| use core::fmt; |
| use core::pin::Pin; |
| use futures_core::future::{FusedFuture, Future}; |
| use futures_core::stream::{FusedStream, Stream}; |
| use futures_core::task::{Context, Poll}; |
| use pin_utils::{unsafe_pinned, unsafe_unpinned}; |
| |
| /// Future for the [`for_each`](super::StreamExt::for_each) method. |
| #[must_use = "futures do nothing unless you `.await` or poll them"] |
| pub struct ForEach<St, Fut, F> { |
| stream: St, |
| f: F, |
| future: Option<Fut>, |
| } |
| |
| impl<St, Fut, F> Unpin for ForEach<St, Fut, F> |
| where |
| St: Unpin, |
| Fut: Unpin, |
| {} |
| |
| impl<St, Fut, F> fmt::Debug for ForEach<St, Fut, F> |
| where |
| St: fmt::Debug, |
| Fut: fmt::Debug, |
| { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| f.debug_struct("ForEach") |
| .field("stream", &self.stream) |
| .field("future", &self.future) |
| .finish() |
| } |
| } |
| |
| impl<St, Fut, F> ForEach<St, Fut, F> |
| where St: Stream, |
| F: FnMut(St::Item) -> Fut, |
| Fut: Future<Output = ()>, |
| { |
| unsafe_pinned!(stream: St); |
| unsafe_unpinned!(f: F); |
| unsafe_pinned!(future: Option<Fut>); |
| |
| pub(super) fn new(stream: St, f: F) -> ForEach<St, Fut, F> { |
| ForEach { |
| stream, |
| f, |
| future: None, |
| } |
| } |
| } |
| |
| impl<St, Fut, F> FusedFuture for ForEach<St, Fut, F> |
| where St: FusedStream, |
| F: FnMut(St::Item) -> Fut, |
| Fut: Future<Output = ()>, |
| { |
| fn is_terminated(&self) -> bool { |
| self.future.is_none() && self.stream.is_terminated() |
| } |
| } |
| |
| impl<St, Fut, F> Future for ForEach<St, Fut, F> |
| where St: Stream, |
| F: FnMut(St::Item) -> Fut, |
| Fut: Future<Output = ()>, |
| { |
| type Output = (); |
| |
| fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<()> { |
| loop { |
| if let Some(future) = self.as_mut().future().as_pin_mut() { |
| ready!(future.poll(cx)); |
| } |
| self.as_mut().future().set(None); |
| |
| match ready!(self.as_mut().stream().poll_next(cx)) { |
| Some(e) => { |
| let future = (self.as_mut().f())(e); |
| self.as_mut().future().set(Some(future)); |
| } |
| None => { |
| return Poll::Ready(()); |
| } |
| } |
| } |
| } |
| } |