Cache the fork block header after snapshot restoration (#2391)

sync/src/api.rs

@@ -15,9 +15,10 @@
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
 use std::sync::Arc;
+use std::collections::HashMap;
 use network::{NetworkProtocolHandler, NetworkService, NetworkContext, PeerId,
 	NetworkConfiguration as BasicNetworkConfiguration, NonReservedPeerMode, NetworkError};
-use util::{U256, H256, Secret, Populatable};
+use util::{U256, H256, Secret, Populatable, Bytes};
 use io::{TimerToken};
 use ethcore::client::{BlockChainClient, ChainNotify};
 use ethcore::header::BlockNumber;
@@ -78,7 +79,11 @@ impl EthSync {
 		let service = try!(NetworkService::new(try!(network_config.into_basic())));
 		let sync = Arc::new(EthSync{
 			network: service,
-			handler: Arc::new(SyncProtocolHandler { sync: RwLock::new(chain_sync), chain: chain }),
+			handler: Arc::new(SyncProtocolHandler {
+				sync: RwLock::new(chain_sync),
+				chain: chain,
+				overlay: RwLock::new(HashMap::new()),
+			}),
 		});
 
 		Ok(sync)
@@ -99,6 +104,8 @@ struct SyncProtocolHandler {
 	chain: Arc<BlockChainClient>,
 	/// Sync strategy
 	sync: RwLock<ChainSync>,
+	/// Chain overlay used to cache data such as fork block.
+	overlay: RwLock<HashMap<BlockNumber, Bytes>>,
 }
 
 impl NetworkProtocolHandler for SyncProtocolHandler {
@@ -107,20 +114,20 @@ impl NetworkProtocolHandler for SyncProtocolHandler {
 	}
 
 	fn read(&self, io: &NetworkContext, peer: &PeerId, packet_id: u8, data: &[u8]) {
-		ChainSync::dispatch_packet(&self.sync, &mut NetSyncIo::new(io, &*self.chain), *peer, packet_id, data);
+		ChainSync::dispatch_packet(&self.sync, &mut NetSyncIo::new(io, &*self.chain, &self.overlay), *peer, packet_id, data);
 	}
 
 	fn connected(&self, io: &NetworkContext, peer: &PeerId) {
-		self.sync.write().on_peer_connected(&mut NetSyncIo::new(io, &*self.chain), *peer);
+		self.sync.write().on_peer_connected(&mut NetSyncIo::new(io, &*self.chain, &self.overlay), *peer);
 	}
 
 	fn disconnected(&self, io: &NetworkContext, peer: &PeerId) {
-		self.sync.write().on_peer_aborting(&mut NetSyncIo::new(io, &*self.chain), *peer);
+		self.sync.write().on_peer_aborting(&mut NetSyncIo::new(io, &*self.chain, &self.overlay), *peer);
 	}
 
 	fn timeout(&self, io: &NetworkContext, _timer: TimerToken) {
-		self.sync.write().maintain_peers(&mut NetSyncIo::new(io, &*self.chain));
-		self.sync.write().maintain_sync(&mut NetSyncIo::new(io, &*self.chain));
+		self.sync.write().maintain_peers(&mut NetSyncIo::new(io, &*self.chain, &self.overlay));
+		self.sync.write().maintain_sync(&mut NetSyncIo::new(io, &*self.chain, &self.overlay));
 	}
 }
 
@@ -134,7 +141,7 @@ impl ChainNotify for EthSync {
 		_duration: u64)
 	{
 		self.network.with_context(ETH_PROTOCOL, |context| {
-			let mut sync_io = NetSyncIo::new(context, &*self.handler.chain);
+			let mut sync_io = NetSyncIo::new(context, &*self.handler.chain, &self.handler.overlay);
 			self.handler.sync.write().chain_new_blocks(
 				&mut sync_io,
 				&imported,
@@ -203,7 +210,7 @@ impl ManageNetwork for EthSync {
 
 	fn stop_network(&self) {
 		self.network.with_context(ETH_PROTOCOL, |context| {
-			let mut sync_io = NetSyncIo::new(context, &*self.handler.chain);
+			let mut sync_io = NetSyncIo::new(context, &*self.handler.chain, &self.handler.overlay);
 			self.handler.sync.write().abort(&mut sync_io);
 		});
 		self.stop();

sync/src/chain.rs

@@ -449,7 +449,9 @@ impl ChainSync {
 		let confirmed = match self.peers.get_mut(&peer_id) {
 			Some(ref mut peer) if peer.asking == PeerAsking::ForkHeader => {
 				let item_count = r.item_count();
-				if item_count == 0 || (item_count == 1 && try!(r.at(0)).as_raw().sha3() == self.fork_block.unwrap().1) {
+				let (fork_number, fork_hash) = self.fork_block.expect("ForkHeader request is sent only fork block is Some; qed").clone();
+				let header = try!(r.at(0)).as_raw();
+				if item_count == 0 || (item_count == 1 && header.sha3() == fork_hash) {
 					peer.asking = PeerAsking::Nothing;
 					if item_count == 0 {
 						trace!(target: "sync", "{}: Chain is too short to confirm the block", peer_id);
@@ -457,6 +459,9 @@ impl ChainSync {
 					} else {
 						trace!(target: "sync", "{}: Confirmed peer", peer_id);
 						peer.confirmation = ForkConfirmation::Confirmed;
+						if !io.chain_overlay().read().contains_key(&fork_number) {
+							io.chain_overlay().write().insert(fork_number, header.to_vec());
+						}
 					}
 					true
 				} else {
@@ -1135,8 +1140,13 @@ impl ChainSync {
 		let mut count = 0;
 		let mut data = Bytes::new();
 		let inc = (skip + 1) as BlockNumber;
+		let overlay = io.chain_overlay().read();
 		while number <= last && count < max_count {
-			if let Some(mut hdr) = io.chain().block_header(BlockID::Number(number)) {
+			if let Some(hdr) = overlay.get(&number) {
+				trace!(target: "sync", "{}: Returning cached fork header", peer_id);
+				data.extend(hdr);
+				count += 1;
+			} else if let Some(mut hdr) = io.chain().block_header(BlockID::Number(number)) {
 				data.append(&mut hdr);
 				count += 1;
 			}

sync/src/sync_io.rs

@@ -14,8 +14,11 @@
 // 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::HashMap;
+use ethcore::header::BlockNumber;
 use network::{NetworkContext, PeerId, PacketId, NetworkError};
 use ethcore::client::BlockChainClient;
+use util::{RwLock, Bytes};
 
 /// IO interface for the syning handler.
 /// Provides peer connection management and an interface to the blockchain client.
@@ -41,20 +44,24 @@ pub trait SyncIo {
 	}
 	/// Check if the session is expired
 	fn is_expired(&self) -> bool;
+	/// Return sync overlay
+	fn chain_overlay(&self) -> &RwLock<HashMap<BlockNumber, Bytes>>;
 }
 
 /// Wraps `NetworkContext` and the blockchain client
 pub struct NetSyncIo<'s, 'h> where 'h: 's {
 	network: &'s NetworkContext<'h>,
-	chain: &'s BlockChainClient
+	chain: &'s BlockChainClient,
+	chain_overlay: &'s RwLock<HashMap<BlockNumber, Bytes>>,
 }
 
 impl<'s, 'h> NetSyncIo<'s, 'h> {
 	/// Creates a new instance from the `NetworkContext` and the blockchain client reference.
-	pub fn new(network: &'s NetworkContext<'h>, chain: &'s BlockChainClient) -> NetSyncIo<'s, 'h> {
+	pub fn new(network: &'s NetworkContext<'h>, chain: &'s BlockChainClient, chain_overlay: &'s RwLock<HashMap<BlockNumber, Bytes>>) -> NetSyncIo<'s, 'h> {
 		NetSyncIo {
 			network: network,
 			chain: chain,
+			chain_overlay: chain_overlay,
 		}
 	}
 }
@@ -80,6 +87,10 @@ impl<'s, 'h> SyncIo for NetSyncIo<'s, 'h> {
 		self.chain
 	}
 
+	fn chain_overlay(&self) -> &RwLock<HashMap<BlockNumber, Bytes>> {
+		self.chain_overlay
+	}
+
 	fn peer_info(&self, peer_id: PeerId) -> String {
 		self.network.peer_info(peer_id)
 	}

sync/src/tests/helpers.rs

@@ -26,6 +26,7 @@ pub struct TestIo<'p> {
 	pub chain: &'p mut TestBlockChainClient,
 	pub queue: &'p mut VecDeque<TestPacket>,
 	pub sender: Option<PeerId>,
+	overlay: RwLock<HashMap<BlockNumber, Bytes>>,
 }
 
 impl<'p> TestIo<'p> {
@@ -33,7 +34,8 @@ impl<'p> TestIo<'p> {
 		TestIo {
 			chain: chain,
 			queue: queue,
-			sender: sender
+			sender: sender,
+			overlay: RwLock::new(HashMap::new()),
 		}
 	}
 }
@@ -70,6 +72,10 @@ impl<'p> SyncIo for TestIo<'p> {
 	fn chain(&self) -> &BlockChainClient {
 		self.chain
 	}
+
+	fn chain_overlay(&self) -> &RwLock<HashMap<BlockNumber, Bytes>> {
+		&self.overlay
+	}
 }
 
 pub struct TestPacket {