futures_time/task/
sleep_until.rs

1use std::future::Future;
2use std::pin::Pin;
3use std::task::{Context, Poll};
4
5use pin_project_lite::pin_project;
6
7use crate::time::Instant;
8
9#[cfg(feature = "web")]
10use crate::task::web_timer::Timer;
11#[cfg(not(feature = "web"))]
12use async_io::Timer;
13
14/// Sleeps until the specified instant.
15pub fn sleep_until(deadline: Instant) -> SleepUntil {
16    SleepUntil {
17        timer: Timer::at(deadline.into()),
18        completed: false,
19    }
20}
21
22pin_project! {
23    /// Sleeps until the specified instant.
24    #[must_use = "futures do nothing unless polled or .awaited"]
25    pub struct SleepUntil {
26        #[pin]
27        timer: Timer,
28        completed: bool,
29    }
30}
31
32impl Future for SleepUntil {
33    type Output = Instant;
34
35    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
36        assert!(!self.completed, "future polled after completing");
37        let this = self.project();
38        match this.timer.poll(cx) {
39            Poll::Ready(instant) => {
40                *this.completed = true;
41                Poll::Ready(instant.into())
42            }
43            Poll::Pending => Poll::Pending,
44        }
45    }
46}
futures_time/task/sleep_until.rs

futures_time/task/
sleep_until.rs
