exclusive access to each peer at a time

ethcore/src/light/net/mod.rs

@@ -99,7 +99,7 @@ struct PendingPeer {
 
 // data about each peer.
 struct Peer {
-	local_buffer: Mutex<Buffer>, // their buffer relative to us
+	local_buffer: Buffer, // their buffer relative to us
 	remote_buffer: Buffer, // our buffer relative to them
 	current_asking: HashSet<usize>, // pending request ids.
 	status: Status,
@@ -112,21 +112,25 @@ impl Peer {
 	// check the maximum cost of a request, returning an error if there's
 	// not enough buffer left.
 	// returns the calculated maximum cost.
-	fn deduct_max(&self, flow_params: &FlowParams, kind: request::Kind, max: usize) -> Result<U256, Error> {
+	fn deduct_max(&mut self, flow_params: &FlowParams, kind: request::Kind, max: usize) -> Result<U256, Error> {
-		let mut local_buffer = self.local_buffer.lock();
+		flow_params.recharge(&mut self.local_buffer);
-		flow_params.recharge(&mut local_buffer);
 
 		let max_cost = flow_params.compute_cost(kind, max);
-		try!(local_buffer.deduct_cost(max_cost));
+		try!(self.local_buffer.deduct_cost(max_cost));
 		Ok(max_cost)
 	}
 
 	// refund buffer for a request. returns new buffer amount.
-	fn refund(&self, flow_params: &FlowParams, amount: U256) -> U256 {
+	fn refund(&mut self, flow_params: &FlowParams, amount: U256) -> U256 {
-		let mut local_buffer = self.local_buffer.lock();
+		flow_params.refund(&mut self.local_buffer, amount);
-		flow_params.refund(&mut local_buffer, amount);
 
-		local_buffer.current()
+		self.local_buffer.current()
+	}
+
+	// recharge remote buffer with remote flow params.
+	fn recharge_remote(&mut self) {
+		let flow = &mut self.remote_flow;
+		flow.recharge(&mut self.remote_buffer);
 	}
 }
 
@@ -171,7 +175,7 @@ pub struct LightProtocol {
 	genesis_hash: H256,
 	network_id: NetworkId,
 	pending_peers: RwLock<HashMap<PeerId, PendingPeer>>,
-	peers: RwLock<HashMap<PeerId, Peer>>,
+	peers: RwLock<HashMap<PeerId, Mutex<Peer>>>,
 	pending_requests: RwLock<HashMap<usize, Requested>>,
 	capabilities: RwLock<Capabilities>,
 	flow_params: FlowParams, // assumed static and same for every peer.
@@ -199,8 +203,9 @@ impl LightProtocol {
 	/// Check the maximum amount of requests of a specific type 
 	/// which a peer would be able to serve.
 	pub fn max_requests(&self, peer: PeerId, kind: request::Kind) -> Option<usize> {
-		self.peers.write().get_mut(&peer).map(|peer| {
+		self.peers.read().get(&peer).map(|peer| {
-			peer.remote_flow.recharge(&mut peer.remote_buffer);
+			let mut peer = peer.lock();
+			peer.recharge_remote();
 			peer.remote_flow.max_amount(&peer.remote_buffer, kind)
 		})
 	}
@@ -212,9 +217,11 @@ impl LightProtocol {
 	/// On success, returns a request id which can later be coordinated 
 	/// with an event.
 	pub fn request_from(&self, io: &NetworkContext, peer_id: &PeerId, request: Request) -> Result<ReqId, Error> {
-		let mut peers = self.peers.write();
+		let peers = self.peers.read();
-		let peer = try!(peers.get_mut(peer_id).ok_or_else(|| Error::UnknownPeer));
+		let peer = try!(peers.get(peer_id).ok_or_else(|| Error::UnknownPeer));
-		peer.remote_flow.recharge(&mut peer.remote_buffer);
+		let mut peer = peer.lock();
+
+		peer.recharge_remote();
 
 		let max = peer.remote_flow.compute_cost(request.kind(), request.amount());
 		try!(peer.remote_buffer.deduct_cost(max));
@@ -251,7 +258,8 @@ impl LightProtocol {
 		self.capabilities.write().update_from(&announcement);
 
 		// calculate reorg info and send packets
-		for (peer_id, peer_info) in self.peers.write().iter_mut() {
+		for (peer_id, peer_info) in self.peers.read().iter() {
+			let mut peer_info = peer_info.lock();
 			let reorg_depth = reorgs_map.entry(peer_info.sent_head)
 				.or_insert_with(|| {
 					match self.provider.reorg_depth(&announcement.head_hash, &peer_info.sent_head) {
@@ -354,15 +362,15 @@ impl LightProtocol {
 			return Err(Error::WrongNetwork);
 		}
 
-		self.peers.write().insert(*peer, Peer {
+		self.peers.write().insert(*peer, Mutex::new(Peer {
-			local_buffer: Mutex::new(self.flow_params.create_buffer()),
+			local_buffer: self.flow_params.create_buffer(),
 			remote_buffer: flow_params.create_buffer(),
 			current_asking: HashSet::new(),
 			status: status.clone(),
 			capabilities: capabilities.clone(),
 			remote_flow: flow_params,
 			sent_head: pending.sent_head,
-		});
+		}));
 
 		for handler in &self.handlers {
 			handler.on_connect(*peer, &status, &capabilities)
@@ -379,13 +387,15 @@ impl LightProtocol {
 		}
 
 		let announcement = try!(status::parse_announcement(data));
-		let mut peers = self.peers.write();
+		let peers = self.peers.read();
 
-		let peer_info = match peers.get_mut(peer) {
+		let peer_info = match peers.get(peer) {
 			Some(info) => info,
 			None => return Ok(()),
 		};
 
+		let mut peer_info = peer_info.lock();
+
 		// update status.
 		{
 			// TODO: punish peer if they've moved backwards.
@@ -420,6 +430,8 @@ impl LightProtocol {
 			}
 		};
 
+		let mut peer = peer.lock();
+
 		let req_id: u64 = try!(data.val_at(0));
 
 		let block = {
@@ -471,6 +483,7 @@ impl LightProtocol {
 				return Ok(())
 			}
 		};
+		let mut peer = peer.lock();
 
 		let req_id: u64 = try!(data.val_at(0));
 
@@ -516,6 +529,7 @@ impl LightProtocol {
 				return Ok(())
 			}
 		};
+		let mut peer = peer.lock();
 
 		let req_id: u64 = try!(data.val_at(0));
 
@@ -561,6 +575,7 @@ impl LightProtocol {
 				return Ok(())
 			}
 		};
+		let mut peer = peer.lock();
 
 		let req_id: u64 = try!(data.val_at(0));
 
@@ -617,6 +632,7 @@ impl LightProtocol {
 				return Ok(())
 			}
 		};
+		let mut peer = peer.lock();
 
 		let req_id: u64 = try!(data.val_at(0));
 
@@ -671,6 +687,7 @@ impl LightProtocol {
 				return Ok(())
 			}
 		};
+		let mut peer = peer.lock();
 
 		let req_id: u64 = try!(data.val_at(0));