| use core::fmt; |
| use core::pin::Pin; |
| use futures_core::future::{FusedFuture, Future}; |
| use futures_core::ready; |
| use futures_core::stream::Stream; |
| use futures_core::task::{Context, Poll}; |
| use pin_project_lite::pin_project; |
| |
| pin_project! { |
| /// Future for the [`any`](super::StreamExt::any) method. |
| #[must_use = "futures do nothing unless you `.await` or poll them"] |
| pub struct Any<St, Fut, F> { |
| #[pin] |
| stream: St, |
| f: F, |
| done: bool, |
| #[pin] |
| future: Option<Fut>, |
| } |
| } |
| |
| impl<St, Fut, F> fmt::Debug for Any<St, Fut, F> |
| where |
| St: fmt::Debug, |
| Fut: fmt::Debug, |
| { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| f.debug_struct("Any") |
| .field("stream", &self.stream) |
| .field("done", &self.done) |
| .field("future", &self.future) |
| .finish() |
| } |
| } |
| |
| impl<St, Fut, F> Any<St, Fut, F> |
| where |
| St: Stream, |
| F: FnMut(St::Item) -> Fut, |
| Fut: Future<Output = bool>, |
| { |
| pub(super) fn new(stream: St, f: F) -> Self { |
| Self { stream, f, done: false, future: None } |
| } |
| } |
| |
| impl<St, Fut, F> FusedFuture for Any<St, Fut, F> |
| where |
| St: Stream, |
| F: FnMut(St::Item) -> Fut, |
| Fut: Future<Output = bool>, |
| { |
| fn is_terminated(&self) -> bool { |
| self.done && self.future.is_none() |
| } |
| } |
| |
| impl<St, Fut, F> Future for Any<St, Fut, F> |
| where |
| St: Stream, |
| F: FnMut(St::Item) -> Fut, |
| Fut: Future<Output = bool>, |
| { |
| type Output = bool; |
| |
| fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<bool> { |
| let mut this = self.project(); |
| Poll::Ready(loop { |
| if let Some(fut) = this.future.as_mut().as_pin_mut() { |
| // we're currently processing a future to produce a new value |
| let res = ready!(fut.poll(cx)); |
| this.future.set(None); |
| if res { |
| *this.done = true; |
| break true; |
| } // early exit |
| } else if !*this.done { |
| // we're waiting on a new item from the stream |
| match ready!(this.stream.as_mut().poll_next(cx)) { |
| Some(item) => { |
| this.future.set(Some((this.f)(item))); |
| } |
| None => { |
| *this.done = true; |
| break false; |
| } |
| } |
| } else { |
| panic!("Any polled after completion") |
| } |
| }) |
| } |
| } |