f no double lookup, nits

Author: valentinewallace

lightning/src/routing/onion_message.rs

@@ -24,7 +24,9 @@ pub fn find_path<L: Deref, GL: Deref>(
 	our_node_pubkey: &PublicKey, destination: &PublicKey, network_graph: &NetworkGraph<GL>, first_hops: Option<&[&PublicKey]>, logger: L
 ) -> Result<Vec<PublicKey>, Error> where L::Target: Logger, GL::Target: Logger
 {
-	log_trace!(logger, "Searching for an onion message path from origin {} to destination {} and {} first hops {}overriding the network graph", our_node_pubkey, destination, first_hops.map(|hops| hops.len()).unwrap_or(0), if first_hops.is_some() { "" } else { "not " });
+	log_trace!(logger, "Searching for an onion message path from origin {} to destination {} and {} first hops {}overriding the network graph",
+		our_node_pubkey, destination, first_hops.map(|hops| hops.len()).unwrap_or(0),
+		if first_hops.is_some() { "" } else { "not " });
 	let graph_lock = network_graph.read_only();
 	let network_channels = graph_lock.channels();
 	let network_nodes = graph_lock.nodes();
@@ -43,10 +45,11 @@ pub fn find_path<L: Deref, GL: Deref>(
 	}
 
 	let mut visited = HashMap::new();
-	while !frontier.is_empty() {
-		let PathBuildingHop { cost, node_id, parent_node_id } = frontier.pop().unwrap();
-		if visited.contains_key(&node_id) { continue; }
-		visited.insert(node_id, parent_node_id);
+	while let Some(PathBuildingHop { cost, node_id, parent_node_id }) = frontier.pop() {
+		match visited.entry(node_id) {
+			hash_map::Entry::Occupied(_) => continue,
+			hash_map::Entry::Vacant(e) => e.insert(parent_node_id),
+		};
 		if node_id == dest_node_id {
 			return Ok(reverse_path(visited, our_node_id, dest_node_id, logger)?)
 		}