make block queue into a more generic verification queue and fix block heap size calculation (#2095)

* move block queue to own module, a couple readability changes

* make block queue generic over verifiable data

also fixes heap size calculation

* make block queue into a more generic verification queue

* some module reoganization

* implement header queue

* clean up verification error messages

ethcore/src/verification/queue/kind.rs

@@ -0,0 +1,182 @@
+// Copyright 2015, 2016 Ethcore (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/>.
+
+//! Definition of valid items for the verification queue.
+
+use engines::Engine;
+use error::Error;
+
+use util::{HeapSizeOf, H256};
+
+pub use self::blocks::Blocks;
+pub use self::headers::Headers;
+
+/// Something which can produce a hash and a parent hash.
+pub trait HasHash {
+	/// Get the hash of this item.
+	fn hash(&self) -> H256;
+
+	/// Get the hash of this item's parent.
+	fn parent_hash(&self) -> H256;
+}
+
+/// Defines transitions between stages of verification.
+///
+/// It starts with a fallible transformation from an "input" into the unverified item.
+/// This consists of quick, simply done checks as well as extracting particular data.
+///
+/// Then, there is a `verify` function which performs more expensive checks and
+/// produces the verified output.
+///
+/// For correctness, the hashes produced by each stage of the pipeline should be
+/// consistent.
+pub trait Kind: 'static + Sized + Send + Sync {
+	/// The first stage: completely unverified.
+	type Input: Sized + Send + HasHash + HeapSizeOf;
+
+	/// The second stage: partially verified.
+	type Unverified: Sized + Send + HasHash + HeapSizeOf;
+
+	/// The third stage: completely verified.
+	type Verified: Sized + Send + HasHash + HeapSizeOf;
+
+	/// Attempt to create the `Unverified` item from the input.
+	fn create(input: Self::Input, engine: &Engine) -> Result<Self::Unverified, Error>;
+
+	/// Attempt to verify the `Unverified` item using the given engine.
+	fn verify(unverified: Self::Unverified, engine: &Engine) -> Result<Self::Verified, Error>;
+}
+
+/// The blocks verification module.
+pub mod blocks {
+	use super::{Kind, HasHash};
+
+	use engines::Engine;
+	use error::Error;
+	use header::Header;
+	use verification::{PreverifiedBlock, verify_block_basic, verify_block_unordered};
+
+	use util::{Bytes, HeapSizeOf, H256};
+
+	/// A mode for verifying blocks.
+	pub struct Blocks;
+
+	impl Kind for Blocks {
+		type Input = Unverified;
+		type Unverified = Unverified;
+		type Verified = PreverifiedBlock;
+
+		fn create(input: Self::Input, engine: &Engine) -> Result<Self::Unverified, Error> {
+			match verify_block_basic(&input.header, &input.bytes, engine) {
+				Ok(()) => Ok(input),
+				Err(e) => {
+					warn!(target: "client", "Stage 1 block verification failed for {}: {:?}", input.hash(), e);
+					Err(e)
+				}
+			}
+		}
+
+		fn verify(un: Self::Unverified, engine: &Engine) -> Result<Self::Verified, Error> {
+			let hash = un.hash();
+			match verify_block_unordered(un.header, un.bytes, engine) {
+				Ok(verified) => Ok(verified),
+				Err(e) => {
+					warn!(target: "client", "Stage 2 block verification failed for {}: {:?}", hash, e);
+					Err(e)
+				}
+			}
+		}
+	}
+
+	/// An unverified block.
+	pub struct Unverified {
+		header: Header,
+		bytes: Bytes,
+	}
+
+	impl Unverified {
+		/// Create an `Unverified` from raw bytes.
+		pub fn new(bytes: Bytes) -> Self {
+			use views::BlockView;
+
+			let header = BlockView::new(&bytes).header();
+			Unverified {
+				header: header,
+				bytes: bytes,
+			}
+		}
+	}
+
+	impl HeapSizeOf for Unverified {
+		fn heap_size_of_children(&self) -> usize {
+			self.header.heap_size_of_children() + self.bytes.heap_size_of_children()
+		}
+	}
+
+	impl HasHash for Unverified {
+		fn hash(&self) -> H256 {
+			self.header.hash()
+		}
+
+		fn parent_hash(&self) -> H256 {
+			self.header.parent_hash().clone()
+		}
+	}
+
+	impl HasHash for PreverifiedBlock {
+		fn hash(&self) -> H256 {
+			self.header.hash()
+		}
+
+		fn parent_hash(&self) -> H256 {
+			self.header.parent_hash().clone()
+		}
+	}
+}
+
+/// Verification for headers.
+pub mod headers {
+	use super::{Kind, HasHash};
+
+	use engines::Engine;
+	use error::Error;
+	use header::Header;
+	use verification::verify_header_params;
+
+	use util::hash::H256;
+
+	impl HasHash for Header {
+		fn hash(&self) -> H256 { self.hash() }
+		fn parent_hash(&self) -> H256 { self.parent_hash().clone() }
+	}
+
+	/// A mode for verifying headers.
+	pub struct Headers;
+
+	impl Kind for Headers {
+		type Input = Header;
+		type Unverified = Header;
+		type Verified = Header;
+
+		fn create(input: Self::Input, engine: &Engine) -> Result<Self::Unverified, Error> {
+			verify_header_params(&input, engine).map(|_| input)
+		}
+
+		fn verify(unverified: Self::Unverified, engine: &Engine) -> Result<Self::Verified, Error> {
+			engine.verify_block_unordered(&unverified, None).map(|_| unverified)
+		}
+	}
+}