn verify_block_unordered(&self, _header: &Header, _block: Option<&[u8]>) -> Result<(), Error> { Ok(()) }
+	/// Phase 1 quick block verification. Only does checks that are cheap. Returns either a null `Ok` or a general error detailing the problem with import.
+	fn verify_block_basic(&self, _header: &M::Header) -> Result<(), M::Error> { Ok(()) }
 
-	/// Phase 3 verification. Check block information against parent and uncles. `block` (the header's full block)
-	/// may be provided for additional checks. Returns either a null `Ok` or a general error detailing the problem with import.
-	fn verify_block_family(&self, _header: &Header, _parent: &Header, _block: Option<&[u8]>) -> Result<(), Error> { Ok(()) }
+	/// Phase 2 verification. Perform costly checks such as transaction signatures. Returns either a null `Ok` or a general error detailing the problem with import.
+	fn verify_block_unordered(&self, _header: &M::Header) -> Result<(), M::Error> { Ok(()) }
+
+	/// Phase 3 verification. Check block information against parent. Returns either a null `Ok` or a general error detailing the problem with import.
+	fn verify_block_family(&self, _header: &M::Header, _parent: &M::Header) -> Result<(), Error> { Ok(()) }
 
 	/// Phase 4 verification. Verify block header against potentially external data.
-	fn verify_block_external(&self, _header: &Header, _block: Option<&[u8]>) -> Result<(), Error> { Ok(()) }
-
-	/// Additional verification for transactions in blocks.
-	// TODO: Add flags for which bits of the transaction to check.
-	// TODO: consider including State in the params.
-	fn verify_transaction_basic(&self, t: &UnverifiedTransaction, _header: &Header) -> Result<(), Error> {
-		t.verify_basic(true, Some(self.params().chain_id), true)?;
-		Ok(())
-	}
-
-	/// Verify a particular transaction is valid.
-	fn verify_transaction(&self, t: UnverifiedTransaction, _header: &Header) -> Result<SignedTransaction, Error> {
-		SignedTransaction::new(t)
-	}
-
-	/// The network ID that transactions should be signed with.
-	fn signing_chain_id(&self, _env_info: &EnvInfo) -> Option<u64> {
-		Some(self.params().chain_id)
-	}
-
-	/// Verify the seal of a block. This is an auxilliary method that actually just calls other `verify_` methods
-	/// to get the job done. By default it must pass `verify_basic` and `verify_block_unordered`. If more or fewer
-	/// methods are needed for an Engine, this may be overridden.
-	fn verify_block_seal(&self, header: &Header) -> Result<(), Error> {
-		self.verify_block_basic(header, None).and_then(|_| self.verify_block_unordered(header, None))
-	}
+	/// Should only be called when `register_client` has been called previously.
+	fn verify_block_external(&self, _header: &M::Header) -> Result<(), Error> { Ok(()) }
 
 	/// Genesis epoch data.
-	fn genesis_epoch_data(&self, _header: &Header, _call: &Call) -> Result<Vec<u8>, String> { Ok(Vec::new()) }
+	fn genesis_epoch_data<'a>(&self, _header: &M::Header, _state: &<M as Localized<'a>>::StateContext) -> Result<Vec<u8>, String> { Ok(Vec::new()) }
 
 	/// Whether an epoch change is signalled at the given header but will require finality.
 	/// If a change can be enacted immediately then return `No` from this function but
 	/// `Yes` from `is_epoch_end`.
 	///
-	/// If the block or receipts are required, return `Unsure` and the function will be
+	/// If auxiliary data of the block is required, return an auxiliary request and the function will be
 	/// called again with them.
 	/// Return `Yes` or `No` when the answer is definitively known.
 	///
 	/// Should not interact with state.
-	fn signals_epoch_end(&self, _header: &Header, _block: Option<&[u8]>, _receipts: Option<&[Receipt]>)
-		-> EpochChange
+	fn signals_epoch_end<'a>(&self, _header: &M::Header, _aux: <M as Localized<'a>>::AuxiliaryData)
+		-> EpochChange<M>
 	{
 		EpochChange::No
 	}
@@ -326,8 +282,8 @@ pub trait Engine : Sync + Send {
 	/// Return optional transition proof.
 	fn is_epoch_end(
 		&self,
-		_chain_head: &Header,
-		_chain: &Headers,
+		_chain_head: &M::Header,
+		_chain: &Headers<M::Header>,
 		_transition_store: &PendingTransitionStore,
 	) -> Option<Vec<u8>> {
 		None
@@ -335,35 +291,21 @@ pub trait Engine : Sync + Send {
 
 	/// Create an epoch verifier from validation proof and a flag indicating
 	/// whether finality is required.
-	fn epoch_verifier<'a>(&self, _header: &Header, _proof: &'a [u8]) -> ConstructedVerifier<'a> {
+	fn epoch_verifier<'a>(&self, _header: &M::Header, _proof: &'a [u8]) -> ConstructedVerifier<'a, M> {
 		ConstructedVerifier::Trusted(Box::new(self::epoch::NoOp))
 	}
 
 	/// Populate a header's fields based on its parent's header.
 	/// Usually implements the chain scoring rule based on weight.
-	/// The gas floor target must not be lower than the engine's minimum gas limit.
-	fn populate_from_parent(&self, header: &mut Header, parent: &Header, _gas_floor_target: U256, _gas_ceil_target: U256) {
-		header.set_difficulty(parent.difficulty().clone());
-		header.set_gas_limit(parent.gas_limit().clone());
-	}
+	fn populate_from_parent(&self, _header: &mut M::Header, _parent: &M::Header) { }
 
 	/// Handle any potential consensus messages;
 	/// updating consensus state and potentially issuing a new one.
-	fn handle_message(&self, _message: &[u8]) -> Result<(), Error> { Err(EngineError::UnexpectedMessage.into()) }
-
-	/// Attempt to get a handle to a built-in contract.
-	/// Only returns references to activated built-ins.
-	// TODO: builtin contract routing - to do this properly, it will require removing the built-in configuration-reading logic
-	// from Spec into here and removing the Spec::builtins field.
-	fn builtin(&self, a: &Address, block_number: ::header::BlockNumber) -> Option<&Builtin> {
-		self.builtins()
-			.get(a)
-			.and_then(|b| if b.is_active(block_number) { Some(b) } else { None })
-	}
+	fn handle_message(&self, _message: &[u8]) -> Result<(), EngineError> { Err(EngineError::UnexpectedMessage) }
 
 	/// Find out if the block is a proposal block and should not be inserted into the DB.
 	/// Takes a header of a fully verified block.
-	fn is_proposal(&self, _verified_header: &Header) -> bool { false }
+	fn is_proposal(&self, _verified_header: &M::Header) -> bool { false }
 
 	/// Register an account which signs consensus messages.
 	fn set_signer(&self, _account_provider: Arc<AccountProvider>, _address: Address, _password: String) {}
@@ -371,8 +313,8 @@ pub trait Engine : Sync + Send {
 	/// Sign using the EngineSigner, to be used for consensus tx signing.
 	fn sign(&self, _hash: H256) -> Result<Signature, Error> { unimplemented!() }
 
-	/// Add Client which can be used for sealing, querying the state and sending messages.
-	fn register_client(&self, _client: Weak<EngineClient>) {}
+	/// Add Client which can be used for sealing, potentially querying the state and sending messages.
+	fn register_client(&self, _client: Weak<M::EngineClient>) {}
 
 	/// Trigger next step of the consensus engine.
 	fn step(&self) {}
@@ -390,118 +332,96 @@ pub trait Engine : Sync + Send {
 	fn supports_warp(&self) -> bool {
 		self.snapshot_components().is_some()
 	}
+}
 
-	/// If this engine supports wasm contracts.
-	fn supports_wasm(&self) -> bool {
-		self.params().wasm
+/// Common type alias for an engine coupled with an Ethereum-like state machine.
+// TODO: make this a _trait_ alias when those exist.
+// fortunately the effect is largely the same since engines are mostly used
+// via trait objects.
+pub trait EthEngine: Engine<::machine::EthereumMachine> {
+	/// Get the general parameters of the chain.
+	fn params(&self) -> &CommonParams {
+		self.machine().params()
+	}
+
+	/// Get the EVM schedule for the given block number.
+	fn schedule(&self, block_number: BlockNumber) -> Schedule {
+		self.machine().schedule(block_number)
+	}
+
+	/// Builtin-contracts for the chain..
+	fn builtins(&self) -> &BTreeMap<Address, Builtin> {
+		self.machine().builtins()
+	}
+
+	/// Attempt to get a handle to a built-in contract.
+	/// Only returns references to activated built-ins.
+	fn builtin(&self, a: &Address, block_number: BlockNumber) -> Option<&Builtin> {
+		self.machine().builtin(a, block_number)
+	}
+
+	/// Some intrinsic operation parameters; by default they take their value from the `spec()`'s `engine_params`.
+	fn maximum_extra_data_size(&self) -> usize {
+		self.machine().maximum_extra_data_size()
+	}
+
+	/// The nonce with which accounts begin at given block.
+	fn account_start_nonce(&self, block: u64) -> U256 {
+		self.machine().account_start_nonce(block)
+	}
+
+	/// The network ID that transactions should be signed with.
+	fn signing_chain_id(&self, env_info: &EnvInfo) -> Option<u64> {
+		self.machine().signing_chain_id(env_info)
 	}
 
 	/// Returns new contract address generation scheme at given block number.
 	fn create_address_scheme(&self, number: BlockNumber) -> CreateContractAddress {
-		if number >= self.params().eip86_transition {
-			CreateContractAddress::FromCodeHash
-		} else {
-			CreateContractAddress::FromSenderAndNonce
-		}
+		self.machine().create_address_scheme(number)
+	}
+
+	/// Verify a particular transaction is valid.
+	fn verify_transaction_unordered(&self, t: UnverifiedTransaction, header: &Header) -> Result<SignedTransaction, Error> {
+		self.machine().verify_transaction_unordered(t, header)
+	}
+
+	/// Additional verification for transactions in blocks.
+	// TODO: Add flags for which bits of the transaction to check.
+	// TODO: consider including State in the params.
+	fn verify_transaction_basic(&self, t: &UnverifiedTransaction, header: &Header) -> Result<(), Error> {
+		self.machine().verify_transaction_basic(t, header)
+	}
+
+	/// If this machine supports wasm.
+	fn supports_wasm(&self) -> bool {
+		self.machine().supports_wasm()
 	}
 }
 
+// convenience wrappers for existing functions.
+impl<T> EthEngine for T where T: Engine<::machine::EthereumMachine> { }
+
 /// Common engine utilities
 pub mod common {
-	use std::sync::Arc;
 	use block::ExecutedBlock;
 	use error::Error;
-	use transaction::SYSTEM_ADDRESS;
-	use executive::Executive;
-	use vm::{CallType, ActionParams, ActionValue, EnvInfo, LastHashes};
-	use trace::{NoopTracer, NoopVMTracer, Tracer, ExecutiveTracer, RewardType};
-	use state::Substate;
+	use trace::{Tracer, ExecutiveTracer, RewardType};
 	use state::CleanupMode;
 
 	use bigint::prelude::U256;
-	use bigint::hash::H256;
-	use util::*;
-	use bytes::{Bytes, BytesRef};
-	use super::Engine;
 
-	/// Execute a call as the system address.
-	pub fn execute_as_system<E: Engine + ?Sized>(
-		block: &mut ExecutedBlock,
-		last_hashes: Arc<LastHashes>,
-		engine: &E,
-		contract_address: Address,
-		gas: U256,
-		data: Option<Bytes>,
-	) -> Result<Bytes, Error> {
-		let env_info = {
-			let header = block.fields().header;
-			EnvInfo {
-				number: header.number(),
-				author: header.author().clone(),
-				timestamp: header.timestamp(),
-				difficulty: header.difficulty().clone(),
-				last_hashes: last_hashes,
-				gas_used: U256::zero(),
-				gas_limit: gas,
-			}
-		};
-
-		let mut state = block.fields_mut().state;
-		let params = ActionParams {
-			code_address: contract_address.clone(),
-			address: contract_address.clone(),
-			sender: SYSTEM_ADDRESS.clone(),
-			origin: SYSTEM_ADDRESS.clone(),
-			gas: gas,
-			gas_price: 0.into(),
-			value: ActionValue::Transfer(0.into()),
-			code: state.code(&contract_address)?,
-			code_hash: Some(state.code_hash(&contract_address)?),
-			data: data,
-			call_type: CallType::Call,
-		};
-		let mut ex = Executive::new(&mut state, &env_info, engine);
-		let mut substate = Substate::new();
-		let mut output = Vec::new();
-		if let Err(e) = ex.call(params, &mut substate, BytesRef::Flexible(&mut output), &mut NoopTracer, &mut NoopVMTracer) {
-			warn!("Encountered error on making system call: {}", e);
-		}
-
-		Ok(output)
-	}
-
-	/// Push last known block hash to the state.
-	pub fn push_last_hash<E: Engine + ?Sized>(block: &mut ExecutedBlock, last_hashes: Arc<LastHashes>, engine: &E, hash: &H256) -> Result<(), Error> {
-		if block.fields().header.number() == engine.params().eip210_transition {
-			let state = block.fields_mut().state;
-			state.init_code(&engine.params().eip210_contract_address, engine.params().eip210_contract_code.clone())?;
-		}
-		if block.fields().header.number() >= engine.params().eip210_transition {
-			let _ = execute_as_system(
-				block,
-				last_hashes,
-				engine,
-				engine.params().eip210_contract_address,
-				engine.params().eip210_contract_gas,
-				Some(hash.to_vec()),
-			)?;
-		}
-		Ok(())
-	}
-
-	/// Trace rewards on closing block
-	pub fn bestow_block_reward<E: Engine + ?Sized>(block: &mut ExecutedBlock, engine: &E) -> Result<(), Error> {
+	/// Give reward and trace.
+	pub fn bestow_block_reward(block: &mut ExecutedBlock, reward: U256) -> Result<(), Error> {
 		let fields = block.fields_mut();
 		// Bestow block reward
-		let reward = engine.params().block_reward;
 		let res = fields.state.add_balance(fields.header.author(), &reward, CleanupMode::NoEmpty)
 			.map_err(::error::Error::from)
 			.and_then(|_| fields.state.commit());
 
 		let block_author = fields.header.author().clone();
-		fields.traces.as_mut().map(|mut traces| {
+		fields.traces.as_mut().map(move |mut traces| {
   			let mut tracer = ExecutiveTracer::default();
-  			tracer.trace_reward(block_author, engine.params().block_reward, RewardType::Block);
+  			tracer.trace_reward(block_author, reward, RewardType::Block);
   			traces.push(tracer.drain())
 		});
 

ethcore/src/engines/null_engine.rs

@@ -14,103 +14,92 @@
 // You should have received a copy of the GNU General Public License
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
-use std::collections::BTreeMap;
-use util::Address;
-use builtin::Builtin;
-use block::{ExecutedBlock, IsBlock};
 use bigint::prelude::U256;
 use engines::Engine;
-use spec::CommonParams;
-use evm::Schedule;
-use header::BlockNumber;
-use error::Error;
-use state::CleanupMode;
-use trace::{Tracer, ExecutiveTracer, RewardType};
+use parity_machine::{Header, LiveBlock, WithBalances};
 
-/// An engine which does not provide any consensus mechanism and does not seal blocks.
-pub struct NullEngine {
-	params: CommonParams,
-	builtins: BTreeMap<Address, Builtin>,
+/// Params for a null engine.
+#[derive(Clone, Default)]
+pub struct NullEngineParams {
+	/// base reward for a block.
+	pub block_reward: U256,
 }
 
-impl NullEngine {
+impl From<::ethjson::spec::NullEngineParams> for NullEngineParams {
+	fn from(p: ::ethjson::spec::NullEngineParams) -> Self {
+		NullEngineParams {
+			block_reward: p.block_reward.map_or_else(Default::default, Into::into),
+		}
+	}
+}
+
+/// An engine which does not provide any consensus mechanism and does not seal blocks.
+pub struct NullEngine<M> {
+	params: NullEngineParams,
+	machine: M,
+}
+
+impl<M> NullEngine<M> {
 	/// Returns new instance of NullEngine with default VM Factory
-	pub fn new(params: CommonParams, builtins: BTreeMap<Address, Builtin>) -> Self {
+	pub fn new(params: NullEngineParams, machine: M) -> Self {
 		NullEngine {
 			params: params,
-			builtins: builtins,
+			machine: machine,
 		}
 	}
 }
 
-impl Default for NullEngine {
+impl<M: Default> Default for NullEngine<M> {
 	fn default() -> Self {
 		Self::new(Default::default(), Default::default())
 	}
 }
 
-impl Engine for NullEngine {
+impl<M: WithBalances> Engine<M> for NullEngine<M> {
 	fn name(&self) -> &str {
 		"NullEngine"
 	}
 
-	fn params(&self) -> &CommonParams {
-		&self.params
+	fn machine(&self) -> &M { &self.machine }
+
+	fn on_close_block(&self, block: &mut M::LiveBlock) -> Result<(), M::Error> {
+		use std::ops::Shr;
+
+		let author = *LiveBlock::header(&*block).author();
+		let number = LiveBlock::header(&*block).number();
+
+		let reward = self.params.block_reward;
+		if reward == U256::zero() { return Ok(()) }
+
+		let n_uncles = LiveBlock::uncles(&*block).len();
+
+		// Bestow block reward
+		let result_block_reward = reward + reward.shr(5) * U256::from(n_uncles);
+		let mut uncle_rewards = Vec::with_capacity(n_uncles);
+
+		self.machine.add_balance(block, &author, &result_block_reward)?;
+
+		// bestow uncle rewards.
+		for u in LiveBlock::uncles(&*block) {
+			let uncle_author = u.author();
+			let result_uncle_reward = (reward * U256::from(8 + u.number() - number)).shr(3);
+
+			uncle_rewards.push((*uncle_author, result_uncle_reward));
 		}
 
-	fn builtins(&self) -> &BTreeMap<Address, Builtin> {
-		&self.builtins
+		for &(ref a, ref reward) in &uncle_rewards {
+			self.machine.add_balance(block, a, reward)?;
 		}
 
-	fn schedule(&self, _block_number: BlockNumber) -> Schedule {
-		Schedule::new_homestead()
+		// note and trace.
+		self.machine.note_rewards(block, &[(author, result_block_reward)], &uncle_rewards)
+	}
+
+	fn verify_local_seal(&self, _header: &M::Header) -> Result<(), M::Error> {
+		Ok(())
 	}
 
 	fn snapshot_components(&self) -> Option<Box<::snapshot::SnapshotComponents>> {
 		Some(Box::new(::snapshot::PowSnapshot::new(10000, 10000)))
 	}
-
-	fn on_close_block(&self, block: &mut ExecutedBlock) -> Result<(), Error> {
-		if self.params.block_reward == U256::zero() {
-			// we don't have to apply reward in this case
-			return Ok(())
-		}
-
-		/// Block reward
-		let tracing_enabled = block.tracing_enabled();
-		let fields = block.fields_mut();
-		let mut tracer = ExecutiveTracer::default();
-
-		let result_block_reward = U256::from(1000000000);
-		fields.state.add_balance(
-			fields.header.author(),
-			&result_block_reward,
-			CleanupMode::NoEmpty
-		)?;
-
-		if tracing_enabled {
-			let block_author = fields.header.author().clone();
-			tracer.trace_reward(block_author, result_block_reward, RewardType::Block);
-		}
-
-		/// Uncle rewards
-		let result_uncle_reward = U256::from(10000000);
-		for u in fields.uncles.iter() {
-			let uncle_author = u.author().clone();
-			fields.state.add_balance(
-				u.author(),
-				&(result_uncle_reward),
-				CleanupMode::NoEmpty
-			)?;
-			if tracing_enabled {
-				tracer.trace_reward(uncle_author, result_uncle_reward, RewardType::Uncle);
-			}
-		}
-
-		fields.state.commit()?;
-		if tracing_enabled {
-			fields.traces.as_mut().map(|mut traces| traces.push(tracer.drain()));
-		}
-		Ok(())
-	}
 }

ethcore/src/engines/tendermint/mod.rs

@@ -27,9 +27,8 @@ mod params;
 
 use std::sync::{Weak, Arc};
 use std::sync::atomic::{AtomicUsize, Ordering as AtomicOrdering};
-use std::collections::{HashSet, BTreeMap, HashMap};
+use std::collections::{HashSet, BTreeMap};
 use hash::keccak;
-use std::cmp;
 use bigint::prelude::{U128, U256};
 use bigint::hash::{H256, H520};
 use parking_lot::RwLock;
@@ -39,12 +38,10 @@ use client::EngineClient;
 use bytes::Bytes;
 use error::{Error, BlockError};
 use header::{Header, BlockNumber};
-use builtin::Builtin;
 use rlp::UntrustedRlp;
 use ethkey::{Message, public_to_address, recover, Signature};
 use account_provider::AccountProvider;
 use block::*;
-use spec::CommonParams;
 use engines::{Engine, Seal, EngineError, ConstructedVerifier};
 use io::IoService;
 use super::signer::EngineSigner;
@@ -54,6 +51,7 @@ use super::vote_collector::VoteCollector;
 use self::message::*;
 use self::params::TendermintParams;
 use semantic_version::SemanticVersion;
+use machine::{AuxiliaryData, EthereumMachine};
 
 #[derive(Debug, PartialEq, Eq, Clone, Copy, Hash)]
 pub enum Step {
@@ -78,8 +76,6 @@ pub type BlockHash = H256;
 
 /// Engine using `Tendermint` consensus algorithm, suitable for EVM chain.
 pub struct Tendermint {
-	params: CommonParams,
-	builtins: BTreeMap<Address, Builtin>,
 	step_service: IoService<Step>,
 	client: RwLock<Option<Weak<EngineClient>>>,
 	/// Blockchain height.
@@ -104,6 +100,10 @@ pub struct Tendermint {
 	last_proposed: RwLock<H256>,
 	/// Set used to determine the current validators.
 	validators: Box<ValidatorSet>,
+	/// Reward per block, in base units.
+	block_reward: U256,
+	/// ethereum machine descriptor
+	machine: EthereumMachine,
 }
 
 struct EpochVerifier<F>
@@ -113,7 +113,7 @@ struct EpochVerifier<F>
 	recover: F
 }
 
-impl <F> super::EpochVerifier for EpochVerifier<F>
+impl <F> super::EpochVerifier<EthereumMachine> for EpochVerifier<F>
 	where F: Fn(&Signature, &Message) -> Result<Address, Error> + Send + Sync
 {
 	fn verify_light(&self, header: &Header) -> Result<(), Error> {
@@ -167,11 +167,9 @@ fn destructure_proofs(combined: &[u8]) -> Result<(BlockNumber, &[u8], &[u8]), Er
 
 impl Tendermint {
 	/// Create a new instance of Tendermint engine
-	pub fn new(params: CommonParams, our_params: TendermintParams, builtins: BTreeMap<Address, Builtin>) -> Result<Arc<Self>, Error> {
+	pub fn new(our_params: TendermintParams, machine: EthereumMachine) -> Result<Arc<Self>, Error> {
 		let engine = Arc::new(
 			Tendermint {
-				params: params,
-				builtins: builtins,
 				client: RwLock::new(None),
 				step_service: IoService::<Step>::start()?,
 				height: AtomicUsize::new(1),
@@ -185,9 +183,13 @@ impl Tendermint {
 				proposal_parent: Default::default(),
 				last_proposed: Default::default(),
 				validators: our_params.validators,
+				block_reward: our_params.block_reward,
+				machine: machine,
 			});
-		let handler = TransitionHandler::new(Arc::downgrade(&engine) as Weak<Engine>, Box::new(our_params.timeouts));
+
+		let handler = TransitionHandler::new(Arc::downgrade(&engine) as Weak<Engine<_>>, Box::new(our_params.timeouts));
 		engine.step_service.register_handler(Arc::new(handler))?;
+
 		Ok(engine)
 	}
 
@@ -438,7 +440,7 @@ impl Tendermint {
 	}
 }
 
-impl Engine for Tendermint {
+impl Engine<EthereumMachine> for Tendermint {
 	fn name(&self) -> &str { "Tendermint" }
 
 	fn version(&self) -> SemanticVersion { SemanticVersion::new(1, 0, 0) }
@@ -446,13 +448,7 @@ impl Engine for Tendermint {
 	/// (consensus view, proposal signature, authority signatures)
 	fn seal_fields(&self) -> usize { 3 }
 
-	fn params(&self) -> &CommonParams { &self.params }
-
-	fn additional_params(&self) -> HashMap<String, String> {
-		hash_map!["registrar".to_owned() => self.params().registrar.hex()]
-	}
-
-	fn builtins(&self) -> &BTreeMap<Address, Builtin> { &self.builtins }
+	fn machine(&self) -> &EthereumMachine { &self.machine }
 
 	fn maximum_uncle_count(&self) -> usize { 0 }
 
@@ -469,19 +465,13 @@ impl Engine for Tendermint {
 		]
 	}
 
-	fn populate_from_parent(&self, header: &mut Header, parent: &Header, gas_floor_target: U256, _gas_ceil_target: U256) {
+	fn populate_from_parent(&self, header: &mut Header, parent: &Header) {
 		// Chain scoring: total weight is sqrt(U256::max_value())*height - view
-		let new_difficulty = U256::from(U128::max_value()) + consensus_view(parent).expect("Header has been verified; qed").into() - self.view.load(AtomicOrdering::SeqCst).into();
+		let new_difficulty = U256::from(U128::max_value())
+			+ consensus_view(parent).expect("Header has been verified; qed").into()
+			- self.view.load(AtomicOrdering::SeqCst).into();
+
 		header.set_difficulty(new_difficulty);
-		header.set_gas_limit({
-			let gas_limit = parent.gas_limit().clone();
-			let bound_divisor = self.params().gas_limit_bound_divisor;
-			if gas_limit < gas_floor_target {
-				cmp::min(gas_floor_target, gas_limit + gas_limit / bound_divisor - 1.into())
-			} else {
-				cmp::max(gas_floor_target, gas_limit - gas_limit / bound_divisor + 1.into())
-			}
-		});
 	}
 
 	/// Should this node participate.
@@ -525,19 +515,27 @@ impl Engine for Tendermint {
 		}
 	}
 
-	fn handle_message(&self, rlp: &[u8]) -> Result<(), Error> {
+	fn handle_message(&self, rlp: &[u8]) -> Result<(), EngineError> {
+		fn fmt_err<T: ::std::fmt::Debug>(x: T) -> EngineError {
+			EngineError::MalformedMessage(format!("{:?}", x))
+		}
+
 		let rlp = UntrustedRlp::new(rlp);
-		let message: ConsensusMessage = rlp.as_val()?;
+		let message: ConsensusMessage = rlp.as_val().map_err(fmt_err)?;
 		if !self.votes.is_old_or_known(&message) {
-			let sender = public_to_address(&recover(&message.signature.into(), &keccak(rlp.at(1)?.as_raw()))?);
+			let msg_hash = keccak(rlp.at(1).map_err(fmt_err)?.as_raw());
+			let sender = public_to_address(
+				&recover(&message.signature.into(), &msg_hash).map_err(fmt_err)?
+			);
+
 			if !self.is_authority(&sender) {
-				return Err(EngineError::NotAuthorized(sender).into());
+				return Err(EngineError::NotAuthorized(sender));
 			}
 			self.broadcast_message(rlp.as_raw().to_vec());
 			if let Some(double) = self.votes.vote(message.clone(), &sender) {
 				let height = message.vote_step.height as BlockNumber;
 				self.validators.report_malicious(&sender, height, height, ::rlp::encode(&double).into_vec());
-				return Err(EngineError::DoubleVote(sender).into());
+				return Err(EngineError::DoubleVote(sender));
 			}
 			trace!(target: "engine", "Handling a valid {:?} from {}.", message, sender);
 			self.handle_valid_message(&message);
@@ -545,12 +543,37 @@ impl Engine for Tendermint {
 		Ok(())
 	}
 
-	/// Apply the block reward on finalisation of the block.
-	fn on_close_block(&self, block: &mut ExecutedBlock) -> Result<(), Error>{
-		::engines::common::bestow_block_reward(block, self)
+	fn on_new_block(&self, block: &mut ExecutedBlock, epoch_begin: bool) -> Result<(), Error> {
+		if !epoch_begin { return Ok(()) }
+
+		// genesis is never a new block, but might as well check.
+		let header = block.fields().header.clone();
+		let first = header.number() == 0;
+
+		let mut call = |to, data| {
+			let result = self.machine.execute_as_system(
+				block,
+				to,
+				U256::max_value(), // unbounded gas? maybe make configurable.
+				Some(data),
+			);
+
+			result.map_err(|e| format!("{}", e))
+		};
+
+		self.validators.on_epoch_begin(first, &header, &mut call)
 	}
 
-	fn verify_block_basic(&self, header: &Header, _block: Option<&[u8]>) -> Result<(), Error> {
+	/// Apply the block reward on finalisation of the block.
+	fn on_close_block(&self, block: &mut ExecutedBlock) -> Result<(), Error>{
+		::engines::common::bestow_block_reward(block, self.block_reward)
+	}
+
+	fn verify_local_seal(&self, _header: &Header) -> Result<(), Error> {
+		Ok(())
+	}
+
+	fn verify_block_basic(&self, header: &Header) -> Result<(), Error> {
 		let seal_length = header.seal().len();
 		if seal_length == self.seal_fields() {
 			// Either proposal or commit.
@@ -568,28 +591,7 @@ impl Engine for Tendermint {
 		}
 	}
 
-	fn verify_block_unordered(&self, _header: &Header, _block: Option<&[u8]>) -> Result<(), Error> {
-		Ok(())
-	}
-
-	/// Verify gas limit.
-	fn verify_block_family(&self, header: &Header, parent: &Header, _block: Option<&[u8]>) -> Result<(), Error> {
-		if header.number() == 0 {
-			return Err(BlockError::RidiculousNumber(OutOfBounds { min: Some(1), max: None, found: header.number() }).into());
-		}
-
-		let gas_limit_divisor = self.params().gas_limit_bound_divisor;
-		let min_gas = parent.gas_limit().clone() - parent.gas_limit().clone() / gas_limit_divisor;
-		let max_gas = parent.gas_limit().clone() + parent.gas_limit().clone() / gas_limit_divisor;
-		if header.gas_limit() <= &min_gas || header.gas_limit() >= &max_gas {
-			self.validators.report_malicious(header.author(), header.number(), header.number(), Default::default());
-			return Err(BlockError::InvalidGasLimit(OutOfBounds { min: Some(min_gas), max: Some(max_gas), found: header.gas_limit().clone() }).into());
-		}
-
-		Ok(())
-	}
-
-	fn verify_block_external(&self, header: &Header, _block: Option<&[u8]>) -> Result<(), Error> {
+	fn verify_block_external(&self, header: &Header) -> Result<(), Error> {
 		if let Ok(proposal) = ConsensusMessage::new_proposal(header) {
 			let proposer = proposal.verify()?;
 			if !self.is_authority(&proposer) {
@@ -630,17 +632,17 @@ impl Engine for Tendermint {
 		}
 	}
 
-	fn signals_epoch_end(&self, header: &Header, block: Option<&[u8]>, receipts: Option<&[::receipt::Receipt]>)
-		-> super::EpochChange
+	fn signals_epoch_end(&self, header: &Header, aux: AuxiliaryData)
+		-> super::EpochChange<EthereumMachine>
 	{
 		let first = header.number() == 0;
-		self.validators.signals_epoch_end(first, header, block, receipts)
+		self.validators.signals_epoch_end(first, header, aux)
 	}
 
 	fn is_epoch_end(
 		&self,
 		chain_head: &Header,
-		_chain: &super::Headers,
+		_chain: &super::Headers<Header>,
 		transition_store: &super::PendingTransitionStore,
 	) -> Option<Vec<u8>> {
 		let first = chain_head.number() == 0;
@@ -657,14 +659,14 @@ impl Engine for Tendermint {
 		None
 	}
 
-	fn epoch_verifier<'a>(&self, _header: &Header, proof: &'a [u8]) -> ConstructedVerifier<'a> {
+	fn epoch_verifier<'a>(&self, _header: &Header, proof: &'a [u8]) -> ConstructedVerifier<'a, EthereumMachine> {
 		let (signal_number, set_proof, finality_proof) = match destructure_proofs(proof) {
 			Ok(x) => x,
 			Err(e) => return ConstructedVerifier::Err(e),
 		};
 
 		let first = signal_number == 0;
-		match self.validators.epoch_set(first, self, signal_number, set_proof) {
+		match self.validators.epoch_set(first, &self.machine, signal_number, set_proof) {
 			Ok((list, finalize)) => {
 				let verifier = Box::new(EpochVerifier {
 					subchain_validators: list,
@@ -785,7 +787,7 @@ mod tests {
 	use tests::helpers::*;
 	use account_provider::AccountProvider;
 	use spec::Spec;
-	use engines::{Engine, EngineError, Seal};
+	use engines::{EthEngine, EngineError, Seal};
 	use engines::epoch::EpochVerifier;
 	use super::*;
 
@@ -810,7 +812,7 @@ mod tests {
 		}
 	}
 
-	fn vote<F>(engine: &Engine, signer: F, height: usize, view: usize, step: Step, block_hash: Option<H256>) -> Bytes where F: FnOnce(H256) -> Result<H520, ::account_provider::SignError> {
+	fn vote<F>(engine: &EthEngine, signer: F, height: usize, view: usize, step: Step, block_hash: Option<H256>) -> Bytes where F: FnOnce(H256) -> Result<H520, ::account_provider::SignError> {
 		let mi = message_info_rlp(&VoteStep::new(height, view, step), block_hash);
 		let m = message_full_rlp(&signer(keccak(&mi)).unwrap().into(), &mi);
 		engine.handle_message(&m).unwrap();
@@ -834,7 +836,7 @@ mod tests {
 		addr
 	}
 
-	fn insert_and_register(tap: &Arc<AccountProvider>, engine: &Engine, acc: &str) -> Address {
+	fn insert_and_register(tap: &Arc<AccountProvider>, engine: &EthEngine, acc: &str) -> Address {
 		let addr = insert_and_unlock(tap, acc);
 		engine.set_signer(tap.clone(), addr.clone(), acc.into());
 		addr
@@ -871,7 +873,7 @@ mod tests {
 		let engine = Spec::new_test_tendermint().engine;
 		let header = Header::default();
 
-		let verify_result = engine.verify_block_basic(&header, None);
+		let verify_result = engine.verify_block_basic(&header);
 
 		match verify_result {
 			Err(Error::Block(BlockError::InvalidSealArity(_))) => {},
@@ -896,14 +898,14 @@ mod tests {
 		let seal = proposal_seal(&tap, &header, 0);
 		header.set_seal(seal);
 		// Good proposer.
-		assert!(engine.verify_block_external(&header, None).is_ok());
+		assert!(engine.verify_block_external(&header).is_ok());
 
 		let validator = insert_and_unlock(&tap, "0");
 		header.set_author(validator);
 		let seal = proposal_seal(&tap, &header, 0);
 		header.set_seal(seal);
 		// Bad proposer.
-		match engine.verify_block_external(&header, None) {
+		match engine.verify_block_external(&header) {
 			Err(Error::Engine(EngineError::NotProposer(_))) => {},
 			_ => panic!(),
 		}
@@ -913,7 +915,7 @@ mod tests {
 		let seal = proposal_seal(&tap, &header, 0);
 		header.set_seal(seal);
 		// Not authority.
-		match engine.verify_block_external(&header, None) {
+		match engine.verify_block_external(&header) {
 			Err(Error::Engine(EngineError::NotAuthorized(_))) => {},
 			_ => panic!(),
 		};
@@ -943,7 +945,7 @@ mod tests {
 		header.set_seal(seal.clone());
 
 		// One good signature is not enough.
-		match engine.verify_block_external(&header, None) {
+		match engine.verify_block_external(&header) {
 			Err(Error::Engine(EngineError::BadSealFieldSize(_))) => {},
 			_ => panic!(),
 		}
@@ -954,7 +956,7 @@ mod tests {
 		seal[2] = ::rlp::encode_list(&vec![H520::from(signature1.clone()), H520::from(signature0.clone())]).into_vec();
 		header.set_seal(seal.clone());
 
-		assert!(engine.verify_block_external(&header, None).is_ok());
+		assert!(engine.verify_block_external(&header).is_ok());
 
 		let bad_voter = insert_and_unlock(&tap, "101");
 		let bad_signature = tap.sign(bad_voter, None, keccak(vote_info)).unwrap();
@@ -963,7 +965,7 @@ mod tests {
 		header.set_seal(seal);
 
 		// One good and one bad signature.
-		match engine.verify_block_external(&header, None) {
+		match engine.verify_block_external(&header) {
 			Err(Error::Engine(EngineError::NotAuthorized(_))) => {},
 			_ => panic!(),
 		};

ethcore/src/engines/tendermint/params.rs

@@ -18,6 +18,7 @@
 
 use ethjson;
 use time::Duration;
+use bigint::prelude::U256;
 use super::super::validator_set::{ValidatorSet, new_validator_set};
 use super::super::transition::Timeouts;
 use super::Step;
@@ -28,6 +29,8 @@ pub struct TendermintParams {
 	pub validators: Box<ValidatorSet>,
 	/// Timeout durations for different steps.
 	pub timeouts: TendermintTimeouts,
+	/// Reward per block in base units.
+	pub block_reward: U256,
 }
 
 /// Base timeout of each step in ms.
@@ -81,6 +84,7 @@ impl From<ethjson::spec::TendermintParams> for TendermintParams {
 				precommit: p.timeout_precommit.map_or(dt.precommit, to_duration),
 				commit: p.timeout_commit.map_or(dt.commit, to_duration),
 			},
+			block_reward: p.block_reward.map_or(U256::default(), Into::into),
 		}
 	}
 }

ethcore/src/engines/transition.rs

@@ -20,6 +20,7 @@ use std::sync::Weak;
 use time::Duration;
 use io::{IoContext, IoHandler, TimerToken};
 use engines::Engine;
+use parity_machine::Machine;
 
 /// Timeouts lookup
 pub trait Timeouts<S: Sync + Send + Clone>: Send + Sync {
@@ -31,14 +32,14 @@ pub trait Timeouts<S: Sync + Send + Clone>: Send + Sync {
 }
 
 /// Timeout transition handling.
-pub struct TransitionHandler<S: Sync + Send + Clone>  {
-	engine: Weak<Engine>,
+pub struct TransitionHandler<S: Sync + Send + Clone, M: Machine>  {
+	engine: Weak<Engine<M>>,
 	timeouts: Box<Timeouts<S>>,
 }
 
-impl<S> TransitionHandler<S> where S: Sync + Send + Clone {
+impl<S, M: Machine> TransitionHandler<S, M> where S: Sync + Send + Clone {
 	/// New step caller by timeouts.
-	pub fn new(engine: Weak<Engine>, timeouts: Box<Timeouts<S>>) -> Self {
+	pub fn new(engine: Weak<Engine<M>>, timeouts: Box<Timeouts<S>>) -> Self {
 		TransitionHandler {
 			engine: engine,
 			timeouts: timeouts,
@@ -54,7 +55,9 @@ fn set_timeout<S: Sync + Send + Clone>(io: &IoContext<S>, timeout: Duration) {
 		.unwrap_or_else(|e| warn!(target: "engine", "Failed to set consensus step timeout: {}.", e))
 }
 
-impl<S> IoHandler<S> for TransitionHandler<S> where S: Sync + Send + Clone + 'static {
+impl<S, M> IoHandler<S> for TransitionHandler<S, M>
+	where S: Sync + Send + Clone + 'static, M: Machine
+{
 	fn initialize(&self, io: &IoContext<S>) {
 		let initial = self.timeouts.initial();
 		trace!(target: "engine", "Setting the initial timeout to {}.", initial);

ethcore/src/engines/validator_set/contract.rs

@@ -27,8 +27,8 @@ use futures::Future;
 use native_contracts::ValidatorReport as Provider;
 
 use client::EngineClient;
-use engines::{Call, Engine};
 use header::{Header, BlockNumber};
+use machine::{AuxiliaryData, Call, EthereumMachine};
 
 use super::{ValidatorSet, SimpleList, SystemCall};
 use super::safe_contract::ValidatorSafeContract;
@@ -91,14 +91,13 @@ impl ValidatorSet for ValidatorContract {
 		&self,
 		first: bool,
 		header: &Header,
-		block: Option<&[u8]>,
-		receipts: Option<&[::receipt::Receipt]>,
-	) -> ::engines::EpochChange {
-		self.validators.signals_epoch_end(first, header, block, receipts)
+		aux: AuxiliaryData,
+	) -> ::engines::EpochChange<EthereumMachine> {
+		self.validators.signals_epoch_end(first, header, aux)
 	}
 
-	fn epoch_set(&self, first: bool, engine: &Engine, number: BlockNumber, proof: &[u8]) -> Result<(SimpleList, Option<H256>), ::error::Error> {
-		self.validators.epoch_set(first, engine, number, proof)
+	fn epoch_set(&self, first: bool, machine: &EthereumMachine, number: BlockNumber, proof: &[u8]) -> Result<(SimpleList, Option<H256>), ::error::Error> {
+		self.validators.epoch_set(first, machine, number, proof)
 	}
 
 	fn contains_with_caller(&self, bh: &H256, address: &Address, caller: &Call) -> bool {
@@ -182,7 +181,7 @@ mod tests {
 		header.set_parent_hash(client.chain_info().best_block_hash);
 
 		// `reportBenign` when the designated proposer releases block from the future (bad clock).
-		assert!(client.engine().verify_block_external(&header, None).is_err());
+		assert!(client.engine().verify_block_external(&header).is_err());
 		// Seal a block.
 		client.engine().step();
 		assert_eq!(client.chain_info().best_block_number, 1);
@@ -190,7 +189,7 @@ mod tests {
 		assert_eq!(client.call_contract(BlockId::Latest, validator_contract, "d8f2e0bf".from_hex().unwrap()).unwrap().to_hex(), "0000000000000000000000007d577a597b2742b498cb5cf0c26cdcd726d39e6e");
 		// Simulate a misbehaving validator by handling a double proposal.
 		let header = client.best_block_header().decode();
-		assert!(client.engine().verify_block_family(&header, &header, None).is_err());
+		assert!(client.engine().verify_block_family(&header, &header).is_err());
 		// Seal a block.
 		client.engine().step();
 		client.engine().step();

ethcore/src/engines/validator_set/mod.rs

@@ -31,6 +31,7 @@ use bytes::Bytes;
 use ethjson::spec::ValidatorSet as ValidatorSpec;
 use client::EngineClient;
 use header::{Header, BlockNumber};
+use machine::{AuxiliaryData, Call, EthereumMachine};
 
 #[cfg(test)]
 pub use self::test::TestSet;
@@ -39,8 +40,6 @@ use self::contract::ValidatorContract;
 use self::safe_contract::ValidatorSafeContract;
 use self::multi::Multi;
 
-use super::{Call, Engine};
-
 /// A system-calling closure. Enacts calls on a block's state from the system address.
 pub type SystemCall<'a> = FnMut(Address, Bytes) -> Result<Bytes, String> + 'a;
 
@@ -113,9 +112,8 @@ pub trait ValidatorSet: Send + Sync {
 		&self,
 		first: bool,
 		header: &Header,
-		block: Option<&[u8]>,
-		receipts: Option<&[::receipt::Receipt]>,
-	) -> ::engines::EpochChange;
+		aux: AuxiliaryData,
+	) -> ::engines::EpochChange<EthereumMachine>;
 
 	/// Recover the validator set from the given proof, the block number, and
 	/// whether this header is first in its set.
@@ -125,7 +123,7 @@ pub trait ValidatorSet: Send + Sync {
 	///
 	/// Returns the set, along with a flag indicating whether finality of a specific
 	/// hash should be proven.
-	fn epoch_set(&self, first: bool, engine: &Engine, number: BlockNumber, proof: &[u8])
+	fn epoch_set(&self, first: bool, machine: &EthereumMachine, number: BlockNumber, proof: &[u8])
 		-> Result<(SimpleList, Option<H256>), ::error::Error>;
 
 	/// Checks if a given address is a validator, with the given function

ethcore/src/engines/validator_set/multi.rs

@@ -18,7 +18,6 @@
 
 use std::collections::BTreeMap;
 use std::sync::Weak;
-use engines::{Call, Engine};
 use bigint::hash::H256;
 use parking_lot::RwLock;
 use util::Address;
@@ -26,6 +25,7 @@ use bytes::Bytes;
 use ids::BlockId;
 use header::{BlockNumber, Header};
 use client::EngineClient;
+use machine::{AuxiliaryData, Call, EthereumMachine};
 use super::{SystemCall, ValidatorSet};
 
 type BlockNumberLookup = Box<Fn(BlockId) -> Result<BlockNumber, String> + Send + Sync + 'static>;
@@ -93,20 +93,20 @@ impl ValidatorSet for Multi {
 		set.is_epoch_end(first, chain_head)
 	}
 
-	fn signals_epoch_end(&self, _first: bool, header: &Header, block: Option<&[u8]>, receipts: Option<&[::receipt::Receipt]>)
-		-> ::engines::EpochChange
+	fn signals_epoch_end(&self, _first: bool, header: &Header, aux: AuxiliaryData)
+		-> ::engines::EpochChange<EthereumMachine>
 	{
 		let (set_block, set) = self.correct_set_by_number(header.number());
 		let first = set_block == header.number();
 
-		set.signals_epoch_end(first, header, block, receipts)
+		set.signals_epoch_end(first, header, aux)
 	}
 
-	fn epoch_set(&self, _first: bool, engine: &Engine, number: BlockNumber, proof: &[u8]) -> Result<(super::SimpleList, Option<H256>), ::error::Error> {
+	fn epoch_set(&self, _first: bool, machine: &EthereumMachine, number: BlockNumber, proof: &[u8]) -> Result<(super::SimpleList, Option<H256>), ::error::Error> {
 		let (set_block, set) = self.correct_set_by_number(number);
 		let first = set_block == number;
 
-		set.epoch_set(first, engine, number, proof)
+		set.epoch_set(first, machine, number, proof)
 	}
 
 	fn contains_with_caller(&self, bh: &H256, address: &Address, caller: &Call) -> bool {
@@ -227,7 +227,7 @@ mod tests {
 		let mut header = Header::new();
 		header.set_number(499);
 
-		match multi.signals_epoch_end(false, &header, None, None) {
+		match multi.signals_epoch_end(false, &header, Default::default()) {
 			EpochChange::No => {},
 			_ => panic!("Expected no epoch signal change."),
 		}
@@ -235,7 +235,7 @@ mod tests {
 
 		header.set_number(500);
 
-		match multi.signals_epoch_end(false, &header, None, None) {
+		match multi.signals_epoch_end(false, &header, Default::default()) {
 			EpochChange::No => {},
 			_ => panic!("Expected no epoch signal change."),
 		}

ethcore/src/engines/validator_set/safe_contract.rs

@@ -33,7 +33,7 @@ use rlp::{UntrustedRlp, RlpStream};
 
 use basic_types::LogBloom;
 use client::EngineClient;
-use engines::{Call, Engine};
+use machine::{AuxiliaryData, Call, EthereumMachine, AuxiliaryRequest};
 use header::Header;
 use ids::BlockId;
 use log_entry::LogEntry;
@@ -58,19 +58,19 @@ struct StateProof {
 	provider: Provider,
 }
 
-impl ::engines::StateDependentProof for StateProof {
+impl ::engines::StateDependentProof<EthereumMachine> for StateProof {
 	fn generate_proof(&self, caller: &Call) -> Result<Vec<u8>, String> {
 		prove_initial(&self.provider, &*self.header.lock(), caller)
 	}
 
-	fn check_proof(&self, engine: &Engine, proof: &[u8]) -> Result<(), String> {
+	fn check_proof(&self, machine: &EthereumMachine, proof: &[u8]) -> Result<(), String> {
 		let (header, state_items) = decode_first_proof(&UntrustedRlp::new(proof))
 			.map_err(|e| format!("proof incorrectly encoded: {}", e))?;
 		if &header != &*self.header.lock(){
 			return Err("wrong header in proof".into());
 		}
 
-		check_first_proof(engine, &self.provider, header, &state_items).map(|_| ())
+		check_first_proof(machine, &self.provider, header, &state_items).map(|_| ())
 	}
 }
 
@@ -94,7 +94,7 @@ fn encode_first_proof(header: &Header, state_items: &[Vec<u8>]) -> Bytes {
 }
 
 // check a first proof: fetch the validator set at the given block.
-fn check_first_proof(engine: &Engine, provider: &Provider, old_header: Header, state_items: &[DBValue])
+fn check_first_proof(machine: &EthereumMachine, provider: &Provider, old_header: Header, state_items: &[DBValue])
 	-> Result<Vec<Address>, String>
 {
 	use transaction::{Action, Transaction};
@@ -117,12 +117,12 @@ fn check_first_proof(engine: &Engine, provider: &Provider, old_header: Header, s
 		gas_used: 0.into(),
 	};
 
-	// check state proof using given engine.
+	// check state proof using given machine.
 	let number = old_header.number();
 	provider.get_validators(move |a, d| {
 		let from = Address::default();
 		let tx = Transaction {
-			nonce: engine.account_start_nonce(number),
+			nonce: machine.account_start_nonce(number),
 			action: Action::Call(a),
 			gas: PROVIDED_GAS.into(),
 			gas_price: U256::default(),
@@ -134,7 +134,7 @@ fn check_first_proof(engine: &Engine, provider: &Provider, old_header: Header, s
 			state_items,
 			*old_header.state_root(),
 			&tx,
-			engine,
+			machine,
 			&env_info,
 		);
 
@@ -336,9 +336,11 @@ impl ValidatorSet for ValidatorSafeContract {
 		None // no immediate transitions to contract.
 	}
 
-	fn signals_epoch_end(&self, first: bool, header: &Header, _block: Option<&[u8]>, receipts: Option<&[Receipt]>)
-		-> ::engines::EpochChange
+	fn signals_epoch_end(&self, first: bool, header: &Header, aux: AuxiliaryData)
+		-> ::engines::EpochChange<EthereumMachine>
 	{
+		let receipts = aux.receipts;
+
 		// transition to the first block of a contract requires finality but has no log event.
 		if first {
 			debug!(target: "engine", "signalling transition to fresh contract.");
@@ -358,7 +360,7 @@ impl ValidatorSet for ValidatorSafeContract {
 		trace!(target: "engine", "detected epoch change event bloom");
 
 		match receipts {
-			None => ::engines::EpochChange::Unsure(::engines::Unsure::NeedsReceipts),
+			None => ::engines::EpochChange::Unsure(AuxiliaryRequest::Receipts),
 			Some(receipts) => match self.extract_from_event(bloom, header, receipts) {
 				None => ::engines::EpochChange::No,
 				Some(list) => {
@@ -372,7 +374,7 @@ impl ValidatorSet for ValidatorSafeContract {
 		}
 	}
 
-	fn epoch_set(&self, first: bool, engine: &Engine, _number: ::header::BlockNumber, proof: &[u8])
+	fn epoch_set(&self, first: bool, machine: &EthereumMachine, _number: ::header::BlockNumber, proof: &[u8])
 		-> Result<(SimpleList, Option<H256>), ::error::Error>
 	{
 		let rlp = UntrustedRlp::new(proof);
@@ -383,7 +385,7 @@ impl ValidatorSet for ValidatorSafeContract {
 			let (old_header, state_items) = decode_first_proof(&rlp)?;
 			let number = old_header.number();
 			let old_hash = old_header.hash();
-			let addresses = check_first_proof(engine, &self.provider, old_header, &state_items)
+			let addresses = check_first_proof(machine, &self.provider, old_header, &state_items)
 				.map_err(::engines::EngineError::InsufficientProof)?;
 
 			trace!(target: "engine", "extracted epoch set at #{}: {} addresses",
@@ -561,7 +563,8 @@ mod tests {
 	#[test]
 	fn detects_bloom() {
 		use header::Header;
-		use engines::{EpochChange, Unsure};
+		use engines::EpochChange;
+		use machine::AuxiliaryRequest;
 		use log_entry::LogEntry;
 
 		let client = generate_dummy_client_with_spec_and_accounts(Spec::new_validator_safe_contract, None);
@@ -581,7 +584,7 @@ mod tests {
 		};
 
 		new_header.set_log_bloom(event.bloom());
-		match engine.signals_epoch_end(&new_header, None, None) {
+		match engine.signals_epoch_end(&new_header, Default::default()) {
 			EpochChange::No => {},
 			_ => panic!("Expected bloom to be unrecognized."),
 		};
@@ -590,8 +593,8 @@ mod tests {
 		event.topics.push(last_hash);
 		new_header.set_log_bloom(event.bloom());
 
-		match engine.signals_epoch_end(&new_header, None, None) {
-			EpochChange::Unsure(Unsure::NeedsReceipts) => {},
+		match engine.signals_epoch_end(&new_header, Default::default()) {
+			EpochChange::Unsure(AuxiliaryRequest::Receipts) => {},
 			_ => panic!("Expected bloom to be recognized."),
 		};
 	}
@@ -607,7 +610,7 @@ mod tests {
 		let mut new_header = Header::default();
 		new_header.set_number(0); // so the validator set doesn't look for a log
 
-		match engine.signals_epoch_end(&new_header, None, None) {
+		match engine.signals_epoch_end(&new_header, Default::default()) {
 			EpochChange::Yes(Proof::WithState(_)) => {},
 			_ => panic!("Expected state to be required to prove initial signal"),
 		};

ethcore/src/engines/validator_set/simple_list.rs

@@ -20,7 +20,7 @@ use heapsize::HeapSizeOf;
 use bigint::hash::H256;
 use util::Address;
 
-use engines::{Call, Engine};
+use machine::{AuxiliaryData, Call, EthereumMachine};
 use header::{BlockNumber, Header};
 use super::ValidatorSet;
 
@@ -76,13 +76,13 @@ impl ValidatorSet for SimpleList {
 		}
 	}
 
-	fn signals_epoch_end(&self, _: bool, _: &Header, _: Option<&[u8]>, _: Option<&[::receipt::Receipt]>)
-		-> ::engines::EpochChange
+	fn signals_epoch_end(&self, _: bool, _: &Header, _: AuxiliaryData)
+		-> ::engines::EpochChange<EthereumMachine>
 	{
 		::engines::EpochChange::No
 	}
 
-	fn epoch_set(&self, _first: bool, _: &Engine, _: BlockNumber, _: &[u8]) -> Result<(SimpleList, Option<H256>), ::error::Error> {
+	fn epoch_set(&self, _first: bool, _: &EthereumMachine, _: BlockNumber, _: &[u8]) -> Result<(SimpleList, Option<H256>), ::error::Error> {
 		Ok((self.clone(), None))
 	}
 

ethcore/src/engines/validator_set/test.rs

@@ -24,7 +24,7 @@ use bigint::hash::H256;
 use util::Address;
 use bytes::Bytes;
 
-use engines::{Call, Engine};
+use machine::{AuxiliaryData, Call, EthereumMachine};
 use header::{Header, BlockNumber};
 use super::{ValidatorSet, SimpleList};
 
@@ -58,13 +58,13 @@ impl ValidatorSet for TestSet {
 
 	fn is_epoch_end(&self, _first: bool, _chain_head: &Header) -> Option<Vec<u8>> { None }
 
-	fn signals_epoch_end(&self, _: bool, _: &Header, _: Option<&[u8]>, _: Option<&[::receipt::Receipt]>)
-		-> ::engines::EpochChange
+	fn signals_epoch_end(&self, _: bool, _: &Header, _: AuxiliaryData)
+		-> ::engines::EpochChange<EthereumMachine>
 	{
 		::engines::EpochChange::No
 	}
 
-	fn epoch_set(&self, _: bool, _: &Engine, _: BlockNumber, _: &[u8]) -> Result<(SimpleList, Option<H256>), ::error::Error> {
+	fn epoch_set(&self, _: bool, _: &EthereumMachine, _: BlockNumber, _: &[u8]) -> Result<(SimpleList, Option<H256>), ::error::Error> {
 		Ok((self.validator.clone(), None))
 	}
 

ethcore/src/ethereum/ethash.rs

@@ -17,33 +17,20 @@
 use std::path::Path;
 use std::cmp;
 use std::collections::{BTreeMap, HashMap};
-use std::sync::{Arc, Weak};
+use std::sync::Arc;
 use hash::{KECCAK_EMPTY_LIST_RLP};
-use ethash::{quick_get_difficulty, slow_get_seedhash, EthashManager};
+use ethash::{quick_get_difficulty, slow_hash_block_number, EthashManager, OptimizeFor};
 use bigint::prelude::U256;
 use bigint::hash::{H256, H64};
-use util::*;
 use unexpected::{OutOfBounds, Mismatch};
 use block::*;
-use builtin::Builtin;
-use vm::EnvInfo;
-use error::{BlockError, Error, TransactionError};
-use trace::{Tracer, ExecutiveTracer, RewardType};
-use header::{Header, BlockNumber};
-use state::CleanupMode;
-use spec::CommonParams;
-use transaction::{UnverifiedTransaction, SignedTransaction};
-use engines::{self, Engine};
-use evm::Schedule;
+use error::{BlockError, Error};
+use header::Header;
+use engines::{self, Engine, EthEngine};
 use ethjson;
 use rlp::{self, UntrustedRlp};
-use vm::LastHashes;
+use machine::EthereumMachine;
 use semantic_version::SemanticVersion;
-use tx_filter::{TransactionFilter};
-use client::EngineClient;
-
-/// Parity tries to round block.gas_limit to multiple of this constant
-pub const PARITY_GAS_LIMIT_DETERMINANT: U256 = U256([37, 0, 0, 0]);
 
 /// Number of blocks in an ethash snapshot.
 // make dependent on difficulty incrment divisor?
@@ -68,12 +55,6 @@ pub struct EthashParams {
 	pub duration_limit: u64,
 	/// Homestead transition block number.
 	pub homestead_transition: u64,
-	/// DAO hard-fork transition block (X).
-	pub dao_hardfork_transition: u64,
-	/// DAO hard-fork refund contract address (C).
-	pub dao_hardfork_beneficiary: Address,
-	/// DAO hard-fork DAO accounts list (L)
-	pub dao_hardfork_accounts: Vec<Address>,
 	/// Transition block for a change of difficulty params (currently just bound_divisor).
 	pub difficulty_hardfork_transition: u64,
 	/// Difficulty param after the difficulty transition.
@@ -82,30 +63,14 @@ pub struct EthashParams {
 	pub bomb_defuse_transition: u64,
 	/// Number of first block where EIP-100 rules begin.
 	pub eip100b_transition: u64,
-	/// Number of first block where EIP-150 rules begin.
-	pub eip150_transition: u64,
-	/// Number of first block where EIP-160 rules begin.
-	pub eip160_transition: u64,
-	/// Number of first block where EIP-161.abc begin.
-	pub eip161abc_transition: u64,
-	/// Number of first block where EIP-161.d begins.
-	pub eip161d_transition: u64,
 	/// Number of first block where ECIP-1010 begins.
 	pub ecip1010_pause_transition: u64,
 	/// Number of first block where ECIP-1010 ends.
 	pub ecip1010_continue_transition: u64,
 	/// Total block number for one ECIP-1017 era.
 	pub ecip1017_era_rounds: u64,
-	/// Maximum amount of code that can be deploying into a contract.
-	pub max_code_size: u64,
-	/// Number of first block where the max gas limit becomes effective.
-	pub max_gas_limit_transition: u64,
-	/// Maximum valid block gas limit,
-	pub max_gas_limit: U256,
-	/// Number of first block where the minimum gas price becomes effective.
-	pub min_gas_price_transition: u64,
-	/// Do not alow transactions with lower gas price.
-	pub min_gas_price: U256,
+	/// Block reward in base units.
+	pub block_reward: U256,
 	/// EIP-649 transition block.
 	pub eip649_transition: u64,
 	/// EIP-649 bomb delay.
@@ -123,25 +88,14 @@ impl From<ethjson::spec::EthashParams> for EthashParams {
 			metropolis_difficulty_increment_divisor: p.metropolis_difficulty_increment_divisor.map_or(9, Into::into),
 			duration_limit: p.duration_limit.map_or(0, Into::into),
 			homestead_transition: p.homestead_transition.map_or(0, Into::into),
-			dao_hardfork_transition: p.dao_hardfork_transition.map_or(u64::max_value(), Into::into),
-			dao_hardfork_beneficiary: p.dao_hardfork_beneficiary.map_or_else(Address::new, Into::into),
-			dao_hardfork_accounts: p.dao_hardfork_accounts.unwrap_or_else(Vec::new).into_iter().map(Into::into).collect(),
 			difficulty_hardfork_transition: p.difficulty_hardfork_transition.map_or(u64::max_value(), Into::into),
 			difficulty_hardfork_bound_divisor: p.difficulty_hardfork_bound_divisor.map_or(p.difficulty_bound_divisor.into(), Into::into),
 			bomb_defuse_transition: p.bomb_defuse_transition.map_or(u64::max_value(), Into::into),
 			eip100b_transition: p.eip100b_transition.map_or(u64::max_value(), Into::into),
-			eip150_transition: p.eip150_transition.map_or(0, Into::into),
-			eip160_transition: p.eip160_transition.map_or(0, Into::into),
-			eip161abc_transition: p.eip161abc_transition.map_or(0, Into::into),
-			eip161d_transition: p.eip161d_transition.map_or(u64::max_value(), Into::into),
 			ecip1010_pause_transition: p.ecip1010_pause_transition.map_or(u64::max_value(), Into::into),
 			ecip1010_continue_transition: p.ecip1010_continue_transition.map_or(u64::max_value(), Into::into),
 			ecip1017_era_rounds: p.ecip1017_era_rounds.map_or(u64::max_value(), Into::into),
-			max_code_size: p.max_code_size.map_or(u64::max_value(), Into::into),
-			max_gas_limit_transition: p.max_gas_limit_transition.map_or(u64::max_value(), Into::into),
-			max_gas_limit: p.max_gas_limit.map_or(U256::max_value(), Into::into),
-			min_gas_price_transition: p.min_gas_price_transition.map_or(u64::max_value(), Into::into),
-			min_gas_price: p.min_gas_price.map_or(U256::zero(), Into::into),
+			block_reward: p.block_reward.map_or_else(Default::default, Into::into),
 			eip649_transition: p.eip649_transition.map_or(u64::max_value(), Into::into),
 			eip649_delay: p.eip649_delay.map_or(DEFAULT_EIP649_DELAY, Into::into),
 			eip649_reward: p.eip649_reward.map(Into::into),
@@ -152,27 +106,23 @@ impl From<ethjson::spec::EthashParams> for EthashParams {
 /// Engine using Ethash proof-of-work consensus algorithm, suitable for Ethereum
 /// mainnet chains in the Olympic, Frontier and Homestead eras.
 pub struct Ethash {
-	params: CommonParams,
 	ethash_params: EthashParams,
-	builtins: BTreeMap<Address, Builtin>,
 	pow: EthashManager,
-	tx_filter: Option<TransactionFilter>,
+	machine: EthereumMachine,
 }
 
 impl Ethash {
 	/// Create a new instance of Ethash engine
-	pub fn new<T: AsRef<Path>>(
-		cache_dir: T,
-		params: CommonParams,
+	pub fn new<T: Into<Option<OptimizeFor>>>(
+		cache_dir: &Path,
 		ethash_params: EthashParams,
-		builtins: BTreeMap<Address, Builtin>,
+		machine: EthereumMachine,
+		optimize_for: T,
 	) -> Arc<Self> {
 		Arc::new(Ethash {
-			tx_filter: TransactionFilter::from_params(&params),
-			params,
 			ethash_params,
-			builtins,
-			pow: EthashManager::new(cache_dir),
+			machine,
+			pow: EthashManager::new(cache_dir.as_ref(), optimize_for.into()),
 		})
 	}
 }
@@ -185,26 +135,23 @@ impl Ethash {
 // for any block in the chain.
 // in the future, we might move the Ethash epoch
 // caching onto this mechanism as well.
-impl engines::EpochVerifier for Arc<Ethash> {
+impl engines::EpochVerifier<EthereumMachine> for Arc<Ethash> {
 	fn verify_light(&self, _header: &Header) -> Result<(), Error> { Ok(()) }
 	fn verify_heavy(&self, header: &Header) -> Result<(), Error> {
-		self.verify_block_unordered(header, None)
+		self.verify_block_unordered(header)
 	}
 }
 
-impl Engine for Arc<Ethash> {
+impl Engine<EthereumMachine> for Arc<Ethash> {
 	fn name(&self) -> &str { "Ethash" }
 	fn version(&self) -> SemanticVersion { SemanticVersion::new(1, 0, 0) }
-	// Two fields - mix
+	fn machine(&self) -> &EthereumMachine { &self.machine }
+
+	// Two fields - nonce and mix.
 	fn seal_fields(&self) -> usize { 2 }
 
-	fn params(&self) -> &CommonParams { &self.params }
 	fn additional_params(&self) -> HashMap<String, String> { hash_map!["registrar".to_owned() => self.params().registrar.hex()] }
 
-	fn builtins(&self) -> &BTreeMap<Address, Builtin> {
-		&self.builtins
-	}
-
 	/// Additional engine-specific information for the user/developer concerning `header`.
 	fn extra_info(&self, header: &Header) -> BTreeMap<String, String> {
 		if header.seal().len() == self.seal_fields() {
@@ -217,90 +164,16 @@ impl Engine for Arc<Ethash> {
 		}
 	}
 
-	fn schedule(&self, block_number: BlockNumber) -> Schedule {
-		trace!(target: "client", "Creating schedule. fCML={}, bGCML={}", self.ethash_params.homestead_transition, self.ethash_params.eip150_transition);
-
-		if block_number < self.ethash_params.homestead_transition {
-			Schedule::new_frontier()
-		} else if block_number < self.ethash_params.eip150_transition {
-			Schedule::new_homestead()
-		} else {
-			/// There's no max_code_size transition so we tie it to eip161abc
-			let max_code_size = if block_number >= self.ethash_params.eip161abc_transition { self.ethash_params.max_code_size as usize } else { usize::max_value() };
-			let mut schedule = Schedule::new_post_eip150(
-				max_code_size,
-				block_number >= self.ethash_params.eip160_transition,
-				block_number >= self.ethash_params.eip161abc_transition,
-				block_number >= self.ethash_params.eip161d_transition);
-
-			self.params().update_schedule(block_number, &mut schedule);
-			schedule
-		}
-	}
-
-	fn signing_chain_id(&self, env_info: &EnvInfo) -> Option<u64> {
-		if env_info.number >= self.params().eip155_transition {
-			Some(self.params().chain_id)
-		} else {
-			None
-		}
-	}
-
-	fn populate_from_parent(&self, header: &mut Header, parent: &Header, gas_floor_target: U256, mut gas_ceil_target: U256) {
+	fn populate_from_parent(&self, header: &mut Header, parent: &Header) {
 		let difficulty = self.calculate_difficulty(header, parent);
-		if header.number() >= self.ethash_params.max_gas_limit_transition && gas_ceil_target > self.ethash_params.max_gas_limit {
-			warn!("Gas limit target is limited to {}", self.ethash_params.max_gas_limit);
-			gas_ceil_target = self.ethash_params.max_gas_limit;
-		}
-		let gas_limit = {
-			let gas_limit = parent.gas_limit().clone();
-			let bound_divisor = self.params().gas_limit_bound_divisor;
-			let lower_limit = gas_limit - gas_limit / bound_divisor + 1.into();
-			let upper_limit = gas_limit + gas_limit / bound_divisor - 1.into();
-			let gas_limit = if gas_limit < gas_floor_target {
-				let gas_limit = cmp::min(gas_floor_target, upper_limit);
-				round_block_gas_limit(gas_limit, lower_limit, upper_limit)
-			} else if gas_limit > gas_ceil_target {
-				let gas_limit = cmp::max(gas_ceil_target, lower_limit);
-				round_block_gas_limit(gas_limit, lower_limit, upper_limit)
-			} else {
-				let total_lower_limit = cmp::max(lower_limit, gas_floor_target);
-				let total_upper_limit = cmp::min(upper_limit, gas_ceil_target);
-				let gas_limit = cmp::max(gas_floor_target, cmp::min(total_upper_limit,
-					lower_limit + (header.gas_used().clone() * 6.into() / 5.into()) / bound_divisor));
-				round_block_gas_limit(gas_limit, total_lower_limit, total_upper_limit)
-			};
-			// ensure that we are not violating protocol limits
-			debug_assert!(gas_limit >= lower_limit);
-			debug_assert!(gas_limit <= upper_limit);
-			gas_limit
-		};
 		header.set_difficulty(difficulty);
-		header.set_gas_limit(gas_limit);
-		if header.number() >= self.ethash_params.dao_hardfork_transition &&
-			header.number() <= self.ethash_params.dao_hardfork_transition + 9 {
-			header.set_extra_data(b"dao-hard-fork"[..].to_owned());
-		}
-		header.note_dirty();
-//		info!("ethash: populate_from_parent #{}: difficulty={} and gas_limit={}", header.number(), header.difficulty(), header.gas_limit());
 	}
 
 	fn on_new_block(
 		&self,
-		block: &mut ExecutedBlock,
-		last_hashes: Arc<LastHashes>,
+		_block: &mut ExecutedBlock,
 		_begins_epoch: bool,
 	) -> Result<(), Error> {
-		let parent_hash = block.fields().header.parent_hash().clone();
-		engines::common::push_last_hash(block, last_hashes, self, &parent_hash)?;
-		if block.fields().header.number() == self.ethash_params.dao_hardfork_transition {
-			let state = block.fields_mut().state;
-			for child in &self.ethash_params.dao_hardfork_accounts {
-				let beneficiary = &self.ethash_params.dao_hardfork_beneficiary;
-				state.balance(child)
-					.and_then(|b| state.transfer_balance(child, beneficiary, &b, CleanupMode::NoEmpty))?;
-			}
-		}
 		Ok(())
 	}
 
@@ -308,68 +181,54 @@ impl Engine for Arc<Ethash> {
 	/// This assumes that all uncles are valid uncles (i.e. of at least one generation before the current).
 	fn on_close_block(&self, block: &mut ExecutedBlock) -> Result<(), Error> {
 		use std::ops::Shr;
-		let tracing_enabled = block.tracing_enabled();
-		let fields = block.fields_mut();
-		let reward = if fields.header.number() >= self.ethash_params.eip649_transition {
-			self.ethash_params.eip649_reward.unwrap_or(self.params().block_reward)
+		use parity_machine::{LiveBlock, WithBalances};
+
+		let author = *LiveBlock::header(&*block).author();
+		let number = LiveBlock::header(&*block).number();
+
+		let reward = if number >= self.ethash_params.eip649_transition {
+			self.ethash_params.eip649_reward.unwrap_or(self.ethash_params.block_reward)
 		} else {
-			self.params().block_reward
+			self.ethash_params.block_reward
 		};
 
 		let eras_rounds = self.ethash_params.ecip1017_era_rounds;
-		let (eras, reward) = ecip1017_eras_block_reward(eras_rounds, reward, fields.header.number());
-		let mut tracer = ExecutiveTracer::default();
+		let (eras, reward) = ecip1017_eras_block_reward(eras_rounds, reward, number);
+
+		let n_uncles = LiveBlock::uncles(&*block).len();
 
 		// Bestow block reward
-		let result_block_reward = reward + reward.shr(5) * U256::from(fields.uncles.len());
-		fields.state.add_balance(
-			fields.header.author(),
-			&result_block_reward,
-			CleanupMode::NoEmpty
-		)?;
+		let result_block_reward = reward + reward.shr(5) * U256::from(n_uncles);
+		let mut uncle_rewards = Vec::with_capacity(n_uncles);
 
-		if tracing_enabled {
-			let block_author = fields.header.author().clone();
-			tracer.trace_reward(block_author, result_block_reward, RewardType::Block);
-		}
+		self.machine.add_balance(block, &author, &result_block_reward)?;
 
-		// Bestow uncle rewards
-		let current_number = fields.header.number();
-		for u in fields.uncles.iter() {
-			let uncle_author = u.author().clone();
-			let result_uncle_reward: U256;
-
-			if eras == 0 {
-				result_uncle_reward = (reward * U256::from(8 + u.number() - current_number)).shr(3);
-				fields.state.add_balance(
-					u.author(),
-					&result_uncle_reward,
-					CleanupMode::NoEmpty
-				)
+		// bestow uncle rewards.
+		for u in LiveBlock::uncles(&*block) {
+			let uncle_author = u.author();
+			let result_uncle_reward = if eras == 0 {
+				(reward * U256::from(8 + u.number() - number)).shr(3)
 			} else {
-				result_uncle_reward = reward.shr(5);
-				fields.state.add_balance(
-					u.author(),
-					&result_uncle_reward,
-					CleanupMode::NoEmpty
-				)
-			}?;
+				reward.shr(5)
+			};
 
-			// Trace uncle rewards
-			if tracing_enabled {
-				tracer.trace_reward(uncle_author, result_uncle_reward, RewardType::Uncle);
-			}
+			uncle_rewards.push((*uncle_author, result_uncle_reward));
 		}
 
-		// Commit state so that we can actually figure out the state root.
-		fields.state.commit()?;
-		if tracing_enabled {
-			fields.traces.as_mut().map(|mut traces| traces.push(tracer.drain()));
-		}
-		Ok(())
+		for &(ref a, ref reward) in &uncle_rewards {
+			self.machine.add_balance(block, a, reward)?;
 		}
 
-	fn verify_block_basic(&self, header: &Header, _block: Option<&[u8]>) -> Result<(), Error> {
+		// note and trace.
+		self.machine.note_rewards(block, &[(author, result_block_reward)], &uncle_rewards)
+	}
+
+	fn verify_local_seal(&self, header: &Header) -> Result<(), Error> {
+		self.verify_block_basic(header)
+			.and_then(|_| self.verify_block_unordered(header))
+	}
+
+	fn verify_block_basic(&self, header: &Header) -> Result<(), Error> {
 		// check the seal fields.
 		if header.seal().len() != self.seal_fields() {
 			return Err(From::from(BlockError::InvalidSealArity(
@@ -394,12 +253,6 @@ impl Engine for Arc<Ethash> {
 			return Err(From::from(BlockError::InvalidProofOfWork(OutOfBounds { min: Some(header.difficulty().clone()), max: None, found: difficulty })));
 		}
 
-		if header.number() >= self.ethash_params.dao_hardfork_transition &&
-			header.number() <= self.ethash_params.dao_hardfork_transition + 9 &&
-			header.extra_data()[..] != b"dao-hard-fork"[..] {
-			return Err(From::from(BlockError::ExtraDataOutOfBounds(OutOfBounds { min: None, max: None, found: 0 })));
-		}
-
 		if header.gas_limit() > &0x7fffffffffffffffu64.into() {
 			return Err(From::from(BlockError::InvalidGasLimit(OutOfBounds { min: None, max: Some(0x7fffffffffffffffu64.into()), found: header.gas_limit().clone() })));
 		}
@@ -407,7 +260,7 @@ impl Engine for Arc<Ethash> {
 		Ok(())
 	}
 
-	fn verify_block_unordered(&self, header: &Header, _block: Option<&[u8]>) -> Result<(), Error> {
+	fn verify_block_unordered(&self, header: &Header) -> Result<(), Error> {
 		if header.seal().len() != self.seal_fields() {
 			return Err(From::from(BlockError::InvalidSealArity(
 				Mismatch { expected: self.seal_fields(), found: header.seal().len() }
@@ -416,7 +269,7 @@ impl Engine for Arc<Ethash> {
 		let result = self.pow.compute_light(header.number() as u64, &header.bare_hash().0, header.nonce().low_u64());
 		let mix = H256(result.mix_hash);
 		let difficulty = Ethash::boundary_to_difficulty(&H256(result.value));
-		trace!(target: "miner", "num: {}, seed: {}, h: {}, non: {}, mix: {}, res: {}" , header.number() as u64, H256(slow_get_seedhash(header.number() as u64)), header.bare_hash(), header.nonce().low_u64(), H256(result.mix_hash), H256(result.value));
+		trace!(target: "miner", "num: {}, seed: {}, h: {}, non: {}, mix: {}, res: {}" , header.number() as u64, H256(slow_hash_block_number(header.number() as u64)), header.bare_hash(), header.nonce().low_u64(), H256(result.mix_hash), H256(result.value));
 		if mix != header.mix_hash() {
 			return Err(From::from(BlockError::MismatchedH256SealElement(Mismatch { expected: mix, found: header.mix_hash() })));
 		}
@@ -426,7 +279,7 @@ impl Engine for Arc<Ethash> {
 		Ok(())
 	}
 
-	fn verify_block_family(&self, header: &Header, parent: &Header, _block: Option<&[u8]>) -> Result<(), Error> {
+	fn verify_block_family(&self, header: &Header, parent: &Header) -> Result<(), Error> {
 		// we should not calculate difficulty for genesis blocks
 		if header.number() == 0 {
 			return Err(From::from(BlockError::RidiculousNumber(OutOfBounds { min: Some(1), max: None, found: header.number() })));
@@ -437,81 +290,17 @@ impl Engine for Arc<Ethash> {
 		if header.difficulty() != &expected_difficulty {
 			return Err(From::from(BlockError::InvalidDifficulty(Mismatch { expected: expected_difficulty, found: header.difficulty().clone() })))
 		}
-		let gas_limit_divisor = self.params().gas_limit_bound_divisor;
-		let parent_gas_limit = *parent.gas_limit();
-		let min_gas = parent_gas_limit - parent_gas_limit / gas_limit_divisor;
-		let max_gas = parent_gas_limit + parent_gas_limit / gas_limit_divisor;
-		if header.gas_limit() <= &min_gas || header.gas_limit() >= &max_gas {
-			return Err(From::from(BlockError::InvalidGasLimit(OutOfBounds { min: Some(min_gas), max: Some(max_gas), found: header.gas_limit().clone() })));
-		}
-		if header.number() >= self.ethash_params.max_gas_limit_transition && header.gas_limit() > &self.ethash_params.max_gas_limit && header.gas_limit() > &parent_gas_limit {
-			return Err(From::from(BlockError::InvalidGasLimit(OutOfBounds { min: Some(min_gas), max: Some(self.ethash_params.max_gas_limit), found: header.gas_limit().clone() })));
-		}
+
 		Ok(())
 	}
 
-	fn verify_transaction_basic(&self, t: &UnverifiedTransaction, header: &Header) -> Result<(), Error> {
-		if header.number() >= self.ethash_params.min_gas_price_transition && t.gas_price < self.ethash_params.min_gas_price {
-			return Err(TransactionError::InsufficientGasPrice { minimal: self.ethash_params.min_gas_price, got: t.gas_price }.into());
-		}
-
-		let check_low_s = header.number() >= self.ethash_params.homestead_transition;
-		let chain_id = if header.number() >= self.params().eip155_transition { Some(self.params().chain_id) } else { None };
-		t.verify_basic(check_low_s, chain_id, false)?;
-		Ok(())
-	}
-
-	fn verify_transaction(&self, t: UnverifiedTransaction, header: &Header) -> Result<SignedTransaction, Error> {
-		let signed = SignedTransaction::new(t)?;
-		if !self.tx_filter.as_ref().map_or(true, |filter| filter.transaction_allowed(header.parent_hash(), &signed)) {
-			return Err(From::from(TransactionError::NotAllowed));
-		}
-		Ok(signed)
-	}
-
-	fn epoch_verifier<'a>(&self, _header: &Header, _proof: &'a [u8]) -> engines::ConstructedVerifier<'a> {
+	fn epoch_verifier<'a>(&self, _header: &Header, _proof: &'a [u8]) -> engines::ConstructedVerifier<'a, EthereumMachine> {
 		engines::ConstructedVerifier::Trusted(Box::new(self.clone()))
 	}
 
 	fn snapshot_components(&self) -> Option<Box<::snapshot::SnapshotComponents>> {
 		Some(Box::new(::snapshot::PowSnapshot::new(SNAPSHOT_BLOCKS, MAX_SNAPSHOT_BLOCKS)))
 	}
-
-	fn register_client(&self, client: Weak<EngineClient>) {
-		if let Some(ref filter) = self.tx_filter {
-			filter.register_client(client);
-		}
-	}
-
-}
-
-// Try to round gas_limit a bit so that:
-// 1) it will still be in desired range
-// 2) it will be a nearest (with tendency to increase) multiple of PARITY_GAS_LIMIT_DETERMINANT
-fn round_block_gas_limit(gas_limit: U256, lower_limit: U256, upper_limit: U256) -> U256 {
-	let increased_gas_limit = gas_limit + (PARITY_GAS_LIMIT_DETERMINANT - gas_limit % PARITY_GAS_LIMIT_DETERMINANT);
-	if increased_gas_limit > upper_limit {
-		let decreased_gas_limit = increased_gas_limit - PARITY_GAS_LIMIT_DETERMINANT;
-		if decreased_gas_limit < lower_limit {
-			gas_limit
-		} else {
-			decreased_gas_limit
-		}
-	} else {
-		increased_gas_limit
-	}
-}
-
-fn ecip1017_eras_block_reward(era_rounds: u64, mut reward: U256, block_number:u64) -> (u64, U256){
-	let eras = if block_number != 0 && block_number % era_rounds == 0 {
-		block_number / era_rounds - 1
-	} else {
-		block_number / era_rounds
-	};
-	for _ in 0..eras {
-		reward = reward / U256::from(5) * U256::from(4);
-	}
-	(eras, reward)
 }
 
 #[cfg_attr(feature="dev", allow(wrong_self_convention))]
@@ -610,7 +399,7 @@ impl Ethash {
 }
 
 impl Header {
-	/// Get the none field of the header.
+	/// Get the nonce field of the header.
 	pub fn nonce(&self) -> H64 {
 		rlp::decode(&self.seal()[1])
 	}
@@ -619,29 +408,34 @@ impl Header {
 	pub fn mix_hash(&self) -> H256 {
 		rlp::decode(&self.seal()[0])
 	}
-
-	/// Set the nonce and mix hash fields of the header.
-	pub fn set_nonce_and_mix_hash(&mut self, nonce: &H64, mix_hash: &H256) {
-		self.set_seal(vec![rlp::encode(mix_hash).into_vec(), rlp::encode(nonce).into_vec()]);
 }
+
+fn ecip1017_eras_block_reward(era_rounds: u64, mut reward: U256, block_number:u64) -> (u64, U256) {
+	let eras = if block_number != 0 && block_number % era_rounds == 0 {
+		block_number / era_rounds - 1
+	} else {
+		block_number / era_rounds
+	};
+	for _ in 0..eras {
+		reward = reward / U256::from(5) * U256::from(4);
+	}
+	(eras, reward)
 }
 
 #[cfg(test)]
 mod tests {
 	use std::str::FromStr;
-	use std::collections::BTreeMap;
 	use std::sync::Arc;
 	use bigint::prelude::U256;
 	use bigint::hash::{H64, H256};
 	use util::*;
 	use block::*;
 	use tests::helpers::*;
-	use engines::Engine;
 	use error::{BlockError, Error};
 	use header::Header;
 	use spec::Spec;
-	use super::super::{new_morden, new_homestead_test};
-	use super::{Ethash, EthashParams, PARITY_GAS_LIMIT_DETERMINANT, ecip1017_eras_block_reward};
+	use super::super::{new_morden, new_homestead_test_machine};
+	use super::{Ethash, EthashParams, ecip1017_eras_block_reward};
 	use rlp;
 
 	fn test_spec() -> Spec {
@@ -660,6 +454,38 @@ mod tests {
 		assert_eq!(b.state().balance(&Address::zero()).unwrap(), U256::from_str("4563918244f40000").unwrap());
 	}
 
+	#[test]
+	fn has_valid_ecip1017_eras_block_reward() {
+		let eras_rounds = 5000000;
+
+		let start_reward: U256 = "4563918244F40000".parse().unwrap();
+
+		let block_number = 0;
+		let (eras, reward) = ecip1017_eras_block_reward(eras_rounds, start_reward, block_number);
+		assert_eq!(0, eras);
+		assert_eq!(U256::from_str("4563918244F40000").unwrap(), reward);
+
+		let block_number = 5000000;
+		let (eras, reward) = ecip1017_eras_block_reward(eras_rounds, start_reward, block_number);
+		assert_eq!(0, eras);
+		assert_eq!(U256::from_str("4563918244F40000").unwrap(), reward);
+
+		let block_number = 10000000;
+		let (eras, reward) = ecip1017_eras_block_reward(eras_rounds, start_reward, block_number);
+		assert_eq!(1, eras);
+		assert_eq!(U256::from_str("3782DACE9D900000").unwrap(), reward);
+
+		let block_number = 20000000;
+		let (eras, reward) = ecip1017_eras_block_reward(eras_rounds, start_reward, block_number);
+		assert_eq!(3, eras);
+		assert_eq!(U256::from_str("2386F26FC1000000").unwrap(), reward);
+
+		let block_number = 80000000;
+		let (eras, reward) = ecip1017_eras_block_reward(eras_rounds, start_reward, block_number);
+		assert_eq!(15, eras);
+		assert_eq!(U256::from_str("271000000000000").unwrap(), reward);
+	}
+
 	#[test]
 	fn on_close_block_with_uncle() {
 		let spec = test_spec();
@@ -698,10 +524,9 @@ mod tests {
 	#[test]
 	fn can_do_seal_verification_fail() {
 		let engine = test_spec().engine;
-		//let engine = Ethash::new_test(test_spec());
 		let header: Header = Header::default();
 
-		let verify_result = engine.verify_block_basic(&header, None);
+		let verify_result = engine.verify_block_basic(&header);
 
 		match verify_result {
 			Err(Error::Block(BlockError::InvalidSealArity(_))) => {},
@@ -716,7 +541,7 @@ mod tests {
 		let mut header: Header = Header::default();
 		header.set_seal(vec![rlp::encode(&H256::zero()).into_vec(), rlp::encode(&H64::zero()).into_vec()]);
 
-		let verify_result = engine.verify_block_basic(&header, None);
+		let verify_result = engine.verify_block_basic(&header);
 
 		match verify_result {
 			Err(Error::Block(BlockError::DifficultyOutOfBounds(_))) => {},
@@ -732,7 +557,7 @@ mod tests {
 		header.set_seal(vec![rlp::encode(&H256::zero()).into_vec(), rlp::encode(&H64::zero()).into_vec()]);
 		header.set_difficulty(U256::from_str("ffffffffffffffffffffffffffffffffffffffffffffaaaaaaaaaaaaaaaaaaaa").unwrap());
 
-		let verify_result = engine.verify_block_basic(&header, None);
+		let verify_result = engine.verify_block_basic(&header);
 
 		match verify_result {
 			Err(Error::Block(BlockError::InvalidProofOfWork(_))) => {},
@@ -746,7 +571,7 @@ mod tests {
 		let engine = test_spec().engine;
 		let header: Header = Header::default();
 
-		let verify_result = engine.verify_block_unordered(&header, None);
+		let verify_result = engine.verify_block_unordered(&header);
 
 		match verify_result {
 			Err(Error::Block(BlockError::InvalidSealArity(_))) => {},
@@ -760,7 +585,7 @@ mod tests {
 		let engine = test_spec().engine;
 		let mut header: Header = Header::default();
 		header.set_seal(vec![rlp::encode(&H256::zero()).into_vec(), rlp::encode(&H64::zero()).into_vec()]);
-		let verify_result = engine.verify_block_unordered(&header, None);
+		let verify_result = engine.verify_block_unordered(&header);
 
 		match verify_result {
 			Err(Error::Block(BlockError::MismatchedH256SealElement(_))) => {},
@@ -776,7 +601,7 @@ mod tests {
 		header.set_seal(vec![rlp::encode(&H256::from("b251bd2e0283d0658f2cadfdc8ca619b5de94eca5742725e2e757dd13ed7503d")).into_vec(), rlp::encode(&H64::zero()).into_vec()]);
 		header.set_difficulty(U256::from_str("ffffffffffffffffffffffffffffffffffffffffffffaaaaaaaaaaaaaaaaaaaa").unwrap());
 
-		let verify_result = engine.verify_block_unordered(&header, None);
+		let verify_result = engine.verify_block_unordered(&header);
 
 		match verify_result {
 			Err(Error::Block(BlockError::InvalidProofOfWork(_))) => {},
@@ -791,7 +616,7 @@ mod tests {
 		let header: Header = Header::default();
 		let parent_header: Header = Header::default();
 
-		let verify_result = engine.verify_block_family(&header, &parent_header, None);
+		let verify_result = engine.verify_block_family(&header, &parent_header);
 
 		match verify_result {
 			Err(Error::Block(BlockError::RidiculousNumber(_))) => {},
@@ -808,7 +633,7 @@ mod tests {
 		let mut parent_header: Header = Header::default();
 		parent_header.set_number(1);
 
-		let verify_result = engine.verify_block_family(&header, &parent_header, None);
+		let verify_result = engine.verify_block_family(&header, &parent_header);
 
 		match verify_result {
 			Err(Error::Block(BlockError::InvalidDifficulty(_))) => {},
@@ -817,24 +642,6 @@ mod tests {
 		}
 	}
 
-	#[test]
-	fn can_verify_block_family_gas_fail() {
-		let engine = test_spec().engine;
-		let mut header: Header = Header::default();
-		header.set_number(2);
-		header.set_difficulty(U256::from_str("0000000000000000000000000000000000000000000000000000000000020000").unwrap());
-		let mut parent_header: Header = Header::default();
-		parent_header.set_number(1);
-
-		let verify_result = engine.verify_block_family(&header, &parent_header, None);
-
-		match verify_result {
-			Err(Error::Block(BlockError::InvalidGasLimit(_))) => {},
-			Err(_) => { panic!("should be invalid difficulty fail (got {:?})", verify_result); },
-			_ => { panic!("Should be error, got Ok"); },
-		}
-	}
-
 	#[test]
 	fn test_difficulty_to_boundary() {
 		// result of f(0) is undefined, so do not assert the result
@@ -847,9 +654,9 @@ mod tests {
 
 	#[test]
 	fn difficulty_frontier() {
-		let spec = new_homestead_test();
+		let machine = new_homestead_test_machine();
 		let ethparams = get_default_ethash_params();
-		let ethash = Ethash::new(&::std::env::temp_dir(), spec.params().clone(), ethparams, BTreeMap::new());
+		let ethash = Ethash::new(&::std::env::temp_dir(), ethparams, machine, None);
 
 		let mut parent_header = Header::default();
 		parent_header.set_number(1000000);
@@ -865,9 +672,9 @@ mod tests {
 
 	#[test]
 	fn difficulty_homestead() {
-		let spec = new_homestead_test();
+		let machine = new_homestead_test_machine();
 		let ethparams = get_default_ethash_params();
-		let ethash = Ethash::new(&::std::env::temp_dir(), spec.params().clone(), ethparams, BTreeMap::new());
+		let ethash = Ethash::new(&::std::env::temp_dir(), ethparams, machine, None);
 
 		let mut parent_header = Header::default();
 		parent_header.set_number(1500000);
@@ -881,46 +688,14 @@ mod tests {
 		assert_eq!(U256::from_str("1fc50f118efe").unwrap(), difficulty);
 	}
 
-	#[test]
-	fn has_valid_ecip1017_eras_block_reward() {
-		let eras_rounds = 5000000;
-
-		let start_reward: U256 = "4563918244F40000".parse().unwrap();
-
-		let block_number = 0;
-		let (eras, reward) = ecip1017_eras_block_reward(eras_rounds, start_reward, block_number);
-		assert_eq!(0, eras);
-		assert_eq!(U256::from_str("4563918244F40000").unwrap(), reward);
-
-		let block_number = 5000000;
-		let (eras, reward) = ecip1017_eras_block_reward(eras_rounds, start_reward, block_number);
-		assert_eq!(0, eras);
-		assert_eq!(U256::from_str("4563918244F40000").unwrap(), reward);
-
-		let block_number = 10000000;
-		let (eras, reward) = ecip1017_eras_block_reward(eras_rounds, start_reward, block_number);
-		assert_eq!(1, eras);
-		assert_eq!(U256::from_str("3782DACE9D900000").unwrap(), reward);
-
-		let block_number = 20000000;
-		let (eras, reward) = ecip1017_eras_block_reward(eras_rounds, start_reward, block_number);
-		assert_eq!(3, eras);
-		assert_eq!(U256::from_str("2386F26FC1000000").unwrap(), reward);
-
-		let block_number = 80000000;
-		let (eras, reward) = ecip1017_eras_block_reward(eras_rounds, start_reward, block_number);
-		assert_eq!(15, eras);
-		assert_eq!(U256::from_str("271000000000000").unwrap(), reward);
-	}
-
 	#[test]
 	fn difficulty_classic_bomb_delay() {
-		let spec = new_homestead_test();
+		let machine = new_homestead_test_machine();
 		let ethparams = EthashParams {
 			ecip1010_pause_transition: 3000000,
 			..get_default_ethash_params()
 		};
-		let ethash = Ethash::new(&::std::env::temp_dir(), spec.params().clone(), ethparams, BTreeMap::new());
+		let ethash = Ethash::new(&::std::env::temp_dir(), ethparams, machine, None);
 
 		let mut parent_header = Header::default();
 		parent_header.set_number(3500000);
@@ -948,13 +723,13 @@ mod tests {
 
 	#[test]
 	fn test_difficulty_bomb_continue() {
-		let spec = new_homestead_test();
+		let machine = new_homestead_test_machine();
 		let ethparams = EthashParams {
 			ecip1010_pause_transition: 3000000,
 			ecip1010_continue_transition: 5000000,
 			..get_default_ethash_params()
 		};
-		let ethash = Ethash::new(&::std::env::temp_dir(), spec.params().clone(), ethparams, BTreeMap::new());
+		let ethash = Ethash::new(&::std::env::temp_dir(), ethparams, machine, None);
 
 		let mut parent_header = Header::default();
 		parent_header.set_number(5000102);
@@ -996,55 +771,11 @@ mod tests {
 		);
 	}
 
-	#[test]
-	fn gas_limit_is_multiple_of_determinant() {
-		let spec = new_homestead_test();
-		let ethparams = get_default_ethash_params();
-		let ethash = Ethash::new(&::std::env::temp_dir(), spec.params().clone(), ethparams, BTreeMap::new());
-		let mut parent = Header::new();
-		let mut header = Header::new();
-		header.set_number(1);
-
-		// this test will work for this constant only
-		assert_eq!(PARITY_GAS_LIMIT_DETERMINANT, U256::from(37));
-
-		// when parent.gas_limit < gas_floor_target:
-		parent.set_gas_limit(U256::from(50_000));
-		ethash.populate_from_parent(&mut header, &parent, U256::from(100_000), U256::from(200_000));
-		assert_eq!(*header.gas_limit(), U256::from(50_024));
-
-		// when parent.gas_limit > gas_ceil_target:
-		parent.set_gas_limit(U256::from(250_000));
-		ethash.populate_from_parent(&mut header, &parent, U256::from(100_000), U256::from(200_000));
-		assert_eq!(*header.gas_limit(), U256::from(249_787));
-
-		// when parent.gas_limit is in miner's range
-		header.set_gas_used(U256::from(150_000));
-		parent.set_gas_limit(U256::from(150_000));
-		ethash.populate_from_parent(&mut header, &parent, U256::from(100_000), U256::from(200_000));
-		assert_eq!(*header.gas_limit(), U256::from(150_035));
-
-		// when parent.gas_limit is in miner's range
-		// && we can NOT increase it to be multiple of constant
-		header.set_gas_used(U256::from(150_000));
-		parent.set_gas_limit(U256::from(150_000));
-		ethash.populate_from_parent(&mut header, &parent, U256::from(100_000), U256::from(150_002));
-		assert_eq!(*header.gas_limit(), U256::from(149_998));
-
-		// when parent.gas_limit is in miner's range
-		// && we can NOT increase it to be multiple of constant
-		// && we can NOT decrease it to be multiple of constant
-		header.set_gas_used(U256::from(150_000));
-		parent.set_gas_limit(U256::from(150_000));
-		ethash.populate_from_parent(&mut header, &parent, U256::from(150_000), U256::from(150_002));
-		assert_eq!(*header.gas_limit(), U256::from(150_002));
-	}
-
 	#[test]
 	fn difficulty_max_timestamp() {
-		let spec = new_homestead_test();
+		let machine = new_homestead_test_machine();
 		let ethparams = get_default_ethash_params();
-		let ethash = Ethash::new(&::std::env::temp_dir(), spec.params().clone(), ethparams, BTreeMap::new());
+		let ethash = Ethash::new(&::std::env::temp_dir(), ethparams, machine, None);
 
 		let mut parent_header = Header::default();
 		parent_header.set_number(1000000);
@@ -1057,82 +788,4 @@ mod tests {
 		let difficulty = ethash.calculate_difficulty(&header, &parent_header);
 		assert_eq!(U256::from(12543204905719u64), difficulty);
 	}
-
-	#[test]
-	fn rejects_blocks_over_max_gas_limit() {
-		let spec = new_homestead_test();
-		let mut ethparams = get_default_ethash_params();
-		ethparams.max_gas_limit_transition = 10;
-		ethparams.max_gas_limit = 100_000.into();
-
-		let mut parent_header = Header::default();
-		parent_header.set_number(1);
-		parent_header.set_gas_limit(100_000.into());
-		let mut header = Header::default();
-		header.set_number(parent_header.number() + 1);
-		header.set_gas_limit(100_001.into());
-		header.set_difficulty(ethparams.minimum_difficulty);
-		let ethash = Ethash::new(&::std::env::temp_dir(), spec.params().clone(), ethparams, BTreeMap::new());
-		assert!(ethash.verify_block_family(&header, &parent_header, None).is_ok());
-
-		parent_header.set_number(9);
-		header.set_number(parent_header.number() + 1);
-
-		parent_header.set_gas_limit(99_999.into());
-		header.set_gas_limit(100_000.into());
-		assert!(ethash.verify_block_family(&header, &parent_header, None).is_ok());
-
-		parent_header.set_gas_limit(200_000.into());
-		header.set_gas_limit(200_000.into());
-		assert!(ethash.verify_block_family(&header, &parent_header, None).is_ok());
-
-		parent_header.set_gas_limit(100_000.into());
-		header.set_gas_limit(100_001.into());
-		assert!(ethash.verify_block_family(&header, &parent_header, None).is_err());
-
-		parent_header.set_gas_limit(200_000.into());
-		header.set_gas_limit(200_001.into());
-		assert!(ethash.verify_block_family(&header, &parent_header, None).is_err());
-	}
-
-	#[test]
-	fn rejects_transactions_below_min_gas_price() {
-		use ethkey::{Generator, Random};
-		use transaction::{Transaction, Action};
-
-		let spec = new_homestead_test();
-		let mut ethparams = get_default_ethash_params();
-		ethparams.min_gas_price_transition = 10;
-		ethparams.min_gas_price = 100000.into();
-
-		let mut header = Header::default();
-		header.set_number(1);
-
-		let keypair = Random.generate().unwrap();
-		let tx1 = Transaction {
-			action: Action::Create,
-			value: U256::zero(),
-			data: Vec::new(),
-			gas: 100_000.into(),
-			gas_price: 100_000.into(),
-			nonce: U256::zero(),
-		}.sign(keypair.secret(), None).into();
-
-		let tx2 = Transaction {
-			action: Action::Create,
-			value: U256::zero(),
-			data: Vec::new(),
-			gas: 100_000.into(),
-			gas_price: 99_999.into(),
-			nonce: U256::zero(),
-		}.sign(keypair.secret(), None).into();
-
-		let ethash = Ethash::new(&::std::env::temp_dir(), spec.params().clone(), ethparams, BTreeMap::new());
-		assert!(ethash.verify_transaction_basic(&tx1, &header).is_ok());
-		assert!(ethash.verify_transaction_basic(&tx2, &header).is_ok());
-
-		header.set_number(10);
-		assert!(ethash.verify_transaction_basic(&tx1, &header).is_ok());
-		assert!(ethash.verify_transaction_basic(&tx2, &header).is_err());
-	}
 }

ethcore/src/ethereum/mod.rs

@@ -27,7 +27,7 @@ pub mod denominations;
 pub use self::ethash::{Ethash};
 pub use self::denominations::*;
 
-use std::path::Path;
+use machine::EthereumMachine;
 use super::spec::*;
 
 /// Most recent fork block that we support on Mainnet.
@@ -39,33 +39,51 @@ pub const FORK_SUPPORTED_ROPSTEN: u64 = 10;
 /// Most recent fork block that we support on Kovan.
 pub const FORK_SUPPORTED_KOVAN: u64 = 0;
 
-fn load<'a, T: 'a + Into<Option<&'a Path>>>(cache_dir: T, b: &[u8]) -> Spec {
-	match cache_dir.into() {
-		Some(path) => Spec::load(path, b),
+fn load<'a, T: Into<Option<SpecParams<'a>>>>(params: T, b: &[u8]) -> Spec {
+	match params.into() {
+		Some(params) => Spec::load(params, b),
 		None => Spec::load(&::std::env::temp_dir(), b)
 	}.expect("chain spec is invalid")
 }
 
+fn load_machine(b: &[u8]) -> EthereumMachine {
+	Spec::load_machine(b).expect("chain spec is invalid")
+}
+
 /// Create a new Foundation Olympic chain spec.
-pub fn new_olympic(cache_dir: &Path) -> Spec { load(cache_dir, include_bytes!("../../res/ethereum/olympic.json")) }
+pub fn new_olympic<'a, T: Into<SpecParams<'a>>>(params: T) -> Spec {
+	load(params.into(), include_bytes!("../../res/ethereum/olympic.json"))
+}
 
 /// Create a new Foundation Mainnet chain spec.
-pub fn new_foundation(cache_dir: &Path) -> Spec { load(cache_dir, include_bytes!("../../res/ethereum/foundation.json")) }
+pub fn new_foundation<'a, T: Into<SpecParams<'a>>>(params: T) -> Spec {
+	load(params.into(), include_bytes!("../../res/ethereum/foundation.json"))
+}
 
 /// Create a new Classic Mainnet chain spec without the DAO hardfork.
-pub fn new_classic(cache_dir: &Path) -> Spec { load(cache_dir, include_bytes!("../../res/ethereum/classic.json")) }
+pub fn new_classic<'a, T: Into<SpecParams<'a>>>(params: T) -> Spec {
+	load(params.into(), include_bytes!("../../res/ethereum/classic.json"))
+}
 
 /// Create a new Expanse mainnet chain spec.
-pub fn new_expanse(cache_dir: &Path) -> Spec { load(cache_dir, include_bytes!("../../res/ethereum/expanse.json")) }
+pub fn new_expanse<'a, T: Into<SpecParams<'a>>>(params: T) -> Spec {
+	load(params.into(), include_bytes!("../../res/ethereum/expanse.json"))
+}
 
 /// Create a new Kovan testnet chain spec.
-pub fn new_kovan(cache_dir: &Path) -> Spec { load(cache_dir, include_bytes!("../../res/ethereum/kovan.json")) }
+pub fn new_kovan<'a, T: Into<SpecParams<'a>>>(params: T) -> Spec {
+	load(params.into(), include_bytes!("../../res/ethereum/kovan.json"))
+}
 
 /// Create a new Foundation Ropsten chain spec.
-pub fn new_ropsten(cache_dir: &Path) -> Spec { load(cache_dir, include_bytes!("../../res/ethereum/ropsten.json")) }
+pub fn new_ropsten<'a, T: Into<SpecParams<'a>>>(params: T) -> Spec {
+	load(params.into(), include_bytes!("../../res/ethereum/ropsten.json"))
+}
 
 /// Create a new Morden chain spec.
-pub fn new_morden(cache_dir: &Path) -> Spec { load(cache_dir, include_bytes!("../../res/ethereum/morden.json")) }
+pub fn new_morden<'a, T: Into<SpecParams<'a>>>(params: T) -> Spec {
+	load(params.into(), include_bytes!("../../res/ethereum/morden.json"))
+}
 
 // For tests
 
@@ -93,6 +111,20 @@ pub fn new_byzantium_test() -> Spec { load(None, include_bytes!("../../res/ether
 /// Create a new Foundation Constantinople era spec.
 pub fn new_constantinople_test() -> Spec { load(None, include_bytes!("../../res/ethereum/constantinople_test.json")) }
 
+// For tests
+
+/// Create a new Foundation Frontier-era chain spec as though it never changes to Homestead.
+pub fn new_frontier_test_machine() -> EthereumMachine { load_machine(include_bytes!("../../res/ethereum/frontier_test.json")) }
+
+/// Create a new Foundation Homestead-era chain spec as though it never changed from Frontier.
+pub fn new_homestead_test_machine() -> EthereumMachine { load_machine(include_bytes!("../../res/ethereum/homestead_test.json")) }
+
+/// Create a new Foundation Byzantium era spec.
+pub fn new_byzantium_test_machine() -> EthereumMachine { load_machine(include_bytes!("../../res/ethereum/byzantium_test.json")) }
+
+/// Create a new Foundation Constantinople era spec.
+pub fn new_constantinople_test_machine() -> EthereumMachine { load_machine(include_bytes!("../../res/ethereum/constantinople_test.json")) }
+
 #[cfg(test)]
 mod tests {
 	use bigint::prelude::U256;

ethcore/src/executive.rs

@@ -23,7 +23,7 @@ use bigint::hash::H256;
 use util::*;
 use bytes::{Bytes, BytesRef};
 use state::{Backend as StateBackend, State, Substate, CleanupMode};
-use engines::Engine;
+use machine::EthereumMachine as Machine;
 use vm::EnvInfo;
 use error::ExecutionError;
 use evm::{CallType, Factory, Finalize, FinalizationResult};
@@ -154,10 +154,8 @@ impl TransactOptions<trace::NoopTracer, trace::NoopVMTracer> {
 	}
 }
 
-pub fn executor<E>(engine: &E, vm_factory: &Factory, params: &ActionParams)
-	-> Box<vm::Vm> where E: Engine + ?Sized
-{
-	if engine.supports_wasm() && params.code.as_ref().map_or(false, |code| code.len() > 4 && &code[0..4] == WASM_MAGIC_NUMBER) {
+pub fn executor(machine: &Machine, vm_factory: &Factory, params: &ActionParams) -> Box<vm::Vm> {
+	if machine.supports_wasm() && params.code.as_ref().map_or(false, |code| code.len() > 4 && &code[0..4] == WASM_MAGIC_NUMBER) {
 		Box::new(
 			wasm::WasmInterpreter::new()
 				// prefer to fail fast
@@ -169,32 +167,32 @@ pub fn executor<E>(engine: &E, vm_factory: &Factory, params: &ActionParams)
 }
 
 /// Transaction executor.
-pub struct Executive<'a, B: 'a + StateBackend, E: 'a + Engine + ?Sized> {
+pub struct Executive<'a, B: 'a + StateBackend> {
 	state: &'a mut State<B>,
 	info: &'a EnvInfo,
-	engine: &'a E,
+	machine: &'a Machine,
 	depth: usize,
 	static_flag: bool,
 }
 
-impl<'a, B: 'a + StateBackend, E: Engine + ?Sized> Executive<'a, B, E> {
+impl<'a, B: 'a + StateBackend> Executive<'a, B> {
 	/// Basic constructor.
-	pub fn new(state: &'a mut State<B>, info: &'a EnvInfo, engine: &'a E) -> Self {
+	pub fn new(state: &'a mut State<B>, info: &'a EnvInfo, machine: &'a Machine) -> Self {
 		Executive {
 			state: state,
 			info: info,
-			engine: engine,
+			machine: machine,
 			depth: 0,
 			static_flag: false,
 		}
 	}
 
 	/// Populates executive from parent properties. Increments executive depth.
-	pub fn from_parent(state: &'a mut State<B>, info: &'a EnvInfo, engine: &'a E, parent_depth: usize, static_flag: bool) -> Self {
+	pub fn from_parent(state: &'a mut State<B>, info: &'a EnvInfo, machine: &'a Machine, parent_depth: usize, static_flag: bool) -> Self {
 		Executive {
 			state: state,
 			info: info,
-			engine: engine,
+			machine: machine,
 			depth: parent_depth + 1,
 			static_flag: static_flag,
 		}
@@ -209,9 +207,9 @@ impl<'a, B: 'a + StateBackend, E: Engine + ?Sized> Executive<'a, B, E> {
 		tracer: &'any mut T,
 		vm_tracer: &'any mut V,
 		static_call: bool,
-	) -> Externalities<'any, T, V, B, E> where T: Tracer, V: VMTracer {
+	) -> Externalities<'any, T, V, B> where T: Tracer, V: VMTracer {
 		let is_static = self.static_flag || static_call;
-		Externalities::new(self.state, self.info, self.engine, self.depth, origin_info, substate, output, tracer, vm_tracer, is_static)
+		Externalities::new(self.state, self.info, self.machine, self.depth, origin_info, substate, output, tracer, vm_tracer, is_static)
 	}
 
 	/// This function should be used to execute transaction.
@@ -250,7 +248,7 @@ impl<'a, B: 'a + StateBackend, E: Engine + ?Sized> Executive<'a, B, E> {
 		let sender = t.sender();
 		let nonce = self.state.nonce(&sender)?;
 
-		let schedule = self.engine.schedule(self.info.number);
+		let schedule = self.machine.schedule(self.info.number);
 		let base_gas_required = U256::from(t.gas_required(&schedule));
 
 		if t.gas < base_gas_required {
@@ -298,7 +296,7 @@ impl<'a, B: 'a + StateBackend, E: Engine + ?Sized> Executive<'a, B, E> {
 
 		let (result, output) = match t.action {
 			Action::Create => {
-				let (new_address, code_hash) = contract_address(self.engine.create_address_scheme(self.info.number), &sender, &nonce, &t.data);
+				let (new_address, code_hash) = contract_address(self.machine.create_address_scheme(self.info.number), &sender, &nonce, &t.data);
 				let params = ActionParams {
 					code_address: new_address.clone(),
 					code_hash: code_hash,
@@ -355,19 +353,19 @@ impl<'a, B: 'a + StateBackend, E: Engine + ?Sized> Executive<'a, B, E> {
 			let vm_factory = self.state.vm_factory();
 			let mut ext = self.as_externalities(OriginInfo::from(&params), unconfirmed_substate, output_policy, tracer, vm_tracer, static_call);
 			trace!(target: "executive", "ext.schedule.have_delegate_call: {}", ext.schedule().have_delegate_call);
-			return executor(self.engine, &vm_factory, &params).exec(params, &mut ext).finalize(ext);
+			return executor(self.machine, &vm_factory, &params).exec(params, &mut ext).finalize(ext);
 		}
 
 		// Start in new thread to reset stack
 		// TODO [todr] No thread builder yet, so we need to reset once for a while
 		// https://github.com/aturon/crossbeam/issues/16
 		crossbeam::scope(|scope| {
-			let engine = self.engine;
+			let machine = self.machine;
 			let vm_factory = self.state.vm_factory();
 			let mut ext = self.as_externalities(OriginInfo::from(&params), unconfirmed_substate, output_policy, tracer, vm_tracer, static_call);
 
 			scope.spawn(move || {
-				executor(engine, &vm_factory, &params).exec(params, &mut ext).finalize(ext)
+				executor(machine, &vm_factory, &params).exec(params, &mut ext).finalize(ext)
 			})
 		}).join()
 	}
@@ -396,7 +394,7 @@ impl<'a, B: 'a + StateBackend, E: Engine + ?Sized> Executive<'a, B, E> {
 		// backup used in case of running out of gas
 		self.state.checkpoint();
 
-		let schedule = self.engine.schedule(self.info.number);
+		let schedule = self.machine.schedule(self.info.number);
 
 		// at first, transfer value to destination
 		if let ActionValue::Transfer(val) = params.value {
@@ -404,7 +402,7 @@ impl<'a, B: 'a + StateBackend, E: Engine + ?Sized> Executive<'a, B, E> {
 		}
 
 		// if destination is builtin, try to execute it
-		if let Some(builtin) = self.engine.builtin(&params.code_address, self.info.number) {
+		if let Some(builtin) = self.machine.builtin(&params.code_address, self.info.number) {
 			// Engines aren't supposed to return builtins until activation, but
 			// prefer to fail rather than silently break consensus.
 			if !builtin.is_active(self.info.number) {
@@ -542,7 +540,7 @@ impl<'a, B: 'a + StateBackend, E: Engine + ?Sized> Executive<'a, B, E> {
 		let mut unconfirmed_substate = Substate::new();
 
 		// create contract and transfer value to it if necessary
-		let schedule = self.engine.schedule(self.info.number);
+		let schedule = self.machine.schedule(self.info.number);
 		let nonce_offset = if schedule.no_empty {1} else {0}.into();
 		let prev_bal = self.state.balance(&params.address)?;
 		if let ActionValue::Transfer(val) = params.value {
@@ -591,7 +589,7 @@ impl<'a, B: 'a + StateBackend, E: Engine + ?Sized> Executive<'a, B, E> {
 		trace: Vec<FlatTrace>,
 		vm_trace: Option<VMTrace>
 	) -> ExecutionResult {
-		let schedule = self.engine.schedule(self.info.number);
+		let schedule = self.machine.schedule(self.info.number);
 
 		// refunds from SSTORE nonzero -> zero
 		let sstore_refunds = U256::from(schedule.sstore_refund_gas) * substate.sstore_clears_count;
@@ -700,6 +698,7 @@ mod tests {
 	use vm::{ActionParams, ActionValue, CallType, EnvInfo, CreateContractAddress};
 	use evm::{Factory, VMType};
 	use error::ExecutionError;
+	use machine::EthereumMachine;
 	use state::{Substate, CleanupMode};
 	use tests::helpers::*;
 	use trace::trace;
@@ -707,6 +706,12 @@ mod tests {
 	use trace::{VMTrace, VMOperation, VMExecutedOperation, MemoryDiff, StorageDiff, VMTracer, NoopVMTracer, ExecutiveVMTracer};
 	use transaction::{Action, Transaction};
 
+	fn make_frontier_machine(max_depth: usize) -> EthereumMachine {
+		let mut machine = ::ethereum::new_frontier_test_machine();
+		machine.set_schedule_creation_rules(Box::new(move |s, _| s.max_depth = max_depth));
+		machine
+	}
+
 	#[test]
 	fn test_contract_address() {
 		let address = Address::from_str("0f572e5295c57f15886f9b263e2f6d2d6c7b5ec6").unwrap();
@@ -728,11 +733,11 @@ mod tests {
 		let mut state = get_temp_state_with_factory(factory);
 		state.add_balance(&sender, &U256::from(0x100u64), CleanupMode::NoEmpty).unwrap();
 		let info = EnvInfo::default();
-		let engine = TestEngine::new(0);
+		let machine = make_frontier_machine(0);
 		let mut substate = Substate::new();
 
 		let FinalizationResult { gas_left, .. } = {
-			let mut ex = Executive::new(&mut state, &info, &engine);
+			let mut ex = Executive::new(&mut state, &info, &machine);
 			ex.create(params, &mut substate, &mut None, &mut NoopTracer, &mut NoopVMTracer).unwrap()
 		};
 
@@ -786,11 +791,11 @@ mod tests {
 		let mut state = get_temp_state_with_factory(factory);
 		state.add_balance(&sender, &U256::from(100), CleanupMode::NoEmpty).unwrap();
 		let info = EnvInfo::default();
-		let engine = TestEngine::new(0);
+		let machine = make_frontier_machine(0);
 		let mut substate = Substate::new();
 
 		let FinalizationResult { gas_left, .. } = {
-			let mut ex = Executive::new(&mut state, &info, &engine);
+			let mut ex = Executive::new(&mut state, &info, &machine);
 			ex.create(params, &mut substate, &mut None, &mut NoopTracer, &mut NoopVMTracer).unwrap()
 		};
 
@@ -842,13 +847,13 @@ mod tests {
 		let mut state = get_temp_state();
 		state.add_balance(&sender, &U256::from(100), CleanupMode::NoEmpty).unwrap();
 		let info = EnvInfo::default();
-		let engine = TestEngine::new(5);
+		let machine = make_frontier_machine(5);
 		let mut substate = Substate::new();
 		let mut tracer = ExecutiveTracer::default();
 		let mut vm_tracer = ExecutiveVMTracer::toplevel();
 
 		let FinalizationResult { gas_left, .. } = {
-			let mut ex = Executive::new(&mut state, &info, &engine);
+			let mut ex = Executive::new(&mut state, &info, &machine);
 			let output = BytesRef::Fixed(&mut[0u8;0]);
 			ex.call(params, &mut substate, output, &mut tracer, &mut vm_tracer).unwrap()
 		};
@@ -951,13 +956,13 @@ mod tests {
 		let mut state = get_temp_state();
 		state.add_balance(&sender, &U256::from(100), CleanupMode::NoEmpty).unwrap();
 		let info = EnvInfo::default();
-		let engine = TestEngine::new(5);
+		let machine = make_frontier_machine(5);
 		let mut substate = Substate::new();
 		let mut tracer = ExecutiveTracer::default();
 		let mut vm_tracer = ExecutiveVMTracer::toplevel();
 
 		let FinalizationResult { gas_left, .. } = {
-			let mut ex = Executive::new(&mut state, &info, &engine);
+			let mut ex = Executive::new(&mut state, &info, &machine);
 			ex.create(params.clone(), &mut substate, &mut None, &mut tracer, &mut vm_tracer).unwrap()
 		};
 
@@ -1038,11 +1043,11 @@ mod tests {
 		let mut state = get_temp_state_with_factory(factory);
 		state.add_balance(&sender, &U256::from(100), CleanupMode::NoEmpty).unwrap();
 		let info = EnvInfo::default();
-		let engine = TestEngine::new(0);
+		let machine = make_frontier_machine(0);
 		let mut substate = Substate::new();
 
 		let FinalizationResult { gas_left, .. } = {
-			let mut ex = Executive::new(&mut state, &info, &engine);
+			let mut ex = Executive::new(&mut state, &info, &machine);
 			ex.create(params, &mut substate, &mut None, &mut NoopTracer, &mut NoopVMTracer).unwrap()
 		};
 
@@ -1089,11 +1094,11 @@ mod tests {
 		let mut state = get_temp_state_with_factory(factory);
 		state.add_balance(&sender, &U256::from(100), CleanupMode::NoEmpty).unwrap();
 		let info = EnvInfo::default();
-		let engine = TestEngine::new(1024);
+		let machine = make_frontier_machine(1024);
 		let mut substate = Substate::new();
 
 		{
-			let mut ex = Executive::new(&mut state, &info, &engine);
+			let mut ex = Executive::new(&mut state, &info, &machine);
 			ex.create(params, &mut substate, &mut None, &mut NoopTracer, &mut NoopVMTracer).unwrap();
 		}
 
@@ -1149,11 +1154,11 @@ mod tests {
 		state.add_balance(&sender, &U256::from(100_000), CleanupMode::NoEmpty).unwrap();
 
 		let info = EnvInfo::default();
-		let engine = TestEngine::new(0);
+		let machine = make_frontier_machine(0);
 		let mut substate = Substate::new();
 
 		let FinalizationResult { gas_left, .. } = {
-			let mut ex = Executive::new(&mut state, &info, &engine);
+			let mut ex = Executive::new(&mut state, &info, &machine);
 			ex.call(params, &mut substate, BytesRef::Fixed(&mut []), &mut NoopTracer, &mut NoopVMTracer).unwrap()
 		};
 
@@ -1193,11 +1198,11 @@ mod tests {
 		let mut state = get_temp_state_with_factory(factory);
 		state.init_code(&address, code).unwrap();
 		let info = EnvInfo::default();
-		let engine = TestEngine::new(0);
+		let machine = make_frontier_machine(0);
 		let mut substate = Substate::new();
 
 		let FinalizationResult { gas_left, .. } = {
-			let mut ex = Executive::new(&mut state, &info, &engine);
+			let mut ex = Executive::new(&mut state, &info, &machine);
 			ex.call(params, &mut substate, BytesRef::Fixed(&mut []), &mut NoopTracer, &mut NoopVMTracer).unwrap()
 		};
 
@@ -1226,10 +1231,10 @@ mod tests {
 		state.add_balance(&sender, &U256::from(18), CleanupMode::NoEmpty).unwrap();
 		let mut info = EnvInfo::default();
 		info.gas_limit = U256::from(100_000);
-		let engine = TestEngine::new(0);
+		let machine = make_frontier_machine(0);
 
 		let executed = {
-			let mut ex = Executive::new(&mut state, &info, &engine);
+			let mut ex = Executive::new(&mut state, &info, &machine);
 			let opts = TransactOptions::with_no_tracing();
 			ex.transact(&t, opts).unwrap()
 		};
@@ -1263,10 +1268,10 @@ mod tests {
 		state.add_balance(&sender, &U256::from(17), CleanupMode::NoEmpty).unwrap();
 		let mut info = EnvInfo::default();
 		info.gas_limit = U256::from(100_000);
-		let engine = TestEngine::new(0);
+		let machine = make_frontier_machine(0);
 
 		let res = {
-			let mut ex = Executive::new(&mut state, &info, &engine);
+			let mut ex = Executive::new(&mut state, &info, &machine);
 			let opts = TransactOptions::with_no_tracing();
 			ex.transact(&t, opts)
 		};
@@ -1296,10 +1301,10 @@ mod tests {
 		let mut info = EnvInfo::default();
 		info.gas_used = U256::from(20_000);
 		info.gas_limit = U256::from(100_000);
-		let engine = TestEngine::new(0);
+		let machine = make_frontier_machine(0);
 
 		let res = {
-			let mut ex = Executive::new(&mut state, &info, &engine);
+			let mut ex = Executive::new(&mut state, &info, &machine);
 			let opts = TransactOptions::with_no_tracing();
 			ex.transact(&t, opts)
 		};
@@ -1329,10 +1334,10 @@ mod tests {
 		state.add_balance(&sender, &U256::from(100_017), CleanupMode::NoEmpty).unwrap();
 		let mut info = EnvInfo::default();
 		info.gas_limit = U256::from(100_000);
-		let engine = TestEngine::new(0);
+		let machine = make_frontier_machine(0);
 
 		let res = {
-			let mut ex = Executive::new(&mut state, &info, &engine);
+			let mut ex = Executive::new(&mut state, &info, &machine);
 			let opts = TransactOptions::with_no_tracing();
 			ex.transact(&t, opts)
 		};
@@ -1362,11 +1367,11 @@ mod tests {
 		let mut state = get_temp_state_with_factory(factory);
 		state.add_balance(&sender, &U256::from_str("152d02c7e14af6800000").unwrap(), CleanupMode::NoEmpty).unwrap();
 		let info = EnvInfo::default();
-		let engine = TestEngine::new(0);
+		let machine = make_frontier_machine(0);
 		let mut substate = Substate::new();
 
 		let result = {
-			let mut ex = Executive::new(&mut state, &info, &engine);
+			let mut ex = Executive::new(&mut state, &info, &machine);
 			ex.create(params, &mut substate, &mut None, &mut NoopTracer, &mut NoopVMTracer)
 		};
 
@@ -1397,12 +1402,12 @@ mod tests {
 		let mut state = get_temp_state_with_factory(factory);
 		state.add_balance(&sender, &U256::from_str("152d02c7e14af68000000").unwrap(), CleanupMode::NoEmpty).unwrap();
 		let info = EnvInfo::default();
-		let engine = TestEngine::new_byzantium();
+		let machine = ::ethereum::new_byzantium_test_machine();
 		let mut substate = Substate::new();
 
 		let mut output = [0u8; 14];
 		let FinalizationResult { gas_left: result, .. } = {
-			let mut ex = Executive::new(&mut state, &info, &engine);
+			let mut ex = Executive::new(&mut state, &info, &machine);
 			ex.call(params, &mut substate, BytesRef::Fixed(&mut output), &mut NoopTracer, &mut NoopVMTracer).unwrap()
 		};
 

ethcore/src/externalities.rs

@@ -22,7 +22,7 @@ use bigint::hash::H256;
 use util::*;
 use bytes::{Bytes, BytesRef};
 use state::{Backend as StateBackend, State, Substate, CleanupMode};
-use engines::Engine;
+use machine::EthereumMachine as Machine;
 use executive::*;
 use vm::{
 	self, ActionParams, ActionValue, EnvInfo, CallType, Schedule,
@@ -65,12 +65,12 @@ impl OriginInfo {
 }
 
 /// Implementation of evm Externalities.
-pub struct Externalities<'a, T: 'a, V: 'a, B: 'a, E: 'a + Engine + ?Sized>
+pub struct Externalities<'a, T: 'a, V: 'a, B: 'a>
 	where T: Tracer, V:  VMTracer, B: StateBackend
 {
 	state: &'a mut State<B>,
 	env_info: &'a EnvInfo,
-	engine: &'a E,
+	machine: &'a Machine,
 	depth: usize,
 	origin_info: OriginInfo,
 	substate: &'a mut Substate,
@@ -81,14 +81,14 @@ pub struct Externalities<'a, T: 'a, V: 'a, B: 'a, E: 'a + Engine + ?Sized>
 	static_flag: bool,
 }
 
-impl<'a, T: 'a, V: 'a, B: 'a, E: 'a> Externalities<'a, T, V, B, E>
-	where T: Tracer, V: VMTracer, B: StateBackend, E: Engine + ?Sized
+impl<'a, T: 'a, V: 'a, B: 'a> Externalities<'a, T, V, B>
+	where T: Tracer, V: VMTracer, B: StateBackend
 {
 	/// Basic `Externalities` constructor.
 	#[cfg_attr(feature="dev", allow(too_many_arguments))]
 	pub fn new(state: &'a mut State<B>,
 		env_info: &'a EnvInfo,
-		engine: &'a E,
+		machine: &'a Machine,
 		depth: usize,
 		origin_info: OriginInfo,
 		substate: &'a mut Substate,
@@ -100,11 +100,11 @@ impl<'a, T: 'a, V: 'a, B: 'a, E: 'a> Externalities<'a, T, V, B, E>
 		Externalities {
 			state: state,
 			env_info: env_info,
-			engine: engine,
+			machine: machine,
 			depth: depth,
 			origin_info: origin_info,
 			substate: substate,
-			schedule: engine.schedule(env_info.number),
+			schedule: machine.schedule(env_info.number),
 			output: output,
 			tracer: tracer,
 			vm_tracer: vm_tracer,
@@ -113,8 +113,8 @@ impl<'a, T: 'a, V: 'a, B: 'a, E: 'a> Externalities<'a, T, V, B, E>
 	}
 }
 
-impl<'a, T: 'a, V: 'a, B: 'a, E: 'a> Ext for Externalities<'a, T, V, B, E>
-	where T: Tracer, V: VMTracer, B: StateBackend, E: Engine + ?Sized
+impl<'a, T: 'a, V: 'a, B: 'a> Ext for Externalities<'a, T, V, B>
+	where T: Tracer, V: VMTracer, B: StateBackend
 {
 	fn storage_at(&self, key: &H256) -> vm::Result<H256> {
 		self.state.storage_at(&self.origin_info.address, key).map_err(Into::into)
@@ -149,8 +149,8 @@ impl<'a, T: 'a, V: 'a, B: 'a, E: 'a> Ext for Externalities<'a, T, V, B, E>
 	}
 
 	fn blockhash(&mut self, number: &U256) -> H256 {
-		if self.env_info.number + 256 >= self.engine.params().eip210_transition {
-			let blockhash_contract_address = self.engine.params().eip210_contract_address;
+		if self.env_info.number + 256 >= self.machine.params().eip210_transition {
+			let blockhash_contract_address = self.machine.params().eip210_contract_address;
 			let code_res = self.state.code(&blockhash_contract_address)
 				.and_then(|code| self.state.code_hash(&blockhash_contract_address).map(|hash| (code, hash)));
 
@@ -165,7 +165,7 @@ impl<'a, T: 'a, V: 'a, B: 'a, E: 'a> Ext for Externalities<'a, T, V, B, E>
 				value: ActionValue::Apparent(self.origin_info.value),
 				code_address: blockhash_contract_address.clone(),
 				origin: self.origin_info.origin.clone(),
-				gas: self.engine.params().eip210_contract_gas,
+				gas: self.machine.params().eip210_contract_gas,
 				gas_price: 0.into(),
 				code: code,
 				code_hash: Some(code_hash),
@@ -174,7 +174,7 @@ impl<'a, T: 'a, V: 'a, B: 'a, E: 'a> Ext for Externalities<'a, T, V, B, E>
 			};
 
 			let mut output = H256::new();
-			let mut ex = Executive::new(self.state, self.env_info, self.engine);
+			let mut ex = Executive::new(self.state, self.env_info, self.machine);
 			let r = ex.call(params, self.substate, BytesRef::Fixed(&mut output), self.tracer, self.vm_tracer);
 			trace!("ext: blockhash contract({}) -> {:?}({}) self.env_info.number={}\n", number, r, output, self.env_info.number);
 			output
@@ -229,7 +229,7 @@ impl<'a, T: 'a, V: 'a, B: 'a, E: 'a> Ext for Externalities<'a, T, V, B, E>
 				}
 			}
 		}
-		let mut ex = Executive::from_parent(self.state, self.env_info, self.engine, self.depth, self.static_flag);
+		let mut ex = Executive::from_parent(self.state, self.env_info, self.machine, self.depth, self.static_flag);
 
 		// TODO: handle internal error separately
 		match ex.create(params, self.substate, &mut None, self.tracer, self.vm_tracer) {
@@ -283,7 +283,7 @@ impl<'a, T: 'a, V: 'a, B: 'a, E: 'a> Ext for Externalities<'a, T, V, B, E>
 			params.value = ActionValue::Transfer(value);
 		}
 
-		let mut ex = Executive::from_parent(self.state, self.env_info, self.engine, self.depth, self.static_flag);
+		let mut ex = Executive::from_parent(self.state, self.env_info, self.machine, self.depth, self.static_flag);
 
 		match ex.call(params, self.substate, BytesRef::Fixed(output), self.tracer, self.vm_tracer) {
 			Ok(FinalizationResult{ gas_left, return_data, apply_state: true }) => MessageCallResult::Success(gas_left, return_data),
@@ -414,7 +414,6 @@ impl<'a, T: 'a, V: 'a, B: 'a, E: 'a> Ext for Externalities<'a, T, V, B, E>
 #[cfg(test)]
 mod tests {
 	use util::*;
-	use engines::Engine;
 	use evm::{EnvInfo, Ext, CallType};
 	use state::{State, Substate};
 	use tests::helpers::*;
@@ -444,7 +443,7 @@ mod tests {
 
 	struct TestSetup {
 		state: State<::state_db::StateDB>,
-		engine: Arc<Engine>,
+		machine: ::machine::EthereumMachine,
 		sub_state: Substate,
 		env_info: EnvInfo
 	}
@@ -459,7 +458,7 @@ mod tests {
 		fn new() -> Self {
 			TestSetup {
 				state: get_temp_state(),
-				engine: get_test_spec().engine,
+				machine: ::spec::Spec::new_test_machine(),
 				sub_state: Substate::new(),
 				env_info: get_test_env_info()
 			}
@@ -473,7 +472,7 @@ mod tests {
 		let mut tracer = NoopTracer;
 		let mut vm_tracer = NoopVMTracer;
 
-		let ext = Externalities::new(state, &setup.env_info, &*setup.engine, 0, get_test_origin(), &mut setup.sub_state, OutputPolicy::InitContract(None), &mut tracer, &mut vm_tracer, false);
+		let ext = Externalities::new(state, &setup.env_info, &setup.machine, 0, get_test_origin(), &mut setup.sub_state, OutputPolicy::InitContract(None), &mut tracer, &mut vm_tracer, false);
 
 		assert_eq!(ext.env_info().number, 100);
 	}
@@ -485,7 +484,7 @@ mod tests {
 		let mut tracer = NoopTracer;
 		let mut vm_tracer = NoopVMTracer;
 
-		let mut ext = Externalities::new(state, &setup.env_info, &*setup.engine, 0, get_test_origin(), &mut setup.sub_state, OutputPolicy::InitContract(None), &mut tracer, &mut vm_tracer, false);
+		let mut ext = Externalities::new(state, &setup.env_info, &setup.machine, 0, get_test_origin(), &mut setup.sub_state, OutputPolicy::InitContract(None), &mut tracer, &mut vm_tracer, false);
 
 		let hash = ext.blockhash(&"0000000000000000000000000000000000000000000000000000000000120000".parse::<U256>().unwrap());
 
@@ -509,7 +508,7 @@ mod tests {
 		let mut tracer = NoopTracer;
 		let mut vm_tracer = NoopVMTracer;
 
-		let mut ext = Externalities::new(state, &setup.env_info, &*setup.engine, 0, get_test_origin(), &mut setup.sub_state, OutputPolicy::InitContract(None), &mut tracer, &mut vm_tracer, false);
+		let mut ext = Externalities::new(state, &setup.env_info, &setup.machine, 0, get_test_origin(), &mut setup.sub_state, OutputPolicy::InitContract(None), &mut tracer, &mut vm_tracer, false);
 
 		let hash = ext.blockhash(&"0000000000000000000000000000000000000000000000000000000000120000".parse::<U256>().unwrap());
 
@@ -524,7 +523,7 @@ mod tests {
 		let mut tracer = NoopTracer;
 		let mut vm_tracer = NoopVMTracer;
 
-		let mut ext = Externalities::new(state, &setup.env_info, &*setup.engine, 0, get_test_origin(), &mut setup.sub_state, OutputPolicy::InitContract(None), &mut tracer, &mut vm_tracer, false);
+		let mut ext = Externalities::new(state, &setup.env_info, &setup.machine, 0, get_test_origin(), &mut setup.sub_state, OutputPolicy::InitContract(None), &mut tracer, &mut vm_tracer, false);
 
 		let mut output = vec![];
 
@@ -552,7 +551,7 @@ mod tests {
 		let mut vm_tracer = NoopVMTracer;
 
 		{
-			let mut ext = Externalities::new(state, &setup.env_info, &*setup.engine, 0, get_test_origin(), &mut setup.sub_state, OutputPolicy::InitContract(None), &mut tracer, &mut vm_tracer, false);
+			let mut ext = Externalities::new(state, &setup.env_info, &setup.machine, 0, get_test_origin(), &mut setup.sub_state, OutputPolicy::InitContract(None), &mut tracer, &mut vm_tracer, false);
 			ext.log(log_topics, &log_data).unwrap();
 		}
 
@@ -569,7 +568,7 @@ mod tests {
 		let mut vm_tracer = NoopVMTracer;
 
 		{
-			let mut ext = Externalities::new(state, &setup.env_info, &*setup.engine, 0, get_test_origin(), &mut setup.sub_state, OutputPolicy::InitContract(None), &mut tracer, &mut vm_tracer, false);
+			let mut ext = Externalities::new(state, &setup.env_info, &setup.machine, 0, get_test_origin(), &mut setup.sub_state, OutputPolicy::InitContract(None), &mut tracer, &mut vm_tracer, false);
 			ext.suicide(refund_account).unwrap();
 		}
 

ethcore/src/header.rs

@@ -312,6 +312,23 @@ impl HeapSizeOf for Header {
 	}
 }
 
+impl ::parity_machine::Header for Header {
+	fn bare_hash(&self) -> H256 { Header::bare_hash(self) }
+
+	fn hash(&self) -> H256 { Header::hash(self) }
+
+	fn seal(&self) -> &[Vec<u8>] { Header::seal(self) }
+
+	fn author(&self) -> &Address { Header::author(self) }
+
+	fn number(&self) -> BlockNumber { Header::number(self) }
+}
+
+impl ::parity_machine::ScoredHeader for Header {
+	fn score(&self) -> &U256 { self.difficulty() }
+	fn set_score(&mut self, score: U256) { self.set_difficulty(score) }
+}
+
 #[cfg(test)]
 mod tests {
 	use rustc_hex::FromHex;

ethcore/src/json_tests/executive.rs

@@ -18,7 +18,6 @@ use std::sync::Arc;
 use super::test_common::*;
 use state::{Backend as StateBackend, State, Substate};
 use executive::*;
-use engines::Engine;
 use evm::{VMType, Finalize};
 use vm::{
 	self, ActionParams, CallType, Schedule, Ext,
@@ -34,6 +33,7 @@ use bytes::{Bytes, BytesRef};
 use trie;
 use rlp::RlpStream;
 use hash::keccak;
+use machine::EthereumMachine as Machine;
 
 #[derive(Debug, PartialEq, Clone)]
 struct CallCreate {
@@ -57,22 +57,22 @@ impl From<ethjson::vm::Call> for CallCreate {
 
 /// Tiny wrapper around executive externalities.
 /// Stores callcreates.
-struct TestExt<'a, T: 'a, V: 'a, B: 'a, E: 'a>
-	where T: Tracer, V: VMTracer, B: StateBackend, E: Engine + ?Sized
+struct TestExt<'a, T: 'a, V: 'a, B: 'a>
+	where T: Tracer, V: VMTracer, B: StateBackend
 {
-	ext: Externalities<'a, T, V, B, E>,
+	ext: Externalities<'a, T, V, B>,
 	callcreates: Vec<CallCreate>,
 	nonce: U256,
 	sender: Address,
 }
 
-impl<'a, T: 'a, V: 'a, B: 'a, E: 'a> TestExt<'a, T, V, B, E>
-	where T: Tracer, V: VMTracer, B: StateBackend, E: Engine + ?Sized
+impl<'a, T: 'a, V: 'a, B: 'a> TestExt<'a, T, V, B>
+	where T: Tracer, V: VMTracer, B: StateBackend,
 {
 	fn new(
 		state: &'a mut State<B>,
 		info: &'a EnvInfo,
-		engine: &'a E,
+		machine: &'a Machine,
 		depth: usize,
 		origin_info: OriginInfo,
 		substate: &'a mut Substate,
@@ -84,15 +84,15 @@ impl<'a, T: 'a, V: 'a, B: 'a, E: 'a> TestExt<'a, T, V, B, E>
 		let static_call = false;
 		Ok(TestExt {
 			nonce: state.nonce(&address)?,
-			ext: Externalities::new(state, info, engine, depth, origin_info, substate, output, tracer, vm_tracer, static_call),
+			ext: Externalities::new(state, info, machine, depth, origin_info, substate, output, tracer, vm_tracer, static_call),
 			callcreates: vec![],
 			sender: address,
 		})
 	}
 }
 
-impl<'a, T: 'a, V: 'a, B: 'a, E: 'a> Ext for TestExt<'a, T, V, B, E>
-	where T: Tracer, V: VMTracer, B: StateBackend, E: Engine + ?Sized
+impl<'a, T: 'a, V: 'a, B: 'a> Ext for TestExt<'a, T, V, B>
+	where T: Tracer, V: VMTracer, B: StateBackend
 {
 	fn storage_at(&self, key: &H256) -> vm::Result<H256> {
 		self.ext.storage_at(key)
@@ -231,7 +231,12 @@ fn do_json_test_for(vm_type: &VMType, json_data: &[u8]) -> Vec<String> {
 		let mut state = get_temp_state();
 		state.populate_from(From::from(vm.pre_state.clone()));
 		let info = From::from(vm.env);
-		let engine = TestEngine::new(1);
+		let machine = {
+			let mut machine = ::ethereum::new_frontier_test_machine();
+			machine.set_schedule_creation_rules(Box::new(move |s, _| s.max_depth = 1));
+			machine
+		};
+
 		let params = ActionParams::from(vm.transaction);
 
 		let mut substate = Substate::new();
@@ -245,7 +250,7 @@ fn do_json_test_for(vm_type: &VMType, json_data: &[u8]) -> Vec<String> {
 			let mut ex = try_fail!(TestExt::new(
 				&mut state,
 				&info,
-				&engine,
+				&machine,
 				0,
 				OriginInfo::from(&params),
 				&mut substate,

ethcore/src/json_tests/test_common.rs

@@ -52,7 +52,8 @@ pub fn run_test_file(path: &Path, runner: fn (json_data: &[u8]) -> Vec<String>)
 	let mut file = File::open(&path).expect("Error opening test file");
 	file.read_to_end(&mut data).expect("Error reading test file");
 	let results = runner(&data);
-	assert!(results.is_empty());
+	let empty: [String; 0] = [];
+	assert_eq!(results, empty);
 }
 
 macro_rules! test {

ethcore/src/lib.rs

@@ -101,6 +101,7 @@ extern crate lru_cache;
 extern crate native_contracts;
 extern crate num_cpus;
 extern crate num;
+extern crate parity_machine;
 extern crate parking_lot;
 extern crate price_info;
 extern crate rand;
@@ -154,6 +155,7 @@ pub mod error;
 pub mod ethereum;
 pub mod executed;
 pub mod header;
+pub mod machine;
 pub mod migrations;
 pub mod miner;
 pub mod pod_state;

ethcore/src/machine.rs

@@ -0,0 +1,531 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Ethereum-like state machine definition.
+
+use std::collections::BTreeMap;
+use std::cmp;
+use std::sync::Arc;
+
+use block::ExecutedBlock;
+use builtin::Builtin;
+use client::BlockChainClient;
+use error::{Error, TransactionError};
+use executive::Executive;
+use header::{BlockNumber, Header};
+use spec::CommonParams;
+use state::{CleanupMode, Substate};
+use trace::{NoopTracer, NoopVMTracer, Tracer, ExecutiveTracer, RewardType};
+use transaction::{SYSTEM_ADDRESS, UnverifiedTransaction, SignedTransaction};
+use tx_filter::TransactionFilter;
+
+use bigint::prelude::U256;
+use bytes::BytesRef;
+use util::Address;
+use vm::{CallType, ActionParams, ActionValue};
+use vm::{EnvInfo, Schedule, CreateContractAddress};
+
+/// Parity tries to round block.gas_limit to multiple of this constant
+pub const PARITY_GAS_LIMIT_DETERMINANT: U256 = U256([37, 0, 0, 0]);
+
+/// Ethash-specific extensions.
+#[derive(Debug, Clone)]
+pub struct EthashExtensions {
+	/// Homestead transition block number.
+	pub homestead_transition: BlockNumber,
+	/// EIP150 transition block number.
+	pub eip150_transition: BlockNumber,
+	/// Number of first block where EIP-160 rules begin.
+	pub eip160_transition: u64,
+	/// Number of first block where EIP-161.abc begin.
+	pub eip161abc_transition: u64,
+	/// Number of first block where EIP-161.d begins.
+	pub eip161d_transition: u64,
+	/// DAO hard-fork transition block (X).
+	pub dao_hardfork_transition: u64,
+	/// DAO hard-fork refund contract address (C).
+	pub dao_hardfork_beneficiary: Address,
+	/// DAO hard-fork DAO accounts list (L)
+	pub dao_hardfork_accounts: Vec<Address>,
+}
+
+impl From<::ethjson::spec::EthashParams> for EthashExtensions {
+	fn from(p: ::ethjson::spec::EthashParams) -> Self {
+		EthashExtensions {
+			homestead_transition: p.homestead_transition.map_or(0, Into::into),
+			eip150_transition: p.eip150_transition.map_or(0, Into::into),
+			eip160_transition: p.eip160_transition.map_or(0, Into::into),
+			eip161abc_transition: p.eip161abc_transition.map_or(0, Into::into),
+			eip161d_transition: p.eip161d_transition.map_or(u64::max_value(), Into::into),
+			dao_hardfork_transition: p.dao_hardfork_transition.map_or(u64::max_value(), Into::into),
+			dao_hardfork_beneficiary: p.dao_hardfork_beneficiary.map_or_else(Address::new, Into::into),
+			dao_hardfork_accounts: p.dao_hardfork_accounts.unwrap_or_else(Vec::new).into_iter().map(Into::into).collect(),
+		}
+	}
+}
+
+/// Special rules to be applied to the schedule.
+pub type ScheduleCreationRules = Fn(&mut Schedule, BlockNumber) + Sync + Send;
+
+/// An ethereum-like state machine.
+pub struct EthereumMachine {
+	params: CommonParams,
+	builtins: Arc<BTreeMap<Address, Builtin>>,
+	tx_filter: Option<Arc<TransactionFilter>>,
+	ethash_extensions: Option<EthashExtensions>,
+	schedule_rules: Option<Box<ScheduleCreationRules>>,
+}
+
+impl EthereumMachine {
+	/// Regular ethereum machine.
+	pub fn regular(params: CommonParams, builtins: BTreeMap<Address, Builtin>) -> EthereumMachine {
+		let tx_filter = TransactionFilter::from_params(&params).map(Arc::new);
+		EthereumMachine {
+			params: params,
+			builtins: Arc::new(builtins),
+			tx_filter: tx_filter,
+			ethash_extensions: None,
+			schedule_rules: None,
+		}
+	}
+
+	/// Ethereum machine with ethash extensions.
+	// TODO: either unify or specify to mainnet specifically and include other specific-chain HFs?
+	pub fn with_ethash_extensions(params: CommonParams, builtins: BTreeMap<Address, Builtin>, extensions: EthashExtensions) -> EthereumMachine {
+		let mut machine = EthereumMachine::regular(params, builtins);
+		machine.ethash_extensions = Some(extensions);
+		machine
+	}
+
+	/// Attach special rules to the creation of schedule.
+	pub fn set_schedule_creation_rules(&mut self, rules: Box<ScheduleCreationRules>) {
+		self.schedule_rules = Some(rules);
+	}
+
+	/// Get a reference to the ethash-specific extensions.
+	pub fn ethash_extensions(&self) -> Option<&EthashExtensions> {
+		self.ethash_extensions.as_ref()
+	}
+}
+
+impl EthereumMachine {
+	/// Execute a call as the system address.
+	pub fn execute_as_system(
+		&self,
+		block: &mut ExecutedBlock,
+		contract_address: Address,
+		gas: U256,
+		data: Option<Vec<u8>>,
+	) -> Result<Vec<u8>, Error> {
+		let env_info = {
+			let mut env_info = block.env_info();
+			env_info.gas_limit = env_info.gas_used + gas;
+			env_info
+		};
+
+		let mut state = block.fields_mut().state;
+		let params = ActionParams {
+			code_address: contract_address.clone(),
+			address: contract_address.clone(),
+			sender: SYSTEM_ADDRESS.clone(),
+			origin: SYSTEM_ADDRESS.clone(),
+			gas: gas,
+			gas_price: 0.into(),
+			value: ActionValue::Transfer(0.into()),
+			code: state.code(&contract_address)?,
+			code_hash: Some(state.code_hash(&contract_address)?),
+			data: data,
+			call_type: CallType::Call,
+		};
+		let mut ex = Executive::new(&mut state, &env_info, self);
+		let mut substate = Substate::new();
+		let mut output = Vec::new();
+		if let Err(e) = ex.call(params, &mut substate, BytesRef::Flexible(&mut output), &mut NoopTracer, &mut NoopVMTracer) {
+			warn!("Encountered error on making system call: {}", e);
+		}
+
+		Ok(output)
+	}
+
+	/// Push last known block hash to the state.
+	fn push_last_hash(&self, block: &mut ExecutedBlock) -> Result<(), Error> {
+		let params = self.params();
+		if block.fields().header.number() == params.eip210_transition {
+			let state = block.fields_mut().state;
+			state.init_code(&params.eip210_contract_address, params.eip210_contract_code.clone())?;
+		}
+		if block.fields().header.number() >= params.eip210_transition {
+			let parent_hash = block.fields().header.parent_hash().clone();
+			let _ = self.execute_as_system(
+				block,
+				params.eip210_contract_address,
+				params.eip210_contract_gas,
+				Some(parent_hash.to_vec()),
+			)?;
+		}
+		Ok(())
+	}
+
+	/// Logic to perform on a new block: updating last hashes and the DAO
+	/// fork, for ethash.
+	pub fn on_new_block(&self, block: &mut ExecutedBlock) -> Result<(), Error> {
+		self.push_last_hash(block)?;
+
+		if let Some(ref ethash_params) = self.ethash_extensions {
+			if block.fields().header.number() == ethash_params.dao_hardfork_transition {
+				let state = block.fields_mut().state;
+				for child in &ethash_params.dao_hardfork_accounts {
+					let beneficiary = &ethash_params.dao_hardfork_beneficiary;
+					state.balance(child)
+						.and_then(|b| state.transfer_balance(child, beneficiary, &b, CleanupMode::NoEmpty))?;
+				}
+			}
+		}
+
+		Ok(())
+	}
+
+	/// Populate a header's fields based on its parent's header.
+	/// Usually implements the chain scoring rule based on weight.
+	/// The gas floor target must not be lower than the engine's minimum gas limit.
+	pub fn populate_from_parent(&self, header: &mut Header, parent: &Header, gas_floor_target: U256, gas_ceil_target: U256) {
+		header.set_difficulty(parent.difficulty().clone());
+
+		if let Some(ref ethash_params) = self.ethash_extensions {
+			let gas_limit = {
+				let gas_limit = parent.gas_limit().clone();
+				let bound_divisor = self.params().gas_limit_bound_divisor;
+				let lower_limit = gas_limit - gas_limit / bound_divisor + 1.into();
+				let upper_limit = gas_limit + gas_limit / bound_divisor - 1.into();
+				let gas_limit = if gas_limit < gas_floor_target {
+					let gas_limit = cmp::min(gas_floor_target, upper_limit);
+					round_block_gas_limit(gas_limit, lower_limit, upper_limit)
+				} else if gas_limit > gas_ceil_target {
+					let gas_limit = cmp::max(gas_ceil_target, lower_limit);
+					round_block_gas_limit(gas_limit, lower_limit, upper_limit)
+				} else {
+					let total_lower_limit = cmp::max(lower_limit, gas_floor_target);
+					let total_upper_limit = cmp::min(upper_limit, gas_ceil_target);
+					let gas_limit = cmp::max(gas_floor_target, cmp::min(total_upper_limit,
+						lower_limit + (header.gas_used().clone() * 6.into() / 5.into()) / bound_divisor));
+					round_block_gas_limit(gas_limit, total_lower_limit, total_upper_limit)
+				};
+				// ensure that we are not violating protocol limits
+				debug_assert!(gas_limit >= lower_limit);
+				debug_assert!(gas_limit <= upper_limit);
+				gas_limit
+			};
+
+			header.set_gas_limit(gas_limit);
+			if header.number() >= ethash_params.dao_hardfork_transition &&
+				header.number() <= ethash_params.dao_hardfork_transition + 9 {
+				header.set_extra_data(b"dao-hard-fork"[..].to_owned());
+			}
+			return
+		}
+
+		header.set_gas_limit({
+			let gas_limit = parent.gas_limit().clone();
+			let bound_divisor = self.params().gas_limit_bound_divisor;
+			if gas_limit < gas_floor_target {
+				cmp::min(gas_floor_target, gas_limit + gas_limit / bound_divisor - 1.into())
+			} else {
+				cmp::max(gas_floor_target, gas_limit - gas_limit / bound_divisor + 1.into())
+			}
+		});
+	}
+
+	/// Get the general parameters of the chain.
+	pub fn params(&self) -> &CommonParams {
+		&self.params
+	}
+
+	/// Get the EVM schedule for the given block number.
+	pub fn schedule(&self, block_number: BlockNumber) -> Schedule {
+		let mut schedule = match self.ethash_extensions {
+			None => self.params.schedule(block_number),
+			Some(ref ext) => {
+				if block_number < ext.homestead_transition {
+					Schedule::new_frontier()
+				} else if block_number < ext.eip150_transition {
+					Schedule::new_homestead()
+				} else {
+					/// There's no max_code_size transition so we tie it to eip161abc
+					let max_code_size = if block_number >= ext.eip161abc_transition {
+						self.params.max_code_size as usize
+					} else {
+						usize::max_value()
+					};
+
+					let mut schedule = Schedule::new_post_eip150(
+						max_code_size,
+						block_number >= ext.eip160_transition,
+						block_number >= ext.eip161abc_transition,
+						block_number >= ext.eip161d_transition
+					);
+
+					self.params.update_schedule(block_number, &mut schedule);
+					schedule
+				}
+			}
+		};
+
+		if let Some(ref rules) = self.schedule_rules {
+			(rules)(&mut schedule, block_number)
+		}
+
+		schedule
+	}
+
+	/// Builtin-contracts for the chain..
+	pub fn builtins(&self) -> &BTreeMap<Address, Builtin> {
+		&*self.builtins
+	}
+
+	/// Attempt to get a handle to a built-in contract.
+	/// Only returns references to activated built-ins.
+	// TODO: builtin contract routing - to do this properly, it will require removing the built-in configuration-reading logic
+	// from Spec into here and removing the Spec::builtins field.
+	pub fn builtin(&self, a: &Address, block_number: BlockNumber) -> Option<&Builtin> {
+		self.builtins()
+			.get(a)
+			.and_then(|b| if b.is_active(block_number) { Some(b) } else { None })
+	}
+
+	/// Some intrinsic operation parameters; by default they take their value from the `spec()`'s `engine_params`.
+	pub fn maximum_extra_data_size(&self) -> usize { self.params().maximum_extra_data_size }
+
+	/// The nonce with which accounts begin at given block.
+	pub fn account_start_nonce(&self, block: u64) -> U256 {
+		let params = self.params();
+
+		if block >= params.dust_protection_transition {
+			U256::from(params.nonce_cap_increment) * U256::from(block)
+		} else {
+			params.account_start_nonce
+		}
+	}
+
+	/// The network ID that transactions should be signed with.
+	pub fn signing_chain_id(&self, env_info: &EnvInfo) -> Option<u64> {
+		let params = self.params();
+
+		if env_info.number >= params.eip155_transition {
+			Some(params.chain_id)
+		} else {
+			None
+		}
+	}
+
+	/// Returns new contract address generation scheme at given block number.
+	pub fn create_address_scheme(&self, number: BlockNumber) -> CreateContractAddress {
+		if number >= self.params().eip86_transition {
+			CreateContractAddress::FromCodeHash
+		} else {
+			CreateContractAddress::FromSenderAndNonce
+		}
+	}
+
+	/// Verify a particular transaction is valid, regardless of order.
+	pub fn verify_transaction_unordered(&self, t: UnverifiedTransaction, _header: &Header) -> Result<SignedTransaction, Error> {
+		SignedTransaction::new(t)
+	}
+
+	/// Does basic verification of the transaction.
+	pub fn verify_transaction_basic(&self, t: &UnverifiedTransaction, header: &Header) -> Result<(), Error> {
+		let check_low_s = match self.ethash_extensions {
+			Some(ref ext) => header.number() >= ext.homestead_transition,
+			None => true,
+		};
+
+		let chain_id = if header.number() >= self.params().eip155_transition {
+			Some(self.params().chain_id)
+		} else {
+			None
+		};
+		t.verify_basic(check_low_s, chain_id, false)?;
+
+		Ok(())
+	}
+
+	/// Does verification of the transaction against the parent state.
+	// TODO: refine the bound here to be a "state provider" or similar as opposed
+	// to full client functionality.
+	pub fn verify_transaction(&self, t: &SignedTransaction, header: &Header, client: &BlockChainClient) -> Result<(), Error> {
+		if let Some(ref filter) = self.tx_filter.as_ref() {
+			if !filter.transaction_allowed(header.parent_hash(), t, client) {
+				return Err(TransactionError::NotAllowed.into())
+			}
+		}
+
+		Ok(())
+	}
+
+	/// If this machine supports wasm.
+	pub fn supports_wasm(&self) -> bool {
+		self.params().wasm
+	}
+}
+
+/// Auxiliary data fetcher for an Ethereum machine. In Ethereum-like machines
+/// there are two kinds of auxiliary data: bodies and receipts.
+#[derive(Default, Clone)]
+pub struct AuxiliaryData<'a> {
+	/// The full block bytes, including the header.
+	pub bytes: Option<&'a [u8]>,
+	/// The block receipts.
+	pub receipts: Option<&'a [::receipt::Receipt]>,
+}
+
+/// Type alias for a function we can make calls through synchronously.
+/// Returns the call result and state proof for each call.
+pub type Call<'a> = Fn(Address, Vec<u8>) -> Result<(Vec<u8>, Vec<Vec<u8>>), String> + 'a;
+
+/// Request for auxiliary data of a block.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub enum AuxiliaryRequest {
+	/// Needs the body.
+	Body,
+	/// Needs the receipts.
+	Receipts,
+	/// Needs both body and receipts.
+	Both,
+}
+
+impl ::parity_machine::Machine for EthereumMachine {
+	type Header = Header;
+
+	type LiveBlock = ExecutedBlock;
+	type EngineClient = ::client::EngineClient;
+	type AuxiliaryRequest = AuxiliaryRequest;
+
+	type Error = Error;
+}
+
+impl<'a> ::parity_machine::LocalizedMachine<'a> for EthereumMachine {
+	type StateContext = Call<'a>;
+	type AuxiliaryData = AuxiliaryData<'a>;
+}
+
+impl ::parity_machine::WithBalances for EthereumMachine {
+	fn balance(&self, live: &ExecutedBlock, address: &Address) -> Result<U256, Error> {
+		live.fields().state.balance(address).map_err(Into::into)
+	}
+
+	fn add_balance(&self, live: &mut ExecutedBlock, address: &Address, amount: &U256) -> Result<(), Error> {
+		live.fields_mut().state.add_balance(address, amount, CleanupMode::NoEmpty).map_err(Into::into)
+	}
+
+	fn note_rewards(
+		&self,
+		live: &mut Self::LiveBlock,
+		direct: &[(Address, U256)],
+		indirect: &[(Address, U256)],
+	) -> Result<(), Self::Error> {
+		use block::IsBlock;
+
+		if !live.tracing_enabled() { return Ok(()) }
+
+		let mut tracer = ExecutiveTracer::default();
+
+		for &(address, amount) in direct {
+			tracer.trace_reward(address, amount, RewardType::Block);
+		}
+
+		for &(address, amount) in indirect {
+			tracer.trace_reward(address, amount, RewardType::Uncle);
+		}
+
+		live.fields_mut().push_traces(tracer);
+
+		Ok(())
+	}
+}
+
+// Try to round gas_limit a bit so that:
+// 1) it will still be in desired range
+// 2) it will be a nearest (with tendency to increase) multiple of PARITY_GAS_LIMIT_DETERMINANT
+fn round_block_gas_limit(gas_limit: U256, lower_limit: U256, upper_limit: U256) -> U256 {
+	let increased_gas_limit = gas_limit + (PARITY_GAS_LIMIT_DETERMINANT - gas_limit % PARITY_GAS_LIMIT_DETERMINANT);
+	if increased_gas_limit > upper_limit {
+		let decreased_gas_limit = increased_gas_limit - PARITY_GAS_LIMIT_DETERMINANT;
+		if decreased_gas_limit < lower_limit {
+			gas_limit
+		} else {
+			decreased_gas_limit
+		}
+	} else {
+		increased_gas_limit
+	}
+}
+
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+
+	#[test]
+	fn ethash_gas_limit_is_multiple_of_determinant() {
+		use bigint::prelude::U256;
+
+		let spec = ::ethereum::new_homestead_test();
+		let ethparams = ::tests::helpers::get_default_ethash_extensions();
+
+		let machine = EthereumMachine::with_ethash_extensions(
+			spec.params().clone(),
+			Default::default(),
+			ethparams,
+		);
+
+		let mut parent = ::header::Header::new();
+		let mut header = ::header::Header::new();
+		header.set_number(1);
+
+		// this test will work for this constant only
+		assert_eq!(PARITY_GAS_LIMIT_DETERMINANT, U256::from(37));
+
+		// when parent.gas_limit < gas_floor_target:
+		parent.set_gas_limit(U256::from(50_000));
+		machine.populate_from_parent(&mut header, &parent, U256::from(100_000), U256::from(200_000));
+		assert_eq!(*header.gas_limit(), U256::from(50_024));
+
+		// when parent.gas_limit > gas_ceil_target:
+		parent.set_gas_limit(U256::from(250_000));
+		machine.populate_from_parent(&mut header, &parent, U256::from(100_000), U256::from(200_000));
+		assert_eq!(*header.gas_limit(), U256::from(249_787));
+
+		// when parent.gas_limit is in miner's range
+		header.set_gas_used(U256::from(150_000));
+		parent.set_gas_limit(U256::from(150_000));
+		machine.populate_from_parent(&mut header, &parent, U256::from(100_000), U256::from(200_000));
+		assert_eq!(*header.gas_limit(), U256::from(150_035));
+
+		// when parent.gas_limit is in miner's range
+		// && we can NOT increase it to be multiple of constant
+		header.set_gas_used(U256::from(150_000));
+		parent.set_gas_limit(U256::from(150_000));
+		machine.populate_from_parent(&mut header, &parent, U256::from(100_000), U256::from(150_002));
+		assert_eq!(*header.gas_limit(), U256::from(149_998));
+
+		// when parent.gas_limit is in miner's range
+		// && we can NOT increase it to be multiple of constant
+		// && we can NOT decrease it to be multiple of constant
+		header.set_gas_used(U256::from(150_000));
+		parent.set_gas_limit(U256::from(150_000));
+		machine.populate_from_parent(&mut header, &parent, U256::from(150_000), U256::from(150_002));
+		assert_eq!(*header.gas_limit(), U256::from(150_002));
+	}
+}

ethcore/src/miner/miner.rs

@@ -35,7 +35,7 @@ use error::*;
 use transaction::{Action, UnverifiedTransaction, PendingTransaction, SignedTransaction, Condition as TransactionCondition};
 use receipt::{Receipt, RichReceipt};
 use spec::Spec;
-use engines::{Engine, Seal};
+use engines::{EthEngine, Seal};
 use miner::{MinerService, MinerStatus, TransactionQueue, RemovalReason, TransactionQueueDetailsProvider, PrioritizationStrategy,
 	AccountDetails, TransactionOrigin};
 use miner::banning_queue::{BanningTransactionQueue, Threshold};
@@ -240,7 +240,7 @@ pub struct Miner {
 	gas_range_target: RwLock<(U256, U256)>,
 	author: RwLock<Address>,
 	extra_data: RwLock<Bytes>,
-	engine: Arc<Engine>,
+	engine: Arc<EthEngine>,
 
 	accounts: Option<Arc<AccountProvider>>,
 	notifiers: RwLock<Vec<Box<NotifyWork>>>,
@@ -662,7 +662,7 @@ impl Miner {
 					return Err(Error::Transaction(TransactionError::AlreadyImported));
 				}
 				match self.engine.verify_transaction_basic(&tx, &best_block_header)
-					.and_then(|_| self.engine.verify_transaction(tx, &best_block_header))
+					.and_then(|_| self.engine.verify_transaction_unordered(tx, &best_block_header))
 				{
 					Err(e) => {
 						debug!(target: "miner", "Rejected tx {:?} with invalid signature: {:?}", hash, e);

ethcore/src/miner/stratum.rs

@@ -171,7 +171,7 @@ impl StratumJobDispatcher {
 	fn payload(&self, pow_hash: H256, difficulty: U256, number: u64) -> String {
 		// TODO: move this to engine
 		let target = Ethash::difficulty_to_boundary(&difficulty);
-		let seed_hash = &self.seed_compute.lock().get_seedhash(number);
+		let seed_hash = &self.seed_compute.lock().hash_block_number(number);
 		let seed_hash = H256::from_slice(&seed_hash[..]);
 		format!(
 			r#"["0x", "0x{}","0x{}","0x{}","0x{:x}"]"#,

ethcore/src/miner/work_notify.rs

@@ -72,7 +72,7 @@ impl NotifyWork for WorkPoster {
 	fn notify(&self, pow_hash: H256, difficulty: U256, number: u64) {
 		// TODO: move this to engine
 		let target = Ethash::difficulty_to_boundary(&difficulty);
-		let seed_hash = &self.seed_compute.lock().get_seedhash(number);
+		let seed_hash = &self.seed_compute.lock().hash_block_number(number);
 		let seed_hash = H256::from_slice(&seed_hash[..]);
 		let body = format!(
 			r#"{{ "result": ["0x{}","0x{}","0x{}","0x{:x}"] }}"#,

ethcore/src/snapshot/consensus/authority.rs

@@ -25,7 +25,8 @@ use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::Arc;
 
 use blockchain::{BlockChain, BlockProvider};
-use engines::{Engine, EpochVerifier, EpochTransition};
+use engines::{EthEngine, EpochVerifier, EpochTransition};
+use machine::EthereumMachine;
 use ids::BlockId;
 use header::Header;
 use receipt::Receipt;
@@ -168,7 +169,7 @@ struct ChunkRebuilder {
 	// and epoch data from last blocks in chunks.
 	// verification for these will be done at the end.
 	unverified_firsts: Vec<(Header, Bytes, H256)>,
-	last_epochs: Vec<(Header, Box<EpochVerifier>)>,
+	last_epochs: Vec<(Header, Box<EpochVerifier<EthereumMachine>>)>,
 }
 
 // verified data.
@@ -180,9 +181,9 @@ struct Verified {
 impl ChunkRebuilder {
 	fn verify_transition(
 		&mut self,
-		last_verifier: &mut Option<Box<EpochVerifier>>,
+		last_verifier: &mut Option<Box<EpochVerifier<EthereumMachine>>>,
 		transition_rlp: UntrustedRlp,
-		engine: &Engine,
+		engine: &EthEngine,
 	) -> Result<Verified, ::error::Error> {
 		use engines::ConstructedVerifier;
 
@@ -238,7 +239,7 @@ impl Rebuilder for ChunkRebuilder {
 	fn feed(
 		&mut self,
 		chunk: &[u8],
-		engine: &Engine,
+		engine: &EthEngine,
 		abort_flag: &AtomicBool,
 	) -> Result<(), ::error::Error> {
 		let rlp = UntrustedRlp::new(chunk);
@@ -346,7 +347,7 @@ impl Rebuilder for ChunkRebuilder {
 		Ok(())
 	}
 
-	fn finalize(&mut self, _engine: &Engine) -> Result<(), ::error::Error> {
+	fn finalize(&mut self, _engine: &EthEngine) -> Result<(), ::error::Error> {
 		if !self.had_genesis {
 			return Err(Error::WrongChunkFormat("No genesis transition included.".into()).into());
 		}

ethcore/src/snapshot/consensus/mod.rs

@@ -21,7 +21,7 @@ use std::sync::atomic::AtomicBool;
 use std::sync::Arc;
 
 use blockchain::BlockChain;
-use engines::Engine;
+use engines::EthEngine;
 use snapshot::{Error, ManifestData};
 
 use bigint::hash::H256;
@@ -84,7 +84,7 @@ pub trait Rebuilder: Send {
 	fn feed(
 		&mut self,
 		chunk: &[u8],
-		engine: &Engine,
+		engine: &EthEngine,
 		abort_flag: &AtomicBool,
 	) -> Result<(), ::error::Error>;
 
@@ -93,5 +93,5 @@ pub trait Rebuilder: Send {
 	///
 	/// This should apply the necessary "glue" between chunks,
 	/// and verify against the restored state.
-	fn finalize(&mut self, engine: &Engine) -> Result<(), ::error::Error>;
+	fn finalize(&mut self, engine: &EthEngine) -> Result<(), ::error::Error>;
 }

ethcore/src/snapshot/consensus/work.rs

@@ -27,7 +27,7 @@ use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::Arc;
 
 use blockchain::{BlockChain, BlockProvider};
-use engines::Engine;
+use engines::EthEngine;
 use snapshot::{Error, ManifestData};
 use snapshot::block::AbridgedBlock;
 use bigint::hash::H256;
@@ -219,7 +219,7 @@ impl PowRebuilder {
 impl Rebuilder for PowRebuilder {
 	/// Feed the rebuilder an uncompressed block chunk.
 	/// Returns the number of blocks fed or any errors.
-	fn feed(&mut self, chunk: &[u8], engine: &Engine, abort_flag: &AtomicBool) -> Result<(), ::error::Error> {
+	fn feed(&mut self, chunk: &[u8], engine: &EthEngine, abort_flag: &AtomicBool) -> Result<(), ::error::Error> {
 		use basic_types::Seal::With;
 		use views::BlockView;
 		use snapshot::verify_old_block;
@@ -271,7 +271,6 @@ impl Rebuilder for PowRebuilder {
 				&block.header,
 				engine,
 				&self.chain,
-				Some(&block_bytes),
 				is_best
 			)?;
 
@@ -298,7 +297,7 @@ impl Rebuilder for PowRebuilder {
 	}
 
 	/// Glue together any disconnected chunks and check that the chain is complete.
-	fn finalize(&mut self, _: &Engine) -> Result<(), ::error::Error> {
+	fn finalize(&mut self, _: &EthEngine) -> Result<(), ::error::Error> {
 		let mut batch = self.db.transaction();
 
 		for (first_num, first_hash) in self.disconnected.drain(..) {

ethcore/src/snapshot/mod.rs

@@ -26,7 +26,7 @@ use hash::{keccak, KECCAK_NULL_RLP, KECCAK_EMPTY};
 
 use account_db::{AccountDB, AccountDBMut};
 use blockchain::{BlockChain, BlockProvider};
-use engines::Engine;
+use engines::EthEngine;
 use header::Header;
 use ids::BlockId;
 
@@ -126,7 +126,7 @@ impl Progress {
 }
 /// Take a snapshot using the given blockchain, starting block hash, and database, writing into the given writer.
 pub fn take_snapshot<W: SnapshotWriter + Send>(
-	engine: &Engine,
+	engine: &EthEngine,
 	chain: &BlockChain,
 	block_at: H256,
 	state_db: &HashDB,
@@ -484,13 +484,13 @@ const POW_VERIFY_RATE: f32 = 0.02;
 /// Verify an old block with the given header, engine, blockchain, body. If `always` is set, it will perform
 /// the fullest verification possible. If not, it will take a random sample to determine whether it will
 /// do heavy or light verification.
-pub fn verify_old_block(rng: &mut OsRng, header: &Header, engine: &Engine, chain: &BlockChain, body: Option<&[u8]>, always: bool) -> Result<(), ::error::Error> {
-	engine.verify_block_basic(header, body)?;
+pub fn verify_old_block(rng: &mut OsRng, header: &Header, engine: &EthEngine, chain: &BlockChain, always: bool) -> Result<(), ::error::Error> {
+	engine.verify_block_basic(header)?;
 
 	if always || rng.gen::<f32>() <= POW_VERIFY_RATE {
-		engine.verify_block_unordered(header, body)?;
+		engine.verify_block_unordered(header)?;
 		match chain.block_header(header.parent_hash()) {
-			Some(parent) => engine.verify_block_family(header, &parent, body),
+			Some(parent) => engine.verify_block_family(header, &parent),
 			None => Ok(()),
 		}
 	} else {

ethcore/src/snapshot/service.rs

@@ -28,7 +28,7 @@ use super::io::{SnapshotReader, LooseReader, SnapshotWriter, LooseWriter};
 
 use blockchain::BlockChain;
 use client::{BlockChainClient, Client};
-use engines::Engine;
+use engines::EthEngine;
 use error::Error;
 use ids::BlockId;
 use service::ClientIoMessage;
@@ -91,7 +91,7 @@ struct RestorationParams<'a> {
 	writer: Option<LooseWriter>, // writer for recovered snapshot.
 	genesis: &'a [u8], // genesis block of the chain.
 	guard: Guard, // guard for the restoration directory.
-	engine: &'a Engine,
+	engine: &'a EthEngine,
 }
 
 impl Restoration {
@@ -145,7 +145,7 @@ impl Restoration {
 	}
 
 	// feeds a block chunk
-	fn feed_blocks(&mut self, hash: H256, chunk: &[u8], engine: &Engine, flag: &AtomicBool) -> Result<(), Error> {
+	fn feed_blocks(&mut self, hash: H256, chunk: &[u8], engine: &EthEngine, flag: &AtomicBool) -> Result<(), Error> {
 		if self.block_chunks_left.contains(&hash) {
 			let len = snappy::decompress_into(chunk, &mut self.snappy_buffer)?;
 
@@ -161,7 +161,7 @@ impl Restoration {
 	}
 
 	// finish up restoration.
-	fn finalize(mut self, engine: &Engine) -> Result<(), Error> {
+	fn finalize(mut self, engine: &EthEngine) -> Result<(), Error> {
 		use trie::TrieError;
 
 		if !self.is_done() { return Ok(()) }
@@ -199,7 +199,7 @@ pub type Channel = IoChannel<ClientIoMessage>;
 /// Snapshot service parameters.
 pub struct ServiceParams {
 	/// The consensus engine this is built on.
-	pub engine: Arc<Engine>,
+	pub engine: Arc<EthEngine>,
 	/// The chain's genesis block.
 	pub genesis_block: Bytes,
 	/// Database configuration options.
@@ -225,7 +225,7 @@ pub struct Service {
 	pruning: Algorithm,
 	status: Mutex<RestorationStatus>,
 	reader: RwLock<Option<LooseReader>>,
-	engine: Arc<Engine>,
+	engine: Arc<EthEngine>,
 	genesis_block: Bytes,
 	state_chunks: AtomicUsize,
 	block_chunks: AtomicUsize,

ethcore/src/snapshot/tests/helpers.rs

@@ -24,7 +24,7 @@ use account_db::AccountDBMut;
 use basic_account::BasicAccount;
 use blockchain::BlockChain;
 use client::{BlockChainClient, Client};
-use engines::Engine;
+use engines::EthEngine;
 use snapshot::{StateRebuilder};
 use snapshot::io::{SnapshotReader, PackedWriter, PackedReader};
 
@@ -160,7 +160,7 @@ pub fn snap(client: &Client) -> GuardedTempResult<Box<SnapshotReader>> {
 /// write into the given database.
 pub fn restore(
 	db: Arc<KeyValueDB>,
-	engine: &Engine,
+	engine: &EthEngine,
 	reader: &SnapshotReader,
 	genesis: &[u8],
 ) -> Result<(), ::error::Error> {

ethcore/src/snapshot/tests/proof_of_work.rs

@@ -38,7 +38,7 @@ fn chunk_and_restore(amount: u64) {
 	let mut finalizer = BlockFinalizer::default();
 	let genesis = canon_chain.generate(&mut finalizer).unwrap();
 
-	let engine = Arc::new(::engines::NullEngine::default());
+	let engine = ::spec::Spec::new_test().engine;
 	let new_path = RandomTempPath::create_dir();
 	let mut snapshot_path = new_path.as_path().to_owned();
 	snapshot_path.push("SNAP");
@@ -128,7 +128,7 @@ fn checks_flag() {
 	let chunk = stream.out();
 
 	let db = Arc::new(kvdb::in_memory(::db::NUM_COLUMNS.unwrap_or(0)));
-	let engine = Arc::new(::engines::NullEngine::default());
+	let engine = ::spec::Spec::new_test().engine;
 	let chain = BlockChain::new(Default::default(), &genesis, db.clone());
 
 	let manifest = ::snapshot::ManifestData {

ethcore/src/spec/spec.rs

@@ -20,30 +20,39 @@ use std::io::Read;
 use std::collections::BTreeMap;
 use std::path::Path;
 use std::sync::Arc;
-use rustc_hex::FromHex;
+
+use bigint::hash::{H256, H2048};
+use bigint::prelude::U256;
+use bytes::Bytes;
+use ethjson;
 use hash::{KECCAK_NULL_RLP, keccak};
+use parking_lot::RwLock;
+use rlp::{Rlp, RlpStream};
+use rustc_hex::FromHex;
+use util::*;
+use vm::{EnvInfo, CallType, ActionValue, ActionParams};
+
 use super::genesis::Genesis;
 use super::seal::Generic as GenericSeal;
 
 use builtin::Builtin;
-use engines::{Engine, NullEngine, InstantSeal, BasicAuthority, AuthorityRound, Tendermint, DEFAULT_BLOCKHASH_CONTRACT};
-use vm::{EnvInfo, CallType, ActionValue, ActionParams};
+use engines::{EthEngine, NullEngine, InstantSeal, BasicAuthority, AuthorityRound, Tendermint, DEFAULT_BLOCKHASH_CONTRACT};
 use error::Error;
-use ethereum;
-use ethjson;
 use executive::Executive;
 use factory::Factories;
 use header::{BlockNumber, Header};
+use machine::EthereumMachine;
 use pod_state::*;
-use rlp::{Rlp, RlpStream};
 use state::{Backend, State, Substate};
 use state::backend::Basic as BasicBackend;
 use trace::{NoopTracer, NoopVMTracer};
-use bigint::prelude::U256;
-use bigint::hash::{H256, H2048};
-use parking_lot::RwLock;
-use util::*;
-use bytes::Bytes;
+
+pub use ethash::OptimizeFor;
+
+// helper for formatting errors.
+fn fmt_err<F: ::std::fmt::Display>(f: F) -> String {
+	format!("Spec json is invalid: {}", f)
+}
 
 /// Parameters common to ethereum-like blockchains.
 /// NOTE: when adding bugfix hard-fork parameters,
@@ -88,7 +97,8 @@ pub struct CommonParams {
 	pub eip210_contract_code: Bytes,
 	/// Gas allocated for EIP-210 blockhash update.
 	pub eip210_contract_gas: U256,
-	/// Number of first block where EIP-211 (Metropolis: RETURNDATASIZE/RETURNDATACOPY) rules begin.
+	/// Number of first block where EIP-211 (Metropolis: RETURNDATASIZE/RETURNDATACOPY) rules
+	/// begin.
 	pub eip211_transition: BlockNumber,
 	/// Number of first block where EIP-214 rules begin.
 	pub eip214_transition: BlockNumber,
@@ -102,12 +112,12 @@ pub struct CommonParams {
 	pub wasm: bool,
 	/// Gas limit bound divisor (how much gas limit can change per block)
 	pub gas_limit_bound_divisor: U256,
-	/// Block reward in wei.
-	pub block_reward: U256,
 	/// Registrar contract address.
 	pub registrar: Address,
 	/// Node permission managing contract address.
 	pub node_permission_contract: Option<Address>,
+	/// Maximum contract code size that can be deployed.
+	pub max_code_size: u64,
 	/// Transaction permission managing contract address.
 	pub transaction_permission_contract: Option<Address>,
 }
@@ -115,7 +125,7 @@ pub struct CommonParams {
 impl CommonParams {
 	/// Schedule for an EVM in the post-EIP-150-era of the Ethereum main net.
 	pub fn schedule(&self, block_number: u64) -> ::vm::Schedule {
-		let mut schedule = ::vm::Schedule::new_post_eip150(usize::max_value(), true, true, true);
+		let mut schedule = ::vm::Schedule::new_post_eip150(self.max_code_size as _, true, true, true);
 		self.update_schedule(block_number, &mut schedule);
 		schedule
 	}
@@ -139,14 +149,10 @@ impl CommonParams {
 
 	/// Whether these params contain any bug-fix hard forks.
 	pub fn contains_bugfix_hard_fork(&self) -> bool {
-		self.eip98_transition != 0 &&
-			self.eip155_transition != 0 &&
-			self.validate_receipts_transition != 0 &&
-			self.eip86_transition != 0 &&
-			self.eip140_transition != 0 &&
-			self.eip210_transition != 0 &&
-			self.eip211_transition != 0 &&
-			self.eip214_transition != 0 &&
+		self.eip98_transition != 0 && self.eip155_transition != 0 &&
+			self.validate_receipts_transition != 0 && self.eip86_transition != 0 &&
+			self.eip140_transition != 0 && self.eip210_transition != 0 &&
+			self.eip211_transition != 0 && self.eip214_transition != 0 &&
 			self.dust_protection_transition != 0
 	}
 }
@@ -157,44 +163,116 @@ impl From<ethjson::spec::Params> for CommonParams {
 			account_start_nonce: p.account_start_nonce.map_or_else(U256::zero, Into::into),
 			maximum_extra_data_size: p.maximum_extra_data_size.into(),
 			network_id: p.network_id.into(),
-			chain_id: if let Some(n) = p.chain_id { n.into() } else { p.network_id.into() },
+			chain_id: if let Some(n) = p.chain_id {
+				n.into()
+			} else {
+				p.network_id.into()
+			},
 			subprotocol_name: p.subprotocol_name.unwrap_or_else(|| "eth".to_owned()),
 			min_gas_limit: p.min_gas_limit.into(),
-			fork_block: if let (Some(n), Some(h)) = (p.fork_block, p.fork_hash) { Some((n.into(), h.into())) } else { None },
+			fork_block: if let (Some(n), Some(h)) = (p.fork_block, p.fork_hash) {
+				Some((n.into(), h.into()))
+			} else {
+				None
+			},
 			eip98_transition: p.eip98_transition.map_or(0, Into::into),
 			eip155_transition: p.eip155_transition.map_or(0, Into::into),
 			validate_receipts_transition: p.validate_receipts_transition.map_or(0, Into::into),
-			eip86_transition: p.eip86_transition.map_or(BlockNumber::max_value(), Into::into),
-			eip140_transition: p.eip140_transition.map_or(BlockNumber::max_value(), Into::into),
-			eip210_transition: p.eip210_transition.map_or(BlockNumber::max_value(), Into::into),
+			eip86_transition: p.eip86_transition.map_or(
+				BlockNumber::max_value(),
+				Into::into,
+			),
+			eip140_transition: p.eip140_transition.map_or(
+				BlockNumber::max_value(),
+				Into::into,
+			),
+			eip210_transition: p.eip210_transition.map_or(
+				BlockNumber::max_value(),
+				Into::into,
+			),
 			eip210_contract_address: p.eip210_contract_address.map_or(0xf0.into(), Into::into),
 			eip210_contract_code: p.eip210_contract_code.map_or_else(
-				|| DEFAULT_BLOCKHASH_CONTRACT.from_hex().expect("Default BLOCKHASH contract is valid"),
-				Into::into),
+				|| {
+					DEFAULT_BLOCKHASH_CONTRACT.from_hex().expect(
+						"Default BLOCKHASH contract is valid",
+					)
+				},
+				Into::into,
+			),
 			eip210_contract_gas: p.eip210_contract_gas.map_or(1000000.into(), Into::into),
-			eip211_transition: p.eip211_transition.map_or(BlockNumber::max_value(), Into::into),
-			eip214_transition: p.eip214_transition.map_or(BlockNumber::max_value(), Into::into),
-			eip658_transition: p.eip658_transition.map_or(BlockNumber::max_value(), Into::into),
-			dust_protection_transition: p.dust_protection_transition.map_or(BlockNumber::max_value(), Into::into),
+			eip211_transition: p.eip211_transition.map_or(
+				BlockNumber::max_value(),
+				Into::into,
+			),
+			eip214_transition: p.eip214_transition.map_or(
+				BlockNumber::max_value(),
+				Into::into,
+			),
+			eip658_transition: p.eip658_transition.map_or(
+				BlockNumber::max_value(),
+				Into::into,
+			),
+			dust_protection_transition: p.dust_protection_transition.map_or(
+				BlockNumber::max_value(),
+				Into::into,
+			),
 			nonce_cap_increment: p.nonce_cap_increment.map_or(64, Into::into),
 			remove_dust_contracts: p.remove_dust_contracts.unwrap_or(false),
 			wasm: p.wasm.unwrap_or(false),
 			gas_limit_bound_divisor: p.gas_limit_bound_divisor.into(),
-			block_reward: p.block_reward.map_or_else(U256::zero, Into::into),
 			registrar: p.registrar.map_or_else(Address::new, Into::into),
 			node_permission_contract: p.node_permission_contract.map(Into::into),
+			max_code_size: p.max_code_size.map_or(u64::max_value(), Into::into),
 			transaction_permission_contract: p.transaction_permission_contract.map(Into::into),
 		}
 	}
 }
 
+/// Runtime parameters for the spec that are related to how the software should run the chain,
+/// rather than integral properties of the chain itself.
+#[derive(Debug, Clone, Copy)]
+pub struct SpecParams<'a> {
+	/// The path to the folder used to cache nodes. This is typically /tmp/ on Unix-like systems
+	pub cache_dir: &'a Path,
+	/// Whether to run slower at the expense of better memory usage, or run faster while using
+	/// more
+	/// memory. This may get more fine-grained in the future but for now is simply a binary
+	/// option.
+	pub optimization_setting: Option<OptimizeFor>,
+}
+
+impl<'a> SpecParams<'a> {
+	/// Create from a cache path, with null values for the other fields
+	pub fn from_path(path: &'a Path) -> Self {
+		SpecParams {
+			cache_dir: path,
+			optimization_setting: None,
+		}
+	}
+
+	/// Create from a cache path and an optimization setting
+	pub fn new(path: &'a Path, optimization: OptimizeFor) -> Self {
+		SpecParams {
+			cache_dir: path,
+			optimization_setting: Some(optimization),
+		}
+	}
+}
+
+impl<'a, T: AsRef<Path>> From<&'a T> for SpecParams<'a> {
+	fn from(path: &'a T) -> Self {
+		Self::from_path(path.as_ref())
+	}
+}
+
+
 /// Parameters for a block chain; includes both those intrinsic to the design of the
 /// chain and those to be interpreted by the active chain engine.
 pub struct Spec {
 	/// User friendly spec name
 	pub name: String,
 	/// What engine are we using for this?
-	pub engine: Arc<Engine>,
+	pub engine: Arc<EthEngine>,
 	/// Name of the subdir inside the main data dir to use for chain data and settings.
 	pub data_dir: String,
 
@@ -257,16 +335,27 @@ impl Clone for Spec {
 	}
 }
 
-/// Load from JSON object.
-pub fn load_from<T: AsRef<Path>>(cache_dir: T, s: ethjson::spec::Spec) -> Result<Spec, Error> {
+fn load_machine_from(s: ethjson::spec::Spec) -> EthereumMachine {
 	let builtins = s.accounts.builtins().into_iter().map(|p| (p.0.into(), From::from(p.1))).collect();
+	let params = CommonParams::from(s.params);
+
+	Spec::machine(&s.engine, params, builtins)
+}
+
+/// Load from JSON object.
+fn load_from(spec_params: SpecParams, s: ethjson::spec::Spec) -> Result<Spec, Error> {
+	let builtins = s.accounts
+		.builtins()
+		.into_iter()
+		.map(|p| (p.0.into(), From::from(p.1)))
+		.collect();
 	let g = Genesis::from(s.genesis);
 	let GenericSeal(seal_rlp) = g.seal.into();
 	let params = CommonParams::from(s.params);
 
 	let mut s = Spec {
 		name: s.name.clone().into(),
-		engine: Spec::engine(cache_dir, s.engine, params, builtins),
+		engine: Spec::engine(spec_params, s.engine, params, builtins),
 		data_dir: s.data_dir.unwrap_or(s.name).into(),
 		nodes: s.nodes.unwrap_or_else(Vec::new),
 		parent_hash: g.parent_hash,
@@ -279,7 +368,11 @@ pub fn load_from<T: AsRef<Path>>(cache_dir: T, s: ethjson::spec::Spec) -> Result
 		timestamp: g.timestamp,
 		extra_data: g.extra_data,
 		seal_rlp: seal_rlp,
-		constructors: s.accounts.constructors().into_iter().map(|(a, c)| (a.into(), c.into())).collect(),
+		constructors: s.accounts
+			.constructors()
+			.into_iter()
+			.map(|(a, c)| (a.into(), c.into()))
+			.collect(),
 		state_root_memo: RwLock::new(Default::default()), // will be overwritten right after.
 		genesis_state: s.accounts.into(),
 	};
@@ -287,7 +380,12 @@ pub fn load_from<T: AsRef<Path>>(cache_dir: T, s: ethjson::spec::Spec) -> Result
 	// use memoized state root if provided.
 	match g.state_root {
 		Some(root) => *s.state_root_memo.get_mut() = root,
-		None => { let _ = s.run_constructors(&Default::default(), BasicBackend(MemoryDB::new()))?; },
+		None => {
+			let _ = s.run_constructors(
+				&Default::default(),
+				BasicBackend(MemoryDB::new()),
+			)?;
+		}
 	}
 
 	Ok(s)
@@ -302,26 +400,52 @@ macro_rules! load_bundled {
 	};
 }
 
+macro_rules! load_machine_bundled {
+	($e:expr) => {
+		Spec::load_machine(
+			include_bytes!(concat!("../../res/", $e, ".json")) as &[u8]
+		).expect(concat!("Chain spec ", $e, " is invalid."))
+	};
+}
+
 impl Spec {
-	/// Convert engine spec into a arc'd Engine of the right underlying type.
-	/// TODO avoid this hard-coded nastiness - use dynamic-linked plugin framework instead.
-	fn engine<T: AsRef<Path>>(
-		cache_dir: T,
-		engine_spec: ethjson::spec::Engine,
+	// create an instance of an Ethereum state machine, minus consensus logic.
+	fn machine(
+		engine_spec: &ethjson::spec::Engine,
 		params: CommonParams,
 		builtins: BTreeMap<Address, Builtin>,
-	) -> Arc<Engine> {
-		match engine_spec {
-			ethjson::spec::Engine::Null => Arc::new(NullEngine::new(params, builtins)),
-			ethjson::spec::Engine::InstantSeal => Arc::new(InstantSeal::new(params, builtins)),
-			ethjson::spec::Engine::Ethash(ethash) => Arc::new(ethereum::Ethash::new(cache_dir, params, From::from(ethash.params), builtins)),
-			ethjson::spec::Engine::BasicAuthority(basic_authority) => Arc::new(BasicAuthority::new(params, From::from(basic_authority.params), builtins)),
-			ethjson::spec::Engine::AuthorityRound(authority_round) => AuthorityRound::new(params, From::from(authority_round.params), builtins).expect("Failed to start AuthorityRound consensus engine."),
-			ethjson::spec::Engine::Tendermint(tendermint) => Tendermint::new(params, From::from(tendermint.params), builtins).expect("Failed to start the Tendermint consensus engine."),
+	) -> EthereumMachine {
+		if let ethjson::spec::Engine::Ethash(ref ethash) = *engine_spec {
+			EthereumMachine::with_ethash_extensions(params, builtins, ethash.params.clone().into())
+		} else {
+			EthereumMachine::regular(params, builtins)
 		}
 	}
 
-	// given a pre-constructor state, run all the given constructors and produce a new state and state root.
+	/// Convert engine spec into a arc'd Engine of the right underlying type.
+	/// TODO avoid this hard-coded nastiness - use dynamic-linked plugin framework instead.
+	fn engine(
+		spec_params: SpecParams,
+		engine_spec: ethjson::spec::Engine,
+		params: CommonParams,
+		builtins: BTreeMap<Address, Builtin>,
+	) -> Arc<EthEngine> {
+		let machine = Self::machine(&engine_spec, params, builtins);
+
+		match engine_spec {
+			ethjson::spec::Engine::Null(null) => Arc::new(NullEngine::new(null.params.into(), machine)),
+			ethjson::spec::Engine::Ethash(ethash) => Arc::new(::ethereum::Ethash::new(spec_params.cache_dir, ethash.params.into(), machine, spec_params.optimization_setting)),
+			ethjson::spec::Engine::InstantSeal => Arc::new(InstantSeal::new(machine)),
+			ethjson::spec::Engine::BasicAuthority(basic_authority) => Arc::new(BasicAuthority::new(basic_authority.params.into(), machine)),
+			ethjson::spec::Engine::AuthorityRound(authority_round) => AuthorityRound::new(authority_round.params.into(), machine)
+				.expect("Failed to start AuthorityRound consensus engine."),
+			ethjson::spec::Engine::Tendermint(tendermint) => Tendermint::new(tendermint.params.into(), machine)
+				.expect("Failed to start the Tendermint consensus engine."),
+		}
+	}
+
+	// given a pre-constructor state, run all the given constructors and produce a new state and
+	// state root.
 	fn run_constructors<T: Backend>(&self, factories: &Factories, mut db: T) -> Result<T, Error> {
 		let mut root = KECCAK_NULL_RLP;
 
@@ -337,20 +461,18 @@ impl Spec {
 		for (address, account) in self.genesis_state.get().iter() {
 			db.note_non_null_account(address);
 			account.insert_additional(
-				&mut *factories.accountdb.create(db.as_hashdb_mut(), keccak(address)),
-				&factories.trie
+				&mut *factories.accountdb.create(
+					db.as_hashdb_mut(),
+					keccak(address),
+				),
+				&factories.trie,
 			);
 		}
 
 		let start_nonce = self.engine.account_start_nonce(0);
 
 		let (root, db) = {
-			let mut state = State::from_existing(
-				db,
-				root,
-				start_nonce,
-				factories.clone(),
-			)?;
+			let mut state = State::from_existing(db, root, start_nonce, factories.clone())?;
 
 			// Execute contract constructors.
 			let env_info = EnvInfo {
@@ -384,7 +506,7 @@ impl Spec {
 				let mut substate = Substate::new();
 
 				{
-					let mut exec = Executive::new(&mut state, &env_info, self.engine.as_ref());
+					let mut exec = Executive::new(&mut state, &env_info, self.engine.machine());
 					if let Err(e) = exec.create(params, &mut substate, &mut None, &mut NoopTracer, &mut NoopVMTracer) {
 						warn!(target: "spec", "Genesis constructor execution at {} failed: {}.", address, e);
 					}
@@ -410,22 +532,34 @@ impl Spec {
 	}
 
 	/// Get common blockchain parameters.
-	pub fn params(&self) -> &CommonParams { &self.engine.params() }
+	pub fn params(&self) -> &CommonParams {
+		&self.engine.params()
+	}
 
 	/// Get the known knodes of the network in enode format.
-	pub fn nodes(&self) -> &[String] { &self.nodes }
+	pub fn nodes(&self) -> &[String] {
+		&self.nodes
+	}
 
 	/// Get the configured Network ID.
-	pub fn network_id(&self) -> u64 { self.params().network_id }
+	pub fn network_id(&self) -> u64 {
+		self.params().network_id
+	}
 
 	/// Get the chain ID used for signing.
-	pub fn chain_id(&self) -> u64 { self.params().chain_id }
+	pub fn chain_id(&self) -> u64 {
+		self.params().chain_id
+	}
 
 	/// Get the configured subprotocol name.
-	pub fn subprotocol_name(&self) -> String { self.params().subprotocol_name.clone() }
+	pub fn subprotocol_name(&self) -> String {
+		self.params().subprotocol_name.clone()
+	}
 
 	/// Get the configured network fork block.
-	pub fn fork_block(&self) -> Option<(BlockNumber, H256)> { self.params().fork_block }
+	pub fn fork_block(&self) -> Option<(BlockNumber, H256)> {
+		self.params().fork_block
+	}
 
 	/// Get the header of the genesis block.
 	pub fn genesis_header(&self) -> Header {
@@ -480,7 +614,10 @@ impl Spec {
 	/// Alter the value of the genesis state.
 	pub fn set_genesis_state(&mut self, s: PodState) -> Result<(), Error> {
 		self.genesis_state = s;
-		let _ = self.run_constructors(&Default::default(), BasicBackend(MemoryDB::new()))?;
+		let _ = self.run_constructors(
+			&Default::default(),
+			BasicBackend(MemoryDB::new()),
+		)?;
 
 		Ok(())
 	}
@@ -496,7 +633,7 @@ impl Spec {
 	/// Ensure that the given state DB has the trie nodes in for the genesis state.
 	pub fn ensure_db_good<T: Backend>(&self, db: T, factories: &Factories) -> Result<T, Error> {
 		if db.as_hashdb().contains(&self.state_root()) {
-			return Ok(db)
+			return Ok(db);
 		}
 
 		// TODO: could optimize so we don't re-run, but `ensure_db_good` is barely ever
@@ -505,15 +642,25 @@ impl Spec {
 		Ok(db)
 	}
 
-	/// Loads spec from json file. Provide factories for executing contracts and ensuring
-	/// storage goes to the right place.
-	pub fn load<T: AsRef<Path>, R>(cache_dir: T, reader: R) -> Result<Self, String> where R: Read {
-		fn fmt<F: ::std::fmt::Display>(f: F) -> String {
-			format!("Spec json is invalid: {}", f)
+	/// Loads just the state machine from a json file.
+	pub fn load_machine<R: Read>(reader: R) -> Result<EthereumMachine, String> {
+		ethjson::spec::Spec::load(reader)
+			.map_err(fmt_err)
+			.map(load_machine_from)
+
 	}
 
-		ethjson::spec::Spec::load(reader).map_err(fmt)
-			.and_then(|x| load_from(cache_dir, x).map_err(fmt))
+	/// Loads spec from json file. Provide factories for executing contracts and ensuring
+	/// storage goes to the right place.
+	pub fn load<'a, T: Into<SpecParams<'a>>, R>(params: T, reader: R) -> Result<Self, String>
+	where
+		R: Read,
+	{
+		ethjson::spec::Spec::load(reader).map_err(fmt_err).and_then(
+			|x| {
+				load_from(params.into(), x).map_err(fmt_err)
+			},
+		)
 	}
 
 	/// initialize genesis epoch data, using in-memory database for
@@ -543,7 +690,7 @@ impl Spec {
 				difficulty: *genesis.difficulty(),
 				gas_limit: *genesis.gas_limit(),
 				last_hashes: Arc::new(Vec::new()),
-				gas_used: 0.into()
+				gas_used: 0.into(),
 			};
 
 			let from = Address::default();
@@ -560,92 +707,145 @@ impl Spec {
 				db.as_hashdb_mut(),
 				*genesis.state_root(),
 				&tx,
-				&*self.engine,
+				self.engine.machine(),
 				&env_info,
 				factories.clone(),
 				true,
 			);
 
-			res.map(|(out, proof)| (out, proof.into_iter().map(|x| x.into_vec()).collect()))
-				.ok_or_else(|| "Failed to prove call: insufficient state".into())
+			res.map(|(out, proof)| {
+				(out, proof.into_iter().map(|x| x.into_vec()).collect())
+			}).ok_or_else(|| "Failed to prove call: insufficient state".into())
 		};
 
 		self.engine.genesis_epoch_data(&genesis, &call)
 	}
 
-	/// Create a new Spec which conforms to the Frontier-era Morden chain except that it's a NullEngine consensus.
-	pub fn new_test() -> Spec { load_bundled!("null_morden") }
+	/// Create a new Spec which conforms to the Frontier-era Morden chain except that it's a
+	/// NullEngine consensus.
+	pub fn new_test() -> Spec {
+		load_bundled!("null_morden")
+	}
+
+	/// Create the EthereumMachine corresponding to Spec::new_test.
+	pub fn new_test_machine() -> EthereumMachine { load_machine_bundled!("null_morden") }
+
 
 	/// Create a new Spec which conforms to the Frontier-era Morden chain except that it's a NullEngine consensus with applying reward on block close.
 	pub fn new_test_with_reward() -> Spec { load_bundled!("null_morden_with_reward") }
 
-	/// Create a new Spec which is a NullEngine consensus with a premine of address whose secret is keccak('').
-	pub fn new_null() -> Spec { load_bundled!("null") }
+	/// Create a new Spec which is a NullEngine consensus with a premine of address whose
+	/// secret is keccak('').
+	pub fn new_null() -> Spec {
+		load_bundled!("null")
+	}
 
 	/// Create a new Spec which constructs a contract at address 5 with storage at 0 equal to 1.
-	pub fn new_test_constructor() -> Spec { load_bundled!("constructor") }
+	pub fn new_test_constructor() -> Spec {
+		load_bundled!("constructor")
+	}
 
-	/// Create a new Spec with InstantSeal consensus which does internal sealing (not requiring work).
-	pub fn new_instant() -> Spec { load_bundled!("instant_seal") }
+	/// Create a new Spec with InstantSeal consensus which does internal sealing (not requiring
+	/// work).
+	pub fn new_instant() -> Spec {
+		load_bundled!("instant_seal")
+	}
 
-	/// Create a new Spec with AuthorityRound consensus which does internal sealing (not requiring work).
+	/// Create a new Spec with AuthorityRound consensus which does internal sealing (not
+	/// requiring work).
 	/// Accounts with secrets keccak("0") and keccak("1") are the validators.
-	pub fn new_test_round() -> Self { load_bundled!("authority_round") }
+	pub fn new_test_round() -> Self {
+		load_bundled!("authority_round")
+	}
 
-	/// Create a new Spec with Tendermint consensus which does internal sealing (not requiring work).
+	/// Create a new Spec with Tendermint consensus which does internal sealing (not requiring
+	/// work).
 	/// Account keccak("0") and keccak("1") are a authorities.
-	pub fn new_test_tendermint() -> Self { load_bundled!("tendermint") }
+	pub fn new_test_tendermint() -> Self {
+		load_bundled!("tendermint")
+	}
 
 	/// TestList.sol used in both specs: https://github.com/paritytech/contracts/pull/30/files
 	/// Accounts with secrets keccak("0") and keccak("1") are initially the validators.
-	/// Create a new Spec with BasicAuthority which uses a contract at address 5 to determine the current validators using `getValidators`.
-	/// Second validator can be removed with "0xbfc708a000000000000000000000000082a978b3f5962a5b0957d9ee9eef472ee55b42f1" and added back in using "0x4d238c8e00000000000000000000000082a978b3f5962a5b0957d9ee9eef472ee55b42f1".
-	pub fn new_validator_safe_contract() -> Self { load_bundled!("validator_safe_contract") }
+	/// Create a new Spec with BasicAuthority which uses a contract at address 5 to determine
+	/// the current validators using `getValidators`.
+	/// Second validator can be removed with
+	/// "0xbfc708a000000000000000000000000082a978b3f5962a5b0957d9ee9eef472ee55b42f1" and added
+	/// back in using
+	/// "0x4d238c8e00000000000000000000000082a978b3f5962a5b0957d9ee9eef472ee55b42f1".
+	pub fn new_validator_safe_contract() -> Self {
+		load_bundled!("validator_safe_contract")
+	}
 
 	/// The same as the `safeContract`, but allows reporting and uses AuthorityRound.
 	/// Account is marked with `reportBenign` it can be checked as disliked with "0xd8f2e0bf".
 	/// Validator can be removed with `reportMalicious`.
-	pub fn new_validator_contract() -> Self { load_bundled!("validator_contract") }
+	pub fn new_validator_contract() -> Self {
+		load_bundled!("validator_contract")
+	}
 
-	/// Create a new Spec with BasicAuthority which uses multiple validator sets changing with height.
-	/// Account with secrets keccak("0") is the validator for block 1 and with keccak("1") onwards.
-	pub fn new_validator_multi() -> Self { load_bundled!("validator_multi") }
+	/// Create a new Spec with BasicAuthority which uses multiple validator sets changing with
+	/// height.
+	/// Account with secrets keccak("0") is the validator for block 1 and with keccak("1")
+	/// onwards.
+	pub fn new_validator_multi() -> Self {
+		load_bundled!("validator_multi")
+	}
 
 	/// Create a new spec for a PoW chain
-	pub fn new_pow_test_spec() -> Self { load_bundled!("ethereum/olympic") }
+	pub fn new_pow_test_spec() -> Self {
+		load_bundled!("ethereum/olympic")
+	}
 }
 
 #[cfg(test)]
 mod tests {
-	use std::str::FromStr;
-	use util::*;
-	use views::*;
-	use tests::helpers::get_temp_state_db;
-	use state::State;
 	use super::*;
+	use state::State;
+	use std::str::FromStr;
+	use tests::helpers::get_temp_state_db;
+	use views::*;
 
 	// https://github.com/paritytech/parity/issues/1840
 	#[test]
 	fn test_load_empty() {
-		assert!(Spec::load(::std::env::temp_dir(), &[] as &[u8]).is_err());
+		assert!(Spec::load(&::std::env::temp_dir(), &[] as &[u8]).is_err());
 	}
 
 	#[test]
 	fn test_chain() {
 		let test_spec = Spec::new_test();
 
-		assert_eq!(test_spec.state_root(), H256::from_str("f3f4696bbf3b3b07775128eb7a3763279a394e382130f27c21e70233e04946a9").unwrap());
+		assert_eq!(
+			test_spec.state_root(),
+			H256::from_str(
+				"f3f4696bbf3b3b07775128eb7a3763279a394e382130f27c21e70233e04946a9",
+			).unwrap()
+		);
 		let genesis = test_spec.genesis_block();
-		assert_eq!(BlockView::new(&genesis).header_view().hash(), H256::from_str("0cd786a2425d16f152c658316c423e6ce1181e15c3295826d7c9904cba9ce303").unwrap());
+		assert_eq!(
+			BlockView::new(&genesis).header_view().hash(),
+			H256::from_str(
+				"0cd786a2425d16f152c658316c423e6ce1181e15c3295826d7c9904cba9ce303",
+			).unwrap()
+		);
 	}
 
 	#[test]
 	fn genesis_constructor() {
 		::ethcore_logger::init_log();
 		let spec = Spec::new_test_constructor();
-		let db = spec.ensure_db_good(get_temp_state_db(), &Default::default()).unwrap();
-		let state = State::from_existing(db.boxed_clone(), spec.state_root(), spec.engine.account_start_nonce(0), Default::default()).unwrap();
-		let expected = H256::from_str("0000000000000000000000000000000000000000000000000000000000000001").unwrap();
+		let db = spec.ensure_db_good(get_temp_state_db(), &Default::default())
+			.unwrap();
+		let state = State::from_existing(
+			db.boxed_clone(),
+			spec.state_root(),
+			spec.engine.account_start_nonce(0),
+			Default::default(),
+		).unwrap();
+		let expected = H256::from_str(
+			"0000000000000000000000000000000000000000000000000000000000000001",
+		).unwrap();
 		let address = Address::from_str("0000000000000000000000000000000000000005").unwrap();
 
 		assert_eq!(state.storage_at(&address, &H256::zero()).unwrap(), expected);

ethcore/src/state/mod.rs

@@ -27,7 +27,7 @@ use std::sync::Arc;
 use hash::{KECCAK_NULL_RLP, KECCAK_EMPTY};
 
 use receipt::{Receipt, TransactionOutcome};
-use engines::Engine;
+use machine::EthereumMachine as Machine;
 use vm::EnvInfo;
 use error::Error;
 use executive::{Executive, TransactOptions};
@@ -196,7 +196,7 @@ pub fn check_proof(
 	proof: &[::util::DBValue],
 	root: H256,
 	transaction: &SignedTransaction,
-	engine: &Engine,
+	machine: &Machine,
 	env_info: &EnvInfo,
 ) -> ProvedExecution {
 	let backend = self::backend::ProofCheck::new(proof);
@@ -206,7 +206,7 @@ pub fn check_proof(
 	let res = State::from_existing(
 		backend,
 		root,
-		engine.account_start_nonce(env_info.number),
+		machine.account_start_nonce(env_info.number),
 		factories
 	);
 
@@ -216,7 +216,7 @@ pub fn check_proof(
 	};
 
 	let options = TransactOptions::with_no_tracing().save_output_from_contract();
-	match state.execute(env_info, engine, transaction, options, true) {
+	match state.execute(env_info, machine, transaction, options, true) {
 		Ok(executed) => ProvedExecution::Complete(executed),
 		Err(ExecutionError::Internal(_)) => ProvedExecution::BadProof,
 		Err(e) => ProvedExecution::Failed(e),
@@ -230,7 +230,7 @@ pub fn prove_transaction<H: AsHashDB + Send + Sync>(
 	db: H,
 	root: H256,
 	transaction: &SignedTransaction,
-	engine: &Engine,
+	machine: &Machine,
 	env_info: &EnvInfo,
 	factories: Factories,
 	virt: bool,
@@ -241,7 +241,7 @@ pub fn prove_transaction<H: AsHashDB + Send + Sync>(
 	let res = State::from_existing(
 		backend,
 		root,
-		engine.account_start_nonce(env_info.number),
+		machine.account_start_nonce(env_info.number),
 		factories,
 	);
 
@@ -251,7 +251,7 @@ pub fn prove_transaction<H: AsHashDB + Send + Sync>(
 	};
 
 	let options = TransactOptions::with_no_tracing().dont_check_nonce().save_output_from_contract();
-	match state.execute(env_info, engine, transaction, options, virt) {
+	match state.execute(env_info, machine, transaction, options, virt) {
 		Err(ExecutionError::Internal(_)) => None,
 		Err(e) => {
 			trace!(target: "state", "Proved call failed: {}", e);
@@ -668,13 +668,13 @@ impl<B: Backend> State<B> {
 
 	/// Execute a given transaction, producing a receipt and an optional trace.
 	/// This will change the state accordingly.
-	pub fn apply(&mut self, env_info: &EnvInfo, engine: &Engine, t: &SignedTransaction, tracing: bool) -> ApplyResult {
+	pub fn apply(&mut self, env_info: &EnvInfo, machine: &Machine, t: &SignedTransaction, tracing: bool) -> ApplyResult {
 		if tracing {
 			let options = TransactOptions::with_tracing();
-			self.apply_with_tracing(env_info, engine, t, options.tracer, options.vm_tracer)
+			self.apply_with_tracing(env_info, machine, t, options.tracer, options.vm_tracer)
 		} else {
 			let options = TransactOptions::with_no_tracing();
-			self.apply_with_tracing(env_info, engine, t, options.tracer, options.vm_tracer)
+			self.apply_with_tracing(env_info, machine, t, options.tracer, options.vm_tracer)
 		}
 	}
 
@@ -683,7 +683,7 @@ impl<B: Backend> State<B> {
 	pub fn apply_with_tracing<V, T>(
 		&mut self,
 		env_info: &EnvInfo,
-		engine: &Engine,
+		machine: &Machine,
 		t: &SignedTransaction,
 		tracer: T,
 		vm_tracer: V,
@@ -692,12 +692,13 @@ impl<B: Backend> State<B> {
 		V: trace::VMTracer,
 	{
 		let options = TransactOptions::new(tracer, vm_tracer);
-		let e = self.execute(env_info, engine, t, options, false)?;
+		let e = self.execute(env_info, machine, t, options, false)?;
+		let params = machine.params();
 
-		let eip658 = env_info.number >= engine.params().eip658_transition;
+		let eip658 = env_info.number >= params.eip658_transition;
 		let no_intermediate_commits =
 			eip658 ||
-			(env_info.number >= engine.params().eip98_transition && env_info.number >= engine.params().validate_receipts_transition);
+			(env_info.number >= params.eip98_transition && env_info.number >= params.validate_receipts_transition);
 
 		let outcome = if no_intermediate_commits {
 			if eip658 {
@@ -726,10 +727,10 @@ impl<B: Backend> State<B> {
 	//
 	// `virt` signals that we are executing outside of a block set and restrictions like
 	// gas limits and gas costs should be lifted.
-	fn execute<T, V>(&mut self, env_info: &EnvInfo, engine: &Engine, t: &SignedTransaction, options: TransactOptions<T, V>, virt: bool)
+	fn execute<T, V>(&mut self, env_info: &EnvInfo, machine: &Machine, t: &SignedTransaction, options: TransactOptions<T, V>, virt: bool)
 		-> Result<Executed, ExecutionError> where T: trace::Tracer, V: trace::VMTracer,
 	{
-		let mut e = Executive::new(self, env_info, engine);
+		let mut e = Executive::new(self, env_info, machine);
 
 		match virt {
 			true => e.transact_virtual(t, options),
@@ -1071,6 +1072,7 @@ mod tests {
 	use bigint::hash::H256;
 	use util::Address;
 	use tests::helpers::*;
+	use machine::EthereumMachine;
 	use vm::EnvInfo;
 	use spec::*;
 	use transaction::*;
@@ -1082,6 +1084,12 @@ mod tests {
 		keccak("").into()
 	}
 
+	fn make_frontier_machine(max_depth: usize) -> EthereumMachine {
+		let mut machine = ::ethereum::new_frontier_test_machine();
+		machine.set_schedule_creation_rules(Box::new(move |s, _| s.max_depth = max_depth));
+		machine
+	}
+
 	#[test]
 	fn should_apply_create_transaction() {
 		init_log();
@@ -1090,7 +1098,7 @@ mod tests {
 
 		let mut info = EnvInfo::default();
 		info.gas_limit = 1_000_000.into();
-		let engine = TestEngine::new(5);
+		let machine = make_frontier_machine(5);
 
 		let t = Transaction {
 			nonce: 0.into(),
@@ -1102,7 +1110,7 @@ mod tests {
 		}.sign(&secret(), None);
 
 		state.add_balance(&t.sender(), &(100.into()), CleanupMode::NoEmpty).unwrap();
-		let result = state.apply(&info, &engine, &t, true).unwrap();
+		let result = state.apply(&info, &machine, &t, true).unwrap();
 		let expected_trace = vec![FlatTrace {
 			trace_address: Default::default(),
 			subtraces: 0,
@@ -1148,7 +1156,7 @@ mod tests {
 
 		let mut info = EnvInfo::default();
 		info.gas_limit = 1_000_000.into();
-		let engine = TestEngine::new(5);
+		let machine = make_frontier_machine(5);
 
 		let t = Transaction {
 			nonce: 0.into(),
@@ -1160,7 +1168,7 @@ mod tests {
 		}.sign(&secret(), None);
 
 		state.add_balance(&t.sender(), &(100.into()), CleanupMode::NoEmpty).unwrap();
-		let result = state.apply(&info, &engine, &t, true).unwrap();
+		let result = state.apply(&info, &machine, &t, true).unwrap();
 		let expected_trace = vec![FlatTrace {
 			trace_address: Default::default(),
 			action: trace::Action::Create(trace::Create {
@@ -1184,7 +1192,7 @@ mod tests {
 
 		let mut info = EnvInfo::default();
 		info.gas_limit = 1_000_000.into();
-		let engine = TestEngine::new(5);
+		let machine = make_frontier_machine(5);
 
 		let t = Transaction {
 			nonce: 0.into(),
@@ -1197,7 +1205,7 @@ mod tests {
 
 		state.init_code(&0xa.into(), FromHex::from_hex("6000").unwrap()).unwrap();
 		state.add_balance(&t.sender(), &(100.into()), CleanupMode::NoEmpty).unwrap();
-		let result = state.apply(&info, &engine, &t, true).unwrap();
+		let result = state.apply(&info, &machine, &t, true).unwrap();
 		let expected_trace = vec![FlatTrace {
 			trace_address: Default::default(),
 			action: trace::Action::Call(trace::Call {
@@ -1226,7 +1234,7 @@ mod tests {
 
 		let mut info = EnvInfo::default();
 		info.gas_limit = 1_000_000.into();
-		let engine = TestEngine::new(5);
+		let machine = make_frontier_machine(5);
 
 		let t = Transaction {
 			nonce: 0.into(),
@@ -1238,7 +1246,7 @@ mod tests {
 		}.sign(&secret(), None);
 
 		state.add_balance(&t.sender(), &(100.into()), CleanupMode::NoEmpty).unwrap();
-		let result = state.apply(&info, &engine, &t, true).unwrap();
+		let result = state.apply(&info, &machine, &t, true).unwrap();
 		let expected_trace = vec![FlatTrace {
 			trace_address: Default::default(),
 			action: trace::Action::Call(trace::Call {
@@ -1267,7 +1275,7 @@ mod tests {
 
 		let mut info = EnvInfo::default();
 		info.gas_limit = 1_000_000.into();
-		let engine = &*Spec::new_test().engine;
+		let machine = Spec::new_test_machine();
 
 		let t = Transaction {
 			nonce: 0.into(),
@@ -1278,7 +1286,7 @@ mod tests {
 			data: vec![],
 		}.sign(&secret(), None);
 
-		let result = state.apply(&info, engine, &t, true).unwrap();
+		let result = state.apply(&info, &machine, &t, true).unwrap();
 
 		let expected_trace = vec![FlatTrace {
 			trace_address: Default::default(),
@@ -1308,7 +1316,7 @@ mod tests {
 
 		let mut info = EnvInfo::default();
 		info.gas_limit = 1_000_000.into();
-		let engine = &*Spec::new_test().engine;
+		let machine = Spec::new_test_machine();
 
 		let t = Transaction {
 			nonce: 0.into(),
@@ -1320,7 +1328,7 @@ mod tests {
 		}.sign(&secret(), None);
 
 		state.init_code(&0xa.into(), FromHex::from_hex("600060006000600060006001610be0f1").unwrap()).unwrap();
-		let result = state.apply(&info, engine, &t, true).unwrap();
+		let result = state.apply(&info, &machine, &t, true).unwrap();
 
 		let expected_trace = vec![FlatTrace {
 			trace_address: Default::default(),
@@ -1333,7 +1341,7 @@ mod tests {
 				call_type: CallType::Call,
 			}),
 			result: trace::Res::Call(trace::CallResult {
-				gas_used: U256::from(28_061),
+				gas_used: U256::from(3_721), // in post-eip150
 				output: vec![]
 			}),
 			subtraces: 0,
@@ -1350,7 +1358,7 @@ mod tests {
 
 		let mut info = EnvInfo::default();
 		info.gas_limit = 1_000_000.into();
-		let engine = &*Spec::new_test().engine;
+		let machine = Spec::new_test_machine();
 
 		let t = Transaction {
 			nonce: 0.into(),
@@ -1363,7 +1371,7 @@ mod tests {
 
 		state.init_code(&0xa.into(), FromHex::from_hex("60006000600060006000600b611000f2").unwrap()).unwrap();
 		state.init_code(&0xb.into(), FromHex::from_hex("6000").unwrap()).unwrap();
-		let result = state.apply(&info, engine, &t, true).unwrap();
+		let result = state.apply(&info, &machine, &t, true).unwrap();
 
 		let expected_trace = vec![FlatTrace {
 			trace_address: Default::default(),
@@ -1377,7 +1385,7 @@ mod tests {
 				call_type: CallType::Call,
 			}),
 			result: trace::Res::Call(trace::CallResult {
-				gas_used: 64.into(),
+				gas_used: 724.into(), // in post-eip150
 				output: vec![]
 			}),
 		}, FlatTrace {
@@ -1409,9 +1417,7 @@ mod tests {
 		let mut info = EnvInfo::default();
 		info.gas_limit = 1_000_000.into();
 		info.number = 0x789b0;
-		let engine = &*Spec::new_test().engine;
-
-		println!("schedule.have_delegate_call: {:?}", engine.schedule(info.number).have_delegate_call);
+		let machine = Spec::new_test_machine();
 
 		let t = Transaction {
 			nonce: 0.into(),
@@ -1424,7 +1430,7 @@ mod tests {
 
 		state.init_code(&0xa.into(), FromHex::from_hex("6000600060006000600b618000f4").unwrap()).unwrap();
 		state.init_code(&0xb.into(), FromHex::from_hex("6000").unwrap()).unwrap();
-		let result = state.apply(&info, engine, &t, true).unwrap();
+		let result = state.apply(&info, &machine, &t, true).unwrap();
 
 		let expected_trace = vec![FlatTrace {
 			trace_address: Default::default(),
@@ -1438,7 +1444,7 @@ mod tests {
 				call_type: CallType::Call,
 			}),
 			result: trace::Res::Call(trace::CallResult {
-				gas_used: U256::from(61),
+				gas_used: U256::from(721), // in post-eip150
 				output: vec![]
 			}),
 		}, FlatTrace {
@@ -1469,7 +1475,7 @@ mod tests {
 
 		let mut info = EnvInfo::default();
 		info.gas_limit = 1_000_000.into();
-		let engine = TestEngine::new(5);
+		let machine = make_frontier_machine(5);
 
 		let t = Transaction {
 			nonce: 0.into(),
@@ -1482,7 +1488,7 @@ mod tests {
 
 		state.init_code(&0xa.into(), FromHex::from_hex("5b600056").unwrap()).unwrap();
 		state.add_balance(&t.sender(), &(100.into()), CleanupMode::NoEmpty).unwrap();
-		let result = state.apply(&info, &engine, &t, true).unwrap();
+		let result = state.apply(&info, &machine, &t, true).unwrap();
 		let expected_trace = vec![FlatTrace {
 			trace_address: Default::default(),
 			action: trace::Action::Call(trace::Call {
@@ -1508,7 +1514,7 @@ mod tests {
 
 		let mut info = EnvInfo::default();
 		info.gas_limit = 1_000_000.into();
-		let engine = TestEngine::new(5);
+		let machine = make_frontier_machine(5);
 
 		let t = Transaction {
 			nonce: 0.into(),
@@ -1522,7 +1528,7 @@ mod tests {
 		state.init_code(&0xa.into(), FromHex::from_hex("60006000600060006000600b602b5a03f1").unwrap()).unwrap();
 		state.init_code(&0xb.into(), FromHex::from_hex("6000").unwrap()).unwrap();
 		state.add_balance(&t.sender(), &(100.into()), CleanupMode::NoEmpty).unwrap();
-		let result = state.apply(&info, &engine, &t, true).unwrap();
+		let result = state.apply(&info, &machine, &t, true).unwrap();
 
 		let expected_trace = vec![FlatTrace {
 			trace_address: Default::default(),
@@ -1567,7 +1573,7 @@ mod tests {
 
 		let mut info = EnvInfo::default();
 		info.gas_limit = 1_000_000.into();
-		let engine = TestEngine::new(5);
+		let machine = make_frontier_machine(5);
 
 		let t = Transaction {
 			nonce: 0.into(),
@@ -1580,7 +1586,7 @@ mod tests {
 
 		state.init_code(&0xa.into(), FromHex::from_hex("60006000600060006045600b6000f1").unwrap()).unwrap();
 		state.add_balance(&t.sender(), &(100.into()), CleanupMode::NoEmpty).unwrap();
-		let result = state.apply(&info, &engine, &t, true).unwrap();
+		let result = state.apply(&info, &machine, &t, true).unwrap();
 		let expected_trace = vec![FlatTrace {
 			trace_address: Default::default(),
 			subtraces: 1,
@@ -1621,7 +1627,7 @@ mod tests {
 
 		let mut info = EnvInfo::default();
 		info.gas_limit = 1_000_000.into();
-		let engine = TestEngine::new(5);
+		let machine = make_frontier_machine(5);
 
 		let t = Transaction {
 			nonce: 0.into(),
@@ -1634,7 +1640,7 @@ mod tests {
 
 		state.init_code(&0xa.into(), FromHex::from_hex("600060006000600060ff600b6000f1").unwrap()).unwrap();	// not enough funds.
 		state.add_balance(&t.sender(), &(100.into()), CleanupMode::NoEmpty).unwrap();
-		let result = state.apply(&info, &engine, &t, true).unwrap();
+		let result = state.apply(&info, &machine, &t, true).unwrap();
 		let expected_trace = vec![FlatTrace {
 			trace_address: Default::default(),
 			subtraces: 0,
@@ -1663,7 +1669,7 @@ mod tests {
 
 		let mut info = EnvInfo::default();
 		info.gas_limit = 1_000_000.into();
-		let engine = TestEngine::new(5);
+		let machine = make_frontier_machine(5);
 
 		let t = Transaction {
 			nonce: 0.into(),
@@ -1677,7 +1683,7 @@ mod tests {
 		state.init_code(&0xa.into(), FromHex::from_hex("60006000600060006000600b602b5a03f1").unwrap()).unwrap();
 		state.init_code(&0xb.into(), FromHex::from_hex("5b600056").unwrap()).unwrap();
 		state.add_balance(&t.sender(), &(100.into()), CleanupMode::NoEmpty).unwrap();
-		let result = state.apply(&info, &engine, &t, true).unwrap();
+		let result = state.apply(&info, &machine, &t, true).unwrap();
 		let expected_trace = vec![FlatTrace {
 			trace_address: Default::default(),
 			subtraces: 1,
@@ -1718,7 +1724,7 @@ mod tests {
 
 		let mut info = EnvInfo::default();
 		info.gas_limit = 1_000_000.into();
-		let engine = TestEngine::new(5);
+		let machine = make_frontier_machine(5);
 
 		let t = Transaction {
 			nonce: 0.into(),
@@ -1733,7 +1739,7 @@ mod tests {
 		state.init_code(&0xb.into(), FromHex::from_hex("60006000600060006000600c602b5a03f1").unwrap()).unwrap();
 		state.init_code(&0xc.into(), FromHex::from_hex("6000").unwrap()).unwrap();
 		state.add_balance(&t.sender(), &(100.into()), CleanupMode::NoEmpty).unwrap();
-		let result = state.apply(&info, &engine, &t, true).unwrap();
+		let result = state.apply(&info, &machine, &t, true).unwrap();
 		let expected_trace = vec![FlatTrace {
 			trace_address: Default::default(),
 			subtraces: 1,
@@ -1792,7 +1798,7 @@ mod tests {
 
 		let mut info = EnvInfo::default();
 		info.gas_limit = 1_000_000.into();
-		let engine = TestEngine::new(5);
+		let machine = make_frontier_machine(5);
 
 		let t = Transaction {
 			nonce: 0.into(),
@@ -1807,7 +1813,7 @@ mod tests {
 		state.init_code(&0xb.into(), FromHex::from_hex("60006000600060006000600c602b5a03f1505b601256").unwrap()).unwrap();
 		state.init_code(&0xc.into(), FromHex::from_hex("6000").unwrap()).unwrap();
 		state.add_balance(&t.sender(), &(100.into()), CleanupMode::NoEmpty).unwrap();
-		let result = state.apply(&info, &engine, &t, true).unwrap();
+		let result = state.apply(&info, &machine, &t, true).unwrap();
 
 		let expected_trace = vec![FlatTrace {
 			trace_address: Default::default(),
@@ -1864,7 +1870,7 @@ mod tests {
 
 		let mut info = EnvInfo::default();
 		info.gas_limit = 1_000_000.into();
-		let engine = TestEngine::new(5);
+		let machine = make_frontier_machine(5);
 
 		let t = Transaction {
 			nonce: 0.into(),
@@ -1878,7 +1884,7 @@ mod tests {
 		state.init_code(&0xa.into(), FromHex::from_hex("73000000000000000000000000000000000000000bff").unwrap()).unwrap();
 		state.add_balance(&0xa.into(), &50.into(), CleanupMode::NoEmpty).unwrap();
 		state.add_balance(&t.sender(), &100.into(), CleanupMode::NoEmpty).unwrap();
-		let result = state.apply(&info, &engine, &t, true).unwrap();
+		let result = state.apply(&info, &machine, &t, true).unwrap();
 		let expected_trace = vec![FlatTrace {
 			trace_address: Default::default(),
 			subtraces: 1,

ethcore/src/tests/client.rs

@@ -362,7 +362,7 @@ fn transaction_proof() {
 	let root = client.best_block_header().state_root();
 
 	let mut state = State::from_existing(backend, root, 0.into(), factories.clone()).unwrap();
-	Executive::new(&mut state, &client.latest_env_info(), &*test_spec.engine)
+	Executive::new(&mut state, &client.latest_env_info(), test_spec.engine.machine())
 		.transact(&transaction, TransactOptions::with_no_tracing().dont_check_nonce()).unwrap();
 
 	assert_eq!(state.balance(&Address::default()).unwrap(), 5.into());

ethcore/src/tests/evm.rs

@@ -24,7 +24,7 @@ fn test_blockhash_eip210(factory: Factory) {
 	let test_blockhash_contract = "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";
 	let blockhash_contract_code = Arc::new(test_blockhash_contract.from_hex().unwrap());
 	let blockhash_contract_code_hash = keccak(blockhash_contract_code.as_ref());
-	let engine = TestEngine::new_constantinople();
+	let machine = ::ethereum::new_constantinople_test_machine();
 	let mut env_info = EnvInfo::default();
 
 	// populate state with 256 last hashes
@@ -46,7 +46,7 @@ fn test_blockhash_eip210(factory: Factory) {
 			data: Some(H256::from(i - 1).to_vec()),
 			call_type: CallType::Call,
 		};
-		let mut ex = Executive::new(&mut state, &env_info, &engine);
+		let mut ex = Executive::new(&mut state, &env_info, &machine);
 		let mut substate = Substate::new();
 		let mut output = [];
 		if let Err(e) = ex.call(params, &mut substate, BytesRef::Fixed(&mut output), &mut NoopTracer, &mut NoopVMTracer) {
@@ -68,7 +68,7 @@ fn test_blockhash_eip210(factory: Factory) {
 		data: None,
 		call_type: CallType::Call,
 	};
-	let mut ex = Executive::new(&mut state, &env_info, &engine);
+	let mut ex = Executive::new(&mut state, &env_info, &machine);
 	let mut substate = Substate::new();
 	let mut output = H256::new();
 	if let Err(e) = ex.call(params, &mut substate, BytesRef::Fixed(&mut output), &mut NoopTracer, &mut NoopVMTracer) {

ethcore/src/tests/helpers.rs

@@ -14,82 +14,31 @@
 // You should have received a copy of the GNU General Public License
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
-use std::collections::BTreeMap;
-use std::sync::Arc;
-use hash::keccak;
-use ethkey::KeyPair;
-use io::*;
-use client::{BlockChainClient, Client, ClientConfig};
-use bigint::prelude::U256;
-use bigint::hash::H256;
-use util::*;
-use bytes::Bytes;
-use spec::*;
 use account_provider::AccountProvider;
-use state_db::StateDB;
+use bigint::hash::H256;
+use bigint::prelude::U256;
 use block::{OpenBlock, Drain};
 use blockchain::{BlockChain, Config as BlockChainConfig};
-use builtin::Builtin;
-use state::*;
-use evm::{Schedule, Factory as EvmFactory};
-use factory::Factories;
-use engines::Engine;
-use ethereum;
+use bytes::Bytes;
+use client::{BlockChainClient, Client, ClientConfig};
 use ethereum::ethash::EthashParams;
-use miner::Miner;
+use ethkey::KeyPair;
+use evm::Factory as EvmFactory;
+use factory::Factories;
+use hash::keccak;
 use header::Header;
-use transaction::{Action, Transaction, SignedTransaction};
+use io::*;
+use machine::EthashExtensions;
+use miner::Miner;
 use rlp::{self, RlpStream};
+use spec::*;
+use state_db::StateDB;
+use state::*;
+use std::sync::Arc;
+use transaction::{Action, Transaction, SignedTransaction};
+use util::*;
 use views::BlockView;
 
-pub struct TestEngine {
-	engine: Arc<Engine>,
-	max_depth: usize,
-}
-
-impl TestEngine {
-	pub fn new(max_depth: usize) -> TestEngine {
-		TestEngine {
-			engine: ethereum::new_frontier_test().engine,
-			max_depth: max_depth,
-		}
-	}
-
-	pub fn new_byzantium() -> TestEngine {
-		TestEngine {
-			engine: ethereum::new_byzantium_test().engine,
-			max_depth: 0,
-		}
-	}
-
-	pub fn new_constantinople() -> TestEngine {
-		TestEngine {
-			engine: ethereum::new_constantinople_test().engine,
-			max_depth: 0,
-		}
-	}
-}
-
-impl Engine for TestEngine {
-	fn name(&self) -> &str {
-		"TestEngine"
-	}
-
-	fn params(&self) -> &CommonParams {
-		self.engine.params()
-	}
-
-	fn builtins(&self) -> &BTreeMap<Address, Builtin> {
-		self.engine.builtins()
-	}
-
-	fn schedule(&self, _block_number: u64) -> Schedule {
-		let mut schedule = self.engine.schedule(0);
-		schedule.max_depth = self.max_depth;
-		schedule
-	}
-}
-
 // TODO: move everything over to get_null_spec.
 pub fn get_test_spec() -> Spec {
 	Spec::new_test()
@@ -233,9 +182,9 @@ pub fn generate_dummy_client_with_spec_accounts_and_data<F>(get_test_spec: F, ac
 
 pub fn push_blocks_to_client(client: &Arc<Client>, timestamp_salt: u64, starting_number: usize, block_number: usize) {
 	let test_spec = get_test_spec();
-	let test_engine = &test_spec.engine;
-	//let test_engine = test_spec.to_engine().unwrap();
 	let state_root = test_spec.genesis_header().state_root().clone();
+	let genesis_gas = test_spec.genesis_header().gas_limit().clone();
+
 	let mut rolling_hash = client.chain_info().best_block_hash;
 	let mut rolling_block_number = starting_number as u64;
 	let mut rolling_timestamp = timestamp_salt + starting_number as u64 * 10;
@@ -243,7 +192,7 @@ pub fn push_blocks_to_client(client: &Arc<Client>, timestamp_salt: u64, starting
 	for _ in 0..block_number {
 		let mut header = Header::new();
 
-		header.set_gas_limit(test_engine.params().min_gas_limit);
+		header.set_gas_limit(genesis_gas);
 		header.set_difficulty(U256::from(0x20000));
 		header.set_timestamp(rolling_timestamp);
 		header.set_number(rolling_block_number);
@@ -272,9 +221,9 @@ pub fn get_test_client_with_blocks(blocks: Vec<Bytes>) -> Arc<Client> {
 		IoChannel::disconnected(),
 	).unwrap();
 
-	for block in &blocks {
-		if client.import_block(block.clone()).is_err() {
-			panic!("panic importing block which is well-formed");
+	for block in blocks {
+		if let Err(e) = client.import_block(block) {
+			panic!("error importing block which is well-formed: {:?}", e);
 		}
 	}
 	client.flush_queue();
@@ -344,13 +293,13 @@ pub fn get_good_dummy_block_seq(count: usize) -> Vec<Bytes> {
 
 pub fn get_good_dummy_block_fork_seq(start_number: usize, count: usize, parent_hash: &H256) -> Vec<Bytes> {
 	let test_spec = get_test_spec();
-	let test_engine = &test_spec.engine;
+	let genesis_gas = test_spec.genesis_header().gas_limit().clone();
 	let mut rolling_timestamp = start_number as u64 * 10;
 	let mut parent = *parent_hash;
 	let mut r = Vec::new();
 	for i in start_number .. start_number + count + 1 {
 		let mut block_header = Header::new();
-		block_header.set_gas_limit(test_engine.params().min_gas_limit);
+		block_header.set_gas_limit(genesis_gas);
 		block_header.set_difficulty(U256::from(i) * U256([0, 1, 0, 0]));
 		block_header.set_timestamp(rolling_timestamp);
 		block_header.set_number(i as u64);
@@ -368,8 +317,8 @@ pub fn get_good_dummy_block_fork_seq(start_number: usize, count: usize, parent_h
 pub fn get_good_dummy_block_hash() -> (H256, Bytes) {
 	let mut block_header = Header::new();
 	let test_spec = get_test_spec();
-	let test_engine = &test_spec.engine;
-	block_header.set_gas_limit(test_engine.params().min_gas_limit);
+	let genesis_gas = test_spec.genesis_header().gas_limit().clone();
+	block_header.set_gas_limit(genesis_gas);
 	block_header.set_difficulty(U256::from(0x20000));
 	block_header.set_timestamp(40);
 	block_header.set_number(1);
@@ -387,8 +336,9 @@ pub fn get_good_dummy_block() -> Bytes {
 pub fn get_bad_state_dummy_block() -> Bytes {
 	let mut block_header = Header::new();
 	let test_spec = get_test_spec();
-	let test_engine = &test_spec.engine;
-	block_header.set_gas_limit(test_engine.params().min_gas_limit);
+	let genesis_gas = test_spec.genesis_header().gas_limit().clone();
+
+	block_header.set_gas_limit(genesis_gas);
 	block_header.set_difficulty(U256::from(0x20000));
 	block_header.set_timestamp(40);
 	block_header.set_number(1);
@@ -398,33 +348,35 @@ pub fn get_bad_state_dummy_block() -> Bytes {
 	create_test_block(&block_header)
 }
 
+pub fn get_default_ethash_extensions() -> EthashExtensions {
+	EthashExtensions {
+		homestead_transition: 1150000,
+		eip150_transition: u64::max_value(),
+		eip160_transition: u64::max_value(),
+		eip161abc_transition: u64::max_value(),
+		eip161d_transition: u64::max_value(),
+		dao_hardfork_transition: u64::max_value(),
+		dao_hardfork_beneficiary: "0000000000000000000000000000000000000001".into(),
+		dao_hardfork_accounts: Vec::new(),
+	}
+}
+
 pub fn get_default_ethash_params() -> EthashParams {
 	EthashParams {
 		minimum_difficulty: U256::from(131072),
 		difficulty_bound_divisor: U256::from(2048),
 		difficulty_increment_divisor: 10,
 		metropolis_difficulty_increment_divisor: 9,
-		duration_limit: 13,
 		homestead_transition: 1150000,
-		dao_hardfork_transition: u64::max_value(),
-		dao_hardfork_beneficiary: "0000000000000000000000000000000000000001".into(),
-		dao_hardfork_accounts: vec![],
+		duration_limit: 13,
+		block_reward: 0.into(),
 		difficulty_hardfork_transition: u64::max_value(),
 		difficulty_hardfork_bound_divisor: U256::from(0),
 		bomb_defuse_transition: u64::max_value(),
 		eip100b_transition: u64::max_value(),
-		eip150_transition: u64::max_value(),
-		eip160_transition: u64::max_value(),
-		eip161abc_transition: u64::max_value(),
-		eip161d_transition: u64::max_value(),
 		ecip1010_pause_transition: u64::max_value(),
 		ecip1010_continue_transition: u64::max_value(),
 		ecip1017_era_rounds: u64::max_value(),
-		max_code_size: u64::max_value(),
-		max_gas_limit_transition: u64::max_value(),
-		max_gas_limit: U256::max_value(),
-		min_gas_price_transition: u64::max_value(),
-		min_gas_price: U256::zero(),
 		eip649_transition: u64::max_value(),
 		eip649_delay: 3_000_000,
 		eip649_reward: None,

ethcore/src/tests/trace.rs

@@ -65,6 +65,8 @@ fn can_trace_block_and_uncle_reward() {
 	// block with transaction and uncle
 
 	let genesis_header = spec.genesis_header();
+	let genesis_gas = genesis_header.gas_limit().clone();
+
 	let mut db = spec.ensure_db_good(get_temp_state_db(), &Default::default()).unwrap();
 	let mut rolling_timestamp = 40;
 	let mut last_hashes = vec![];
@@ -165,7 +167,7 @@ fn can_trace_block_and_uncle_reward() {
 	let uncle_author: Address = "ef2d6d194084c2de36e0dabfce45d046b37d1106".into();
 	uncle.set_author(uncle_author);
 	uncle.set_parent_hash(root_header.hash());
-	uncle.set_gas_limit(U256::from(50_000));
+	uncle.set_gas_limit(genesis_gas);
 	uncle.set_number(root_header.number() + 1);
 	uncle.set_timestamp(rolling_timestamp);
 	block.push_uncle(uncle).unwrap();
@@ -186,6 +188,8 @@ fn can_trace_block_and_uncle_reward() {
 		range: (BlockId::Number(1)..BlockId::Number(3)),
 		from_address: vec![],
 		to_address: vec![],
+		after: None,
+		count: None,
 	};
 
 	let traces = client.filter_traces(filter);

ethcore/src/tx_filter.rs

@@ -16,15 +16,14 @@
 
 //! Smart contract based transaction filter.
 
-use std::sync::Weak;
 use std::collections::HashMap;
 use std::collections::hash_map::Entry;
 use bigint::hash::H256;
 use native_contracts::TransactAcl as Contract;
-use client::{EngineClient, BlockId, ChainNotify};
+use client::{BlockChainClient, BlockId, ChainNotify};
 use util::Address;
 use bytes::Bytes;
-use parking_lot::{Mutex, RwLock};
+use parking_lot::Mutex;
 use futures::{self, Future};
 use spec::CommonParams;
 use transaction::{Action, SignedTransaction};
@@ -44,7 +43,6 @@ mod tx_permissions {
 /// Connection filter that uses a contract to manage permissions.
 pub struct TransactionFilter {
 	contract: Mutex<Option<Contract>>,
-	client: RwLock<Option<Weak<EngineClient>>>,
 	contract_address: Address,
 	permission_cache: Mutex<HashMap<(H256, Address), u32>>,
 }
@@ -55,7 +53,6 @@ impl TransactionFilter {
 		params.transaction_permission_contract.map(|address|
 			TransactionFilter {
 				contract: Mutex::new(None),
-				client: RwLock::new(None),
 				contract_address: address,
 				permission_cache: Mutex::new(HashMap::new()),
 			}
@@ -67,24 +64,9 @@ impl TransactionFilter {
 		self.permission_cache.lock().clear();
 	}
 
-	/// Set client reference to be used for contract call.
-	pub fn register_client(&self, client: Weak<EngineClient>) {
-		*self.client.write() = Some(client);
-	}
-
 	/// Check if transaction is allowed at given block.
-	pub fn transaction_allowed(&self, parent_hash: &H256, transaction: &SignedTransaction) -> bool {
-		self.client.read().as_ref().map_or(false, |client| {
+	pub fn transaction_allowed(&self, parent_hash: &H256, transaction: &SignedTransaction, client: &BlockChainClient) -> bool {
 		let mut cache = self.permission_cache.lock(); let len = cache.len();
-			let client = match client.upgrade() {
-				Some(client) => client,
-				_ => return false,
-			};
-
-			let client = match client.as_full_client() {
-				Some(client) => client,
-				_ => return false, // TODO: how to handle verification for light clients?
-			};
 
 		let tx_type = match transaction.action {
 			Action::Create => tx_permissions::CREATE,
@@ -123,7 +105,6 @@ impl TransactionFilter {
 				permissions & tx_type != 0
 			}
 		}
-		})
 	}
 }
 
@@ -137,7 +118,7 @@ impl ChainNotify for TransactionFilter {
 
 #[cfg(test)]
 mod test {
-	use std::sync::{Arc, Weak};
+	use std::sync::Arc;
 	use spec::Spec;
 	use client::{BlockChainClient, Client, ClientConfig, BlockId};
 	use miner::Miner;
@@ -196,7 +177,7 @@ mod test {
 		}
 		"#;
 
-		let spec = Spec::load(::std::env::temp_dir(), spec_data.as_bytes()).unwrap();
+		let spec = Spec::load(&::std::env::temp_dir(), spec_data.as_bytes()).unwrap();
 		let client_db = Arc::new(::util::kvdb::in_memory(::db::NUM_COLUMNS.unwrap_or(0)));
 
 		let client = Client::new(
@@ -212,7 +193,6 @@ mod test {
 		let key4 = KeyPair::from_secret(Secret::from("0000000000000000000000000000000000000000000000000000000000000004")).unwrap();
 
 		let filter = TransactionFilter::from_params(spec.params()).unwrap();
-		filter.register_client(Arc::downgrade(&client) as Weak<_>);
 		let mut basic_tx = Transaction::default();
 		basic_tx.action = Action::Call(Address::from("000000000000000000000000000000000000032"));
 		let create_tx = Transaction::default();
@@ -221,21 +201,21 @@ mod test {
 
 		let genesis = client.block_hash(BlockId::Latest).unwrap();
 
-		assert!(filter.transaction_allowed(&genesis, &basic_tx.clone().sign(key1.secret(), None)));
-		assert!(filter.transaction_allowed(&genesis, &create_tx.clone().sign(key1.secret(), None)));
-		assert!(filter.transaction_allowed(&genesis, &call_tx.clone().sign(key1.secret(), None)));
+		assert!(filter.transaction_allowed(&genesis, &basic_tx.clone().sign(key1.secret(), None), &*client));
+		assert!(filter.transaction_allowed(&genesis, &create_tx.clone().sign(key1.secret(), None), &*client));
+		assert!(filter.transaction_allowed(&genesis, &call_tx.clone().sign(key1.secret(), None), &*client));
 
-		assert!(filter.transaction_allowed(&genesis, &basic_tx.clone().sign(key2.secret(), None)));
-		assert!(!filter.transaction_allowed(&genesis, &create_tx.clone().sign(key2.secret(), None)));
-		assert!(filter.transaction_allowed(&genesis, &call_tx.clone().sign(key2.secret(), None)));
+		assert!(filter.transaction_allowed(&genesis, &basic_tx.clone().sign(key2.secret(), None), &*client));
+		assert!(!filter.transaction_allowed(&genesis, &create_tx.clone().sign(key2.secret(), None), &*client));
+		assert!(filter.transaction_allowed(&genesis, &call_tx.clone().sign(key2.secret(), None), &*client));
 
-		assert!(filter.transaction_allowed(&genesis, &basic_tx.clone().sign(key3.secret(), None)));
-		assert!(!filter.transaction_allowed(&genesis, &create_tx.clone().sign(key3.secret(), None)));
-		assert!(!filter.transaction_allowed(&genesis, &call_tx.clone().sign(key3.secret(), None)));
+		assert!(filter.transaction_allowed(&genesis, &basic_tx.clone().sign(key3.secret(), None), &*client));
+		assert!(!filter.transaction_allowed(&genesis, &create_tx.clone().sign(key3.secret(), None), &*client));
+		assert!(!filter.transaction_allowed(&genesis, &call_tx.clone().sign(key3.secret(), None), &*client));
 
-		assert!(!filter.transaction_allowed(&genesis, &basic_tx.clone().sign(key4.secret(), None)));
-		assert!(!filter.transaction_allowed(&genesis, &create_tx.clone().sign(key4.secret(), None)));
-		assert!(!filter.transaction_allowed(&genesis, &call_tx.clone().sign(key4.secret(), None)));
+		assert!(!filter.transaction_allowed(&genesis, &basic_tx.clone().sign(key4.secret(), None), &*client));
+		assert!(!filter.transaction_allowed(&genesis, &create_tx.clone().sign(key4.secret(), None), &*client));
+		assert!(!filter.transaction_allowed(&genesis, &call_tx.clone().sign(key4.secret(), None), &*client));
 	}
 }
 

ethcore/src/verification/canon_verifier.rs

@@ -16,8 +16,7 @@
 
 //! Canonical verifier.
 
-use blockchain::BlockProvider;
-use engines::Engine;
+use engines::EthEngine;
 use error::Error;
 use header::Header;
 use super::Verifier;
@@ -27,15 +26,21 @@ use super::verification;
 pub struct CanonVerifier;
 
 impl Verifier for CanonVerifier {
-	fn verify_block_family(&self, header: &Header, bytes: &[u8], engine: &Engine, bc: &BlockProvider) -> Result<(), Error> {
-		verification::verify_block_family(header, bytes, engine, bc)
+	fn verify_block_family(
+		&self,
+		header: &Header,
+		parent: &Header,
+		engine: &EthEngine,
+		do_full: Option<verification::FullFamilyParams>,
+	) -> Result<(), Error> {
+		verification::verify_block_family(header, parent, engine, do_full)
 	}
 
 	fn verify_block_final(&self, expected: &Header, got: &Header) -> Result<(), Error> {
 		verification::verify_block_final(expected, got)
 	}
 
-	fn verify_block_external(&self, header: &Header, bytes: &[u8], engine: &Engine) -> Result<(), Error> {
-		engine.verify_block_external(header, Some(bytes))
+	fn verify_block_external(&self, header: &Header, engine: &EthEngine) -> Result<(), Error> {
+		engine.verify_block_external(header)
 	}
 }

ethcore/src/verification/noop_verifier.rs

@@ -16,18 +16,23 @@
 
 //! No-op verifier.
 
-use blockchain::BlockProvider;
-use engines::Engine;
+use engines::EthEngine;
 use error::Error;
 use header::Header;
-use super::Verifier;
+use super::{verification, Verifier};
 
 /// A no-op verifier -- this will verify everything it's given immediately.
 #[allow(dead_code)]
 pub struct NoopVerifier;
 
 impl Verifier for NoopVerifier {
-	fn verify_block_family(&self, _header: &Header, _bytes: &[u8], _engine: &Engine, _bc: &BlockProvider) -> Result<(), Error> {
+	fn verify_block_family(
+		&self,
+		_: &Header,
+		_t: &Header,
+		_: &EthEngine,
+		_: Option<verification::FullFamilyParams>
+	) -> Result<(), Error> {
 		Ok(())
 	}
 
@@ -35,7 +40,7 @@ impl Verifier for NoopVerifier {
 		Ok(())
 	}
 
-	fn verify_block_external(&self, _header: &Header, _bytes: &[u8], _engine: &Engine) -> Result<(), Error> {
+	fn verify_block_external(&self, _header: &Header, _engine: &EthEngine) -> Result<(), Error> {
 		Ok(())
 	}
 }

ethcore/src/verification/queue/kind.rs

@@ -16,7 +16,7 @@
 
 //! Definition of valid items for the verification queue.
 
-use engines::Engine;
+use engines::EthEngine;
 use error::Error;
 
 use heapsize::HeapSizeOf;
@@ -59,17 +59,17 @@ pub trait Kind: 'static + Sized + Send + Sync {
 	type Verified: Sized + Send + BlockLike + HeapSizeOf;
 
 	/// Attempt to create the `Unverified` item from the input.
-	fn create(input: Self::Input, engine: &Engine) -> Result<Self::Unverified, Error>;
+	fn create(input: Self::Input, engine: &EthEngine) -> Result<Self::Unverified, Error>;
 
 	/// Attempt to verify the `Unverified` item using the given engine.
-	fn verify(unverified: Self::Unverified, engine: &Engine, check_seal: bool) -> Result<Self::Verified, Error>;
+	fn verify(unverified: Self::Unverified, engine: &EthEngine, check_seal: bool) -> Result<Self::Verified, Error>;
 }
 
 /// The blocks verification module.
 pub mod blocks {
 	use super::{Kind, BlockLike};
 
-	use engines::Engine;
+	use engines::EthEngine;
 	use error::Error;
 	use header::Header;
 	use verification::{PreverifiedBlock, verify_block_basic, verify_block_unordered};
@@ -87,7 +87,7 @@ pub mod blocks {
 		type Unverified = Unverified;
 		type Verified = PreverifiedBlock;
 
-		fn create(input: Self::Input, engine: &Engine) -> Result<Self::Unverified, Error> {
+		fn create(input: Self::Input, engine: &EthEngine) -> Result<Self::Unverified, Error> {
 			match verify_block_basic(&input.header, &input.bytes, engine) {
 				Ok(()) => Ok(input),
 				Err(e) => {
@@ -97,7 +97,7 @@ pub mod blocks {
 			}
 		}
 
-		fn verify(un: Self::Unverified, engine: &Engine, check_seal: bool) -> Result<Self::Verified, Error> {
+		fn verify(un: Self::Unverified, engine: &EthEngine, check_seal: bool) -> Result<Self::Verified, Error> {
 			let hash = un.hash();
 			match verify_block_unordered(un.header, un.bytes, engine, check_seal) {
 				Ok(verified) => Ok(verified),
@@ -167,7 +167,7 @@ pub mod blocks {
 pub mod headers {
 	use super::{Kind, BlockLike};
 
-	use engines::Engine;
+	use engines::EthEngine;
 	use error::Error;
 	use header::Header;
 	use verification::verify_header_params;
@@ -189,13 +189,13 @@ pub mod headers {
 		type Unverified = Header;
 		type Verified = Header;
 
-		fn create(input: Self::Input, engine: &Engine) -> Result<Self::Unverified, Error> {
+		fn create(input: Self::Input, engine: &EthEngine) -> Result<Self::Unverified, Error> {
 			verify_header_params(&input, engine, true).map(|_| input)
 		}
 
-		fn verify(unverified: Self::Unverified, engine: &Engine, check_seal: bool) -> Result<Self::Verified, Error> {
+		fn verify(unverified: Self::Unverified, engine: &EthEngine, check_seal: bool) -> Result<Self::Verified, Error> {
 			match check_seal {
-				true => engine.verify_block_unordered(&unverified, None).map(|_| unverified),
+				true => engine.verify_block_unordered(&unverified,).map(|_| unverified),
 				false => Ok(unverified),
 			}
 		}

ethcore/src/verification/queue/mod.rs

@@ -28,7 +28,7 @@ use bigint::hash::H256;
 use parking_lot::{Condvar, Mutex, RwLock};
 use io::*;
 use error::*;
-use engines::Engine;
+use engines::EthEngine;
 use service::*;
 
 use self::kind::{BlockLike, Kind};
@@ -141,7 +141,7 @@ struct Sizes {
 /// A queue of items to be verified. Sits between network or other I/O and the `BlockChain`.
 /// Keeps them in the same order as inserted, minus invalid items.
 pub struct VerificationQueue<K: Kind> {
-	engine: Arc<Engine>,
+	engine: Arc<EthEngine>,
 	more_to_verify: Arc<SCondvar>,
 	verification: Arc<Verification<K>>,
 	deleting: Arc<AtomicBool>,
@@ -213,7 +213,7 @@ struct Verification<K: Kind> {
 
 impl<K: Kind> VerificationQueue<K> {
 	/// Creates a new queue instance.
-	pub fn new(config: Config, engine: Arc<Engine>, message_channel: IoChannel<ClientIoMessage>, check_seal: bool) -> Self {
+	pub fn new(config: Config, engine: Arc<EthEngine>, message_channel: IoChannel<ClientIoMessage>, check_seal: bool) -> Self {
 		let verification = Arc::new(Verification {
 			unverified: Mutex::new(VecDeque::new()),
 			verifying: Mutex::new(VecDeque::new()),
@@ -294,7 +294,7 @@ impl<K: Kind> VerificationQueue<K> {
 
 	fn verify(
 		verification: Arc<Verification<K>>,
-		engine: Arc<Engine>,
+		engine: Arc<EthEngine>,
 		wait: Arc<SCondvar>,
 		ready: Arc<QueueSignal>,
 		empty: Arc<SCondvar>,

ethcore/src/verification/verification.rs

@@ -22,20 +22,24 @@
 //! 3. Final verification against the blockchain done before enactment.
 
 use std::collections::HashSet;
-use hash::keccak;
-use triehash::ordered_trie_root;
-use heapsize::HeapSizeOf;
-use bigint::hash::H256;
-use unexpected::{Mismatch, OutOfBounds};
-use bytes::Bytes;
-use engines::Engine;
-use error::{BlockError, Error};
+
 use blockchain::*;
+use client::BlockChainClient;
+use engines::EthEngine;
+use error::{BlockError, Error};
 use header::{BlockNumber, Header};
-use rlp::UntrustedRlp;
 use transaction::SignedTransaction;
 use views::BlockView;
+
+use bigint::hash::H256;
+use bigint::prelude::U256;
+use bytes::Bytes;
+use hash::keccak;
+use heapsize::HeapSizeOf;
+use rlp::UntrustedRlp;
 use time::get_time;
+use triehash::ordered_trie_root;
+use unexpected::{Mismatch, OutOfBounds};
 
 /// Preprocessed block data gathered in `verify_block_unordered` call
 pub struct PreverifiedBlock {
@@ -56,14 +60,14 @@ impl HeapSizeOf for PreverifiedBlock {
 }
 
 /// Phase 1 quick block verification. Only does checks that are cheap. Operates on a single block
-pub fn verify_block_basic(header: &Header, bytes: &[u8], engine: &Engine) -> Result<(), Error> {
+pub fn verify_block_basic(header: &Header, bytes: &[u8], engine: &EthEngine) -> Result<(), Error> {
 	verify_header_params(&header, engine, true)?;
 	verify_block_integrity(bytes, &header.transactions_root(), &header.uncles_hash())?;
-	engine.verify_block_basic(&header, Some(bytes))?;
+	engine.verify_block_basic(&header)?;
 	for u in UntrustedRlp::new(bytes).at(2)?.iter().map(|rlp| rlp.as_val::<Header>()) {
 		let u = u?;
 		verify_header_params(&u, engine, false)?;
-		engine.verify_block_basic(&u, None)?;
+		engine.verify_block_basic(&u)?;
 	}
 	// Verify transactions.
 	// TODO: either use transaction views or cache the decoded transactions.
@@ -77,11 +81,11 @@ pub fn verify_block_basic(header: &Header, bytes: &[u8], engine: &Engine) -> Res
 /// Phase 2 verification. Perform costly checks such as transaction signatures and block nonce for ethash.
 /// Still operates on a individual block
 /// Returns a `PreverifiedBlock` structure populated with transactions
-pub fn verify_block_unordered(header: Header, bytes: Bytes, engine: &Engine, check_seal: bool) -> Result<PreverifiedBlock, Error> {
+pub fn verify_block_unordered(header: Header, bytes: Bytes, engine: &EthEngine, check_seal: bool) -> Result<PreverifiedBlock, Error> {
 	if check_seal {
-		engine.verify_block_unordered(&header, Some(&bytes))?;
+		engine.verify_block_unordered(&header)?;
 		for u in UntrustedRlp::new(&bytes).at(2)?.iter().map(|rlp| rlp.as_val::<Header>()) {
-			engine.verify_block_unordered(&u?, None)?;
+			engine.verify_block_unordered(&u?)?;
 		}
 	}
 	// Verify transactions.
@@ -92,7 +96,7 @@ pub fn verify_block_unordered(header: Header, bytes: Bytes, engine: &Engine, che
 	{
 		let v = BlockView::new(&bytes);
 		for t in v.transactions() {
-			let t = engine.verify_transaction(t, &header)?;
+			let t = engine.verify_transaction_unordered(t, &header)?;
 			if let Some(max_nonce) = nonce_cap {
 				if t.nonce >= max_nonce {
 					return Err(BlockError::TooManyTransactions(t.sender()).into());
@@ -108,13 +112,30 @@ pub fn verify_block_unordered(header: Header, bytes: Bytes, engine: &Engine, che
 	})
 }
 
-/// Phase 3 verification. Check block information against parent and uncles.
-pub fn verify_block_family(header: &Header, bytes: &[u8], engine: &Engine, bc: &BlockProvider) -> Result<(), Error> {
-	// TODO: verify timestamp
-	let parent = bc.block_header(&header.parent_hash()).ok_or_else(|| Error::from(BlockError::UnknownParent(header.parent_hash().clone())))?;
-	verify_parent(&header, &parent)?;
-	engine.verify_block_family(&header, &parent, Some(bytes))?;
+/// Parameters for full verification of block family: block bytes, transactions, blockchain, and state access.
+pub type FullFamilyParams<'a> = (&'a [u8], &'a [SignedTransaction], &'a BlockProvider, &'a BlockChainClient);
 
+/// Phase 3 verification. Check block information against parent and uncles.
+pub fn verify_block_family(header: &Header, parent: &Header, engine: &EthEngine, do_full: Option<FullFamilyParams>) -> Result<(), Error> {
+	// TODO: verify timestamp
+	verify_parent(&header, &parent, engine.params().gas_limit_bound_divisor)?;
+	engine.verify_block_family(&header, &parent)?;
+
+	let (bytes, txs, bc, client) = match do_full {
+		Some(x) => x,
+		None => return Ok(()),
+	};
+
+	verify_uncles(header, bytes, bc, engine)?;
+
+	for transaction in txs {
+		engine.machine().verify_transaction(transaction, header, client)?;
+	}
+
+	Ok(())
+}
+
+fn verify_uncles(header: &Header, bytes: &[u8], bc: &BlockProvider, engine: &EthEngine) -> Result<(), Error> {
 	let num_uncles = UntrustedRlp::new(bytes).at(2)?.item_count()?;
 	if num_uncles != 0 {
 		if num_uncles > engine.maximum_uncle_count() {
@@ -189,11 +210,12 @@ pub fn verify_block_family(header: &Header, bytes: &[u8], engine: &Engine, bc: &
 				return Err(From::from(BlockError::UncleParentNotInChain(uncle_parent.hash())));
 			}
 
-			verify_parent(&uncle, &uncle_parent)?;
-			engine.verify_block_family(&uncle, &uncle_parent, Some(bytes))?;
+			verify_parent(&uncle, &uncle_parent, engine.params().gas_limit_bound_divisor)?;
+			engine.verify_block_family(&uncle, &uncle_parent)?;
 			verified.insert(uncle.hash());
 		}
 	}
+
 	Ok(())
 }
 
@@ -215,7 +237,13 @@ pub fn verify_block_final(expected: &Header, got: &Header) -> Result<(), Error>
 }
 
 /// Check basic header parameters.
-pub fn verify_header_params(header: &Header, engine: &Engine, is_full: bool) -> Result<(), Error> {
+pub fn verify_header_params(header: &Header, engine: &EthEngine, is_full: bool) -> Result<(), Error> {
+	if header.seal().len() != engine.seal_fields() {
+		return Err(From::from(BlockError::InvalidSealArity(
+			Mismatch { expected: engine.seal_fields(), found: header.seal().len() }
+		)));
+	}
+
 	if header.number() >= From::from(BlockNumber::max_value()) {
 		return Err(From::from(BlockError::RidiculousNumber(OutOfBounds { max: Some(From::from(BlockNumber::max_value())), min: None, found: header.number() })))
 	}
@@ -230,6 +258,15 @@ pub fn verify_header_params(header: &Header, engine: &Engine, is_full: bool) ->
 	if header.number() != 0 && header.extra_data().len() > maximum_extra_data_size {
 		return Err(From::from(BlockError::ExtraDataOutOfBounds(OutOfBounds { min: None, max: Some(maximum_extra_data_size), found: header.extra_data().len() })));
 	}
+
+	if let Some(ref ext) = engine.machine().ethash_extensions() {
+		if header.number() >= ext.dao_hardfork_transition &&
+			header.number() <= ext.dao_hardfork_transition + 9 &&
+			header.extra_data()[..] != b"dao-hard-fork"[..] {
+			return Err(From::from(BlockError::ExtraDataOutOfBounds(OutOfBounds { min: None, max: None, found: 0 })));
+		}
+	}
+
 	if is_full {
 		let max_time = get_time().sec as u64 + 30;
 		if header.timestamp() > max_time {
@@ -240,7 +277,7 @@ pub fn verify_header_params(header: &Header, engine: &Engine, is_full: bool) ->
 }
 
 /// Check header parameters agains parent header.
-fn verify_parent(header: &Header, parent: &Header) -> Result<(), Error> {
+fn verify_parent(header: &Header, parent: &Header, gas_limit_divisor: U256) -> Result<(), Error> {
 	if !header.parent_hash().is_zero() && &parent.hash() != header.parent_hash() {
 		return Err(From::from(BlockError::InvalidParentHash(Mismatch { expected: parent.hash(), found: header.parent_hash().clone() })))
 	}
@@ -250,6 +287,18 @@ fn verify_parent(header: &Header, parent: &Header) -> Result<(), Error> {
 	if header.number() != parent.number() + 1 {
 		return Err(From::from(BlockError::InvalidNumber(Mismatch { expected: parent.number() + 1, found: header.number() })));
 	}
+
+	if header.number() == 0 {
+		return Err(BlockError::RidiculousNumber(OutOfBounds { min: Some(1), max: None, found: header.number() }).into());
+	}
+
+	let parent_gas_limit = *parent.gas_limit();
+	let min_gas = parent_gas_limit - parent_gas_limit / gas_limit_divisor;
+	let max_gas = parent_gas_limit + parent_gas_limit / gas_limit_divisor;
+	if header.gas_limit() <= &min_gas || header.gas_limit() >= &max_gas {
+		return Err(From::from(BlockError::InvalidGasLimit(OutOfBounds { min: Some(min_gas), max: Some(max_gas), found: header.gas_limit().clone() })));
+	}
+
 	Ok(())
 }
 
@@ -285,7 +334,7 @@ mod tests {
 	use error::BlockError::*;
 	use views::*;
 	use blockchain::*;
-	use engines::Engine;
+	use engines::EthEngine;
 	use spec::*;
 	use transaction::*;
 	use tests::helpers::*;
@@ -406,17 +455,38 @@ mod tests {
 		}
 	}
 
-	fn basic_test(bytes: &[u8], engine: &Engine) -> Result<(), Error> {
+	fn basic_test(bytes: &[u8], engine: &EthEngine) -> Result<(), Error> {
 		let header = BlockView::new(bytes).header();
 		verify_block_basic(&header, bytes, engine)
 	}
 
-	fn family_test<BC>(bytes: &[u8], engine: &Engine, bc: &BC) -> Result<(), Error> where BC: BlockProvider {
-		let header = BlockView::new(bytes).header();
-		verify_block_family(&header, bytes, engine, bc)
+	fn family_test<BC>(bytes: &[u8], engine: &EthEngine, bc: &BC) -> Result<(), Error> where BC: BlockProvider {
+		let view = BlockView::new(bytes);
+		let header = view.header();
+		let transactions: Vec<_> = view.transactions()
+			.into_iter()
+			.map(SignedTransaction::new)
+			.collect::<Result<_,_>>()?;
+
+		// TODO: client is really meant to be used for state query here by machine
+		// additions that need access to state (tx filter in specific)
+		// no existing tests need access to test, so having this not function
+		// is fine.
+		let client = ::client::TestBlockChainClient::default();
+
+		let parent = bc.block_header(header.parent_hash())
+			.ok_or(BlockError::UnknownParent(header.parent_hash().clone()))?;
+
+		let full_params: FullFamilyParams = (
+			bytes,
+			&transactions[..],
+			bc as &BlockProvider,
+			&client as &::client::BlockChainClient
+		);
+		verify_block_family(&header, &parent, engine, Some(full_params))
 	}
 
-	fn unordered_test(bytes: &[u8], engine: &Engine) -> Result<(), Error> {
+	fn unordered_test(bytes: &[u8], engine: &EthEngine) -> Result<(), Error> {
 		let header = BlockView::new(bytes).header();
 		verify_block_unordered(header, bytes.to_vec(), engine, false)?;
 		Ok(())
@@ -590,6 +660,15 @@ mod tests {
 		check_fail(family_test(&create_test_block_with_data(&header, &good_transactions, &bad_uncles), engine, &bc),
 			DuplicateUncle(good_uncle1.hash()));
 
+		header = good.clone();
+		header.set_gas_limit(0.into());
+		header.set_difficulty("0000000000000000000000000000000000000000000000000000000000020000".parse::<U256>().unwrap());
+		match family_test(&create_test_block(&header), engine, &bc) {
+			Err(Error::Block(InvalidGasLimit(_))) => {},
+			Err(_) => { panic!("should be invalid difficulty fail"); },
+			_ => { panic!("Should be error, got Ok"); },
+		}
+
 		// TODO: some additional uncle checks
 	}
 
@@ -597,6 +676,7 @@ mod tests {
 	fn dust_protection() {
 		use ethkey::{Generator, Random};
 		use transaction::{Transaction, Action};
+		use machine::EthereumMachine;
 		use engines::NullEngine;
 
 		let mut params = CommonParams::default();
@@ -618,7 +698,8 @@ mod tests {
 
 		let good_transactions = [bad_transactions[0].clone(), bad_transactions[1].clone()];
 
-		let engine = NullEngine::new(params, BTreeMap::new());
+		let machine = EthereumMachine::regular(params, BTreeMap::new());
+		let engine = NullEngine::new(Default::default(), machine);
 		check_fail(unordered_test(&create_test_block_with_data(&header, &bad_transactions, &[]), &engine), TooManyTransactions(keypair.address()));
 		unordered_test(&create_test_block_with_data(&header, &good_transactions, &[]), &engine).unwrap();
 	}

ethcore/src/verification/verifier.rs

@@ -16,17 +16,24 @@
 
 //! A generic verifier trait.
 
-use blockchain::BlockProvider;
-use engines::Engine;
+use engines::EthEngine;
 use error::Error;
 use header::Header;
+use super::verification;
 
 /// Should be used to verify blocks.
 pub trait Verifier: Send + Sync {
 	/// Verify a block relative to its parent and uncles.
-	fn verify_block_family(&self, header: &Header, bytes: &[u8], engine: &Engine, bc: &BlockProvider) -> Result<(), Error>;
+    fn verify_block_family(
+		&self,
+		header: &Header,
+		parent: &Header,
+		engine: &EthEngine,
+		do_full: Option<verification::FullFamilyParams>
+	) -> Result<(), Error>;
+
 	/// Do a final verification check for an enacted header vs its expected counterpart.
 	fn verify_block_final(&self, expected: &Header, got: &Header) -> Result<(), Error>;
 	/// Verify a block, inspecing external state.
-	fn verify_block_external(&self, header: &Header, bytes: &[u8], engine: &Engine) -> Result<(), Error>;
+	fn verify_block_external(&self, header: &Header, engine: &EthEngine) -> Result<(), Error>;
 }

ethcore/types/src/trace_filter.rs

@@ -28,4 +28,8 @@ pub struct Filter {
 	pub from_address: Vec<Address>,
 	/// To address.
 	pub to_address: Vec<Address>,
+	/// Output offset
+	pub after: Option<usize>,
+	/// Output amount
+	pub count: Option<usize>,
 }

evmbin/src/main.rs

@@ -230,7 +230,7 @@ impl Args {
 		Ok(match self.flag_chain {
 			Some(ref filename) =>  {
 				let file = fs::File::open(filename).map_err(|e| format!("{}", e))?;
-				spec::Spec::load(::std::env::temp_dir(), file)?
+				spec::Spec::load(&::std::env::temp_dir(), file)?
 			},
 			None => {
 				ethcore::ethereum::new_foundation(&::std::env::temp_dir())

ipc/rpc/src/interface.rs

@@ -52,7 +52,7 @@ pub trait IpcConfig {
 /// Error in dispatching or invoking methods via IPC
 #[derive(Debug)]
 pub enum Error {
-	UnkownSystemCall,
+	UnknownSystemCall,
 	ClientUnsupported,
 	RemoteServiceUnsupported,
 	HandshakeFailed,

js/package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "Parity",
-  "version": "1.8.21",
+  "version": "1.8.25",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {

js/package.json

@@ -1,6 +1,6 @@
 {
   "name": "Parity",
-  "version": "1.8.21",
+  "version": "1.8.25",
   "main": "src/index.parity.js",
   "jsnext:main": "src/index.parity.js",
   "author": "Parity Team <admin@parity.io>",

js/src/FirstRun/firstRun.js

@@ -80,16 +80,23 @@ class FirstRun extends Component {
     hasAccounts: PropTypes.bool.isRequired,
     newError: PropTypes.func.isRequired,
     onClose: PropTypes.func.isRequired,
-    visible: PropTypes.bool.isRequired
+    visible: PropTypes.bool.isRequired,
+    isTest: PropTypes.bool.isRequired
   }
 
-  createStore = new CreateStore(this.context.api, {}, true, false);
+  createStore = new CreateStore(this.context.api, {}, this.props.isTest, false);
 
   state = {
     stage: 0,
     hasAcceptedTnc: false
   }
 
+  componentWillReceiveProps (nextProps) {
+    if (nextProps.isTest !== this.props.isTest) {
+      this.createStore.setIsTest(nextProps.isTest);
+    }
+  }
+
   render () {
     const { visible } = this.props;
     const { stage } = this.state;
@@ -350,9 +357,10 @@ class FirstRun extends Component {
 
 function mapStateToProps (state) {
   const { hasAccounts } = state.personal;
+  const { isTest } = state.nodeStatus;
 
   return {
-    hasAccounts
+    hasAccounts, isTest
   };
 }
 

js/src/FirstRun/firstRun.spec.js

@@ -35,6 +35,9 @@ function createRedux () {
       return {
         personal: {
           hasAccounts: false
+        },
+        nodeStatus: {
+          isTest: false
         }
       };
     }

js/src/secureApi.js

@@ -98,7 +98,7 @@ export default class SecureApi extends Api {
 
     return {
       host,
-      port: parseInt(port, 10)
+      port: port ? parseInt(port, 10) : null
     };
   }
 
@@ -109,7 +109,9 @@ export default class SecureApi extends Api {
   get dappsUrl () {
     const { port } = this._dappsAddress;
 
-    return `${this.protocol()}//${this.hostname}:${port}`;
+    return port
+      ? `${this.protocol()}//${this.hostname}:${port}`
+      : `${this.protocol()}//${this.hostname}`;
   }
 
   get hostname () {
@@ -262,7 +264,7 @@ export default class SecureApi extends Api {
           .then(() => true);
       })
       .catch((error) => {
-        log.error('unkown error in _connect', error);
+        log.error('unknown error in _connect', error);
         return false;
       });
   }

json/src/spec/authority_round.rs

@@ -40,6 +40,9 @@ pub struct AuthorityRoundParams {
 	/// Whether transitions should be immediate.
 	#[serde(rename="immediateTransitions")]
 	pub immediate_transitions: Option<bool>,
+	/// Reward per block in wei.
+	#[serde(rename="blockReward")]
+	pub block_reward: Option<Uint>,
 }
 
 /// Authority engine deserialization.
@@ -67,7 +70,8 @@ mod tests {
 					"list" : ["0xc6d9d2cd449a754c494264e1809c50e34d64562b"]
 				},
 				"startStep" : 24,
-				"validateStepTransition": 150
+				"validateStepTransition": 150,
+				"blockReward": 5000000
 			}
 		}"#;
 
@@ -76,5 +80,6 @@ mod tests {
 		assert_eq!(deserialized.params.validators, ValidatorSet::List(vec![Address(H160::from("0xc6d9d2cd449a754c494264e1809c50e34d64562b"))]));
 		assert_eq!(deserialized.params.start_step, Some(Uint(U256::from(24))));
 		assert_eq!(deserialized.params.immediate_transitions, None);
+
 	}
 }

json/src/spec/engine.rs

@@ -16,14 +16,14 @@
 
 //! Engine deserialization.
 
-use super::{Ethash, BasicAuthority, AuthorityRound, Tendermint};
+use super::{Ethash, BasicAuthority, AuthorityRound, Tendermint, NullEngine};
 
 /// Engine deserialization.
 #[derive(Debug, PartialEq, Deserialize)]
 pub enum Engine {
 	/// Null engine.
 	#[serde(rename="null")]
-	Null,
+	Null(NullEngine),
 	/// Instantly sealing engine.
 	#[serde(rename="instantSeal")]
 	InstantSeal,
@@ -48,11 +48,18 @@ mod tests {
 	#[test]
 	fn engine_deserialization() {
 		let s = r#"{
-			"null": null
+			"null": {
+				"params": {
+					"blockReward": "0x0d"
+				}
+			}
 		}"#;
 
 		let deserialized: Engine = serde_json::from_str(s).unwrap();
-		assert_eq!(Engine::Null, deserialized);
+		match deserialized {
+			Engine::Null(_) => {}, // unit test in its own file.
+			_ => panic!(),
+		}
 
 		let s = r#"{
 			"instantSeal": null
@@ -61,7 +68,7 @@ mod tests {
 		let deserialized: Engine = serde_json::from_str(s).unwrap();
 		match deserialized {
 			Engine::InstantSeal => {},	// instant seal is unit tested in its own file.
-			_ => assert!(false),
+			_ => panic!(),
 		};
 
 		let s = r#"{
@@ -82,7 +89,7 @@ mod tests {
 		let deserialized: Engine = serde_json::from_str(s).unwrap();
 		match deserialized {
 			Engine::Ethash(_) => {},	// ethash is unit tested in its own file.
-			_ => assert!(false),
+			_ => panic!(),
 		};
 
 		let s = r#"{
@@ -98,7 +105,7 @@ mod tests {
 		let deserialized: Engine = serde_json::from_str(s).unwrap();
 		match deserialized {
 			Engine::BasicAuthority(_) => {}, // basicAuthority is unit tested in its own file.
-			_ => assert!(false),
+			_ => panic!(),
 		};
 
 		let s = r#"{
@@ -116,7 +123,7 @@ mod tests {
 		let deserialized: Engine = serde_json::from_str(s).unwrap();
 		match deserialized {
 			Engine::AuthorityRound(_) => {}, // AuthorityRound is unit tested in its own file.
-			_ => assert!(false),
+			_ => panic!(),
 		};
 
 		let s = r#"{
@@ -131,7 +138,7 @@ mod tests {
 		let deserialized: Engine = serde_json::from_str(s).unwrap();
 		match deserialized {
 			Engine::Tendermint(_) => {}, // Tendermint is unit tested in its own file.
-			_ => assert!(false),
+			_ => panic!(),
 		};
 	}
 }