Merge branch 'master' of github.com:ethcore/parity into move_hash

ethcore/src/client/client.rs

@@ -594,19 +594,35 @@ impl Client {
 		}
 	}
 
-	/// Take a snapshot.
-	pub fn take_snapshot<W: snapshot_io::SnapshotWriter + Send>(&self, writer: W) -> Result<(), ::error::Error> {
+	/// Take a snapshot at the given block.
+	/// If the ID given is "latest", this will default to 1000 blocks behind.
+	pub fn take_snapshot<W: snapshot_io::SnapshotWriter + Send>(&self, writer: W, at: BlockID, p: &snapshot::Progress) -> Result<(), ::error::Error> {
 		let db = self.state_db.lock().boxed_clone();
 		let best_block_number = self.chain_info().best_block_number;
-		let start_block_number = if best_block_number > 1000 {
-			best_block_number - 1000
-		} else {
-			0
-		};
-		let start_hash = self.block_hash(BlockID::Number(start_block_number))
-			.expect("blocks within HISTORY are always stored.");
+		let block_number = try!(self.block_number(at).ok_or(snapshot::Error::InvalidStartingBlock(at)));
 
-		try!(snapshot::take_snapshot(&self.chain, start_hash, db.as_hashdb(), writer));
+		if best_block_number > HISTORY + block_number && db.is_pruned() {
+			return Err(snapshot::Error::OldBlockPrunedDB.into());
+		}
+
+		let start_hash = match at {
+			BlockID::Latest => {
+				let start_num = if best_block_number > 1000 {
+					best_block_number - 1000
+				} else {
+					0
+				};
+
+				self.block_hash(BlockID::Number(start_num))
+					.expect("blocks within HISTORY are always stored.")
+			}
+			_ => match self.block_hash(at) {
+				Some(hash) => hash,
+				None => return Err(snapshot::Error::InvalidStartingBlock(at).into()),
+			},
+		};
+
+		try!(snapshot::take_snapshot(&self.chain, start_hash, db.as_hashdb(), writer, p));
 
 		Ok(())
 	}
@@ -784,8 +800,8 @@ impl BlockChainClient for Client {
 		Self::block_hash(&self.chain, id)
 	}
 
-	fn code(&self, address: &Address) -> Option<Bytes> {
-		self.state().code(address)
+	fn code(&self, address: &Address, id: BlockID) -> Option<Option<Bytes>> {
+		self.state_at(id).map(|s| s.code(address))
 	}
 
 	fn balance(&self, address: &Address, id: BlockID) -> Option<U256> {

ethcore/src/client/test_client.rs

@@ -319,8 +319,11 @@ impl BlockChainClient for TestBlockChainClient {
 		self.nonce(address, BlockID::Latest).unwrap()
 	}
 
-	fn code(&self, address: &Address) -> Option<Bytes> {
-		self.code.read().get(address).cloned()
+	fn code(&self, address: &Address, id: BlockID) -> Option<Option<Bytes>> {
+		match id {
+			BlockID::Latest => Some(self.code.read().get(address).cloned()),
+			_ => None,
+		}
 	}
 
 	fn balance(&self, address: &Address, id: BlockID) -> Option<U256> {

ethcore/src/client/traits.rs

@@ -78,8 +78,14 @@ pub trait BlockChainClient : Sync + Send {
 	/// Get block hash.
 	fn block_hash(&self, id: BlockID) -> Option<H256>;
 
-	/// Get address code.
-	fn code(&self, address: &Address) -> Option<Bytes>;
+	/// Get address code at given block's state.
+	fn code(&self, address: &Address, id: BlockID) -> Option<Option<Bytes>>;
+
+	/// Get address code at the latest block's state.
+	fn latest_code(&self, address: &Address) -> Option<Bytes> {
+		self.code(address, BlockID::Latest)
+			.expect("code will return Some if given BlockID::Latest; qed")
+	}
 
 	/// Get address balance at the given block's state.
 	///