| use core::fmt; |
| use core::pin::Pin; |
| use futures_core::stream::{FusedStream, Stream}; |
| use futures_core::task::{Context, Poll}; |
| #[cfg(feature = "sink")] |
| use futures_sink::Sink; |
| use pin_project::pin_project; |
| |
| use crate::fns::FnMut1; |
| |
| /// Stream for the [`map`](super::StreamExt::map) method. |
| #[pin_project] |
| #[must_use = "streams do nothing unless polled"] |
| pub struct Map<St, F> { |
| #[pin] |
| stream: St, |
| f: F, |
| } |
| |
| impl<St, F> fmt::Debug for Map<St, F> |
| where |
| St: fmt::Debug, |
| { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| f.debug_struct("Map") |
| .field("stream", &self.stream) |
| .finish() |
| } |
| } |
| |
| impl<St, F> Map<St, F> { |
| pub(crate) fn new(stream: St, f: F) -> Map<St, F> { |
| Map { stream, f } |
| } |
| |
| delegate_access_inner!(stream, St, ()); |
| } |
| |
| impl<St, F> FusedStream for Map<St, F> |
| where St: FusedStream, |
| F: FnMut1<St::Item>, |
| { |
| fn is_terminated(&self) -> bool { |
| self.stream.is_terminated() |
| } |
| } |
| |
| impl<St, F> Stream for Map<St, F> |
| where St: Stream, |
| F: FnMut1<St::Item>, |
| { |
| type Item = F::Output; |
| |
| fn poll_next( |
| self: Pin<&mut Self>, |
| cx: &mut Context<'_>, |
| ) -> Poll<Option<Self::Item>> { |
| let mut this = self.project(); |
| let res = ready!(this.stream.as_mut().poll_next(cx)); |
| Poll::Ready(res.map(|x| this.f.call_mut(x))) |
| } |
| |
| fn size_hint(&self) -> (usize, Option<usize>) { |
| self.stream.size_hint() |
| } |
| } |
| |
| // Forwarding impl of Sink from the underlying stream |
| #[cfg(feature = "sink")] |
| impl<St, F, Item> Sink<Item> for Map<St, F> |
| where St: Stream + Sink<Item>, |
| F: FnMut1<St::Item>, |
| { |
| type Error = St::Error; |
| |
| delegate_sink!(stream, Item); |
| } |