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
52
53
54
55
56
57
58
59
60
61

use std::fmt;
use std::pin::Pin;

use crate::io::{self, Write};
use crate::task::{Context, Poll};

/// Creates a writer that consumes and drops all data.

///

/// # Examples

///

/// ```rust

/// # fn main() -> std::io::Result<()> { async_std::task::block_on(async {

/// #

/// use async_std::io;

/// use async_std::prelude::*;

///

/// let mut writer = io::sink();

/// writer.write(b"hello world").await?;

/// #

/// # Ok(()) }) }

/// ```

pub fn sink() -> Sink {
    Sink { _private: () }
}

/// A writer that consumes and drops all data.

///

/// This writer is constructed by the [`sink`] function. See its documentation

/// for more.

///

/// [`sink`]: fn.sink.html

pub struct Sink {
    _private: (),
}

impl fmt::Debug for Sink {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.pad("Sink { .. }")
    }
}

impl Write for Sink {
    #[inline]
    fn poll_write(
        self: Pin<&mut Self>,
        _: &mut Context<'_>,
        buf: &[u8],
    ) -> Poll<io::Result<usize>> {
        Poll::Ready(Ok(buf.len()))
    }

    #[inline]
    fn poll_flush(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<io::Result<()>> {
        Poll::Ready(Ok(()))
    }

    #[inline]
    fn poll_close(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<io::Result<()>> {
        Poll::Ready(Ok(()))
    }
}