Drop ChannelMonitor::write_for_watchtower

Not only was watchtower mode never implemented, but the bits that
we had were removed some time ago. It doesn't seem likely we'll
move forward with a "watchtower-mode" ChannelMonitor, instead
we'll likely have some other, separate struct for this.

Author: TheBlueMatt

fuzz/src/chanmon_deser.rs

@@ -32,8 +32,6 @@ pub fn do_test(data: &[u8]) {
 		let deserialized_copy = <(Sha256dHash, channelmonitor::ChannelMonitor<EnforcingChannelKeys>)>::read(&mut Cursor::new(&w.0), logger.clone()).unwrap();
 		assert!(latest_block_hash == deserialized_copy.0);
 		assert!(monitor == deserialized_copy.1);
-		w.0.clear();
-		monitor.write_for_watchtower(&mut w).unwrap();
 	}
 }
 

lightning/src/ln/channelmonitor.rs

@@ -833,8 +833,14 @@ impl<ChanSigner: ChannelKeys> PartialEq for ChannelMonitor<ChanSigner> {
 }
 
 impl<ChanSigner: ChannelKeys + Writeable> ChannelMonitor<ChanSigner> {
-	/// Serializes into a vec, with various modes for the exposed pub fns
-	fn write<W: Writer>(&self, writer: &mut W, for_local_storage: bool) -> Result<(), ::std::io::Error> {
+	/// 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 not just starting at the same height but starting at the highest
+	/// common block that appears on your best chain as well as on the chain which contains the
+	/// last block hash returned) upon deserializing the object!
+	pub fn write_for_disk<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::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])?;
@@ -929,14 +935,10 @@ impl<ChanSigner: ChannelKeys + Writeable> ChannelMonitor<ChanSigner> {
 			}
 		}
 
-		if for_local_storage {
-			writer.write_all(&byte_utils::be64_to_array(self.remote_hash_commitment_number.len() as u64))?;
-			for (ref payment_hash, commitment_number) in self.remote_hash_commitment_number.iter() {
-				writer.write_all(&payment_hash.0[..])?;
-				writer.write_all(&byte_utils::be48_to_array(*commitment_number))?;
-			}
-		} else {
-			writer.write_all(&byte_utils::be64_to_array(0))?;
+		writer.write_all(&byte_utils::be64_to_array(self.remote_hash_commitment_number.len() as u64))?;
+		for (ref payment_hash, commitment_number) in self.remote_hash_commitment_number.iter() {
+			writer.write_all(&payment_hash.0[..])?;
+			writer.write_all(&byte_utils::be48_to_array(*commitment_number))?;
 		}
 
 		macro_rules! serialize_local_tx {
@@ -977,17 +979,8 @@ impl<ChanSigner: ChannelKeys + Writeable> ChannelMonitor<ChanSigner> {
 			writer.write_all(&[0; 1])?;
 		}
 
-		if for_local_storage {
-			writer.write_all(&byte_utils::be48_to_array(self.current_remote_commitment_number))?;
-		} else {
-			writer.write_all(&byte_utils::be48_to_array(0))?;
-		}
-
-		if for_local_storage {
-			writer.write_all(&byte_utils::be48_to_array(self.current_local_commitment_number))?;
-		} else {
-			writer.write_all(&byte_utils::be48_to_array(0))?;
-		}
+		writer.write_all(&byte_utils::be48_to_array(self.current_remote_commitment_number))?;
+		writer.write_all(&byte_utils::be48_to_array(self.current_local_commitment_number))?;
 
 		writer.write_all(&byte_utils::be64_to_array(self.payment_preimages.len() as u64))?;
 		for payment_preimage in self.payment_preimages.values() {
@@ -1039,28 +1032,6 @@ impl<ChanSigner: ChannelKeys + Writeable> ChannelMonitor<ChanSigner> {
 
 		Ok(())
 	}
-
-	/// 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 not just starting at the same height but starting at the highest
-	/// common block that appears on your best chain as well as on the chain which contains the
-	/// last block hash returned) upon deserializing the object!
-	pub fn write_for_disk<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
-		self.write(writer, true)
-	}
-
-	/// Encodes this monitor into the given writer, suitable for sending to a remote watchtower
-	///
-	/// 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 not just starting at the same height but starting at the highest
-	/// common block that appears on your best chain as well as on the chain which contains the
-	/// last block hash returned) upon deserializing the object!
-	pub fn write_for_watchtower<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
-		self.write(writer, false)
-	}
 }
 
 impl<ChanSigner: ChannelKeys> ChannelMonitor<ChanSigner> {

lightning/src/util/test_utils.rs

@@ -71,8 +71,6 @@ impl<'a> channelmonitor::ManyChannelMonitor<EnforcingChannelKeys> for TestChanne
 		let new_monitor = <(Sha256dHash, channelmonitor::ChannelMonitor<EnforcingChannelKeys>)>::read(
 				&mut ::std::io::Cursor::new(&w.0), Arc::new(TestLogger::new())).unwrap().1;
 		assert!(new_monitor == monitor);
-		w.0.clear();
-		monitor.write_for_watchtower(&mut w).unwrap(); // This at least shouldn't crash...
 		self.latest_monitor_update_id.lock().unwrap().insert(funding_txo.to_channel_id(), (funding_txo, monitor.get_latest_update_id()));
 		self.added_monitors.lock().unwrap().push((funding_txo, monitor));
 		assert!(self.simple_monitor.add_monitor(funding_txo, new_monitor).is_ok());
@@ -97,8 +95,6 @@ impl<'a> channelmonitor::ManyChannelMonitor<EnforcingChannelKeys> for TestChanne
 		let new_monitor = <(Sha256dHash, channelmonitor::ChannelMonitor<EnforcingChannelKeys>)>::read(
 				&mut ::std::io::Cursor::new(&w.0), Arc::new(TestLogger::new())).unwrap().1;
 		assert!(new_monitor == *monitor);
-		w.0.clear();
-		monitor.write_for_watchtower(&mut w).unwrap(); // This at least shouldn't crash...
 		self.added_monitors.lock().unwrap().push((funding_txo, new_monitor));
 		self.update_ret.lock().unwrap().clone()
 	}