async_std/future/future/
delay.rs

1use std::future::Future;
2use std::pin::Pin;
3use std::time::Duration;
4
5use pin_project_lite::pin_project;
6
7use crate::task::{Context, Poll};
8use crate::utils::{timer_after, Timer};
9
10pin_project! {
11    #[doc(hidden)]
12    #[allow(missing_debug_implementations)]
13    pub struct DelayFuture<F> {
14        #[pin]
15        future: F,
16        #[pin]
17        delay: Timer,
18    }
19}
20
21impl<F> DelayFuture<F> {
22    pub fn new(future: F, dur: Duration) -> DelayFuture<F> {
23        let delay = timer_after(dur);
24
25        DelayFuture { future, delay }
26    }
27}
28
29impl<F: Future> Future for DelayFuture<F> {
30    type Output = F::Output;
31
32    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
33        let this = self.project();
34
35        match this.delay.poll(cx) {
36            Poll::Pending => Poll::Pending,
37            Poll::Ready(_) => match this.future.poll(cx) {
38                Poll::Ready(v) => Poll::Ready(v),
39                Poll::Pending => Poll::Pending,
40            },
41        }
42    }
43}
async_std/future/future/delay.rs

async_std/future/future/
delay.rs
