Sha256: fc7565d21d39565790859eeac9ae8dd74123a9d15b88258d3abe894f1876cc39
Contents?: true
Size: 1.56 KB
Versions: 27
Compression:
Stored size: 1.56 KB
Contents
use core::pin::Pin;
use futures_core::ready;
use futures_core::stream::{FusedStream, Stream};
use futures_core::task::{Context, Poll};
#[cfg(feature = "sink")]
use futures_sink::Sink;
use pin_project_lite::pin_project;
pin_project! {
/// Stream for the [`enumerate`](super::StreamExt::enumerate) method.
#[derive(Debug)]
#[must_use = "streams do nothing unless polled"]
pub struct Enumerate<St> {
#[pin]
stream: St,
count: usize,
}
}
impl<St: Stream> Enumerate<St> {
pub(super) fn new(stream: St) -> Self {
Self { stream, count: 0 }
}
delegate_access_inner!(stream, St, ());
}
impl<St: Stream + FusedStream> FusedStream for Enumerate<St> {
fn is_terminated(&self) -> bool {
self.stream.is_terminated()
}
}
impl<St: Stream> Stream for Enumerate<St> {
type Item = (usize, St::Item);
fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
let this = self.project();
match ready!(this.stream.poll_next(cx)) {
Some(item) => {
let prev_count = *this.count;
*this.count += 1;
Poll::Ready(Some((prev_count, item)))
}
None => Poll::Ready(None),
}
}
fn size_hint(&self) -> (usize, Option<usize>) {
self.stream.size_hint()
}
}
// Forwarding impl of Sink from the underlying stream
#[cfg(feature = "sink")]
impl<S, Item> Sink<Item> for Enumerate<S>
where
S: Stream + Sink<Item>,
{
type Error = S::Error;
delegate_sink!(stream, Item);
}
Version data entries
27 entries across 27 versions & 1 rubygems