tokio_core/reactor/
timeout.rs

1//! Support for creating futures that represent timeouts.
2//!
3//! This module contains the `Timeout` type which is a future that will resolve
4//! at a particular point in the future.
5
6use std::io;
7use std::time::{Duration, Instant};
8
9use futures::{Future, Poll};
10use tokio_timer::Delay;
11
12use reactor::Handle;
13
14/// A future representing the notification that a timeout has occurred.
15///
16/// Timeouts are created through the `Timeout::new` or
17/// `Timeout::new_at` methods indicating when a timeout should fire at.
18/// Note that timeouts are not intended for high resolution timers, but rather
19/// they will likely fire some granularity after the exact instant that they're
20/// otherwise indicated to fire at.
21#[must_use = "futures do nothing unless polled"]
22#[derive(Debug)]
23pub struct Timeout {
24    delay: Delay
25}
26
27impl Timeout {
28    /// Creates a new timeout which will fire at `dur` time into the future.
29    ///
30    /// This function will return a Result with the actual timeout object or an
31    /// error. The timeout object itself is then a future which will be
32    /// set to fire at the specified point in the future.
33    pub fn new(dur: Duration, handle: &Handle) -> io::Result<Timeout> {
34        Timeout::new_at(Instant::now() + dur, handle)
35    }
36
37    /// Creates a new timeout which will fire at the time specified by `at`.
38    ///
39    /// This function will return a Result with the actual timeout object or an
40    /// error. The timeout object itself is then a future which will be
41    /// set to fire at the specified point in the future.
42    pub fn new_at(at: Instant, handle: &Handle) -> io::Result<Timeout> {
43        Ok(Timeout {
44            delay: handle.remote.timer_handle.delay(at)
45        })
46    }
47
48    /// Resets this timeout to an new timeout which will fire at the time
49    /// specified by `at`.
50    ///
51    /// This method is usable even of this instance of `Timeout` has "already
52    /// fired". That is, if this future has resolved, calling this method means
53    /// that the future will still re-resolve at the specified instant.
54    ///
55    /// If `at` is in the past then this future will immediately be resolved
56    /// (when `poll` is called).
57    ///
58    /// Note that if any task is currently blocked on this future then that task
59    /// will be dropped. It is required to call `poll` again after this method
60    /// has been called to ensure that a task is blocked on this future.
61    pub fn reset(&mut self, at: Instant) {
62        self.delay.reset(at)
63    }
64}
65
66impl Future for Timeout {
67    type Item = ();
68    type Error = io::Error;
69
70    fn poll(&mut self) -> Poll<(), io::Error> {
71        self.delay.poll()
72            .map_err(|err| io::Error::new(io::ErrorKind::Other, err))
73    }
74}
tokio_core/reactor/timeout.rs

tokio_core/reactor/
timeout.rs
