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Remove Unpin bound from SelectAll

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This commit is contained in:
alexmoon 2022-04-04 21:24:10 -04:00
parent 04a263c700
commit e42295c4c5
1 changed files with 18 additions and 16 deletions
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24
embassy/src/util/select_all.rs
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@ -1,11 +1,7 @@
#![allow(dead_code)]
use core::future::Future; use core::future::Future;
use core::pin::Pin; use core::pin::Pin;
use core::task::{Context, Poll}; use core::task::{Context, Poll};
use futures::future::FutureExt;
/// Future for the [`select_all`] function. /// Future for the [`select_all`] function.
#[derive(Debug)] #[derive(Debug)]
#[must_use = "futures do nothing unless you `.await` or poll them"] #[must_use = "futures do nothing unless you `.await` or poll them"]
@ -24,9 +20,9 @@ impl<Fut: Unpin, const N: usize> Unpin for SelectAll<Fut, N> {}
/// # Panics /// # Panics
/// ///
/// This function will panic if the array specified contains no items. /// This function will panic if the array specified contains no items.
pub fn select_all<Fut: Future + Unpin, const N: usize>(arr: [Fut; N]) -> Option<SelectAll<Fut, N>> { pub fn select_all<Fut: Future, const N: usize>(arr: [Fut; N]) -> SelectAll<Fut, N> {
assert!(N > 0); assert!(N > 0);
Some(SelectAll { inner: arr }) SelectAll { inner: arr }
} }
impl<Fut, const N: usize> SelectAll<Fut, N> { impl<Fut, const N: usize> SelectAll<Fut, N> {
@ -36,18 +32,24 @@ impl<Fut, const N: usize> SelectAll<Fut, N> {
} }
} }
impl<Fut: Future + Unpin, const N: usize> Future for SelectAll<Fut, N> { impl<Fut: Future, const N: usize> Future for SelectAll<Fut, N> {
type Output = (Fut::Output, usize); type Output = (Fut::Output, usize);
fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
let item = self // Safety: Since `self` is pinned, `inner` cannot move. Since `inner` cannot move,
// its elements also cannot move. Therefore it is safe to access `inner` and pin
// references to the contained futures.
let item = unsafe {
self.get_unchecked_mut()
.inner .inner
.iter_mut() .iter_mut()
.enumerate() .enumerate()
.find_map(|(i, f)| match f.poll_unpin(cx) { .find_map(|(i, f)| match Pin::new_unchecked(f).poll(cx) {
Poll::Pending => None, Poll::Pending => None,
Poll::Ready(e) => Some((i, e)), Poll::Ready(e) => Some((i, e)),
}); })
};
match item { match item {
Some((idx, res)) => Poll::Ready((res, idx)), Some((idx, res)) => Poll::Ready((res, idx)),
None => Poll::Pending, None => Poll::Pending,