forked from mirror/async-std
bac74c2d7f
* Add future::poll_fn * Replace all uses of poll_fn with the new one * Remove some uses of futures * Simplify ReadDir and DirEntry * Remove some use of futures from File * Use futures subcrates * Fix imports in docs * Remove futures-util dependency * Remove futures-executor-preview * Refactor * Require more features in the futures-preview crate
44 lines
820 B
Rust
44 lines
820 B
Rust
use std::marker::PhantomData;
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use std::pin::Pin;
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use crate::future::Future;
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use crate::task::{Context, Poll};
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/// Never resolves to a value.
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///
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/// # Examples
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///
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/// ```
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/// # fn main() { async_std::task::block_on(async {
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/// #
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/// use std::time::Duration;
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///
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/// use async_std::future;
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/// use async_std::io;
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///
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/// let dur = Duration::from_secs(1);
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/// let fut = future::pending();
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///
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/// let res: io::Result<()> = io::timeout(dur, fut).await;
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/// assert!(res.is_err());
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/// #
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/// # }) }
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/// ```
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pub async fn pending<T>() -> T {
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let fut = Pending {
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_marker: PhantomData,
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};
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fut.await
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}
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struct Pending<T> {
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_marker: PhantomData<T>,
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}
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impl<T> Future for Pending<T> {
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type Output = T;
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fn poll(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<T> {
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Poll::Pending
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}
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}
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