1 | use super::{copy_buf, BufReader, CopyBuf}; |
2 | use futures_core::future::Future; |
3 | use futures_core::task::{Context, Poll}; |
4 | use futures_io::{AsyncRead, AsyncWrite}; |
5 | use pin_project_lite::pin_project; |
6 | use std::io; |
7 | use std::pin::Pin; |
8 | |
9 | /// Creates a future which copies all the bytes from one object to another. |
10 | /// |
11 | /// The returned future will copy all the bytes read from this `AsyncRead` into the |
12 | /// `writer` specified. This future will only complete once the `reader` has hit |
13 | /// EOF and all bytes have been written to and flushed from the `writer` |
14 | /// provided. |
15 | /// |
16 | /// On success the number of bytes is returned. |
17 | /// |
18 | /// # Examples |
19 | /// |
20 | /// ``` |
21 | /// # futures::executor::block_on(async { |
22 | /// use futures::io::{self, AsyncWriteExt, Cursor}; |
23 | /// |
24 | /// let reader = Cursor::new([1, 2, 3, 4]); |
25 | /// let mut writer = Cursor::new(vec![0u8; 5]); |
26 | /// |
27 | /// let bytes = io::copy(reader, &mut writer).await?; |
28 | /// writer.close().await?; |
29 | /// |
30 | /// assert_eq!(bytes, 4); |
31 | /// assert_eq!(writer.into_inner(), [1, 2, 3, 4, 0]); |
32 | /// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap(); |
33 | /// ``` |
34 | pub fn copy<R, W>(reader: R, writer: &mut W) -> Copy<'_, R, W> |
35 | where |
36 | R: AsyncRead, |
37 | W: AsyncWrite + Unpin + ?Sized, |
38 | { |
39 | Copy { inner: copy_buf(reader:BufReader::new(inner:reader), writer) } |
40 | } |
41 | |
42 | pin_project! { |
43 | /// Future for the [`copy()`] function. |
44 | #[derive(Debug)] |
45 | #[must_use = "futures do nothing unless you `.await` or poll them" ] |
46 | pub struct Copy<'a, R, W: ?Sized> { |
47 | #[pin] |
48 | inner: CopyBuf<'a, BufReader<R>, W>, |
49 | } |
50 | } |
51 | |
52 | impl<R: AsyncRead, W: AsyncWrite + Unpin + ?Sized> Future for Copy<'_, R, W> { |
53 | type Output = io::Result<u64>; |
54 | |
55 | fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { |
56 | self.project().inner.poll(cx) |
57 | } |
58 | } |
59 | |