created an abstract interface to streaming serialised IO

src/broadcast/mod.rs

@@ -494,11 +494,9 @@ fn index_of_path(mut path: Vec<bool>) -> usize {
     path.reverse();
 
     for &dir in path.iter() {
-        if dir == false {
-            idx = idx << 1;
-        }
-        else {
-            idx = (idx << 1) | 1;
+        idx = idx << 1;
+        if dir == true {
+            idx = idx | 1;
         }
     }
     idx

src/commst.rs

@@ -12,6 +12,7 @@ use proto::Message;
 use proto_io;
 use proto_io::CodecIo;
 use messaging::SourcedMessage;
+use stream_io::StreamIo;
 
 #[derive(Debug)]
 pub enum Error {
@@ -26,21 +27,19 @@ impl From<io::Error> for Error {
 /// consensus algorithm.
 pub struct CommsTask<'a, T: 'a + Clone + Debug + Send + Sync +
                      From<Vec<u8>> + Into<Vec<u8>>>
-where Vec<u8>: From<T>
 {
     /// The transmit side of the multiple producer channel from comms threads.
     tx: &'a Sender<SourcedMessage<T>>,
     /// The receive side of the channel to the comms thread.
     rx: &'a Receiver<Message<T>>,
     /// The socket IO task.
-    io: CodecIo,
+    io: CodecIo<T>,
     /// The index of this comms task for identification against its remote node.
     pub node_index: usize
 }
 
 impl<'a, T: Clone + Debug + Send + Sync + From<Vec<u8>> + Into<Vec<u8>>>
     CommsTask<'a, T>
-where Vec<u8>: From<T>
 {
     pub fn new(tx: &'a Sender<SourcedMessage<T>>,
                rx: &'a Receiver<Message<T>>,
@@ -54,7 +53,7 @@ where Vec<u8>: From<T>
         CommsTask {
             tx: tx,
             rx: rx,
-            io: CodecIo::new(stream),
+            io: StreamIo::from_stream(stream),
             node_index: node_index
         }
     }
@@ -76,14 +75,14 @@ where Vec<u8>: From<T>
                     let message = rx.recv().unwrap();
                     debug!("Node {} <- {:?}", node_index, message);
                     // Forward the message to the remote node.
-                    io1.send_message(message).unwrap();
+                    io1.send(message).unwrap();
                 }
             });
 
             // Remote comms receive loop.
             debug!("Starting remote RX loop for node {}", node_index);
             loop {
-                match self.io.receive_message() {
+                match self.io.recv() {
                     Ok(message) => {
                         debug!("Node {} -> {:?}", node_index, message);
                         tx.send(

src/lib.rs

@@ -47,6 +47,7 @@ extern crate reed_solomon_erasure;
 
 mod connection;
 mod messaging;
+mod stream_io;
 mod proto;
 mod proto_io;
 mod commst;

src/proto/mod.rs

@@ -16,9 +16,6 @@ pub enum Message<T: Send + Sync> {
     Agreement(AgreementMessage)
 }
 
-//unsafe impl<T: Send + Sync> Send for Message<T> { }
-//impl<T: Send + Sync> !Sync for Message<T> { }
-
 /// The three kinds of message sent during the reliable broadcast stage of the
 /// consensus algorithm.
 #[derive (Clone, Debug, PartialEq)]

src/proto_io.rs

@@ -6,6 +6,7 @@ use std::net::TcpStream;
 use protobuf;
 use protobuf::Message as ProtobufMessage;
 use proto::*;
+use stream_io::StreamIo;
 
 /// A magic key to put right before each message. An atavism of primitive serial
 /// protocols.
@@ -57,29 +58,34 @@ fn decode_u32_from_be(buffer: &[u8]) -> Result<u32, Error> {
     Ok(result)
 }
 
-pub struct CodecIo {
+pub struct CodecIo<T> {
     stream: TcpStream,
     buffer: [u8; 1024 * 4],
+    /// FIXME: remove this dependent argument
+    phant: T
 }
 
 /// A message handling task.
-impl CodecIo where {
-    pub fn new(stream: TcpStream) -> Self {
+impl<T> StreamIo<TcpStream, T, Error> for CodecIo<T>
+where T: Clone + Send + Sync + From<Vec<u8>> + Into<Vec<u8>>
+{
+    fn from_stream(stream: TcpStream) -> Self {
         CodecIo {
             stream,
-            buffer: [0; 1024 * 4]
+            buffer: [0; 1024 * 4],
+            phant: T::from(Vec::new())
         }
     }
 
-    pub fn try_clone(&self) -> Result<CodecIo, ::std::io::Error> {
+    fn try_clone(&self) -> Result<CodecIo<T>, ::std::io::Error> {
         Ok(CodecIo {
             stream: self.stream.try_clone()?,
-            buffer: [0; 1024 * 4]
+            buffer: self.buffer.clone(),
+            phant: T::from(Vec::new())
         })
     }
 
-    pub fn receive_message<T>(&mut self) -> Result<Message<T>, Error>
-    where T: From<Vec<u8>> + Send + Sync
+    fn recv(&mut self) -> Result<Message<T>, Error>
     {
         self.stream.read_exact(&mut self.buffer[0..4])?;
         let frame_start = decode_u32_from_be(&self.buffer[0..4])?;
@@ -103,9 +109,7 @@ impl CodecIo where {
             .map_err(|e| Error::ProtobufError(e))
     }
 
-    pub fn send_message<T>(&mut self, message: Message<T>)
-                           -> Result<(), Error>
-    where T: Into<Vec<u8>> + Send + Sync
+    fn send(&mut self, message: Message<T>) -> Result<(), Error>
     {
         let mut buffer: [u8; 4] = [0; 4];
         // Wrap stream

src/stream_io.rs

@@ -0,0 +1,20 @@
+//! Abstract interface to serialised IO.
+
+use std::io;
+use std::io::{Read, Write};
+
+use proto::*;
+
+/// Trait of types of streams carrying payload of type `Message<T>` and
+/// returning errors of type `Error`.
+///
+/// This is a stream interface independent of the choice of serialisation
+/// methods.
+pub trait StreamIo<Stream, T, Error>: Sized
+where Stream: Read + Write, T: Send + Sync // From implies Into
+{
+    fn from_stream(stream: Stream) -> Self;
+    fn try_clone(&self) -> Result<Self, io::Error>;
+    fn recv(&mut self) -> Result<Message<T>, Error>;
+    fn send(&mut self, m: Message<T>) -> Result<(), Error>;
+}