Avoid unnecessarily alloc'ing a new buffer when decrypting messages

[rust-lightning] / lightning / src / ln / peer_handler.rs

diff --git a/lightning/src/ln/peer_handler.rs b/lightning/src/ln/peer_handler.rs
index 5f0d88a95273734d6242b3485e42e9575e270a98..a1a4d4b26729c6822227b7d58f576ed0e1725ad1 100644 (file)
--- a/lightning/src/ln/peer_handler.rs
+++ b/lightning/src/ln/peer_handler.rs
@@ -1402,17 +1402,18 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                                                                        }
                                                                        peer.pending_read_is_header = false;
                                                                } else {
-                                                                       let msg_data = try_potential_handleerror!(peer,
-                                                                               peer.channel_encryptor.decrypt_message(&peer.pending_read_buffer[..]));
-                                                                       assert!(msg_data.len() >= 2);
+                                                                       debug_assert!(peer.pending_read_buffer.len() >= 2 + 16);
+                                                                       try_potential_handleerror!(peer,
+                                                                               peer.channel_encryptor.decrypt_message(&mut peer.pending_read_buffer[..]));
+
+                                                                       let mut reader = io::Cursor::new(&peer.pending_read_buffer[..peer.pending_read_buffer.len() - 16]);
+                                                                       let message_result = wire::read(&mut reader, &*self.message_handler.custom_message_handler);
 
                                                                        // Reset read buffer
                                                                        if peer.pending_read_buffer.capacity() > 8192 { peer.pending_read_buffer = Vec::new(); }
                                                                        peer.pending_read_buffer.resize(18, 0);
                                                                        peer.pending_read_is_header = true;
 
-                                                                       let mut reader = io::Cursor::new(&msg_data[..]);
-                                                                       let message_result = wire::read(&mut reader, &*self.message_handler.custom_message_handler);
                                                                        let message = match message_result {
                                                                                Ok(x) => x,
                                                                                Err(e) => {