Trait fuchsia_async::ReadableHandle

pub trait ReadableHandle {
    // Required methods
    fn poll_readable(
        &self,
        cx: &mut Context<'_>
    ) -> Poll<Result<ReadableState, Status>>;
    fn need_readable(&self, cx: &mut Context<'_>) -> Result<(), Status>;
}

A Handle that receives notifications when it is readable.

Examples

ready!(self.poll_readable(cx))?;
match /* make read syscall */ {
    Err(zx::Status::SHOULD_WAIT) => {
        self.need_readable(cx)?;
        Poll::Pending
    }
    status => Poll::Ready(status),
}

Required Methods

fn poll_readable( &self, cx: &mut Context<'_> ) -> Poll<Result<ReadableState, Status>>

If the object is ready for reading, returns Ready with the readable state. If the implementor returns Pending, it should first ensure that need_readable is called.

This should be called in a poll function before making a read syscall. If the syscall returns SHOULD_WAIT, you must call need_readable to schedule wakeup when the object is readable.

The returned ReadableState does not necessarily reflect an observed OBJECT_READABLE signal. We optimistically assume the object remains readable until need_readable is called. If you only want to read once the object is confirmed to be readable, call need_readable with a no-op waker before the first poll.

fn need_readable(&self, cx: &mut Context<'_>) -> Result<(), Status>

Arranges for the current task to be woken when the object receives an OBJECT_READABLE or OBJECT_PEER_CLOSED signal.

Implementors

impl ReadableHandle for Socket

impl<T> ReadableHandle for RWHandle<T>where T: AsHandleRef,