Use Writeable for ChannelMonitor instead of a specific function.

There's no reason to have ChannelMonitor::write_for_disk instead of
just using the Writeable trait anymore. Previously, it was used to
differentiate with `write_for_watchtower`, but support for
watchtower-mode ChannelMonitors was never completed and the partial
bits were removed long ago.

This has the nice benefit of hitting the custom Writeable codepaths
in C bindings instead of trying to hit trait-generics paths.

Author: TheBlueMatt

fuzz/src/chanmon_consistency.rs

@@ -112,7 +112,7 @@ impl chain::Watch for TestChainMonitor {
 
 	fn watch_channel(&self, funding_txo: OutPoint, monitor: channelmonitor::ChannelMonitor<EnforcingChannelKeys>) -> Result<(), channelmonitor::ChannelMonitorUpdateErr> {
 		let mut ser = VecWriter(Vec::new());
-		monitor.serialize_for_disk(&mut ser).unwrap();
+		monitor.write(&mut ser).unwrap();
 		if let Some(_) = self.latest_monitors.lock().unwrap().insert(funding_txo, (monitor.get_latest_update_id(), ser.0)) {
 			panic!("Already had monitor pre-watch_channel");
 		}
@@ -131,7 +131,7 @@ impl chain::Watch for TestChainMonitor {
 			read(&mut Cursor::new(&map_entry.get().1)).unwrap().1;
 		deserialized_monitor.update_monitor(&update, &&TestBroadcaster{}, &&FuzzEstimator{}, &self.logger).unwrap();
 		let mut ser = VecWriter(Vec::new());
-		deserialized_monitor.serialize_for_disk(&mut ser).unwrap();
+		deserialized_monitor.write(&mut ser).unwrap();
 		map_entry.insert((update.update_id, ser.0));
 		self.should_update_manager.store(true, atomic::Ordering::Relaxed);
 		self.update_ret.lock().unwrap().clone()

fuzz/src/chanmon_deser.rs

@@ -5,7 +5,7 @@ use bitcoin::hash_types::BlockHash;
 
 use lightning::chain::channelmonitor;
 use lightning::util::enforcing_trait_impls::EnforcingChannelKeys;
-use lightning::util::ser::{Readable, Writer};
+use lightning::util::ser::{Readable, Writer, Writeable};
 
 use utils::test_logger;
 
@@ -26,7 +26,7 @@ impl Writer for VecWriter {
 pub fn do_test<Out: test_logger::Output>(data: &[u8], _out: Out) {
 	if let Ok((latest_block_hash, monitor)) = <(BlockHash, channelmonitor::ChannelMonitor<EnforcingChannelKeys>)>::read(&mut Cursor::new(data)) {
 		let mut w = VecWriter(Vec::new());
-		monitor.serialize_for_disk(&mut w).unwrap();
+		monitor.write(&mut w).unwrap();
 		let deserialized_copy = <(BlockHash, channelmonitor::ChannelMonitor<EnforcingChannelKeys>)>::read(&mut Cursor::new(&w.0)).unwrap();
 		assert!(latest_block_hash == deserialized_copy.0);
 		assert!(monitor == deserialized_copy.1);

lightning-persister/src/lib.rs

@@ -45,7 +45,7 @@ trait DiskWriteable {
 
 impl<ChanSigner: ChannelKeys> DiskWriteable for ChannelMonitor<ChanSigner> {
 	fn write(&self, writer: &mut fs::File) -> Result<(), Error> {
-		self.serialize_for_disk(writer)
+		Writeable::write(self, writer)
 	}
 }
 

lightning/src/chain/channelmonitor.rs

@@ -617,6 +617,12 @@ impl Readable for ChannelMonitorUpdateStep {
 /// get_and_clear_pending_monitor_events or get_and_clear_pending_events are serialized to disk and
 /// reloaded at deserialize-time. Thus, you must ensure that, when handling events, all events
 /// gotten are fully handled before re-serializing the new state.
+///
+/// Note that the deserializer is only implemented for (Sha256dHash, ChannelMonitor), which
+/// tells you the last block hash which was block_connect()ed. You MUST rescan any blocks along
+/// the "reorg path" (ie disconnecting blocks until you find a common ancestor from both the
+/// returned block hash and the the current chain and then reconnecting blocks to get to the
+/// best chain) upon deserializing the object!
 pub struct ChannelMonitor<ChanSigner: ChannelKeys> {
 	latest_update_id: u64,
 	commitment_transaction_number_obscure_factor: u64,
@@ -755,15 +761,8 @@ impl<ChanSigner: ChannelKeys> PartialEq for ChannelMonitor<ChanSigner> {
 	}
 }
 
-impl<ChanSigner: ChannelKeys> ChannelMonitor<ChanSigner> {
-	/// Writes this monitor into the given writer, suitable for writing to disk.
-	///
-	/// Note that the deserializer is only implemented for (Sha256dHash, ChannelMonitor), which
-	/// tells you the last block hash which was block_connect()ed. You MUST rescan any blocks along
-	/// the "reorg path" (ie disconnecting blocks until you find a common ancestor from both the
-	/// returned block hash and the the current chain and then reconnecting blocks to get to the
-	/// best chain) upon deserializing the object!
-	pub fn serialize_for_disk<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
+impl<ChanSigner: ChannelKeys> Writeable for ChannelMonitor<ChanSigner> {
+	fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
 		//TODO: We still write out all the serialization here manually instead of using the fancy
 		//serialization framework we have, we should migrate things over to it.
 		writer.write_all(&[SERIALIZATION_VERSION; 1])?;

lightning/src/ln/chanmon_update_fail_tests.rs

@@ -26,7 +26,7 @@ use routing::router::get_route;
 use util::enforcing_trait_impls::EnforcingChannelKeys;
 use util::events::{Event, EventsProvider, MessageSendEvent, MessageSendEventsProvider};
 use util::errors::APIError;
-use util::ser::Readable;
+use util::ser::{Readable, Writeable};
 
 use bitcoin::hashes::sha256::Hash as Sha256;
 use bitcoin::hashes::Hash;
@@ -105,7 +105,7 @@ fn test_monitor_and_persister_update_fail() {
 		let monitors = nodes[0].chain_monitor.chain_monitor.monitors.lock().unwrap();
 		let monitor = monitors.get(&outpoint).unwrap();
 		let mut w = test_utils::TestVecWriter(Vec::new());
-		monitor.serialize_for_disk(&mut w).unwrap();
+		monitor.write(&mut w).unwrap();
 		let new_monitor = <(BlockHash, ChannelMonitor<EnforcingChannelKeys>)>::read(
 			&mut ::std::io::Cursor::new(&w.0)).unwrap().1;
 		assert!(new_monitor == *monitor);

lightning/src/ln/functional_test_utils.rs

@@ -170,7 +170,7 @@ impl<'a, 'b, 'c> Drop for Node<'a, 'b, 'c> {
 				let old_monitors = self.chain_monitor.chain_monitor.monitors.lock().unwrap();
 				for (_, old_monitor) in old_monitors.iter() {
 					let mut w = test_utils::TestVecWriter(Vec::new());
-					old_monitor.serialize_for_disk(&mut w).unwrap();
+					old_monitor.write(&mut w).unwrap();
 					let (_, deserialized_monitor) = <(BlockHash, ChannelMonitor<EnforcingChannelKeys>)>::read(
 						&mut ::std::io::Cursor::new(&w.0)).unwrap();
 					deserialized_monitors.push(deserialized_monitor);

lightning/src/ln/functional_tests.rs

@@ -4279,7 +4279,7 @@ fn test_no_txn_manager_serialize_deserialize() {
 
 	let nodes_0_serialized = nodes[0].node.encode();
 	let mut chan_0_monitor_serialized = test_utils::TestVecWriter(Vec::new());
-	nodes[0].chain_monitor.chain_monitor.monitors.lock().unwrap().iter().next().unwrap().1.serialize_for_disk(&mut chan_0_monitor_serialized).unwrap();
+	nodes[0].chain_monitor.chain_monitor.monitors.lock().unwrap().iter().next().unwrap().1.write(&mut chan_0_monitor_serialized).unwrap();
 
 	logger = test_utils::TestLogger::new();
 	fee_estimator = test_utils::TestFeeEstimator { sat_per_kw: 253 };
@@ -4388,7 +4388,7 @@ fn test_manager_serialize_deserialize_events() {
 	// Start the de/seriailization process mid-channel creation to check that the channel manager will hold onto events that are serialized
 	let nodes_0_serialized = nodes[0].node.encode();
 	let mut chan_0_monitor_serialized = test_utils::TestVecWriter(Vec::new());
-	nodes[0].chain_monitor.chain_monitor.monitors.lock().unwrap().iter().next().unwrap().1.serialize_for_disk(&mut chan_0_monitor_serialized).unwrap();
+	nodes[0].chain_monitor.chain_monitor.monitors.lock().unwrap().iter().next().unwrap().1.write(&mut chan_0_monitor_serialized).unwrap();
 
 	fee_estimator = test_utils::TestFeeEstimator { sat_per_kw: 253 };
 	logger = test_utils::TestLogger::new();
@@ -4480,7 +4480,7 @@ fn test_simple_manager_serialize_deserialize() {
 
 	let nodes_0_serialized = nodes[0].node.encode();
 	let mut chan_0_monitor_serialized = test_utils::TestVecWriter(Vec::new());
-	nodes[0].chain_monitor.chain_monitor.monitors.lock().unwrap().iter().next().unwrap().1.serialize_for_disk(&mut chan_0_monitor_serialized).unwrap();
+	nodes[0].chain_monitor.chain_monitor.monitors.lock().unwrap().iter().next().unwrap().1.write(&mut chan_0_monitor_serialized).unwrap();
 
 	logger = test_utils::TestLogger::new();
 	fee_estimator = test_utils::TestFeeEstimator { sat_per_kw: 253 };
@@ -4539,7 +4539,7 @@ fn test_manager_serialize_deserialize_inconsistent_monitor() {
 	let mut node_0_stale_monitors_serialized = Vec::new();
 	for monitor in nodes[0].chain_monitor.chain_monitor.monitors.lock().unwrap().iter() {
 		let mut writer = test_utils::TestVecWriter(Vec::new());
-		monitor.1.serialize_for_disk(&mut writer).unwrap();
+		monitor.1.write(&mut writer).unwrap();
 		node_0_stale_monitors_serialized.push(writer.0);
 	}
 
@@ -4558,7 +4558,7 @@ fn test_manager_serialize_deserialize_inconsistent_monitor() {
 	let mut node_0_monitors_serialized = Vec::new();
 	for monitor in nodes[0].chain_monitor.chain_monitor.monitors.lock().unwrap().iter() {
 		let mut writer = test_utils::TestVecWriter(Vec::new());
-		monitor.1.serialize_for_disk(&mut writer).unwrap();
+		monitor.1.write(&mut writer).unwrap();
 		node_0_monitors_serialized.push(writer.0);
 	}
 
@@ -7392,7 +7392,7 @@ fn test_data_loss_protect() {
 	// Cache node A state before any channel update
 	let previous_node_state = nodes[0].node.encode();
 	let mut previous_chain_monitor_state = test_utils::TestVecWriter(Vec::new());
-	nodes[0].chain_monitor.chain_monitor.monitors.lock().unwrap().iter().next().unwrap().1.serialize_for_disk(&mut previous_chain_monitor_state).unwrap();
+	nodes[0].chain_monitor.chain_monitor.monitors.lock().unwrap().iter().next().unwrap().1.write(&mut previous_chain_monitor_state).unwrap();
 
 	send_payment(&nodes[0], &vec!(&nodes[1])[..], 8000000, 8_000_000);
 	send_payment(&nodes[0], &vec!(&nodes[1])[..], 8000000, 8_000_000);
@@ -8274,7 +8274,7 @@ fn test_update_err_monitor_lockdown() {
 		let monitors = nodes[0].chain_monitor.chain_monitor.monitors.lock().unwrap();
 		let monitor = monitors.get(&outpoint).unwrap();
 		let mut w = test_utils::TestVecWriter(Vec::new());
-		monitor.serialize_for_disk(&mut w).unwrap();
+		monitor.write(&mut w).unwrap();
 		let new_monitor = <(BlockHash, channelmonitor::ChannelMonitor<EnforcingChannelKeys>)>::read(
 				&mut ::std::io::Cursor::new(&w.0)).unwrap().1;
 		assert!(new_monitor == *monitor);
@@ -8333,7 +8333,7 @@ fn test_concurrent_monitor_claim() {
 		let monitors = nodes[0].chain_monitor.chain_monitor.monitors.lock().unwrap();
 		let monitor = monitors.get(&outpoint).unwrap();
 		let mut w = test_utils::TestVecWriter(Vec::new());
-		monitor.serialize_for_disk(&mut w).unwrap();
+		monitor.write(&mut w).unwrap();
 		let new_monitor = <(BlockHash, channelmonitor::ChannelMonitor<EnforcingChannelKeys>)>::read(
 				&mut ::std::io::Cursor::new(&w.0)).unwrap().1;
 		assert!(new_monitor == *monitor);
@@ -8359,7 +8359,7 @@ fn test_concurrent_monitor_claim() {
 		let monitors = nodes[0].chain_monitor.chain_monitor.monitors.lock().unwrap();
 		let monitor = monitors.get(&outpoint).unwrap();
 		let mut w = test_utils::TestVecWriter(Vec::new());
-		monitor.serialize_for_disk(&mut w).unwrap();
+		monitor.write(&mut w).unwrap();
 		let new_monitor = <(BlockHash, channelmonitor::ChannelMonitor<EnforcingChannelKeys>)>::read(
 				&mut ::std::io::Cursor::new(&w.0)).unwrap().1;
 		assert!(new_monitor == *monitor);

lightning/src/util/test_utils.rs

@@ -87,7 +87,7 @@ impl<'a> chain::Watch for TestChainMonitor<'a> {
 		// At every point where we get a monitor update, we should be able to send a useful monitor
 		// to a watchtower and disk...
 		let mut w = TestVecWriter(Vec::new());
-		monitor.serialize_for_disk(&mut w).unwrap();
+		monitor.write(&mut w).unwrap();
 		let new_monitor = <(BlockHash, channelmonitor::ChannelMonitor<EnforcingChannelKeys>)>::read(
 			&mut ::std::io::Cursor::new(&w.0)).unwrap().1;
 		assert!(new_monitor == monitor);
@@ -120,7 +120,7 @@ impl<'a> chain::Watch for TestChainMonitor<'a> {
 		let monitors = self.chain_monitor.monitors.lock().unwrap();
 		let monitor = monitors.get(&funding_txo).unwrap();
 		w.0.clear();
-		monitor.serialize_for_disk(&mut w).unwrap();
+		monitor.write(&mut w).unwrap();
 		let new_monitor = <(BlockHash, channelmonitor::ChannelMonitor<EnforcingChannelKeys>)>::read(
 			&mut ::std::io::Cursor::new(&w.0)).unwrap().1;
 		assert!(new_monitor == *monitor);