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

sync/src/chain.rs

@@ -199,6 +199,16 @@ enum PeerAsking {
 	Heads,
 }
 
+#[derive(Clone, Eq, PartialEq)]
+enum ForkConfirmation {
+	/// Fork block confirmation pending.
+	Unconfirmed,
+	/// Peers chain is too short to confirm the fork.
+	TooShort,
+	/// Fork is confurmed.
+	Confirmed,
+}
+
 #[derive(Clone)]
 /// Syncing peer information
 struct PeerInfo {
@@ -224,13 +234,17 @@ struct PeerInfo {
 	ask_time: f64,
 	/// Pending request is expird and result should be ignored
 	expired: bool,
-	/// Peer fork confirmed
-	confirmed: bool,
+	/// Peer fork confirmation status
+	confirmation: ForkConfirmation,
 }
 
 impl PeerInfo {
-	fn is_available(&self) -> bool {
-		self.confirmed && !self.expired
+	fn can_sync(&self) -> bool {
+		self.confirmation == ForkConfirmation::Confirmed && !self.expired
+	}
+
+	fn is_allowed(&self) -> bool {
+		self.confirmation != ForkConfirmation::Unconfirmed && !self.expired
 	}
 }
 
@@ -307,8 +321,8 @@ impl ChainSync {
 			highest_block_number: self.highest_block.map(|n| max(n, self.last_imported_block)),
 			blocks_received: if self.last_imported_block > self.starting_block { self.last_imported_block - self.starting_block } else { 0 },
 			blocks_total: match self.highest_block { Some(x) if x > self.starting_block => x - self.starting_block, _ => 0 },
-			num_peers: self.peers.values().filter(|p| p.confirmed).count(),
-			num_active_peers: self.peers.values().filter(|p| p.confirmed && p.asking != PeerAsking::Nothing).count(),
+			num_peers: self.peers.values().filter(|p| p.is_allowed()).count(),
+			num_active_peers: self.peers.values().filter(|p| p.is_allowed() && p.asking != PeerAsking::Nothing).count(),
 			mem_used:
 				self.blocks.heap_size()
 				+ self.peers.heap_size_of_children()
@@ -330,7 +344,7 @@ impl ChainSync {
 			p.asking_blocks.clear();
 			p.asking_hash = None;
 			// mark any pending requests as expired
-			if p.asking != PeerAsking::Nothing && p.confirmed {
+			if p.asking != PeerAsking::Nothing && p.is_allowed() {
 				p.expired = true;
 			}
 		}
@@ -384,7 +398,7 @@ impl ChainSync {
 			asking_hash: None,
 			ask_time: 0f64,
 			expired: false,
-			confirmed: self.fork_block.is_none(),
+			confirmation: if self.fork_block.is_none() { ForkConfirmation::Confirmed } else { ForkConfirmation::Unconfirmed },
 		};
 
 		trace!(target: "sync", "New peer {} (protocol: {}, network: {:?}, difficulty: {:?}, latest:{}, genesis:{})", peer_id, peer.protocol_version, peer.network_id, peer.difficulty, peer.latest_hash, peer.genesis);
@@ -427,14 +441,19 @@ impl ChainSync {
 			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) {
-					trace!(target: "sync", "{}: Confirmed peer", peer_id);
 					peer.asking = PeerAsking::Nothing;
-					peer.confirmed = true;
+					if item_count == 0 {
+						trace!(target: "sync", "{}: Chain is too short to confirm the block", peer_id);
+						peer.confirmation = ForkConfirmation::TooShort;
+					} else {
+						trace!(target: "sync", "{}: Confirmed peer", peer_id);
+						peer.confirmation = ForkConfirmation::Confirmed;
+					}
 					true
 				} else {
 					trace!(target: "sync", "{}: Fork mismatch", peer_id);
 					io.disconnect_peer(peer_id);
-					false
+					return Ok(());
 				}
 			},
 			_ => false,
@@ -586,7 +605,7 @@ impl ChainSync {
 	/// Called by peer once it has new block bodies
 	#[cfg_attr(feature="dev", allow(cyclomatic_complexity))]
 	fn on_peer_new_block(&mut self, io: &mut SyncIo, peer_id: PeerId, r: &UntrustedRlp) -> Result<(), PacketDecodeError> {
-		if !self.peers.get(&peer_id).map_or(false, |p| p.confirmed) {
+		if !self.peers.get(&peer_id).map_or(false, |p| p.can_sync()) {
 			trace!(target: "sync", "Ignoring new block from unconfirmed peer {}", peer_id);
 			return Ok(());
 		}
@@ -654,7 +673,7 @@ impl ChainSync {
 
 	/// Handles `NewHashes` packet. Initiates headers download for any unknown hashes.
 	fn on_peer_new_hashes(&mut self, io: &mut SyncIo, peer_id: PeerId, r: &UntrustedRlp) -> Result<(), PacketDecodeError> {
-		if !self.peers.get(&peer_id).map_or(false, |p| p.confirmed) {
+		if !self.peers.get(&peer_id).map_or(false, |p| p.can_sync()) {
 			trace!(target: "sync", "Ignoring new hashes from unconfirmed peer {}", peer_id);
 			return Ok(());
 		}
@@ -741,7 +760,7 @@ impl ChainSync {
 	/// Resume downloading
 	fn continue_sync(&mut self, io: &mut SyncIo) {
 		let mut peers: Vec<(PeerId, U256)> = self.peers.iter().filter_map(|(k, p)|
-			if p.is_available() { Some((*k, p.difficulty.unwrap_or_else(U256::zero))) } else { None }).collect();
+			if p.can_sync() { Some((*k, p.difficulty.unwrap_or_else(U256::zero))) } else { None }).collect();
 		thread_rng().shuffle(&mut peers); //TODO: sort by rating
 		trace!(target: "sync", "Syncing with {}/{} peers", self.active_peers.len(), peers.len());
 		for (p, _) in peers {
@@ -749,7 +768,7 @@ impl ChainSync {
 				self.sync_peer(io, p, false);
 			}
 		}
-		if self.state != SyncState::Waiting && !self.peers.values().any(|p| p.asking != PeerAsking::Nothing && p.is_available()) {
+		if self.state != SyncState::Waiting && !self.peers.values().any(|p| p.asking != PeerAsking::Nothing && p.can_sync()) {
 			self.complete_sync();
 		}
 	}
@@ -775,7 +794,7 @@ impl ChainSync {
 		}
 		let (peer_latest, peer_difficulty) = {
 			let peer = self.peers.get_mut(&peer_id).unwrap();
-			if peer.asking != PeerAsking::Nothing || !peer.is_available() {
+			if peer.asking != PeerAsking::Nothing || !peer.can_sync() {
 				return;
 			}
 			if self.state == SyncState::Waiting {
@@ -1037,7 +1056,7 @@ impl ChainSync {
 		if !io.is_chain_queue_empty() {
 			return Ok(());
 		}
-		if !self.peers.get(&peer_id).map_or(false, |p| p.confirmed) {
+		if !self.peers.get(&peer_id).map_or(false, |p| p.can_sync()) {
 			trace!(target: "sync", "{} Ignoring transactions from unconfirmed/unknown peer", peer_id);
 		}
 
@@ -1693,7 +1712,7 @@ mod tests {
 				asking_hash: None,
 				ask_time: 0f64,
 				expired: false,
-				confirmed: true,
+				confirmation: super::ForkConfirmation::Confirmed,
 			});
 		sync
 	}