diff options
Diffstat (limited to 'vendor/tokio/src/io/util/write_buf.rs')
-rw-r--r-- | vendor/tokio/src/io/util/write_buf.rs | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/vendor/tokio/src/io/util/write_buf.rs b/vendor/tokio/src/io/util/write_buf.rs new file mode 100644 index 000000000..82fd7a759 --- /dev/null +++ b/vendor/tokio/src/io/util/write_buf.rs @@ -0,0 +1,55 @@ +use crate::io::AsyncWrite; + +use bytes::Buf; +use pin_project_lite::pin_project; +use std::future::Future; +use std::io; +use std::marker::PhantomPinned; +use std::pin::Pin; +use std::task::{Context, Poll}; + +pin_project! { + /// A future to write some of the buffer to an `AsyncWrite`. + #[derive(Debug)] + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub struct WriteBuf<'a, W, B> { + writer: &'a mut W, + buf: &'a mut B, + #[pin] + _pin: PhantomPinned, + } +} + +/// Tries to write some bytes from the given `buf` to the writer in an +/// asynchronous manner, returning a future. +pub(crate) fn write_buf<'a, W, B>(writer: &'a mut W, buf: &'a mut B) -> WriteBuf<'a, W, B> +where + W: AsyncWrite + Unpin, + B: Buf, +{ + WriteBuf { + writer, + buf, + _pin: PhantomPinned, + } +} + +impl<W, B> Future for WriteBuf<'_, W, B> +where + W: AsyncWrite + Unpin, + B: Buf, +{ + type Output = io::Result<usize>; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<usize>> { + let me = self.project(); + + if !me.buf.has_remaining() { + return Poll::Ready(Ok(0)); + } + + let n = ready!(Pin::new(me.writer).poll_write(cx, me.buf.chunk()))?; + me.buf.advance(n); + Poll::Ready(Ok(n)) + } +} |