Remove UdpCodec (#109)

`UdpFramed` is updated to use the `Encoder` and
`Decoder` traits from `tokio-io`.

examples/udp-codec.rs

@@ -1,40 +1,24 @@
-//! This is a basic example of leveraging `UdpCodec` to create a simple UDP
+//! This is a basic example of leveraging `BytesCodec` to create a simple UDP
 //! client and server which speak a custom protocol.
 //!
-//! Here we're using the a custom codec to convert a UDP socket to a stream of
+//! Here we're using the codec from tokio-io to convert a UDP socket to a stream of
 //! client messages. These messages are then processed and returned back as a
 //! new message with a new destination. Overall, we then use this to construct a
 //! "ping pong" pair where two sockets are sending messages back and forth.
 
 extern crate tokio;
+extern crate tokio_io;
 extern crate env_logger;
 extern crate futures;
 extern crate futures_cpupool;
 
-use std::io;
 use std::net::SocketAddr;
 
 use futures::{Future, Stream, Sink};
 use futures::future::Executor;
 use futures_cpupool::CpuPool;
-use tokio::net::{UdpSocket, UdpCodec};
-
-pub struct LineCodec;
-
-impl UdpCodec for LineCodec {
-    type In = (SocketAddr, Vec<u8>);
-    type Out = (SocketAddr, Vec<u8>);
-    type Error = io::Error;
-
-    fn decode(&mut self, addr: &SocketAddr, buf: &[u8]) -> io::Result<Self::In> {
-        Ok((*addr, buf.to_vec()))
-    }
-
-    fn encode(&mut self, (addr, buf): Self::Out, into: &mut Vec<u8>) -> io::Result<SocketAddr> {
-        into.extend(buf);
-        Ok(addr)
-    }
-}
+use tokio::net::UdpSocket;
+use tokio_io::codec::BytesCodec;
 
 fn main() {
     drop(env_logger::init());
@@ -50,27 +34,27 @@ fn main() {
 
     // We're parsing each socket with the `LineCodec` defined above, and then we
     // `split` each codec into the sink/stream halves.
-    let (a_sink, a_stream) = a.framed(LineCodec).split();
-    let (b_sink, b_stream) = b.framed(LineCodec).split();
+    let (a_sink, a_stream) = a.framed(BytesCodec::new()).split();
+    let (b_sink, b_stream) = b.framed(BytesCodec::new()).split();
 
     // Start off by sending a ping from a to b, afterwards we just print out
     // what they send us and continually send pings
     // let pings = stream::iter((0..5).map(Ok));
-    let a = a_sink.send((b_addr, b"PING".to_vec())).and_then(|a_sink| {
+    let a = a_sink.send(("PING".into(), b_addr)).and_then(|a_sink| {
         let mut i = 0;
-        let a_stream = a_stream.take(4).map(move |(addr, msg)| {
+        let a_stream = a_stream.take(4).map(move |(msg, addr)| {
             i += 1;
             println!("[a] recv: {}", String::from_utf8_lossy(&msg));
-            (addr, format!("PING {}", i).into_bytes())
+            (format!("PING {}", i).into(), addr)
         });
         a_sink.send_all(a_stream)
     });
 
     // The second client we have will receive the pings from `a` and then send
     // back pongs.
-    let b_stream = b_stream.map(|(addr, msg)| {
+    let b_stream = b_stream.map(|(msg, addr)| {
         println!("[b] recv: {}", String::from_utf8_lossy(&msg));
-        (addr, b"PONG".to_vec())
+        ("PONG".into(), addr)
     });
     let b = b_sink.send_all(b_stream);