1use crate::Stream;
2
3use core::future::Future;
4use core::marker::PhantomPinned;
5use core::pin::Pin;
6use core::task::{Context, Poll};
7use pin_project_lite::pin_project;
8
9pin_project! {
10 /// Future for the [`any`](super::StreamExt::any) method.
11 #[derive(Debug)]
12 #[must_use = "futures do nothing unless you `.await` or poll them"]
13 pub struct AnyFuture<'a, St: ?Sized, F> {
14 stream: &'a mut St,
15 f: F,
16 // Make this future `!Unpin` for compatibility with async trait methods.
17 #[pin]
18 _pin: PhantomPinned,
19 }
20}
21
22impl<'a, St: ?Sized, F> AnyFuture<'a, St, F> {
23 pub(super) fn new(stream: &'a mut St, f: F) -> Self {
24 Self {
25 stream,
26 f,
27 _pin: PhantomPinned,
28 }
29 }
30}
31
32impl<St, F> Future for AnyFuture<'_, St, F>
33where
34 St: ?Sized + Stream + Unpin,
35 F: FnMut(St::Item) -> bool,
36{
37 type Output = bool;
38
39 fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
40 let me = self.project();
41 let mut stream = Pin::new(me.stream);
42
43 // Take a maximum of 32 items from the stream before yielding.
44 for _ in 0..32 {
45 match futures_core::ready!(stream.as_mut().poll_next(cx)) {
46 Some(v) => {
47 if (me.f)(v) {
48 return Poll::Ready(true);
49 }
50 }
51 None => return Poll::Ready(false),
52 }
53 }
54
55 cx.waker().wake_by_ref();
56 Poll::Pending
57 }
58}
59