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