async_std/stream/stream/
le.rs

1use core::cmp::Ordering;
2use core::future::Future;
3use core::pin::Pin;
4
5use pin_project_lite::pin_project;
6
7use super::partial_cmp::PartialCmpFuture;
8use crate::stream::stream::StreamExt;
9use crate::stream::Stream;
10use crate::task::{Context, Poll};
11
12pin_project! {
13    /// Determines if the elements of this `Stream` are lexicographically
14    /// less or equal to those of another.
15    #[doc(hidden)]
16    #[allow(missing_debug_implementations)]
17    pub struct LeFuture<L: Stream, R: Stream> {
18        #[pin]
19        partial_cmp: PartialCmpFuture<L, R>,
20    }
21}
22
23impl<L: Stream, R: Stream> LeFuture<L, R>
24where
25    L::Item: PartialOrd<R::Item>,
26{
27    pub(super) fn new(l: L, r: R) -> Self {
28        Self {
29            partial_cmp: l.partial_cmp(r),
30        }
31    }
32}
33
34impl<L: Stream, R: Stream> Future for LeFuture<L, R>
35where
36    L: Stream + Sized,
37    R: Stream + Sized,
38    L::Item: PartialOrd<R::Item>,
39{
40    type Output = bool;
41
42    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
43        let result = futures_core::ready!(self.project().partial_cmp.poll(cx));
44
45        match result {
46            Some(Ordering::Less) | Some(Ordering::Equal) => Poll::Ready(true),
47            _ => Poll::Ready(false),
48        }
49    }
50}
async_std/stream/stream/le.rs

async_std/stream/stream/
le.rs
