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#![warn(rust_2018_idioms)]
#![cfg(feature = "full")]
use bytes::BytesMut;
use futures::ready;
use tokio::io::{self, AsyncRead, AsyncReadExt, AsyncWrite, AsyncWriteExt, ReadBuf};
use tokio_test::assert_ok;
use std::pin::Pin;
use std::task::{Context, Poll};
#[tokio::test]
async fn copy() {
struct Rd(bool);
impl AsyncRead for Rd {
fn poll_read(
mut self: Pin<&mut Self>,
_cx: &mut Context<'_>,
buf: &mut ReadBuf<'_>,
) -> Poll<io::Result<()>> {
if self.0 {
buf.put_slice(b"hello world");
self.0 = false;
Poll::Ready(Ok(()))
} else {
Poll::Ready(Ok(()))
}
}
}
let mut rd = Rd(true);
let mut wr = Vec::new();
let n = assert_ok!(io::copy(&mut rd, &mut wr).await);
assert_eq!(n, 11);
assert_eq!(wr, b"hello world");
}
#[tokio::test]
async fn proxy() {
struct BufferedWd {
buf: BytesMut,
writer: io::DuplexStream,
}
impl AsyncWrite for BufferedWd {
fn poll_write(
self: Pin<&mut Self>,
_cx: &mut Context<'_>,
buf: &[u8],
) -> Poll<io::Result<usize>> {
self.get_mut().buf.extend_from_slice(buf);
Poll::Ready(Ok(buf.len()))
}
fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
let this = self.get_mut();
while !this.buf.is_empty() {
let n = ready!(Pin::new(&mut this.writer).poll_write(cx, &this.buf))?;
let _ = this.buf.split_to(n);
}
Pin::new(&mut this.writer).poll_flush(cx)
}
fn poll_shutdown(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
Pin::new(&mut self.writer).poll_shutdown(cx)
}
}
let (rd, wd) = io::duplex(1024);
let mut rd = rd.take(1024);
let mut wd = BufferedWd {
buf: BytesMut::new(),
writer: wd,
};
// write start bytes
assert_ok!(wd.write_all(&[0x42; 512]).await);
assert_ok!(wd.flush().await);
let n = assert_ok!(io::copy(&mut rd, &mut wd).await);
assert_eq!(n, 1024);
}
#[tokio::test]
async fn copy_is_cooperative() {
tokio::select! {
biased;
_ = async {
loop {
let mut reader: &[u8] = b"hello";
let mut writer: Vec<u8> = vec![];
let _ = io::copy(&mut reader, &mut writer).await;
}
} => {},
_ = tokio::task::yield_now() => {}
}
}