Struct tokio::io::util::mem::SimplexStream

pub struct SimplexStream {
    buffer: BytesMut,
    is_closed: bool,
    max_buf_size: usize,
    read_waker: Option<Waker>,
    write_waker: Option<Waker>,
}

A unidirectional pipe to read and write bytes in memory.

It can be constructed by simplex function which will create a pair of reader and writer or by calling SimplexStream::new_unsplit that will create a handle for both reading and writing.

Example

let (mut receiver, mut sender) = tokio::io::simplex(64);

sender.write_all(b"ping").await?;

let mut buf = [0u8; 4];
receiver.read_exact(&mut buf).await?;
assert_eq!(&buf, b"ping");

Fields

buffer: BytesMut

The buffer storing the bytes written, also read from.

Using a BytesMut because it has efficient Buf and BufMut functionality already. Additionally, it can try to copy data in the same buffer if there read index has advanced far enough.

is_closed: bool

Determines if the write side has been closed.

max_buf_size: usize

The maximum amount of bytes that can be written before returning Poll::Pending.

read_waker: Option<Waker>

If the read side has been polled and is pending, this is the waker for that parked task.

write_waker: Option<Waker>

If the write side has filled the max_buf_size and returned Poll::Pending, this is the waker for that parked task.

Implementations

impl SimplexStream

pub fn new_unsplit(max_buf_size: usize) -> SimplexStream

Creates unidirectional buffer that acts like in memory pipe. To create split version with separate reader and writer you can use simplex function.

The max_buf_size argument is the maximum amount of bytes that can be written to a buffer before the it returns Poll::Pending.

fn close_write(&mut self)

fn close_read(&mut self)

fn poll_read_internal( self: Pin<&mut Self>, cx: &mut Context<'_>, buf: &mut ReadBuf<'_>, ) -> Poll<Result<()>>

fn poll_write_internal( self: Pin<&mut Self>, cx: &mut Context<'_>, buf: &[u8], ) -> Poll<Result<usize>>

fn poll_write_vectored_internal( self: Pin<&mut Self>, cx: &mut Context<'_>, bufs: &[IoSlice<'_>], ) -> Poll<Result<usize, Error>>

Trait Implementations

impl AsyncRead for SimplexStream

fn poll_read( self: Pin<&mut Self>, cx: &mut Context<'_>, buf: &mut ReadBuf<'_>, ) -> Poll<Result<()>>

Attempts to read from the AsyncRead into buf.

impl AsyncWrite for SimplexStream

fn poll_write( self: Pin<&mut Self>, cx: &mut Context<'_>, buf: &[u8], ) -> Poll<Result<usize>>

Attempt to write bytes from buf into the object.

fn poll_write_vectored( self: Pin<&mut Self>, cx: &mut Context<'_>, bufs: &[IoSlice<'_>], ) -> Poll<Result<usize, Error>>

Like poll_write, except that it writes from a slice of buffers.

fn is_write_vectored(&self) -> bool

Determines if this writer has an efficient poll_write_vectored implementation.

fn poll_flush(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Result<()>>

Attempts to flush the object, ensuring that any buffered data reach their destination.

fn poll_shutdown(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Result<()>>

Initiates or attempts to shut down this writer, returning success when the I/O connection has completely shut down.

impl Debug for SimplexStream

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.