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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 00:47:55 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 00:47:55 +0000 |
commit | 26a029d407be480d791972afb5975cf62c9360a6 (patch) | |
tree | f435a8308119effd964b339f76abb83a57c29483 /third_party/rust/tokio-stream/src/iter.rs | |
parent | Initial commit. (diff) | |
download | firefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz firefox-26a029d407be480d791972afb5975cf62c9360a6.zip |
Adding upstream version 124.0.1.upstream/124.0.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/rust/tokio-stream/src/iter.rs')
-rw-r--r-- | third_party/rust/tokio-stream/src/iter.rs | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/third_party/rust/tokio-stream/src/iter.rs b/third_party/rust/tokio-stream/src/iter.rs new file mode 100644 index 0000000000..128be616fc --- /dev/null +++ b/third_party/rust/tokio-stream/src/iter.rs @@ -0,0 +1,67 @@ +use crate::Stream; + +use core::pin::Pin; +use core::task::{Context, Poll}; + +/// Stream for the [`iter`](fn@iter) function. +#[derive(Debug)] +#[must_use = "streams do nothing unless polled"] +pub struct Iter<I> { + iter: I, + yield_amt: usize, +} + +impl<I> Unpin for Iter<I> {} + +/// Converts an `Iterator` into a `Stream` which is always ready +/// to yield the next value. +/// +/// Iterators in Rust don't express the ability to block, so this adapter +/// simply always calls `iter.next()` and returns that. +/// +/// ``` +/// # async fn dox() { +/// use tokio_stream::{self as stream, StreamExt}; +/// +/// let mut stream = stream::iter(vec![17, 19]); +/// +/// assert_eq!(stream.next().await, Some(17)); +/// assert_eq!(stream.next().await, Some(19)); +/// assert_eq!(stream.next().await, None); +/// # } +/// ``` +pub fn iter<I>(i: I) -> Iter<I::IntoIter> +where + I: IntoIterator, +{ + Iter { + iter: i.into_iter(), + yield_amt: 0, + } +} + +impl<I> Stream for Iter<I> +where + I: Iterator, +{ + type Item = I::Item; + + fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<I::Item>> { + // TODO: add coop back + if self.yield_amt >= 32 { + self.yield_amt = 0; + + cx.waker().wake_by_ref(); + + Poll::Pending + } else { + self.yield_amt += 1; + + Poll::Ready(self.iter.next()) + } + } + + fn size_hint(&self) -> (usize, Option<usize>) { + self.iter.size_hint() + } +} |