Sha256: a3623e037db59efab227a769698098597f1b531a75b6c045e75f068c0137c738
Contents?: true
Size: 1.52 KB
Versions: 20
Compression:
Stored size: 1.52 KB
Contents
use futures_core::future::Future;
use futures_core::task::{Context, Poll};
use futures_io::AsyncBufRead;
use std::io;
use std::pin::Pin;
use std::slice;
/// 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 {
Self { 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) {
Poll::Ready(Ok(slice)) => {
// With polonius it is possible to remove this lifetime transmutation and just have
// the correct lifetime of the reference inferred based on which branch is taken
let slice: &'a [u8] = unsafe { slice::from_raw_parts(slice.as_ptr(), slice.len()) };
Poll::Ready(Ok(slice))
}
Poll::Ready(Err(err)) => Poll::Ready(Err(err)),
Poll::Pending => {
this.reader = Some(reader);
Poll::Pending
}
}
}
}
Version data entries
20 entries across 20 versions & 1 rubygems