blob: a73e16f7125d1d5c6cce4df1845227a43189d3fc [file] [log] [blame]
use core::marker::Unpin;
use core::pin::Pin;
use futures_core::stream::{FusedStream, Stream, TryStream};
use futures_core::task::{LocalWaker, Poll};
use pin_utils::{unsafe_pinned, unsafe_unpinned};
/// Stream for the [`map_err`](super::TryStreamExt::map_err) combinator.
#[derive(Debug)]
#[must_use = "streams do nothing unless polled"]
pub struct MapErr<St, F> {
stream: St,
f: F,
}
impl<St, F> MapErr<St, F> {
unsafe_pinned!(stream: St);
unsafe_unpinned!(f: F);
/// Creates a new MapErr.
pub(super) fn new(stream: St, f: F) -> Self {
MapErr { stream, f }
}
}
impl<St: Unpin, F> Unpin for MapErr<St, F> {}
impl<St: FusedStream, F> FusedStream for MapErr<St, F> {
fn is_terminated(&self) -> bool {
self.stream.is_terminated()
}
}
impl<St, F, E> Stream for MapErr<St, F>
where
St: TryStream,
F: FnMut(St::Error) -> E,
{
type Item = Result<St::Ok, E>;
#[allow(clippy::redundant_closure)] // https://github.com/rust-lang-nursery/rust-clippy/issues/1439
fn poll_next(
mut self: Pin<&mut Self>,
lw: &LocalWaker,
) -> Poll<Option<Self::Item>> {
match self.as_mut().stream().try_poll_next(lw) {
Poll::Pending => Poll::Pending,
Poll::Ready(opt) =>
Poll::Ready(opt.map(|res| res.map_err(|e| self.as_mut().f()(e)))),
}
}
}