Trait polkadot_node_subsystem::gen::futures::prelude::AsyncWrite
pub trait AsyncWrite {
// Required methods
fn poll_write(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &[u8],
) -> Poll<Result<usize, Error>>;
fn poll_flush(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Result<(), Error>>;
fn poll_close(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Result<(), Error>>;
// Provided method
fn poll_write_vectored(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
bufs: &[IoSlice<'_>],
) -> Poll<Result<usize, Error>> { ... }
}
Expand description
Write bytes asynchronously.
This trait is analogous to the std::io::Write
trait, but integrates
with the asynchronous task system. In particular, the poll_write
method, unlike Write::write
, will automatically queue the current task
for wakeup and return if the writer cannot take more data, rather than blocking
the calling thread.
Required Methods§
fn poll_write(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &[u8],
) -> Poll<Result<usize, Error>>
fn poll_write( self: Pin<&mut Self>, cx: &mut Context<'_>, buf: &[u8], ) -> Poll<Result<usize, Error>>
Attempt to write bytes from buf
into the object.
On success, returns Poll::Ready(Ok(num_bytes_written))
.
If the object is not ready for writing, 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
writable 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.
poll_write
must try to make progress by flushing the underlying object if
that is the only way the underlying object can become writable again.
fn poll_flush(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Result<(), Error>>
fn poll_flush( self: Pin<&mut Self>, cx: &mut Context<'_>, ) -> Poll<Result<(), Error>>
Attempt to flush the object, ensuring that any buffered data reach their destination.
On success, returns Poll::Ready(Ok(()))
.
If flushing cannot immediately complete, this method returns
Poll::Pending
and arranges for the current task (via
cx.waker().wake_by_ref()
) to receive a notification when the object can make
progress towards flushing.
§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.
It only makes sense to do anything here if you actually buffer data.
fn poll_close(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Result<(), Error>>
fn poll_close( self: Pin<&mut Self>, cx: &mut Context<'_>, ) -> Poll<Result<(), Error>>
Attempt to close the object.
On success, returns Poll::Ready(Ok(()))
.
If closing cannot immediately complete, this function returns
Poll::Pending
and arranges for the current task (via
cx.waker().wake_by_ref()
) to receive a notification when the object can make
progress towards closing.
§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_write_vectored(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
bufs: &[IoSlice<'_>],
) -> Poll<Result<usize, Error>>
fn poll_write_vectored( self: Pin<&mut Self>, cx: &mut Context<'_>, bufs: &[IoSlice<'_>], ) -> Poll<Result<usize, Error>>
Attempt to write bytes from bufs
into the object using vectored
IO operations.
This method is similar to poll_write
, but allows data from multiple buffers to be written
using a single operation.
On success, returns Poll::Ready(Ok(num_bytes_written))
.
If the object is not ready for writing, 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
writable or is closed.
By default, this method delegates to using poll_write
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 AsyncWrite for Vec<u8>
impl AsyncWrite for Vec<u8>
fn poll_write( self: Pin<&mut Vec<u8>>, _: &mut Context<'_>, buf: &[u8], ) -> Poll<Result<usize, Error>>
fn poll_write_vectored( self: Pin<&mut Vec<u8>>, _: &mut Context<'_>, bufs: &[IoSlice<'_>], ) -> Poll<Result<usize, Error>>
fn poll_flush( self: Pin<&mut Vec<u8>>, _: &mut Context<'_>, ) -> Poll<Result<(), Error>>
fn poll_close( self: Pin<&mut Vec<u8>>, cx: &mut Context<'_>, ) -> Poll<Result<(), Error>>
§impl AsyncWrite for DummyStream
impl AsyncWrite for DummyStream
§impl AsyncWrite for Stream
impl AsyncWrite for Stream
fn poll_write( self: Pin<&mut Stream>, cx: &mut Context<'_>, buf: &[u8], ) -> Poll<Result<usize, Error>>
fn poll_write_vectored( self: Pin<&mut Stream>, cx: &mut Context<'_>, bufs: &[IoSlice<'_>], ) -> Poll<Result<usize, Error>>
fn poll_flush( self: Pin<&mut Stream>, cx: &mut Context<'_>, ) -> Poll<Result<(), Error>>
fn poll_close( self: Pin<&mut Stream>, cx: &mut Context<'_>, ) -> Poll<Result<(), Error>>
§impl AsyncWrite for Stream
impl AsyncWrite for Stream
fn poll_write( self: Pin<&mut Stream>, cx: &mut Context<'_>, buf: &[u8], ) -> Poll<Result<usize, Error>>
fn poll_write_vectored( self: Pin<&mut Stream>, cx: &mut Context<'_>, bufs: &[IoSlice<'_>], ) -> Poll<Result<usize, Error>>
fn poll_flush( self: Pin<&mut Stream>, cx: &mut Context<'_>, ) -> Poll<Result<(), Error>>
fn poll_close( self: Pin<&mut Stream>, cx: &mut Context<'_>, ) -> Poll<Result<(), Error>>
§impl AsyncWrite for Stream
impl AsyncWrite for Stream
§impl AsyncWrite for Stream
impl AsyncWrite for Stream
§impl AsyncWrite for Stream
impl AsyncWrite for Stream
§impl AsyncWrite for SubstreamBox
impl AsyncWrite for SubstreamBox
fn poll_write( self: Pin<&mut SubstreamBox>, cx: &mut Context<'_>, buf: &[u8], ) -> Poll<Result<usize, Error>>
fn poll_write_vectored( self: Pin<&mut SubstreamBox>, cx: &mut Context<'_>, bufs: &[IoSlice<'_>], ) -> Poll<Result<usize, Error>>
fn poll_flush( self: Pin<&mut SubstreamBox>, cx: &mut Context<'_>, ) -> Poll<Result<(), Error>>
fn poll_close( self: Pin<&mut SubstreamBox>, cx: &mut Context<'_>, ) -> Poll<Result<(), Error>>
§impl AsyncWrite for TcpStream
impl AsyncWrite for TcpStream
fn poll_write( self: Pin<&mut TcpStream>, cx: &mut Context<'_>, buf: &[u8], ) -> Poll<Result<usize, Error>>
fn poll_flush( self: Pin<&mut TcpStream>, cx: &mut Context<'_>, ) -> Poll<Result<(), Error>>
fn poll_close( self: Pin<&mut TcpStream>, cx: &mut Context<'_>, ) -> Poll<Result<(), Error>>
fn poll_write_vectored( self: Pin<&mut TcpStream>, cx: &mut Context<'_>, bufs: &[IoSlice<'_>], ) -> Poll<Result<usize, Error>>
§impl<IO> AsyncWrite for TlsStream<IO>
impl<IO> AsyncWrite for TlsStream<IO>
§fn poll_write(
self: Pin<&mut TlsStream<IO>>,
cx: &mut Context<'_>,
buf: &[u8],
) -> Poll<Result<usize, Error>>
fn poll_write( self: Pin<&mut TlsStream<IO>>, cx: &mut Context<'_>, buf: &[u8], ) -> Poll<Result<usize, Error>>
Note: that it does not guarantee the final data to be sent.
To be cautious, you must manually call flush
.
fn poll_write_vectored( self: Pin<&mut TlsStream<IO>>, cx: &mut Context<'_>, bufs: &[IoSlice<'_>], ) -> Poll<Result<usize, Error>>
fn poll_flush( self: Pin<&mut TlsStream<IO>>, cx: &mut Context<'_>, ) -> Poll<Result<(), Error>>
fn poll_close( self: Pin<&mut TlsStream<IO>>, cx: &mut Context<'_>, ) -> Poll<Result<(), Error>>
§impl<IO> AsyncWrite for TlsStream<IO>
impl<IO> AsyncWrite for TlsStream<IO>
§fn poll_write(
self: Pin<&mut TlsStream<IO>>,
cx: &mut Context<'_>,
buf: &[u8],
) -> Poll<Result<usize, Error>>
fn poll_write( self: Pin<&mut TlsStream<IO>>, cx: &mut Context<'_>, buf: &[u8], ) -> Poll<Result<usize, Error>>
Note: that it does not guarantee the final data to be sent.
To be cautious, you must manually call flush
.