Merge branch 'master' of github.com:gavofyork/ethcore into verification

src/basic_types.rs

@@ -0,0 +1,7 @@
+use util::*;
+
+/// Type for a 2048-bit log-bloom, as used by our blocks.
+pub type LogBloom = H2048;
+
+/// Constant 2048-bit datum for 0. Often used as a default.
+pub static ZERO_LOGBLOOM: LogBloom = H2048([0x00; 256]);

src/block.rs

@@ -1,9 +1,5 @@
-use util::*;
+use common::*;
-use transaction::*;
-use receipt::*;
 use engine::*;
-use header::*;
-use env_info::*;
 use state::*;
 
 /// A transaction/receipt execution entry.
@@ -21,6 +17,8 @@ pub struct Block {
 
 	archive: Vec<Entry>,
 	archive_set: HashSet<H256>,
+
+	uncles: Vec<Header>,
 }
 
 impl Block {
@@ -30,6 +28,7 @@ impl Block {
 			state: state,
 			archive: Vec::new(),
 			archive_set: HashSet::new(),
+			uncles: Vec::new(),
 		}
 	}
 
@@ -49,6 +48,9 @@ pub trait IsBlock {
 
 	/// Get all information on transactions in this block.
 	fn archive(&self) -> &Vec<Entry> { &self.block().archive }
+
+	/// Get all uncles in this block.
+	fn uncles(&self) -> &Vec<Header> { &self.block().uncles }
 }
 
 impl IsBlock for Block {
@@ -71,7 +73,7 @@ pub struct OpenBlock<'engine> {
 /// There is no function available to push a transaction. If you want that you'll need to `reopen()` it.
 pub struct ClosedBlock<'engine> {
 	open_block: OpenBlock<'engine>,
-	_uncles: Vec<Header>,
+	uncle_bytes: Bytes,
 }
 
 /// A block that has a valid seal.
@@ -79,23 +81,52 @@ pub struct ClosedBlock<'engine> {
 /// The block's header has valid seal arguments. The block cannot be reversed into a ClosedBlock or OpenBlock.
 pub struct SealedBlock {
 	block: Block,
-	_bytes: Bytes,
+	uncle_bytes: Bytes,
 }
 
 impl<'engine> OpenBlock<'engine> {
 	/// Create a new OpenBlock ready for transaction pushing.
-	pub fn new<'a>(engine: &'a Engine, db: OverlayDB, parent: &Header, last_hashes: LastHashes) -> OpenBlock<'a> {
+	pub fn new<'a>(engine: &'a Engine, db: OverlayDB, parent: &Header, last_hashes: LastHashes, author: Address, extra_data: Bytes) -> OpenBlock<'a> {
 		let mut r = OpenBlock {
 			block: Block::new(State::from_existing(db, parent.state_root.clone(), engine.account_start_nonce())),
 			engine: engine,
 			last_hashes: last_hashes,
 		};
 
+		r.block.header.set_author(author);
+		r.block.header.set_extra_data(extra_data);
 		engine.populate_from_parent(&mut r.block.header, parent);
 		engine.on_new_block(&mut r.block);
 		r
 	}
 
+	/// Alter the author for the block.
+	pub fn set_author(&mut self, author: Address) { self.block.header.set_author(author); }
+
+	/// Alter the extra_data for the block.
+	pub fn set_extra_data(&mut self, extra_data: Bytes) -> Result<(), BlockError> {
+		if extra_data.len() > self.engine.maximum_extra_data_size() {
+			Err(BlockError::ExtraDataOutOfBounds(OutOfBounds{min: 0, max: self.engine.maximum_extra_data_size(), found: extra_data.len()}))
+		} else {
+			self.block.header.set_extra_data(extra_data);
+			Ok(())
+		}
+	}
+
+	/// Add an uncle to the block, if possible.
+	///
+	/// NOTE Will check chain constraints and the uncle number but will NOT check
+	/// that the header itself is actually valid.
+	pub fn push_uncle(&mut self, valid_uncle_header: Header) -> Result<(), BlockError> {
+		if self.block.uncles.len() >= self.engine.maximum_uncle_count() {
+			return Err(BlockError::TooManyUncles);
+		}
+		// TODO: check number
+		// TODO: check not a direct ancestor (use last_hashes for that)
+		self.block.uncles.push(valid_uncle_header);
+		Ok(())
+	}
+
 	/// Get the environment info concerning this block.
 	pub fn env_info(&self) -> EnvInfo {
 		// TODO: memoise.
@@ -105,17 +136,19 @@ impl<'engine> OpenBlock<'engine> {
 			timestamp: self.block.header.timestamp.clone(),
 			difficulty: self.block.header.difficulty.clone(),
 			last_hashes: self.last_hashes.clone(),
-			gas_used: if let Some(ref t) = self.block.archive.last() {t.receipt.gas_used} else {U256::from(0)},
+			gas_used: self.block.archive.last().map(|t| t.receipt.gas_used).unwrap_or(U256::from(0)),
 			gas_limit: self.block.header.gas_limit.clone(),
 		}
 	}
 
-	/// Push a transaction into the block. It will be executed, and archived together with the receipt.
+	/// Push a transaction into the block.
-	pub fn push_transaction(&mut self, t: Transaction, h: Option<H256>) -> Result<&Receipt, EthcoreError> {
+	///
+	/// If valid, it will be executed, and archived together with the receipt.
+	pub fn push_transaction(&mut self, t: Transaction, h: Option<H256>) -> Result<&Receipt, Error> {
 		let env_info = self.env_info();
 		match self.block.state.apply(&env_info, self.engine, &t, true) {
 			Ok(x) => {
-				self.block.archive_set.insert(h.unwrap_or_else(||t.sha3()));
+				self.block.archive_set.insert(h.unwrap_or_else(||t.hash()));
 				self.block.archive.push(Entry { transaction: t, receipt: x.receipt });
 				Ok(&self.block.archive.last().unwrap().receipt)
 			}
@@ -123,30 +156,68 @@ impl<'engine> OpenBlock<'engine> {
 		}
 	}
 
-	/// Turn this into a `ClosedBlock`. A BlockChain must be provided in order to figure ou the uncles.
+	/// Turn this into a `ClosedBlock`. A BlockChain must be provided in order to figure out the uncles.
-	pub fn close(self, _uncles: Vec<Header>) -> ClosedBlock<'engine> { unimplemented!(); }
+	pub fn close(self) -> ClosedBlock<'engine> {
+		let mut s = self;
+		s.engine.on_close_block(&mut s.block);
+		s.block.header.transactions_root = ordered_trie_root(s.block.archive.iter().map(|ref e| e.transaction.rlp_bytes()).collect());
+		let uncle_bytes = s.block.uncles.iter().fold(RlpStream::new_list(s.block.uncles.len()), |mut s, u| {s.append(&u.rlp(Seal::With)); s} ).out();
+		s.block.header.uncles_hash = uncle_bytes.sha3();
+		s.block.header.state_root = s.block.state.root().clone();
+		s.block.header.receipts_root = ordered_trie_root(s.block.archive.iter().map(|ref e| e.receipt.rlp_bytes()).collect());
+		s.block.header.log_bloom = s.block.archive.iter().fold(LogBloom::zero(), |mut b, e| {b |= &e.receipt.log_bloom; b});
+		s.block.header.gas_used = s.block.archive.last().map(|t| t.receipt.gas_used).unwrap_or(U256::from(0));
+		s.block.header.note_dirty();
+
+		ClosedBlock::new(s, uncle_bytes)
+	}
 }
 
 impl<'engine> IsBlock for OpenBlock<'engine> {
 	fn block(&self) -> &Block { &self.block }
 }
 
-impl<'engine> ClosedBlock<'engine> {
-	/// Get the hash of the header without seal arguments.
-	pub fn preseal_hash(&self) -> H256 { unimplemented!(); }
-
-	/// Turn this into a `ClosedBlock`. A BlockChain must be provided in order to figure ou the uncles.
-	pub fn seal(self, _seal_fields: Vec<Bytes>) -> SealedBlock { unimplemented!(); }
-
-	/// Turn this back into an `OpenBlock`.
-	pub fn reopen(self) -> OpenBlock<'engine> { unimplemented!(); }
-}
-
 impl<'engine> IsBlock for ClosedBlock<'engine> {
 	fn block(&self) -> &Block { &self.open_block.block }
 }
 
+impl<'engine> ClosedBlock<'engine> {
+	fn new<'a>(open_block: OpenBlock<'a>, uncle_bytes: Bytes) -> ClosedBlock<'a> {
+		ClosedBlock {
+			open_block: open_block,
+			uncle_bytes: uncle_bytes,
+		}
+	}
+
+	/// Get the hash of the header without seal arguments.
+	pub fn hash(&self) -> H256 { self.header().rlp_sha3(Seal::Without) }
+
+	/// 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, seal: Vec<Bytes>) -> Result<SealedBlock, BlockError> {
+		let mut s = self;
+		if seal.len() != s.open_block.engine.seal_fields() {
+			return Err(BlockError::InvalidSealArity(Mismatch{expected: s.open_block.engine.seal_fields(), found: seal.len()}));
+		}
+		s.open_block.block.header.set_seal(seal);
+		Ok(SealedBlock { block: s.open_block.block, uncle_bytes: s.uncle_bytes })
+	}
+
+	/// Turn this back into an `OpenBlock`.
+	pub fn reopen(self) -> OpenBlock<'engine> { self.open_block }
+}
+
 impl SealedBlock {
+	/// Get the RLP-encoding of the block.
+	pub fn rlp_bytes(&self) -> Bytes {
+		let mut block_rlp = RlpStream::new_list(3);
+		self.block.header.stream_rlp(&mut block_rlp, Seal::With);
+		block_rlp.append_list(self.block.archive.len());
+		for e in self.block.archive.iter() { e.transaction.rlp_append(&mut block_rlp); }
+		block_rlp.append_raw(&self.uncle_bytes, 1);
+		block_rlp.out()
+	}		
 }
 
 impl IsBlock for SealedBlock {
@@ -155,11 +226,12 @@ impl IsBlock for SealedBlock {
 
 #[test]
 fn open_block() {
-	use super::*;
 	use spec::*;
 	let engine = Spec::new_test().to_engine().unwrap();
 	let genesis_header = engine.spec().genesis_header();
 	let mut db = OverlayDB::new_temp();
 	engine.spec().ensure_db_good(&mut db);
-	let b = OpenBlock::new(engine.deref(), db, &genesis_header, vec![genesis_header.hash()]);
+	let b = OpenBlock::new(engine.deref(), db, &genesis_header, vec![genesis_header.hash()], Address::zero(), vec![]);
+	let b = b.close();
+	let _ = b.seal(vec![]);
 }

src/common.rs

@@ -1,4 +1,6 @@
 pub use util::*;
+pub use basic_types::*;
+pub use error::*;
 pub use env_info::*;
 pub use evm_schedule::*;
 pub use views::*;
@@ -6,3 +8,4 @@ pub use builtin::*;
 pub use header::*;
 pub use account::*;
 pub use transaction::*;
+pub use receipt::*;

src/engine.rs

@@ -12,7 +12,7 @@ pub trait Engine {
 	fn version(&self) -> SemanticVersion { SemanticVersion::new(0, 0, 0) }
 
 	/// The number of additional header fields required for this engine.
-	fn seal_fields(&self) -> u32 { 0 }
+	fn seal_fields(&self) -> usize { 0 }
 	/// Default values of the additional fields RLP-encoded in a raw (non-list) harness.
 	fn seal_rlp(&self) -> Bytes { vec![] }
 
@@ -27,6 +27,7 @@ pub trait Engine {
 
 	/// Some intrinsic operation parameters; by default they take their value from the `spec()`'s `engine_params`.
 	fn maximum_extra_data_size(&self) -> usize { decode(&self.spec().engine_params.get("maximumExtraDataSize").unwrap()) }
+	fn maximum_uncle_count(&self) -> usize { 2 }
 	fn account_start_nonce(&self) -> U256 { decode(&self.spec().engine_params.get("accountStartNonce").unwrap()) }
 
 	/// Block transformation functions, before and after the transactions.
@@ -37,12 +38,12 @@ pub trait Engine {
 	/// `parent` (the parent header) and `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.
 	// TODO: consider including State in the params.
-	fn verify_block(&self, _mode: VerificationMode, _header: &Header, _parent: Option<&Header>, _block: Option<&[u8]>) -> Result<(), VerificationError> { Ok(()) }
+	fn verify_block(&self, _mode: VerificationMode, _header: &Header, _parent: Option<&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(&self, _t: &Transaction, _header: &Header) -> Result<(), VerificationError> { Ok(()) }
+	fn verify_transaction(&self, _t: &Transaction, _header: &Header) -> Result<(), Error> { Ok(()) }
 
 	/// Don't forget to call Super::populateFromParent when subclassing & overriding.
 	// TODO: consider including State in the params.

src/error.rs

@@ -0,0 +1,52 @@
+//! General error types for use in ethcore.
+
+use util::*;
+
+#[derive(Debug)]
+pub struct Mismatch<T: fmt::Debug> {
+	pub expected: T,
+	pub found: T,
+}
+
+#[derive(Debug)]
+pub struct OutOfBounds<T: fmt::Debug> {
+	pub min: T,
+	pub max: T,
+	pub found: T,
+}
+
+#[derive(Debug)]
+pub enum BlockError {
+	TooManyUncles,
+	UncleWrongGeneration,
+	ExtraDataOutOfBounds(OutOfBounds<usize>),
+	InvalidSealArity(Mismatch<usize>),
+}
+
+#[derive(Debug)]
+/// General error type which should be capable of representing all errors in ethcore.
+pub enum Error {
+	Util(UtilError),
+	Block(BlockError),
+	UnknownEngineName(String),
+}
+
+impl From<BlockError> for Error {
+	fn from(err: BlockError) -> Error {
+		Error::Block(err)
+	}
+}
+
+// TODO: uncomment below once https://github.com/rust-lang/rust/issues/27336 sorted.
+/*#![feature(concat_idents)]
+macro_rules! assimilate {
+    ($name:ident) => (
+		impl From<concat_idents!($name, Error)> for Error {
+			fn from(err: concat_idents!($name, Error)) -> Error {
+				Error:: $name (err)
+			}
+		}
+    )
+}
+assimilate!(FromHex);
+assimilate!(BaseData);*/

src/ethereum/ethash.rs

@@ -24,7 +24,7 @@ impl Engine for Ethash {
 	/// Apply the block reward on finalisation of the block.
 	fn on_close_block(&self, block: &mut Block) {
 		let a = block.header().author.clone();
-		block.state_mut().add_balance(&a, &decode(&self.spec().engine_params.get("block_reward").unwrap()));
+		block.state_mut().add_balance(&a, &decode(&self.spec().engine_params.get("blockReward").unwrap()));
 	}
 
 	fn verify_block(&self, mode: VerificationMode, header: &Header, parent: Option<&Header>, block: Option<&[u8]>) -> Result<(), VerificationError> { 
@@ -113,11 +113,9 @@ impl Ethash {
 	}
 }
 
-// TODO: test for on_close_block.
 #[test]
-fn playpen() {
+fn on_close_block() {
 	use super::*;
-	use state::*;
 	let engine = new_morden().to_engine().unwrap();
 	let genesis_header = engine.spec().genesis_header();
 	let mut db = OverlayDB::new_temp();

src/ethereum/mod.rs

@@ -56,7 +56,7 @@ mod tests {
 		let genesis = morden.genesis_block();
 		assert_eq!(BlockView::new(&genesis).header_view().sha3(), H256::from_str("0cd786a2425d16f152c658316c423e6ce1181e15c3295826d7c9904cba9ce303").unwrap());
 
-		morden.to_engine();
+		let _ = morden.to_engine();
 	}
 
 	#[test]
@@ -67,6 +67,6 @@ mod tests {
 		let genesis = frontier.genesis_block();
 		assert_eq!(BlockView::new(&genesis).header_view().sha3(), H256::from_str("d4e56740f876aef8c010b86a40d5f56745a118d0906a34e69aec8c0db1cb8fa3").unwrap());
 
-		frontier.to_engine();
+		let _ = frontier.to_engine();
 	}
 }

src/header.rs

@@ -1,14 +1,5 @@
 use util::*;
-
+use basic_types::*;
-/// Type for a 2048-bit log-bloom, as used by our blocks.
-pub type LogBloom = H2048;
-
-/// Constant address for point 0. Often used as a default.
-pub static ZERO_ADDRESS: Address = Address([0x00; 20]);
-/// Constant 256-bit datum for 0. Often used as a default.
-pub static ZERO_H256: H256 = H256([0x00; 32]);
-/// Constant 2048-bit datum for 0. Often used as a default.
-pub static ZERO_LOGBLOOM: LogBloom = H2048([0x00; 256]);
 
 /// A block header.
 ///
@@ -18,6 +9,7 @@ pub static ZERO_LOGBLOOM: LogBloom = H2048([0x00; 256]);
 /// Doesn't do all that much on its own.
 #[derive(Debug)]
 pub struct Header {
+	// TODO: make all private.
 	pub parent_hash: H256,
 	pub timestamp: U256,
 	pub number: U256,
@@ -36,7 +28,12 @@ pub struct Header {
 	pub difficulty: U256,
 	pub seal: Vec<Bytes>,
 
-	pub hash: RefCell<Option<H256>>, //TODO: make this private
+	pub hash: RefCell<Option<H256>>,
+}
+
+pub enum Seal {
+	With,
+	Without,
 }
 
 impl Header {
@@ -64,19 +61,64 @@ impl Header {
 		}
 	}
 
+	pub fn author(&self) -> &Address { &self.author }
+	pub fn extra_data(&self) -> &Bytes { &self.extra_data }
+	pub fn seal(&self) -> &Vec<Bytes> { &self.seal }
+
+	// TODO: seal_at, set_seal_at &c.
+
+	pub fn set_author(&mut self, a: Address) { if a != self.author { self.author = a; self.note_dirty(); } }
+	pub fn set_extra_data(&mut self, a: Bytes) { if a != self.extra_data { self.extra_data = a; self.note_dirty(); } }
+	pub fn set_seal(&mut self, a: Vec<Bytes>) { self.seal = a; self.note_dirty(); }
+
+	/// Get the hash of this header (sha3 of the RLP).
 	pub fn hash(&self) -> H256 {
  		let mut hash = self.hash.borrow_mut();
  		match &mut *hash {
  			&mut Some(ref h) => h.clone(),
  			hash @ &mut None => {
- 				let mut stream = RlpStream::new();
+ 				*hash = Some(self.rlp_sha3(Seal::With));
- 				stream.append(self);
+ 				hash.as_ref().unwrap().clone()
- 				let h = stream.as_raw().sha3();
- 				*hash = Some(h.clone());
- 				h.clone()
  			}
 		}
 	}
+
+	/// Note that some fields have changed. Resets the memoised hash.
+	pub fn note_dirty(&self) {
+ 		*self.hash.borrow_mut() = None;
+	}
+
+	// TODO: get hash without seal.
+
+	// TODO: make these functions traity 
+	pub fn stream_rlp(&self, s: &mut RlpStream, with_seal: Seal) {
+		s.append_list(13 + match with_seal { Seal::With => self.seal.len(), _ => 0 });
+		s.append(&self.parent_hash);
+		s.append(&self.uncles_hash);
+		s.append(&self.author);
+		s.append(&self.state_root);
+		s.append(&self.transactions_root);
+		s.append(&self.receipts_root);
+		s.append(&self.log_bloom);
+		s.append(&self.difficulty);
+		s.append(&self.number);
+		s.append(&self.gas_limit);
+		s.append(&self.gas_used);
+		s.append(&self.timestamp);
+		s.append(&self.extra_data);
+		match with_seal {
+			Seal::With => for b in self.seal.iter() { s.append_raw(&b, 1); },
+			_ => {}
+		}
+	}
+
+	pub fn rlp(&self, with_seal: Seal) -> Bytes {
+		let mut s = RlpStream::new();
+		self.stream_rlp(&mut s, with_seal);
+		s.out()
+	}
+
+	pub fn rlp_sha3(&self, with_seal: Seal) -> H256 { self.rlp(with_seal).sha3() }
 }
 
 impl Decodable for Header {
@@ -132,28 +174,6 @@ impl Encodable for Header {
 		})
 	}
 }
-/*
-trait RlpStandard {
-	fn append(&self, s: &mut RlpStream);
-}
-
-impl RlpStandard for Header {
-	fn append(&self, s: &mut RlpStream) {
-		s.append_list(13);
-		s.append(self.parent_hash);
-		s.append_raw(self.seal[0]);
-		s.append_standard(self.x);
-	}
-	fn populate(&mut self, s: &Rlp) {
-	}
-}
-
-impl RlpStream {
-	fn append_standard<O>(&mut self, o: &O) where O: RlpStandard {
-		o.append(self);
-	}
-}
-*/
 
 #[cfg(test)]
 mod tests {

src/lib.rs

@@ -1,5 +1,5 @@
 #![feature(cell_extras)]
-
+#![feature(augmented_assignments)]
 //! Ethcore's ethereum implementation
 //!
 //! ### Rust version
@@ -85,6 +85,8 @@ extern crate evmjit;
 extern crate ethcore_util as util;
 
 pub mod common;
+pub mod basic_types;
+pub mod error;
 pub mod env_info;
 pub mod engine;
 pub mod state;

src/receipt.rs

@@ -1,8 +1,47 @@
 use util::*;
+use basic_types::LogBloom;
+
+/// A single log's entry.
+pub struct LogEntry {
+	pub address: Address,
+	pub topics: Vec<H256>,
+	pub data: Bytes,
+}
+
+impl RlpStandard for LogEntry {
+	fn rlp_append(&self, s: &mut RlpStream) {
+		s.append_list(3);
+		s.append(&self.address);
+		s.append(&self.topics);
+		s.append(&self.data);
+	}
+}
+
+impl LogEntry {
+	pub fn bloom(&self) -> LogBloom {
+		self.topics.iter().fold(LogBloom::from_bloomed(&self.address.sha3()), |b, t| b.with_bloomed(&t.sha3()))
+	}
+}
 
 /// Information describing execution of a transaction.
 pub struct Receipt {
-	// TODO
 	pub state_root: H256,
 	pub gas_used: U256,
+	pub log_bloom: LogBloom,
+	pub logs: Vec<LogEntry>,
+}
+
+impl RlpStandard for Receipt {
+	fn rlp_append(&self, s: &mut RlpStream) {
+		s.append_list(4);
+		s.append(&self.state_root);
+		s.append(&self.gas_used);
+		s.append(&self.log_bloom);
+		// TODO: make work:
+		//s.append(&self.logs);
+		s.append_list(self.logs.len());
+		for l in self.logs.iter() {
+			l.rlp_append(s);
+		}
+	}
 }

src/spec.rs

@@ -73,11 +73,11 @@ pub struct Spec {
 impl Spec {
 	/// Convert this object into a boxed Engine of the right underlying type.
 	// TODO avoid this hard-coded nastiness - use dynamic-linked plugin framework instead.
-	pub fn to_engine(self) -> Result<Box<Engine>, EthcoreError> {
+	pub fn to_engine(self) -> Result<Box<Engine>, Error> {
 		match self.engine_name.as_ref() {
 			"NullEngine" => Ok(NullEngine::new_boxed(self)),
 			"Ethash" => Ok(super::ethereum::Ethash::new_boxed(self)),
-			_ => Err(EthcoreError::UnknownName)
+			_ => Err(Error::UnknownEngineName(self.engine_name.clone()))
 		}
 	}
 

src/state.rs

@@ -1,8 +1,4 @@
-use util::*;
+use common::*;
-use account::Account;
-use transaction::Transaction;
-use receipt::Receipt;
-use env_info::EnvInfo;
 use engine::Engine;
 
 /// Information concerning the result of the `State::apply` operation.
@@ -10,7 +6,7 @@ pub struct ApplyInfo {
 	pub receipt: Receipt,
 }
 
-pub type ApplyResult = Result<ApplyInfo, EthcoreError>;
+pub type ApplyResult = Result<ApplyInfo, Error>;
 
 /// Representation of the entire state of all accounts in the system.
 pub struct State {
@@ -79,6 +75,11 @@ impl State {
 		self.require_or_from(contract, false, || Account::new_contract(U256::from(0u8)), |r| r.reset_code());
 	}
 
+	/// Remove an existing account.
+	pub fn kill_account(&mut self, account: &Address) {
+		self.cache.borrow_mut().insert(account.clone(), None);
+	}
+
 	/// Get the balance of account `a`.
 	pub fn balance(&self, a: &Address) -> U256 {
 		self.get(a, false).as_ref().map(|account| account.balance().clone()).unwrap_or(U256::from(0u8))
@@ -228,12 +229,11 @@ use util::hash::*;
 use util::trie::*;
 use util::rlp::*;
 use util::uint::*;
-use std::str::FromStr;
 use account::*;
 
 #[test]
 fn code_from_database() {
-	let a = Address::from_str("0000000000000000000000000000000000000000").unwrap();
+	let a = Address::zero();
 	let (r, db) = {
 		let mut s = State::new_temp();
 		s.require_or_from(&a, false, ||Account::new_contract(U256::from(42u32)), |_|{});
@@ -250,7 +250,7 @@ fn code_from_database() {
 
 #[test]
 fn storage_at_from_database() {
-	let a = Address::from_str("0000000000000000000000000000000000000000").unwrap();
+	let a = Address::zero();
 	let (r, db) = {
 		let mut s = State::new_temp();
 		s.set_storage(&a, H256::from(&U256::from(01u64)), H256::from(&U256::from(69u64)));
@@ -264,7 +264,7 @@ fn storage_at_from_database() {
 
 #[test]
 fn get_from_database() {
-	let a = Address::from_str("0000000000000000000000000000000000000000").unwrap();
+	let a = Address::zero();
 	let (r, db) = {
 		let mut s = State::new_temp();
 		s.inc_nonce(&a);
@@ -279,11 +279,45 @@ fn get_from_database() {
 	assert_eq!(s.nonce(&a), U256::from(1u64));
 }
 
+#[test]
+fn remove() {
+	let a = Address::zero();
+	let mut s = State::new_temp();
+	s.inc_nonce(&a);
+	assert_eq!(s.nonce(&a), U256::from(1u64));
+	s.kill_account(&a);
+	assert_eq!(s.nonce(&a), U256::from(0u64));
+}
+
+#[test]
+fn remove_from_database() {
+	let a = Address::zero();
+	let (r, db) = {
+		let mut s = State::new_temp();
+		s.inc_nonce(&a);
+		s.commit();
+		assert_eq!(s.nonce(&a), U256::from(1u64));
+		s.drop()
+	};
+
+	let (r, db) = {
+		let mut s = State::from_existing(db, r, U256::from(0u8));
+		assert_eq!(s.nonce(&a), U256::from(1u64));
+		s.kill_account(&a);
+		s.commit();
+		assert_eq!(s.nonce(&a), U256::from(0u64));
+		s.drop()
+	};
+
+	let s = State::from_existing(db, r, U256::from(0u8));
+	assert_eq!(s.nonce(&a), U256::from(0u64));
+}
+
 #[test]
 fn alter_balance() {
 	let mut s = State::new_temp();
-	let a = Address::from_str("0000000000000000000000000000000000000000").unwrap();
+	let a = Address::zero();
-	let b = Address::from_str("0000000000000000000000000000000000000001").unwrap();
+	let b = address_from_u64(1u64);
 	s.add_balance(&a, &U256::from(69u64));
 	assert_eq!(s.balance(&a), U256::from(69u64));
 	s.commit();
@@ -303,7 +337,7 @@ fn alter_balance() {
 #[test]
 fn alter_nonce() {
 	let mut s = State::new_temp();
-	let a = Address::from_str("0000000000000000000000000000000000000000").unwrap();
+	let a = Address::zero();
 	s.inc_nonce(&a);
 	assert_eq!(s.nonce(&a), U256::from(1u64));
 	s.inc_nonce(&a);
@@ -319,7 +353,7 @@ fn alter_nonce() {
 #[test]
 fn balance_nonce() {
 	let mut s = State::new_temp();
-	let a = Address::from_str("0000000000000000000000000000000000000000").unwrap();
+	let a = Address::zero();
 	assert_eq!(s.balance(&a), U256::from(0u64));
 	assert_eq!(s.nonce(&a), U256::from(0u64));
 	s.commit();
@@ -330,7 +364,7 @@ fn balance_nonce() {
 #[test]
 fn ensure_cached() {
 	let mut s = State::new_temp();
-	let a = Address::from_str("0000000000000000000000000000000000000000").unwrap();
+	let a = Address::zero();
 	s.require(&a, false);
 	s.commit();
 	assert_eq!(s.root().hex(), "0ce23f3c809de377b008a4a3ee94a0834aac8bec1f86e28ffe4fdb5a15b0c785");

src/transaction.rs

@@ -9,6 +9,8 @@ pub struct Transaction {
 	to: Option<Address>,
 	value: U256,
 	data: Bytes,
+
+	hash: RefCell<Option<H256>>, //TODO: make this private
 }
 
 impl Transaction {
@@ -21,10 +23,36 @@ impl Transaction {
 	pub fn is_message_call(&self) -> bool {
 		!self.is_contract_creation()
 	}
+}
 
-	/// Get the hash of this transaction.
+impl RlpStandard for Transaction {
-	pub fn sha3(&self) -> H256 {
+	fn rlp_append(&self, s: &mut RlpStream) {
-		unimplemented!();
+		s.append_list(6);
+		s.append(&self.nonce);
+		s.append(&self.gas_price);
+		s.append(&self.gas);
+		s.append(&self.to);
+		s.append(&self.value);
+		s.append(&self.data);
+	}
+}
+
+impl Transaction {
+	/// Get the hash of this header (sha3 of the RLP).
+	pub fn hash(&self) -> H256 {
+ 		let mut hash = self.hash.borrow_mut();
+ 		match &mut *hash {
+ 			&mut Some(ref h) => h.clone(),
+ 			hash @ &mut None => {
+ 				*hash = Some(self.rlp_sha3());
+ 				hash.as_ref().unwrap().clone()
+ 			}
+		}
+	}
+
+	/// Note that some fields have changed. Resets the memoised hash.
+	pub fn note_dirty(&self) {
+ 		*self.hash.borrow_mut() = None;
 	}
 }
 
@@ -52,6 +80,7 @@ impl Decodable for Transaction {
 			to: try!(Decodable::decode(&d[3])),
 			value: try!(Decodable::decode(&d[4])),
 			data: try!(Decodable::decode(&d[5])),
+			hash: RefCell::new(None)
 		};
 
 		Ok(transaction)