forked from rust-lang/futures-rs
/
poll.rs
35 lines (31 loc) · 978 Bytes
/
poll.rs
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
use crate::future::FutureExt;
use core::pin::Pin;
use futures_core::future::Future;
use futures_core::task::{Context, Poll};
/// A macro which returns the result of polling a future once within the
/// current `async` context.
///
/// This macro is only usable inside of `async` functions, closures, and blocks.
/// It is also gated behind the `async-await` feature of this library, which is
/// _not_ activated by default.
#[macro_export]
macro_rules! poll {
($x:expr $(,)?) => {
$crate::async_await::poll($x).await
}
}
#[doc(hidden)]
pub fn poll<F: Future + Unpin>(future: F) -> PollOnce<F> {
PollOnce { future }
}
#[allow(missing_debug_implementations)]
#[doc(hidden)]
pub struct PollOnce<F: Future + Unpin> {
future: F,
}
impl<F: Future + Unpin> Future for PollOnce<F> {
type Output = Poll<F::Output>;
fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
Poll::Ready(self.future.poll_unpin(cx))
}
}