File: io_write_all.rs

package info (click to toggle)
rustc-web 1.78.0%2Bdfsg1-2~deb12u3
  • links: PTS, VCS
  • area: main
  • in suites: bookworm
  • size: 1,245,420 kB
  • sloc: xml: 147,985; javascript: 18,022; sh: 11,083; python: 10,265; ansic: 6,172; cpp: 5,023; asm: 4,390; makefile: 4,269
file content (51 lines) | stat: -rw-r--r-- 1,184 bytes parent folder | download | duplicates (51)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
#![warn(rust_2018_idioms)]
#![cfg(feature = "full")]

use tokio::io::{AsyncWrite, AsyncWriteExt};
use tokio_test::assert_ok;

use bytes::BytesMut;
use std::cmp;
use std::io;
use std::pin::Pin;
use std::task::{Context, Poll};

#[tokio::test]
async fn write_all() {
    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());
            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,
    };

    assert_ok!(wr.write_all(b"hello world").await);
    assert_eq!(wr.buf, b"hello world"[..]);
    assert_eq!(wr.cnt, 3);
}