1 use crate::io::AsyncRead;
2 use futures_core::future::Future;
3 use futures_core::task::{Context, Poll};
4 use std::io;
5 use std::pin::Pin;
6 
7 /// Future for the [`read`](super::AsyncReadExt::read) method.
8 #[derive(Debug)]
9 #[must_use = "futures do nothing unless you `.await` or poll them"]
10 pub struct Read<'a, R: ?Sized> {
11     reader: &'a mut R,
12     buf: &'a mut [u8],
13 }
14 
15 impl<R: ?Sized + Unpin> Unpin for Read<'_, R> {}
16 
17 impl<'a, R: AsyncRead + ?Sized + Unpin> Read<'a, R> {
new(reader: &'a mut R, buf: &'a mut [u8]) -> Self18     pub(super) fn new(reader: &'a mut R, buf: &'a mut [u8]) -> Self {
19         Self { reader, buf }
20     }
21 }
22 
23 impl<R: AsyncRead + ?Sized + Unpin> Future for Read<'_, R> {
24     type Output = io::Result<usize>;
25 
poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output>26     fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
27         let this = &mut *self;
28         Pin::new(&mut this.reader).poll_read(cx, this.buf)
29     }
30 }
31