| use core::pin::Pin; |
| use futures_core::stream::{FusedStream, Stream, TryStream}; |
| use futures_core::task::{Waker, 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>, |
| waker: &Waker, |
| ) -> Poll<Option<Self::Item>> { |
| match self.as_mut().stream().try_poll_next(waker) { |
| Poll::Pending => Poll::Pending, |
| Poll::Ready(opt) => |
| Poll::Ready(opt.map(|res| res.map_err(|e| self.as_mut().f()(e)))), |
| } |
| } |
| } |