blob: 3a15fd253e29a88b0913fd60191844f6be8421c8 [file] [log] [blame]
use core::marker::Unpin;
use core::pin::Pin;
use futures_core::stream::{Stream, TryStream};
use futures_core::task::{LocalWaker, Poll};
use pin_utils::{unsafe_pinned, unsafe_unpinned};
/// Stream for the [`map_ok`](super::TryStreamExt::map_ok) combinator.
#[derive(Debug)]
#[must_use = "streams do nothing unless polled"]
pub struct MapOk<St, F> {
stream: St,
f: F,
}
impl<St, F> MapOk<St, F> {
unsafe_pinned!(stream: St);
unsafe_unpinned!(f: F);
/// Creates a new MapOk.
pub(super) fn new(stream: St, f: F) -> Self {
MapOk { stream, f }
}
}
impl<St: Unpin, F> Unpin for MapOk<St, F> {}
impl<St, F, T> Stream for MapOk<St, F>
where
St: TryStream,
F: FnMut(St::Ok) -> T,
{
type Item = Result<T, St::Error>;
#[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.stream().try_poll_next(lw) {
Poll::Pending => Poll::Pending,
Poll::Ready(opt) =>
Poll::Ready(opt.map(|res| res.map(|x| self.f()(x)))),
}
}
}