Keep the same read buffer unless the last message was overly large

This avoids repeatedly deallocating-allocating a Vec for the peer
read buffer after every message/header.

diff --git a/lightning/src/ln/peer_handler.rs b/lightning/src/ln/peer_handler.rs
index 0685785db1ceb9b61cfc5276e9da77c1fc7768b2..f771cf4ff2a4b36d25720f526ad577a182e8b1e0 100644 (file)
--- a/lightning/src/ln/peer_handler.rs
+++ b/lightning/src/ln/peer_handler.rs
@@ -972,7 +972,7 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref, CMH: Deref> P
                                                                if peer.pending_read_is_header {
                                                                        let msg_len = try_potential_handleerror!(peer,
                                                                                peer.channel_encryptor.decrypt_length_header(&peer.pending_read_buffer[..]));
-                                                                       peer.pending_read_buffer = Vec::with_capacity(msg_len as usize + 16);
+                                                                       if peer.pending_read_buffer.capacity() > 8192 { peer.pending_read_buffer = Vec::new(); }
                                                                        peer.pending_read_buffer.resize(msg_len as usize + 16, 0);
                                                                        if msg_len < 2 { // Need at least the message type tag
                                                                                return Err(PeerHandleError{ no_connection_possible: false });
@@ -984,7 +984,8 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref, CMH: Deref> P
                                                                        assert!(msg_data.len() >= 2);
 
                                                                        // Reset read buffer
-                                                                       peer.pending_read_buffer = [0; 18].to_vec();
+                                                                       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[..]);