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use std::io;
use std::net::{SocketAddr, Ipv4Addr, SocketAddrV4};
use futures::{Async, Poll, Stream, Sink, StartSend, AsyncSink};
use net::UdpSocket;
pub trait UdpCodec {
type In;
type Out;
fn decode(&mut self, src: &SocketAddr, buf: &[u8]) -> io::Result<Self::In>;
fn encode(&mut self, msg: Self::Out, buf: &mut Vec<u8>) -> SocketAddr;
}
pub struct UdpFramed<C> {
socket: UdpSocket,
codec: C,
rd: Vec<u8>,
wr: Vec<u8>,
out_addr: SocketAddr,
flushed: bool,
}
impl<C: UdpCodec> Stream for UdpFramed<C> {
type Item = C::In;
type Error = io::Error;
fn poll(&mut self) -> Poll<Option<C::In>, io::Error> {
let (n, addr) = try_nb!(self.socket.recv_from(&mut self.rd));
trace!("received {} bytes, decoding", n);
let frame = try!(self.codec.decode(&addr, &self.rd[..n]));
trace!("frame decoded from buffer");
Ok(Async::Ready(Some(frame)))
}
}
impl<C: UdpCodec> Sink for UdpFramed<C> {
type SinkItem = C::Out;
type SinkError = io::Error;
fn start_send(&mut self, item: C::Out) -> StartSend<C::Out, io::Error> {
trace!("sending frame");
if !self.flushed {
match try!(self.poll_complete()) {
Async::Ready(()) => {},
Async::NotReady => return Ok(AsyncSink::NotReady(item)),
}
}
self.out_addr = self.codec.encode(item, &mut self.wr);
self.flushed = false;
trace!("frame encoded; length={}", self.wr.len());
Ok(AsyncSink::Ready)
}
fn poll_complete(&mut self) -> Poll<(), io::Error> {
if self.flushed {
return Ok(Async::Ready(()))
}
trace!("flushing frame; length={}", self.wr.len());
let n = try_nb!(self.socket.send_to(&self.wr, &self.out_addr));
trace!("written {}", n);
let wrote_all = n == self.wr.len();
self.wr.clear();
self.flushed = true;
if wrote_all {
Ok(Async::Ready(()))
} else {
Err(io::Error::new(io::ErrorKind::Other,
"failed to write entire datagram to socket"))
}
}
fn close(&mut self) -> Poll<(), io::Error> {
try_ready!(self.poll_complete());
Ok(().into())
}
}
pub fn new<C: UdpCodec>(socket: UdpSocket, codec: C) -> UdpFramed<C> {
UdpFramed {
socket: socket,
codec: codec,
out_addr: SocketAddr::V4(SocketAddrV4::new(Ipv4Addr::new(0, 0, 0, 0), 0)),
rd: vec![0; 64 * 1024],
wr: Vec::with_capacity(8 * 1024),
flushed: true,
}
}
impl<C> UdpFramed<C> {
pub fn get_ref(&self) -> &UdpSocket {
&self.socket
}
pub fn get_mut(&mut self) -> &mut UdpSocket {
&mut self.socket
}
pub fn into_inner(self) -> UdpSocket {
self.socket
}
}