tokio_udp/
recv_dgram.rs

1use super::socket::UdpSocket;
2
3use std::io;
4use std::net::SocketAddr;
5
6use futures::{Async, Future, Poll};
7
8/// A future used to receive a datagram from a UDP socket.
9///
10/// This is created by the `UdpSocket::recv_dgram` method.
11#[must_use = "futures do nothing unless polled"]
12#[derive(Debug)]
13pub struct RecvDgram<T> {
14    /// None means future was completed
15    state: Option<RecvDgramInner<T>>,
16}
17
18/// A struct is used to represent the full info of RecvDgram.
19#[derive(Debug)]
20struct RecvDgramInner<T> {
21    /// Rx socket
22    socket: UdpSocket,
23    /// The received data will be put in the buffer
24    buffer: T,
25}
26
27/// Components of a `RecvDgram` future, returned from `into_parts`.
28#[derive(Debug)]
29pub struct Parts<T> {
30    /// The socket
31    pub socket: UdpSocket,
32    /// The buffer
33    pub buffer: T,
34
35    _priv: (),
36}
37
38impl<T> RecvDgram<T> {
39    /// Create a new future to receive UDP Datagram
40    pub(crate) fn new(socket: UdpSocket, buffer: T) -> RecvDgram<T> {
41        let inner = RecvDgramInner {
42            socket: socket,
43            buffer: buffer,
44        };
45        RecvDgram { state: Some(inner) }
46    }
47
48    /// Consume the `RecvDgram`, returning the socket and buffer.
49    ///
50    /// ```
51    /// # extern crate tokio_udp;
52    ///
53    /// use tokio_udp::UdpSocket;
54    ///
55    /// # pub fn main() {
56    ///
57    /// let socket = UdpSocket::bind(&([127, 0, 0, 1], 0).into()).unwrap();
58    /// let mut buffer = vec![0; 4096];
59    ///
60    /// let future = socket.recv_dgram(buffer);
61    ///
62    /// // ... polling `future` ... giving up (e.g. after timeout)
63    ///
64    /// let parts = future.into_parts();
65    ///
66    /// let socket = parts.socket; // extract the socket
67    /// let buffer = parts.buffer; // extract the buffer
68    ///
69    /// # }
70    /// ```
71    /// # Panics
72    ///
73    /// If called after the future has completed.
74    pub fn into_parts(mut self) -> Parts<T> {
75        let state = self
76            .state
77            .take()
78            .expect("into_parts called after completion");
79
80        Parts {
81            socket: state.socket,
82            buffer: state.buffer,
83            _priv: (),
84        }
85    }
86}
87
88impl<T> Future for RecvDgram<T>
89where
90    T: AsMut<[u8]>,
91{
92    type Item = (UdpSocket, T, usize, SocketAddr);
93    type Error = io::Error;
94
95    fn poll(&mut self) -> Poll<Self::Item, io::Error> {
96        let (n, addr) = {
97            let ref mut inner = self
98                .state
99                .as_mut()
100                .expect("RecvDgram polled after completion");
101
102            try_ready!(inner.socket.poll_recv_from(inner.buffer.as_mut()))
103        };
104
105        let inner = self.state.take().unwrap();
106        Ok(Async::Ready((inner.socket, inner.buffer, n, addr)))
107    }
108}
tokio_udp/recv_dgram.rs

tokio_udp/
recv_dgram.rs
