async_std/stream/stream/
cycle.rs

1use core::pin::Pin;
2
3use futures_core::ready;
4use pin_project_lite::pin_project;
5
6use crate::stream::Stream;
7use crate::task::{Context, Poll};
8
9pin_project! {
10    /// A stream that will repeatedly yield the same list of elements.
11    #[derive(Debug)]
12    pub struct Cycle<S> {
13        orig: S,
14        #[pin]
15        source: S,
16    }
17}
18
19impl<S> Cycle<S>
20where
21    S: Stream + Clone,
22{
23    pub(crate) fn new(source: S) -> Self {
24        Self {
25            orig: source.clone(),
26            source,
27        }
28    }
29}
30
31impl<S> Stream for Cycle<S>
32where
33    S: Stream + Clone,
34{
35    type Item = S::Item;
36
37    fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
38        let mut this = self.project();
39
40        match ready!(this.source.as_mut().poll_next(cx)) {
41            None => {
42                this.source.set(this.orig.clone());
43                this.source.poll_next(cx)
44            }
45            item => Poll::Ready(item),
46        }
47    }
48}
async_std/stream/stream/cycle.rs

async_std/stream/stream/
cycle.rs
