diff options
Diffstat (limited to 'vendor/futures-util/src/io/sink.rs')
-rw-r--r-- | vendor/futures-util/src/io/sink.rs | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/vendor/futures-util/src/io/sink.rs b/vendor/futures-util/src/io/sink.rs new file mode 100644 index 000000000..4a32ca704 --- /dev/null +++ b/vendor/futures-util/src/io/sink.rs @@ -0,0 +1,67 @@ +use futures_core::task::{Context, Poll}; +use futures_io::{AsyncWrite, IoSlice}; +use std::fmt; +use std::io; +use std::pin::Pin; + +/// Writer for the [`sink()`] function. +#[must_use = "writers do nothing unless polled"] +pub struct Sink { + _priv: (), +} + +/// Creates an instance of a writer which will successfully consume all data. +/// +/// All calls to `poll_write` on the returned instance will return `Poll::Ready(Ok(buf.len()))` +/// and the contents of the buffer will not be inspected. +/// +/// # Examples +/// +/// ```rust +/// # futures::executor::block_on(async { +/// use futures::io::{self, AsyncWriteExt}; +/// +/// let buffer = vec![1, 2, 3, 5, 8]; +/// let mut writer = io::sink(); +/// let num_bytes = writer.write(&buffer).await?; +/// assert_eq!(num_bytes, 5); +/// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap(); +/// ``` +pub fn sink() -> Sink { + Sink { _priv: () } +} + +impl AsyncWrite 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_write_vectored( + self: Pin<&mut Self>, + _: &mut Context<'_>, + bufs: &[IoSlice<'_>], + ) -> Poll<io::Result<usize>> { + Poll::Ready(Ok(bufs.iter().map(|b| b.len()).sum())) + } + + #[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(())) + } +} + +impl fmt::Debug for Sink { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.pad("Sink { .. }") + } +} |