Trait futures_io::AsyncRead [−][src]
Read bytes asynchronously.
This trait is analogous to the std::io::Read
trait, but integrates
with the asynchronous task system. In particular, the poll_read
method, unlike Read::read
, will automatically queue the current task
for wakeup and return if data is not yet available, rather than blocking
the calling thread.
Required methods
fn poll_read(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut [u8]
) -> Poll<Result<usize>>
[src]
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut [u8]
) -> Poll<Result<usize>>
Attempt to read from the AsyncRead
into buf
.
On success, returns Poll::Ready(Ok(num_bytes_read))
.
If no data is available for reading, the method returns
Poll::Pending
and arranges for the current task (via
cx.waker().wake_by_ref()
) to receive a notification when the object becomes
readable or is closed.
Implementation
This function may not return errors of kind WouldBlock
or
Interrupted
. Implementations must convert WouldBlock
into
Poll::Pending
and either internally retry or convert
Interrupted
into another error kind.
Provided methods
fn poll_read_vectored(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
bufs: &mut [IoSliceMut<'_>]
) -> Poll<Result<usize>>
[src]
self: Pin<&mut Self>,
cx: &mut Context<'_>,
bufs: &mut [IoSliceMut<'_>]
) -> Poll<Result<usize>>
Attempt to read from the AsyncRead
into bufs
using vectored
IO operations.
This method is similar to poll_read
, but allows data to be read
into multiple buffers using a single operation.
On success, returns Poll::Ready(Ok(num_bytes_read))
.
If no data is available for reading, the method returns
Poll::Pending
and arranges for the current task (via
cx.waker().wake_by_ref()
) to receive a notification when the object becomes
readable or is closed.
By default, this method delegates to using poll_read
on the first
nonempty buffer in bufs
, or an empty one if none exists. Objects which
support vectored IO should override this method.
Implementation
This function may not return errors of kind WouldBlock
or
Interrupted
. Implementations must convert WouldBlock
into
Poll::Pending
and either internally retry or convert
Interrupted
into another error kind.
Implementations on Foreign Types
impl<T: ?Sized + AsyncRead + Unpin> AsyncRead for Box<T>
[src]
fn poll_read(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut [u8]
) -> Poll<Result<usize>>
[src]
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut [u8]
) -> Poll<Result<usize>>
fn poll_read_vectored(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
bufs: &mut [IoSliceMut<'_>]
) -> Poll<Result<usize>>
[src]
self: Pin<&mut Self>,
cx: &mut Context<'_>,
bufs: &mut [IoSliceMut<'_>]
) -> Poll<Result<usize>>
impl<T: ?Sized + AsyncRead + Unpin> AsyncRead for &mut T
[src]
fn poll_read(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut [u8]
) -> Poll<Result<usize>>
[src]
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut [u8]
) -> Poll<Result<usize>>
fn poll_read_vectored(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
bufs: &mut [IoSliceMut<'_>]
) -> Poll<Result<usize>>
[src]
self: Pin<&mut Self>,
cx: &mut Context<'_>,
bufs: &mut [IoSliceMut<'_>]
) -> Poll<Result<usize>>
impl<P> AsyncRead for Pin<P> where
P: DerefMut + Unpin,
P::Target: AsyncRead,
[src]
P: DerefMut + Unpin,
P::Target: AsyncRead,
fn poll_read(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut [u8]
) -> Poll<Result<usize>>
[src]
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut [u8]
) -> Poll<Result<usize>>
fn poll_read_vectored(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
bufs: &mut [IoSliceMut<'_>]
) -> Poll<Result<usize>>
[src]
self: Pin<&mut Self>,
cx: &mut Context<'_>,
bufs: &mut [IoSliceMut<'_>]
) -> Poll<Result<usize>>
impl AsyncRead for &[u8]
[src]
fn poll_read(
self: Pin<&mut Self>,
_: &mut Context<'_>,
buf: &mut [u8]
) -> Poll<Result<usize>>
[src]
self: Pin<&mut Self>,
_: &mut Context<'_>,
buf: &mut [u8]
) -> Poll<Result<usize>>
fn poll_read_vectored(
self: Pin<&mut Self>,
_: &mut Context<'_>,
bufs: &mut [IoSliceMut<'_>]
) -> Poll<Result<usize>>
[src]
self: Pin<&mut Self>,
_: &mut Context<'_>,
bufs: &mut [IoSliceMut<'_>]
) -> Poll<Result<usize>>