[TBS] del trailing whitespaces + retain instead of drain

Author: Antoine Riard

src/ln/channelmonitor.rs

@@ -287,26 +287,28 @@ impl ChannelMonitor {
 			}
 		}
 
-		let mut pruned_payment_preimages = HashMap::with_capacity(self.payment_preimages.capacity());
-		for (k, v) in self.payment_preimages.drain() {
-			for (htlc, _s1, _s2) in &self.current_local_signed_commitment_tx.as_ref().expect("Channel need at least an initial commitment tx !").htlc_outputs {
-				if k == htlc.payment_hash {
-					pruned_payment_preimages.insert(k, v); 
-				}
-			}
-			for (_tx, htlcs) in &self.remote_claimable_outpoints {
-				for htlc in htlcs {
+		let local_signed_commitment_tx = &self.current_local_signed_commitment_tx;
+		let remote_claimable_outpoints = &self.remote_claimable_outpoints;
+		self.payment_preimages.retain( | &k, _| 
+			{
+				for (htlc, _s1, _s2) in &local_signed_commitment_tx.as_ref().expect("Channel needs at least an initial commitment tx !").htlc_outputs {
 					if k == htlc.payment_hash {
-						pruned_payment_preimages.insert(k, v);
+						return true
 					}
 				}
-			}
-		}
-		self.payment_preimages = pruned_payment_preimages;
+				for (_tx, htlcs) in remote_claimable_outpoints {
+					for htlc in htlcs {
+						if k == htlc.payment_hash {
+							return true
+						}
+					}
+				}
+				false
+			});
 
 		Ok(())
 	}
-	
+
 	/// Informs this monitor of the latest remote (ie non-broadcastable) commitment transaction.
 	/// The monitor watches for it to be broadcasted and then uses the HTLC information (and
 	/// possibly future revocation/preimage information) to claim outputs where possible.