async_std/stream/stream/
cloned.rs

1use crate::stream::Stream;
2use crate::task::{Context, Poll};
3use pin_project_lite::pin_project;
4use core::pin::Pin;
5
6pin_project! {
7    /// A stream that clones the elements of an underlying stream.
8    #[derive(Debug)]
9    pub struct Cloned<S> {
10        #[pin]
11        stream: S,
12    }
13}
14
15impl<S> Cloned<S> {
16    pub(super) fn new(stream: S) -> Self {
17        Self { stream }
18    }
19}
20
21impl<'a, S, T: 'a> Stream for Cloned<S>
22where
23    S: Stream<Item = &'a T>,
24    T: Clone,
25{
26    type Item = T;
27
28    fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
29        let this = self.project();
30        let next = futures_core::ready!(this.stream.poll_next(cx));
31        Poll::Ready(next.cloned())
32    }
33}