Use Infallible for the unconstructable default custom message type

[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 2470058f58960378f199a3e02e5703d22feb92e2..22568e506668f127a3f8d179f8df356d383724cd 100644 (file)
--- a/lightning/src/ln/peer_handler.rs
+++ b/lightning/src/ln/peer_handler.rs
@@ -37,6 +37,7 @@ use sync::{Arc, Mutex};
 use core::sync::atomic::{AtomicUsize, Ordering};
 use core::{cmp, hash, fmt, mem};
 use core::ops::Deref;
+use core::convert::Infallible;
 #[cfg(feature = "std")] use std::error;
 
 use bitcoin::hashes::sha256::Hash as Sha256;
@@ -80,21 +81,21 @@ impl Deref for IgnoringMessageHandler {
        fn deref(&self) -> &Self { self }
 }
 
-impl wire::Type for () {
+// Implement Type for Infallible, note that it cannot be constructed, and thus you can never call a
+// method that takes self for it.
+impl wire::Type for Infallible {
        fn type_id(&self) -> u16 {
-               // We should never call this for `DummyCustomType`
                unreachable!();
        }
 }
-
-impl Writeable for () {
+impl Writeable for Infallible {
        fn write<W: Writer>(&self, _: &mut W) -> Result<(), io::Error> {
                unreachable!();
        }
 }
 
 impl wire::CustomMessageReader for IgnoringMessageHandler {
-       type CustomMessage = ();
+       type CustomMessage = Infallible;
        fn read<R: io::Read>(&self, _message_type: u16, _buffer: &mut R) -> Result<Option<Self::CustomMessage>, msgs::DecodeError> {
                Ok(None)
        }
@@ -720,7 +721,7 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref, CMH: Deref> P
 
        /// Append a message to a peer's pending outbound/write buffer, and update the map of peers needing sends accordingly.
        fn enqueue_message<M: wire::Type + Writeable + Debug>(&self, peer: &mut Peer, message: &M) {
-               let mut buffer = VecWriter(Vec::new());
+               let mut buffer = VecWriter(Vec::with_capacity(2048));
                wire::write(message, &mut buffer).unwrap(); // crash if the write failed
                let encoded_message = buffer.0;
 
@@ -1169,6 +1170,9 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref, CMH: Deref> P
        /// May call [`send_data`] on [`SocketDescriptor`]s. Thus, be very careful with reentrancy
        /// issues!
        ///
+       /// You don't have to call this function explicitly if you are using [`lightning-net-tokio`]
+       /// or one of the other clients provided in our language bindings.
+       ///
        /// [`send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
        /// [`ChannelManager::process_pending_htlc_forwards`]: crate::ln::channelmanager::ChannelManager::process_pending_htlc_forwards
        /// [`send_data`]: SocketDescriptor::send_data