| use crate::Stream; |
| |
| use core::fmt; |
| use core::pin::Pin; |
| use core::task::{Context, Poll}; |
| use pin_project_lite::pin_project; |
| |
| pin_project! { |
| /// Stream for the [`map`](super::StreamExt::map) method. |
| #[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(super) fn new(stream: St, f: F) -> Self { |
| Map { stream, f } |
| } |
| } |
| |
| impl<St, F, T> Stream for Map<St, F> |
| where |
| St: Stream, |
| F: FnMut(St::Item) -> T, |
| { |
| type Item = T; |
| |
| fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<T>> { |
| self.as_mut() |
| .project() |
| .stream |
| .poll_next(cx) |
| .map(|opt| opt.map(|x| (self.as_mut().project().f)(x))) |
| } |
| |
| fn size_hint(&self) -> (usize, Option<usize>) { |
| self.stream.size_hint() |
| } |
| } |