Merge pull request #830 from TheBlueMatt/2021-03-chanmon-deser-utils

Make chain::Filter slightly easier with some ChannelMonitor utilities.

Author: TheBlueMatt

lightning/src/chain/chainmonitor.rs

@@ -193,12 +193,7 @@ where C::Target: chain::Filter,
 			log_trace!(self.logger, "Got new Channel Monitor for channel {}", log_bytes!(funding_txo.0.to_channel_id()[..]));
 
 			if let Some(ref chain_source) = self.chain_source {
-				chain_source.register_tx(&funding_txo.0.txid, &funding_txo.1);
-				for (txid, outputs) in monitor.get_outputs_to_watch().iter() {
-					for (idx, script_pubkey) in outputs.iter() {
-						chain_source.register_output(&OutPoint { txid: *txid, index: *idx as u16 }, script_pubkey);
-					}
-				}
+				monitor.load_outputs_to_watch(chain_source);
 			}
 		}
 		entry.insert(monitor);

lightning/src/chain/channelmonitor.rs

@@ -45,6 +45,7 @@ use chain;
 use chain::chaininterface::{BroadcasterInterface, FeeEstimator};
 use chain::transaction::{OutPoint, TransactionData};
 use chain::keysinterface::{SpendableOutputDescriptor, StaticPaymentOutputDescriptor, DelayedPaymentOutputDescriptor, Sign, KeysInterface};
+use chain::Filter;
 use util::logger::Logger;
 use util::ser::{Readable, ReadableArgs, MaybeReadable, Writer, Writeable, U48};
 use util::byte_utils;
@@ -1165,10 +1166,23 @@ impl<Signer: Sign> ChannelMonitor<Signer> {
 
 	/// Gets a list of txids, with their output scripts (in the order they appear in the
 	/// transaction), which we must learn about spends of via block_connected().
-	///
-	/// (C-not exported) because we have no HashMap bindings
-	pub fn get_outputs_to_watch(&self) -> HashMap<Txid, Vec<(u32, Script)>> {
-		self.inner.lock().unwrap().get_outputs_to_watch().clone()
+	pub fn get_outputs_to_watch(&self) -> Vec<(Txid, Vec<(u32, Script)>)> {
+		self.inner.lock().unwrap().get_outputs_to_watch()
+			.iter().map(|(txid, outputs)| (*txid, outputs.clone())).collect()
+	}
+
+	/// Loads the funding txo and outputs to watch into the given `chain::Filter` by repeatedly
+	/// calling `chain::Filter::register_output` and `chain::Filter::register_tx` until all outputs
+	/// have been registered.
+	pub fn load_outputs_to_watch<F: Deref>(&self, filter: &F) where F::Target: chain::Filter {
+		let lock = self.inner.lock().unwrap();
+		filter.register_tx(&lock.get_funding_txo().0.txid, &lock.get_funding_txo().1);
+		for (txid, outputs) in lock.get_outputs_to_watch().iter() {
+			for (index, script_pubkey) in outputs.iter() {
+				assert!(*index <= u16::max_value() as u32);
+				filter.register_output(&OutPoint { txid: *txid, index: *index as u16 }, script_pubkey);
+			}
+		}
 	}
 
 	/// Get the list of HTLCs who's status has been updated on chain. This should be called by