f - Look up in HashMap rather than iterate over it in spends_watched_output

Author: jkczyz

lightning/src/ln/channelmonitor.rs

@@ -2017,9 +2017,9 @@ impl<ChanSigner: ChannelKeys> ChannelMonitor<ChanSigner> {
 	/// Checks if a given transaction spends any watched outputs.
 	fn spends_watched_output(&self, tx: &Transaction) -> bool {
 		for input in tx.input.iter() {
-			for (txid, outputs) in self.get_outputs_to_watch().iter() {
+			if let Some(outputs) = self.get_outputs_to_watch().get(&input.previous_output.txid) {
 				for (idx, _script_pubkey) in outputs.iter().enumerate() {
-					if txid == &input.previous_output.txid && idx == input.previous_output.vout as usize {
+					if idx == input.previous_output.vout as usize {
 						return true;
 					}
 				}