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fixes to stream::min_by (#162)

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* fixes to stream::min_by

* no reason to split these impls

* remove Debug derive from MinByFuture
This commit is contained in:
Fedor Sakharov 2019-09-10 14:53:30 +03:00 committed by Yoshua Wuyts
parent a8090be3eb
commit 272f74c1da
2 changed files with 17 additions and 17 deletions
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30
src/stream/stream/min_by.rs
View file

@ -2,20 +2,20 @@ use std::cmp::Ordering;
use std::pin::Pin;
use crate::future::Future;
use crate::stream::Stream;
use crate::task::{Context, Poll};
/// A future that yields the minimum item in a stream by a given comparison function.
#[derive(Clone, Debug)]
pub struct MinByFuture<S: Stream, F> {
#[allow(missing_debug_implementations)]
pub struct MinByFuture<S, F, T> {
stream: S,
compare: F,
min: Option<S::Item>,
min: Option<T>,
}
impl<S: Stream + Unpin, F> Unpin for MinByFuture<S, F> {}
impl<S, F, T> MinByFuture<S, F, T> {
pin_utils::unsafe_pinned!(stream: S);
pin_utils::unsafe_unpinned!(compare: F);
pin_utils::unsafe_unpinned!(min: Option<T>);
impl<S: Stream + Unpin, F> MinByFuture<S, F> {
pub(super) fn new(stream: S, compare: F) -> Self {
MinByFuture {
stream,
@ -25,25 +25,25 @@ impl<S: Stream + Unpin, F> MinByFuture<S, F> {
}
}
impl<S, F> Future for MinByFuture<S, F>
impl<S, F> Future for MinByFuture<S, F, S::Item>
where
S: futures_core::stream::Stream + Unpin,
S: futures_core::stream::Stream + Unpin + Sized,
S::Item: Copy,
F: FnMut(&S::Item, &S::Item) -> Ordering,
{
type Output = Option<S::Item>;
fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
let next = futures_core::ready!(Pin::new(&mut self.stream).poll_next(cx));
let next = futures_core::ready!(self.as_mut().stream().poll_next(cx));
match next {
Some(new) => {
cx.waker().wake_by_ref();
match self.as_mut().min.take() {
None => self.as_mut().min = Some(new),
Some(old) => match (&mut self.as_mut().compare)(&new, &old) {
Ordering::Less => self.as_mut().min = Some(new),
_ => self.as_mut().min = Some(old),
match self.as_mut().min().take() {
None => *self.as_mut().min() = Some(new),
Some(old) => match (&mut self.as_mut().compare())(&new, &old) {
Ordering::Less => *self.as_mut().min() = Some(new),
_ => *self.as_mut().min() = Some(old),
},
}
Poll::Pending

4
src/stream/stream/mod.rs
View file

@ -153,9 +153,9 @@ pub trait Stream {
/// #
/// # }) }
/// ```
fn min_by<F>(self, compare: F) -> MinByFuture<Self, F>
fn min_by<F>(self, compare: F) -> MinByFuture<Self, F, Self::Item>
where
Self: Sized + Unpin,
Self: Sized,
F: FnMut(&Self::Item, &Self::Item) -> Ordering,
{
MinByFuture::new(self, compare)