-
Notifications
You must be signed in to change notification settings - Fork 620
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Add AsyncBufReadExt::fill_buf (#2225)
- Loading branch information
Showing
3 changed files
with
107 additions
and
2 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,50 @@ | ||
use futures_core::future::Future; | ||
use futures_core::task::{Context, Poll}; | ||
use futures_io::AsyncBufRead; | ||
use std::io; | ||
use std::pin::Pin; | ||
|
||
/// Future for the [`fill_buf`](super::AsyncBufReadExt::fill_buf) method. | ||
#[derive(Debug)] | ||
#[must_use = "futures do nothing unless you `.await` or poll them"] | ||
pub struct FillBuf<'a, R: ?Sized> { | ||
reader: Option<&'a mut R>, | ||
} | ||
|
||
impl<R: ?Sized> Unpin for FillBuf<'_, R> {} | ||
|
||
impl<'a, R: AsyncBufRead + ?Sized + Unpin> FillBuf<'a, R> { | ||
pub(super) fn new(reader: &'a mut R) -> Self { | ||
FillBuf { reader: Some(reader) } | ||
} | ||
} | ||
|
||
impl<'a, R> Future for FillBuf<'a, R> | ||
where R: AsyncBufRead + ?Sized + Unpin, | ||
{ | ||
type Output = io::Result<&'a [u8]>; | ||
|
||
fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { | ||
let this = &mut *self; | ||
let reader = this.reader.take().expect("Polled FillBuf after completion"); | ||
|
||
match Pin::new(&mut *reader).poll_fill_buf(cx) { | ||
// With polinius it is possible to remove this inner match and just have the correct | ||
// lifetime of the reference inferred based on which branch is taken | ||
Poll::Ready(Ok(_)) => match Pin::new(reader).poll_fill_buf(cx) { | ||
Poll::Ready(Ok(slice)) => Poll::Ready(Ok(slice)), | ||
Poll::Ready(Err(err)) => { | ||
unreachable!("reader indicated readiness but then returned an error: {:?}", err) | ||
} | ||
Poll::Pending => { | ||
unreachable!("reader indicated readiness but then returned pending") | ||
} | ||
}, | ||
Poll::Ready(Err(err)) => Poll::Ready(Err(err)), | ||
Poll::Pending => { | ||
this.reader = Some(reader); | ||
Poll::Pending | ||
} | ||
} | ||
} | ||
} |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters