diff options
Diffstat (limited to 'third_party/rust/futures-util/src/io/read_until.rs')
-rw-r--r-- | third_party/rust/futures-util/src/io/read_until.rs | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/third_party/rust/futures-util/src/io/read_until.rs b/third_party/rust/futures-util/src/io/read_until.rs new file mode 100644 index 0000000000..72b59eab13 --- /dev/null +++ b/third_party/rust/futures-util/src/io/read_until.rs @@ -0,0 +1,60 @@ +use futures_core::future::Future; +use futures_core::ready; +use futures_core::task::{Context, Poll}; +use futures_io::AsyncBufRead; +use std::io; +use std::mem; +use std::pin::Pin; + +/// Future for the [`read_until`](super::AsyncBufReadExt::read_until) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct ReadUntil<'a, R: ?Sized> { + reader: &'a mut R, + byte: u8, + buf: &'a mut Vec<u8>, + read: usize, +} + +impl<R: ?Sized + Unpin> Unpin for ReadUntil<'_, R> {} + +impl<'a, R: AsyncBufRead + ?Sized + Unpin> ReadUntil<'a, R> { + pub(super) fn new(reader: &'a mut R, byte: u8, buf: &'a mut Vec<u8>) -> Self { + Self { reader, byte, buf, read: 0 } + } +} + +pub(super) fn read_until_internal<R: AsyncBufRead + ?Sized>( + mut reader: Pin<&mut R>, + cx: &mut Context<'_>, + byte: u8, + buf: &mut Vec<u8>, + read: &mut usize, +) -> Poll<io::Result<usize>> { + loop { + let (done, used) = { + let available = ready!(reader.as_mut().poll_fill_buf(cx))?; + if let Some(i) = memchr::memchr(byte, available) { + buf.extend_from_slice(&available[..=i]); + (true, i + 1) + } else { + buf.extend_from_slice(available); + (false, available.len()) + } + }; + reader.as_mut().consume(used); + *read += used; + if done || used == 0 { + return Poll::Ready(Ok(mem::replace(read, 0))); + } + } +} + +impl<R: AsyncBufRead + ?Sized + Unpin> Future for ReadUntil<'_, R> { + type Output = io::Result<usize>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let Self { reader, byte, buf, read } = &mut *self; + read_until_internal(Pin::new(reader), cx, *byte, buf, read) + } +} |