forked from mirror/async-std
update stream::fuse
Signed-off-by: Yoshua Wuyts <yoshuawuyts@gmail.com>
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commit
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2 changed files with 19 additions and 41 deletions
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@ -1,51 +1,29 @@
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use std::pin::Pin;
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use std::task::{Context, Poll};
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use crate::task::{Context, Poll};
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/// A `Stream` that is permanently closed
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/// once a single call to `poll` results in
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/// `Poll::Ready(None)`, returning `Poll::Ready(None)`
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/// for all future calls to `poll`.
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/// A `Stream` that is permanently closed once a single call to `poll` results in
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/// `Poll::Ready(None)`, returning `Poll::Ready(None)` for all future calls to `poll`.
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#[derive(Clone, Debug)]
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pub struct Fuse<S> {
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stream: S,
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done: bool,
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pub(crate) stream: S,
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pub(crate) done: bool,
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}
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impl<S: Unpin> Unpin for Fuse<S> {}
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impl<S: futures::Stream> Fuse<S> {
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impl<S: futures_core::Stream> Fuse<S> {
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pin_utils::unsafe_pinned!(stream: S);
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pin_utils::unsafe_unpinned!(done: bool);
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/// Returns `true` if the underlying stream is fused.
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///
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/// If this `Stream` is fused, all future calls to
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/// `poll` will return `Poll::Ready(None)`.
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pub fn is_done(&self) -> bool {
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self.done
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}
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/// Consumes this `Fuse` and returns the inner
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/// `Stream`, unfusing it if it had become
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/// fused.
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pub fn into_inner(self) -> S
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where
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S: Sized,
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{
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self.stream
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}
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}
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impl<S: futures::Stream> futures::Stream for Fuse<S> {
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impl<S: futures_core::Stream> futures_core::Stream for Fuse<S> {
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type Item = S::Item;
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fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<S::Item>> {
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if self.done {
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Poll::Ready(None)
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} else {
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let next = futures::ready!(self.as_mut().stream().poll_next(cx));
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let next = futures_core::ready!(self.as_mut().stream().poll_next(cx));
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if next.is_none() {
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*self.as_mut().done() = true;
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}
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@ -248,29 +248,29 @@ pub trait Stream {
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Enumerate::new(self)
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}
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/// Transforms this `Stream` into a "fused" `Stream`
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/// such that after the first time `poll` returns
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/// `Poll::Ready(None)`, all future calls to
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/// `poll` will also return `Poll::Ready(None)`.
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/// Transforms this `Stream` into a "fused" `Stream` such that after the first time `poll`
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/// returns `Poll::Ready(None)`, all future calls to `poll` will also return
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/// `Poll::Ready(None)`.
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///
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/// # Examples
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///
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/// ```
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/// # #![feature(async_await)]
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/// # fn main() { async_std::task::block_on(async {
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/// #
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/// use async_std::prelude::*;
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/// use async_std::stream;
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///
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/// let mut s = stream::repeat(9).take(3);
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///
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/// while let Some(v) = s.next().await {
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/// assert_eq!(v, 9);
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/// }
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/// let mut s = stream::once(1).fuse();
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/// assert_eq!(s.next().await, Some(1));
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/// assert_eq!(s.next().await, None);
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/// assert_eq!(s.next().await, None);
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/// #
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/// # }) }
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/// ```
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fn fuse(self) -> Fuse<Self> {
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fn fuse(self) -> Fuse<Self>
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where
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Self: Sized,
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{
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Fuse {
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stream: self,
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done: false,
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