diff options
Diffstat (limited to 'vendor/futures-util/src/io/read_exact.rs')
-rw-r--r-- | vendor/futures-util/src/io/read_exact.rs | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/vendor/futures-util/src/io/read_exact.rs b/vendor/futures-util/src/io/read_exact.rs new file mode 100644 index 000000000..02e38c35b --- /dev/null +++ b/vendor/futures-util/src/io/read_exact.rs @@ -0,0 +1,42 @@ +use crate::io::AsyncRead; +use futures_core::future::Future; +use futures_core::ready; +use futures_core::task::{Context, Poll}; +use std::io; +use std::mem; +use std::pin::Pin; + +/// Future for the [`read_exact`](super::AsyncReadExt::read_exact) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct ReadExact<'a, R: ?Sized> { + reader: &'a mut R, + buf: &'a mut [u8], +} + +impl<R: ?Sized + Unpin> Unpin for ReadExact<'_, R> {} + +impl<'a, R: AsyncRead + ?Sized + Unpin> ReadExact<'a, R> { + pub(super) fn new(reader: &'a mut R, buf: &'a mut [u8]) -> Self { + Self { reader, buf } + } +} + +impl<R: AsyncRead + ?Sized + Unpin> Future for ReadExact<'_, R> { + type Output = io::Result<()>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let this = &mut *self; + while !this.buf.is_empty() { + let n = ready!(Pin::new(&mut this.reader).poll_read(cx, this.buf))?; + { + let (_, rest) = mem::replace(&mut this.buf, &mut []).split_at_mut(n); + this.buf = rest; + } + if n == 0 { + return Poll::Ready(Err(io::ErrorKind::UnexpectedEof.into())); + } + } + Poll::Ready(Ok(())) + } +} |