Move events into ChannelMonitor from ManyChannelMonitor

This is the next step after "Move pending-HTLC-updated ChannelMonitor
from ManyChannelMonitor", moving our events into ChannelMonitor as
well and leaving only new-outputs-to-watch in the return value for
ChannelMonitor::block_connected (which is fine as those are
duplicatively tracked in the ChannelMonitor directly, so
losing/replaying them is acceptable).

Author: TheBlueMatt

lightning/src/ln/channelmonitor.rs

@@ -37,7 +37,7 @@ use chain::chaininterface::{ChainListener, ChainWatchInterface, BroadcasterInter
 use chain::transaction::OutPoint;
 use chain::keysinterface::{SpendableOutputDescriptor, ChannelKeys};
 use util::logger::Logger;
-use util::ser::{ReadableArgs, Readable, Writer, Writeable, U48};
+use util::ser::{ReadableArgs, Readable, MaybeReadable, Writer, Writeable, U48};
 use util::{byte_utils, events};
 
 use std::collections::{HashMap, hash_map, HashSet};
@@ -219,7 +219,6 @@ pub struct SimpleManyChannelMonitor<Key, ChanSigner: ChannelKeys, T: Deref> wher
 	monitors: Mutex<HashMap<Key, ChannelMonitor<ChanSigner>>>,
 	chain_monitor: Arc<ChainWatchInterface>,
 	broadcaster: T,
-	pending_events: Mutex<Vec<events::Event>>,
 	logger: Arc<Logger>,
 	fee_estimator: Arc<FeeEstimator>
 }
@@ -229,16 +228,10 @@ impl<'a, Key : Send + cmp::Eq + hash::Hash, ChanSigner: ChannelKeys, T: Deref +
 {
 	fn block_connected(&self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], _indexes_of_txn_matched: &[u32]) {
 		let block_hash = header.bitcoin_hash();
-		let mut new_events: Vec<events::Event> = Vec::with_capacity(0);
 		{
 			let mut monitors = self.monitors.lock().unwrap();
 			for monitor in monitors.values_mut() {
-				let (txn_outputs, spendable_outputs) = monitor.block_connected(txn_matched, height, &block_hash, &*self.broadcaster, &*self.fee_estimator);
-				if spendable_outputs.len() > 0 {
-					new_events.push(events::Event::SpendableOutputs {
-						outputs: spendable_outputs,
-					});
-				}
+				let txn_outputs = monitor.block_connected(txn_matched, height, &block_hash, &*self.broadcaster, &*self.fee_estimator);
 
 				for (ref txid, ref outputs) in txn_outputs {
 					for (idx, output) in outputs.iter().enumerate() {
@@ -247,8 +240,6 @@ impl<'a, Key : Send + cmp::Eq + hash::Hash, ChanSigner: ChannelKeys, T: Deref +
 				}
 			}
 		}
-		let mut pending_events = self.pending_events.lock().unwrap();
-		pending_events.append(&mut new_events);
 	}
 
 	fn block_disconnected(&self, header: &BlockHeader, disconnected_height: u32) {
@@ -270,7 +261,6 @@ impl<Key : Send + cmp::Eq + hash::Hash + 'static, ChanSigner: ChannelKeys, T: De
 			monitors: Mutex::new(HashMap::new()),
 			chain_monitor,
 			broadcaster,
-			pending_events: Mutex::new(Vec::new()),
 			logger,
 			fee_estimator: feeest,
 		};
@@ -354,10 +344,11 @@ impl<Key : Send + cmp::Eq + hash::Hash, ChanSigner: ChannelKeys, T: Deref> event
 	where T::Target: BroadcasterInterface
 {
 	fn get_and_clear_pending_events(&self) -> Vec<events::Event> {
-		let mut pending_events = self.pending_events.lock().unwrap();
-		let mut ret = Vec::new();
-		mem::swap(&mut ret, &mut *pending_events);
-		ret
+		let mut pending_events = Vec::new();
+		for chan in self.monitors.lock().unwrap().values_mut() {
+			pending_events.append(&mut chan.get_and_clear_pending_events());
+		}
+		pending_events
 	}
 }
 
@@ -827,6 +818,7 @@ pub struct ChannelMonitor<ChanSigner: ChannelKeys> {
 	payment_preimages: HashMap<PaymentHash, PaymentPreimage>,
 
 	pending_htlcs_updated: Vec<HTLCUpdate>,
+	pending_events: Vec<events::Event>,
 
 	destination_script: Script,
 	// Thanks to data loss protection, we may be able to claim our non-htlc funds
@@ -940,6 +932,7 @@ impl<ChanSigner: ChannelKeys> PartialEq for ChannelMonitor<ChanSigner> {
 			self.current_local_signed_commitment_tx != other.current_local_signed_commitment_tx ||
 			self.payment_preimages != other.payment_preimages ||
 			self.pending_htlcs_updated != other.pending_htlcs_updated ||
+			self.pending_events.len() != other.pending_events.len() || // We trust events to round-trip properly
 			self.destination_script != other.destination_script ||
 			self.to_remote_rescue != other.to_remote_rescue ||
 			self.pending_claim_requests != other.pending_claim_requests ||
@@ -1127,6 +1120,11 @@ impl<ChanSigner: ChannelKeys + Writeable> ChannelMonitor<ChanSigner> {
 			data.write(writer)?;
 		}
 
+		writer.write_all(&byte_utils::be64_to_array(self.pending_events.len() as u64))?;
+		for event in self.pending_events.iter() {
+			event.write(writer)?;
+		}
+
 		self.last_block_hash.write(writer)?;
 		self.destination_script.write(writer)?;
 		if let Some((ref to_remote_script, ref local_key)) = self.to_remote_rescue {
@@ -1259,6 +1257,7 @@ impl<ChanSigner: ChannelKeys> ChannelMonitor<ChanSigner> {
 
 			payment_preimages: HashMap::new(),
 			pending_htlcs_updated: Vec::new(),
+			pending_events: Vec::new(),
 
 			destination_script: destination_script.clone(),
 			to_remote_rescue: None,
@@ -1552,6 +1551,18 @@ impl<ChanSigner: ChannelKeys> ChannelMonitor<ChanSigner> {
 		ret
 	}
 
+	/// Gets the list of pending events which were generated by previous actions, clearing the list
+	/// in the process.
+	///
+	/// This is called by ManyChannelMonitor::get_and_clear_pending_events() and is equivalent to
+	/// EventsProvider::get_and_clear_pending_events() except that it requires &mut self as we do
+	/// no internal locking in ChannelMonitors.
+	pub fn get_and_clear_pending_events(&mut self) -> Vec<events::Event> {
+		let mut ret = Vec::new();
+		mem::swap(&mut ret, &mut self.pending_events);
+		ret
+	}
+
 	/// Can only fail if idx is < get_min_seen_secret
 	pub(super) fn get_secret(&self, idx: u64) -> Option<[u8; 32]> {
 		self.commitment_secrets.get_secret(idx)
@@ -2522,7 +2533,7 @@ impl<ChanSigner: ChannelKeys> ChannelMonitor<ChanSigner> {
 	/// Eventually this should be pub and, roughly, implement ChainListener, however this requires
 	/// &mut self, as well as returns new spendable outputs and outpoints to watch for spending of
 	/// on-chain.
-	fn block_connected<B: Deref>(&mut self, txn_matched: &[&Transaction], height: u32, block_hash: &Sha256dHash, broadcaster: B, fee_estimator: &FeeEstimator)-> (Vec<(Sha256dHash, Vec<TxOut>)>, Vec<SpendableOutputDescriptor>)
+	fn block_connected<B: Deref>(&mut self, txn_matched: &[&Transaction], height: u32, block_hash: &Sha256dHash, broadcaster: B, fee_estimator: &FeeEstimator)-> Vec<(Sha256dHash, Vec<TxOut>)>
 		where B::Target: BroadcasterInterface
 	{
 		for tx in txn_matched {
@@ -2754,7 +2765,14 @@ impl<ChanSigner: ChannelKeys> ChannelMonitor<ChanSigner> {
 		for &(ref txid, ref output_scripts) in watch_outputs.iter() {
 			self.outputs_to_watch.insert(txid.clone(), output_scripts.iter().map(|o| o.script_pubkey.clone()).collect());
 		}
-		(watch_outputs, spendable_outputs)
+
+		if spendable_outputs.len() > 0 {
+			self.pending_events.push(events::Event::SpendableOutputs {
+				outputs: spendable_outputs,
+			});
+		}
+
+		watch_outputs
 	}
 
 	fn block_disconnected<B: Deref>(&mut self, height: u32, block_hash: &Sha256dHash, broadcaster: B, fee_estimator: &FeeEstimator)
@@ -3353,6 +3371,14 @@ impl<R: ::std::io::Read, ChanSigner: ChannelKeys + Readable<R>> ReadableArgs<R,
 			pending_htlcs_updated.push(Readable::read(reader)?);
 		}
 
+		let pending_events_len: u64 = Readable::read(reader)?;
+		let mut pending_events = Vec::with_capacity(cmp::min(pending_events_len as usize, MAX_ALLOC_SIZE / mem::size_of::<events::Event>()));
+		for _ in 0..pending_events_len {
+			if let Some(event) = MaybeReadable::read(reader)? {
+				pending_events.push(event);
+			}
+		}
+
 		let last_block_hash: Sha256dHash = Readable::read(reader)?;
 		let destination_script = Readable::read(reader)?;
 		let to_remote_rescue = match <u8 as Readable<R>>::read(reader)? {
@@ -3455,6 +3481,7 @@ impl<R: ::std::io::Read, ChanSigner: ChannelKeys + Readable<R>> ReadableArgs<R,
 
 			payment_preimages,
 			pending_htlcs_updated,
+			pending_events,
 
 			destination_script,
 			to_remote_rescue,