Move channel restoration after monitor update to a two-part macro

The channel restoration code in channel monitor updating and peer
reconnection both do incredibly similar things, and there is
little reason to have them be separate. Sadly because they require
holding a lock with a reference to elements in the lock, its not
practical to make them utility functions, so instead we introduce
a two-step macro here which will eventually be used for both.

Because we still support pre-NLL Rust, the macro has to be in two
parts - one which runs with the channel_state lock, and one which
does not.

Author: TheBlueMatt

lightning/src/ln/channelmanager.rs

@@ -814,6 +814,80 @@ macro_rules! maybe_break_monitor_err {
 	}
 }
 
+macro_rules! handle_chan_restoration_locked {
+	($self: expr, $channel_lock: expr, $channel_state: expr, $channel_entry: expr,
+	 $raa: expr, $commitment_update: expr, $order: expr,
+	 $pending_forwards: expr, $pending_failures: expr, $funding_broadcastable: expr, $funding_locked: expr) => { {
+		let mut htlc_forwards = Vec::new();
+		let mut htlc_failures = Vec::new();
+		let mut pending_events = Vec::new();
+
+		{
+			if !$pending_forwards.is_empty() {
+				htlc_forwards.push(($channel_entry.get().get_short_channel_id().expect("We can't have pending forwards before funding confirmation"),
+					$channel_entry.get().get_funding_txo().unwrap(), $pending_forwards));
+			}
+			htlc_failures.append(&mut $pending_failures);
+
+			macro_rules! handle_cs { () => {
+				if let Some(update) = $commitment_update {
+					$channel_state.pending_msg_events.push(events::MessageSendEvent::UpdateHTLCs {
+						node_id: $channel_entry.get().get_counterparty_node_id(),
+						updates: update,
+					});
+				}
+			} }
+			macro_rules! handle_raa { () => {
+				if let Some(revoke_and_ack) = $raa {
+					$channel_state.pending_msg_events.push(events::MessageSendEvent::SendRevokeAndACK {
+						node_id: $channel_entry.get().get_counterparty_node_id(),
+						msg: revoke_and_ack,
+					});
+				}
+			} }
+			match $order {
+				RAACommitmentOrder::CommitmentFirst => {
+					handle_cs!();
+					handle_raa!();
+				},
+				RAACommitmentOrder::RevokeAndACKFirst => {
+					handle_raa!();
+					handle_cs!();
+				},
+			}
+			if let Some(tx) = $funding_broadcastable {
+				$self.tx_broadcaster.broadcast_transaction(&tx);
+			}
+			if let Some(msg) = $funding_locked {
+				$channel_state.pending_msg_events.push(events::MessageSendEvent::SendFundingLocked {
+					node_id: $channel_entry.get().get_counterparty_node_id(),
+					msg,
+				});
+				if let Some(announcement_sigs) = $self.get_announcement_sigs($channel_entry.get()) {
+					$channel_state.pending_msg_events.push(events::MessageSendEvent::SendAnnouncementSignatures {
+						node_id: $channel_entry.get().get_counterparty_node_id(),
+						msg: announcement_sigs,
+					});
+				}
+				$channel_state.short_to_id.insert($channel_entry.get().get_short_channel_id().unwrap(), $channel_entry.get().channel_id());
+			}
+		}
+		(htlc_forwards, htlc_failures, pending_events)
+	} }
+}
+
+macro_rules! post_handle_chan_restoration {
+	($self: expr, $locked_res: expr) => { {
+		let (mut htlc_forwards, mut htlc_failures, mut pending_events) = $locked_res;
+		$self.pending_events.lock().unwrap().append(&mut pending_events);
+
+		for failure in htlc_failures.drain(..) {
+			$self.fail_htlc_backwards_internal($self.channel_state.lock().unwrap(), failure.0, &failure.1, failure.2);
+		}
+		$self.forward_htlcs(&mut htlc_forwards[..]);
+	} }
+}
+
 impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelManager<Signer, M, T, K, F, L>
 	where M::Target: chain::Watch<Signer>,
         T::Target: BroadcasterInterface,
@@ -2436,79 +2510,21 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 	pub fn channel_monitor_updated(&self, funding_txo: &OutPoint, highest_applied_update_id: u64) {
 		let _persistence_guard = PersistenceNotifierGuard::new(&self.total_consistency_lock, &self.persistence_notifier);
 
-		let mut htlc_forwards = Vec::new();
-		let mut htlc_failures = Vec::new();
-		let mut pending_events = Vec::new();
-
-		{
+		let chan_restoration_res = {
 			let mut channel_lock = self.channel_state.lock().unwrap();
 			let channel_state = &mut *channel_lock;
-			let short_to_id = &mut channel_state.short_to_id;
-			let pending_msg_events = &mut channel_state.pending_msg_events;
-			let channel = match channel_state.by_id.get_mut(&funding_txo.to_channel_id()) {
-				Some(chan) => chan,
-				None => return,
+			let mut channel = match channel_state.by_id.entry(funding_txo.to_channel_id()) {
+				hash_map::Entry::Occupied(chan) => chan,
+				hash_map::Entry::Vacant(_) => return,
 			};
-			if !channel.is_awaiting_monitor_update() || channel.get_latest_monitor_update_id() != highest_applied_update_id {
+			if !channel.get().is_awaiting_monitor_update() || channel.get().get_latest_monitor_update_id() != highest_applied_update_id {
 				return;
 			}
 
-			let (raa, commitment_update, order, pending_forwards, mut pending_failures, funding_broadcastable, funding_locked) = channel.monitor_updating_restored(&self.logger);
-			if !pending_forwards.is_empty() {
-				htlc_forwards.push((channel.get_short_channel_id().expect("We can't have pending forwards before funding confirmation"), funding_txo.clone(), pending_forwards));
-			}
-			htlc_failures.append(&mut pending_failures);
-
-			macro_rules! handle_cs { () => {
-				if let Some(update) = commitment_update {
-					pending_msg_events.push(events::MessageSendEvent::UpdateHTLCs {
-						node_id: channel.get_counterparty_node_id(),
-						updates: update,
-					});
-				}
-			} }
-			macro_rules! handle_raa { () => {
-				if let Some(revoke_and_ack) = raa {
-					pending_msg_events.push(events::MessageSendEvent::SendRevokeAndACK {
-						node_id: channel.get_counterparty_node_id(),
-						msg: revoke_and_ack,
-					});
-				}
-			} }
-			match order {
-				RAACommitmentOrder::CommitmentFirst => {
-					handle_cs!();
-					handle_raa!();
-				},
-				RAACommitmentOrder::RevokeAndACKFirst => {
-					handle_raa!();
-					handle_cs!();
-				},
-			}
-			if let Some(tx) = funding_broadcastable {
-				self.tx_broadcaster.broadcast_transaction(&tx);
-			}
-			if let Some(msg) = funding_locked {
-				pending_msg_events.push(events::MessageSendEvent::SendFundingLocked {
-					node_id: channel.get_counterparty_node_id(),
-					msg,
-				});
-				if let Some(announcement_sigs) = self.get_announcement_sigs(channel) {
-					pending_msg_events.push(events::MessageSendEvent::SendAnnouncementSignatures {
-						node_id: channel.get_counterparty_node_id(),
-						msg: announcement_sigs,
-					});
-				}
-				short_to_id.insert(channel.get_short_channel_id().unwrap(), channel.channel_id());
-			}
-		}
-
-		self.pending_events.lock().unwrap().append(&mut pending_events);
-
-		for failure in htlc_failures.drain(..) {
-			self.fail_htlc_backwards_internal(self.channel_state.lock().unwrap(), failure.0, &failure.1, failure.2);
-		}
-		self.forward_htlcs(&mut htlc_forwards[..]);
+			let (raa, commitment_update, order, pending_forwards, mut pending_failures, funding_broadcastable, funding_locked) = channel.get_mut().monitor_updating_restored(&self.logger);
+			handle_chan_restoration_locked!(self, channel_lock, channel_state, channel, raa, commitment_update, order, pending_forwards, pending_failures, funding_broadcastable, funding_locked)
+		};
+		post_handle_chan_restoration!(self, chan_restoration_res);
 	}
 
 	fn internal_open_channel(&self, counterparty_node_id: &PublicKey, their_features: InitFeatures, msg: &msgs::OpenChannel) -> Result<(), MsgHandleErrInternal> {