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#![warn(rust_2018_idioms)]
#![cfg(feature = "full")]
use tokio::io::{AsyncWrite, AsyncWriteExt};
use tokio_test::{assert_err, assert_ok};
use bytes::{Buf, Bytes, BytesMut};
use std::cmp;
use std::io;
use std::pin::Pin;
use std::task::{Context, Poll};
#[tokio::test]
async fn write_all_buf() {
struct Wr {
buf: BytesMut,
cnt: usize,
}
impl AsyncWrite for Wr {
fn poll_write(
mut self: Pin<&mut Self>,
_cx: &mut Context<'_>,
buf: &[u8],
) -> Poll<io::Result<usize>> {
let n = cmp::min(4, buf.len());
dbg!(buf);
let buf = &buf[0..n];
self.cnt += 1;
self.buf.extend(buf);
Ok(buf.len()).into()
}
fn poll_flush(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<io::Result<()>> {
Ok(()).into()
}
fn poll_shutdown(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<io::Result<()>> {
Ok(()).into()
}
}
let mut wr = Wr {
buf: BytesMut::with_capacity(64),
cnt: 0,
};
let mut buf = Bytes::from_static(b"hello").chain(Bytes::from_static(b"world"));
assert_ok!(wr.write_all_buf(&mut buf).await);
assert_eq!(wr.buf, b"helloworld"[..]);
// expect 4 writes, [hell],[o],[worl],[d]
assert_eq!(wr.cnt, 4);
assert!(!buf.has_remaining());
}
#[tokio::test]
async fn write_buf_err() {
/// Error out after writing the first 4 bytes
struct Wr {
cnt: usize,
}
impl AsyncWrite for Wr {
fn poll_write(
mut self: Pin<&mut Self>,
_cx: &mut Context<'_>,
_buf: &[u8],
) -> Poll<io::Result<usize>> {
self.cnt += 1;
if self.cnt == 2 {
return Poll::Ready(Err(io::Error::new(io::ErrorKind::Other, "whoops")));
}
Poll::Ready(Ok(4))
}
fn poll_flush(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<io::Result<()>> {
Ok(()).into()
}
fn poll_shutdown(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<io::Result<()>> {
Ok(()).into()
}
}
let mut wr = Wr { cnt: 0 };
let mut buf = Bytes::from_static(b"hello").chain(Bytes::from_static(b"world"));
assert_err!(wr.write_all_buf(&mut buf).await);
assert_eq!(
buf.copy_to_bytes(buf.remaining()),
Bytes::from_static(b"oworld")
);
}