Struct tokio_reactor::poll_evented::PollEvented[][src]

pub struct PollEvented<E: Evented> {
    io: Option<E>,
    inner: Inner,
}
Expand description

Associates an I/O resource that implements the std::io::Read and/or std::io::Write traits with the reactor that drives it.

PollEvented uses Registration internally to take a type that implements mio::Evented as well as std::io::Read and or std::io::Write and associate it with a reactor that will drive it.

Once the mio::Evented type is wrapped by PollEvented, it can be used from within the future’s execution model. As such, the PollEvented type provides AsyncRead and AsyncWrite implementations using the underlying I/O resource as well as readiness events provided by the reactor.

Note: While PollEvented is Sync (if the underlying I/O type is Sync), the caller must ensure that there are at most two tasks that use a PollEvented instance concurrently. One for reading and one for writing. While violating this requirement is “safe” from a Rust memory model point of view, it will result in unexpected behavior in the form of lost notifications and tasks hanging.

Readiness events

Besides just providing AsyncRead and AsyncWrite implementations, this type also supports access to the underlying readiness event stream. While similar in function to what Registration provides, the semantics are a bit different.

Two functions are provided to access the readiness events: poll_read_ready and poll_write_ready. These functions return the current readiness state of the PollEvented instance. If poll_read_ready indicates read readiness, immediately calling poll_read_ready again will also indicate read readiness.

When the operation is attempted and is unable to succeed due to the I/O resource not being ready, the caller must call clear_read_ready or clear_write_ready. This clears the readiness state until a new readiness event is received.

This allows the caller to implement additional functions. For example, TcpListener implements poll_accept by using poll_read_ready and clear_read_ready.

pub fn poll_accept(&mut self) -> Poll<(net::TcpStream, SocketAddr), io::Error> {
    let ready = Ready::readable();

    try_ready!(self.poll_evented.poll_read_ready(ready));

    match self.poll_evented.get_ref().accept_std() {
        Ok(pair) => Ok(Async::Ready(pair)),
        Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
            self.poll_evented.clear_read_ready(ready);
            Ok(Async::NotReady)
        }
        Err(e) => Err(e),
    }
}

Platform-specific events

PollEvented also allows receiving platform-specific mio::Ready events. These events are included as part of the read readiness event stream. The write readiness event stream is only for Ready::writable() events.

Fields

io: Option<E>inner: Inner

Implementations

Creates a new PollEvented associated with the default reactor.

Creates a new PollEvented associated with the specified reactor.

Returns a shared reference to the underlying I/O object this readiness stream is wrapping.

Returns a mutable reference to the underlying I/O object this readiness stream is wrapping.

Consumes self, returning the inner I/O object

This function will deregister the I/O resource from the reactor before returning. If the deregistration operation fails, an error is returned.

Note that deregistering does not guarantee that the I/O resource can be registered with a different reactor. Some I/O resource types can only be associated with a single reactor instance for their lifetime.

Check the I/O resource’s read readiness state.

The mask argument allows specifying what readiness to notify on. This can be any value, including platform specific readiness, except writable. HUP is always implicitly included on platforms that support it.

If the resource is not ready for a read then Async::NotReady is returned and the current task is notified once a new event is received.

The I/O resource will remain in a read-ready state until readiness is cleared by calling clear_read_ready.

Panics

This function panics if:

  • ready includes writable.
  • called from outside of a task context.

Clears the I/O resource’s read readiness state and registers the current task to be notified once a read readiness event is received.

After calling this function, poll_read_ready will return NotReady until a new read readiness event has been received.

The mask argument specifies the readiness bits to clear. This may not include writable or hup.

Panics

This function panics if:

  • ready includes writable or HUP
  • called from outside of a task context.

Check the I/O resource’s write readiness state.

This always checks for writable readiness and also checks for HUP readiness on platforms that support it.

If the resource is not ready for a write then Async::NotReady is returned and the current task is notified once a new event is received.

The I/O resource will remain in a write-ready state until readiness is cleared by calling clear_write_ready.

Panics

This function panics if:

  • ready contains bits besides writable and hup.
  • called from outside of a task context.

Resets the I/O resource’s write readiness state and registers the current task to be notified once a write readiness event is received.

This only clears writable readiness. HUP (on platforms that support HUP) cannot be cleared as it is a final state.

After calling this function, poll_write_ready(Ready::writable()) will return NotReady until a new write readiness event has been received.

Panics

This function will panic if called from outside of a task context.

Ensure that the I/O resource is registered with the reactor.

Trait Implementations

Prepares an uninitialized buffer to be safe to pass to read. Returns true if the supplied buffer was zeroed out. Read more

Attempt to read from the AsyncRead into buf. Read more

Pull some bytes from this source into the specified BufMut, returning how many bytes were read. Read more

👎 Deprecated since 0.1.7:

Use tokio_codec::Decoder::framed instead

Provides a Stream and Sink interface for reading and writing to this I/O object, using Decode and Encode to read and write the raw data. Read more

Helper method for splitting this read/write object into two halves. Read more

Prepares an uninitialized buffer to be safe to pass to read. Returns true if the supplied buffer was zeroed out. Read more

Attempt to read from the AsyncRead into buf. Read more

Pull some bytes from this source into the specified BufMut, returning how many bytes were read. Read more

👎 Deprecated since 0.1.7:

Use tokio_codec::Decoder::framed instead

Provides a Stream and Sink interface for reading and writing to this I/O object, using Decode and Encode to read and write the raw data. Read more

Helper method for splitting this read/write object into two halves. Read more

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

Attempt to write bytes from buf into the object. Read more

Attempt to flush the object, ensuring that any buffered data reach their destination. Read more

Write a Buf into this value, returning how many bytes were written. Read more

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

Attempt to write bytes from buf into the object. Read more

Attempt to flush the object, ensuring that any buffered data reach their destination. Read more

Write a Buf into this value, returning how many bytes were written. Read more

Formats the value using the given formatter. Read more

Executes the destructor for this type. Read more

Pull some bytes from this source into the specified buffer, returning how many bytes were read. Read more

Like read, except that it reads into a slice of buffers. Read more

🔬 This is a nightly-only experimental API. (can_vector)

Determines if this Reader has an efficient read_vectored implementation. Read more

🔬 This is a nightly-only experimental API. (read_initializer)

Determines if this Reader can work with buffers of uninitialized memory. Read more

Read all bytes until EOF in this source, placing them into buf. Read more

Read all bytes until EOF in this source, appending them to buf. Read more

Read the exact number of bytes required to fill buf. Read more

Creates a “by reference” adapter for this instance of Read. Read more

Transforms this Read instance to an Iterator over its bytes. Read more

Creates an adapter which will chain this stream with another. Read more

Creates an adapter which will read at most limit bytes from it. Read more

Pull some bytes from this source into the specified buffer, returning how many bytes were read. Read more

Like read, except that it reads into a slice of buffers. Read more

🔬 This is a nightly-only experimental API. (can_vector)

Determines if this Reader has an efficient read_vectored implementation. Read more

🔬 This is a nightly-only experimental API. (read_initializer)

Determines if this Reader can work with buffers of uninitialized memory. Read more

Read all bytes until EOF in this source, placing them into buf. Read more

Read all bytes until EOF in this source, appending them to buf. Read more

Read the exact number of bytes required to fill buf. Read more

Creates a “by reference” adapter for this instance of Read. Read more

Transforms this Read instance to an Iterator over its bytes. Read more

Creates an adapter which will chain this stream with another. Read more

Creates an adapter which will read at most limit bytes from it. Read more

Write a buffer into this writer, returning how many bytes were written. Read more

Flush this output stream, ensuring that all intermediately buffered contents reach their destination. Read more

Like write, except that it writes from a slice of buffers. Read more

🔬 This is a nightly-only experimental API. (can_vector)

Determines if this Writer has an efficient write_vectored implementation. Read more

Attempts to write an entire buffer into this writer. Read more

🔬 This is a nightly-only experimental API. (write_all_vectored)

Attempts to write multiple buffers into this writer. Read more

Writes a formatted string into this writer, returning any error encountered. Read more

Creates a “by reference” adapter for this instance of Write. Read more

Write a buffer into this writer, returning how many bytes were written. Read more

Flush this output stream, ensuring that all intermediately buffered contents reach their destination. Read more

Like write, except that it writes from a slice of buffers. Read more

🔬 This is a nightly-only experimental API. (can_vector)

Determines if this Writer has an efficient write_vectored implementation. Read more

Attempts to write an entire buffer into this writer. Read more

🔬 This is a nightly-only experimental API. (write_all_vectored)

Attempts to write multiple buffers into this writer. Read more

Writes a formatted string into this writer, returning any error encountered. Read more

Creates a “by reference” adapter for this instance of Write. Read more

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Performs the conversion.

Performs the conversion.

Reads an unsigned 8 bit integer from the underlying reader. Read more

Reads a signed 8 bit integer from the underlying reader. Read more

Reads an unsigned 16 bit integer from the underlying reader. Read more

Reads a signed 16 bit integer from the underlying reader. Read more

Reads an unsigned 24 bit integer from the underlying reader. Read more

Reads a signed 24 bit integer from the underlying reader. Read more

Reads an unsigned 32 bit integer from the underlying reader. Read more

Reads a signed 32 bit integer from the underlying reader. Read more

Reads an unsigned 48 bit integer from the underlying reader. Read more

Reads a signed 48 bit integer from the underlying reader. Read more

Reads an unsigned 64 bit integer from the underlying reader. Read more

Reads a signed 64 bit integer from the underlying reader. Read more

Reads an unsigned 128 bit integer from the underlying reader. Read more

Reads a signed 128 bit integer from the underlying reader. Read more

Reads an unsigned n-bytes integer from the underlying reader. Read more

Reads a signed n-bytes integer from the underlying reader. Read more

Reads an unsigned n-bytes integer from the underlying reader.

Reads a signed n-bytes integer from the underlying reader.

Reads a IEEE754 single-precision (4 bytes) floating point number from the underlying reader. Read more

Reads a IEEE754 double-precision (8 bytes) floating point number from the underlying reader. Read more

Reads a sequence of unsigned 16 bit integers from the underlying reader. Read more

Reads a sequence of unsigned 32 bit integers from the underlying reader. Read more

Reads a sequence of unsigned 64 bit integers from the underlying reader. Read more

Reads a sequence of unsigned 128 bit integers from the underlying reader. Read more

Reads a sequence of signed 8 bit integers from the underlying reader. Read more

Reads a sequence of signed 16 bit integers from the underlying reader. Read more

Reads a sequence of signed 32 bit integers from the underlying reader. Read more

Reads a sequence of signed 64 bit integers from the underlying reader. Read more

Reads a sequence of signed 128 bit integers from the underlying reader. Read more

Reads a sequence of IEEE754 single-precision (4 bytes) floating point numbers from the underlying reader. Read more

👎 Deprecated since 1.2.0:

please use read_f32_into instead

DEPRECATED. Read more

Reads a sequence of IEEE754 double-precision (8 bytes) floating point numbers from the underlying reader. Read more

👎 Deprecated since 1.2.0:

please use read_f64_into instead

DEPRECATED. Read more

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.

Writes an unsigned 8 bit integer to the underlying writer. Read more

Writes a signed 8 bit integer to the underlying writer. Read more

Writes an unsigned 16 bit integer to the underlying writer. Read more

Writes a signed 16 bit integer to the underlying writer. Read more

Writes an unsigned 24 bit integer to the underlying writer. Read more

Writes a signed 24 bit integer to the underlying writer. Read more

Writes an unsigned 32 bit integer to the underlying writer. Read more

Writes a signed 32 bit integer to the underlying writer. Read more

Writes an unsigned 48 bit integer to the underlying writer. Read more

Writes a signed 48 bit integer to the underlying writer. Read more

Writes an unsigned 64 bit integer to the underlying writer. Read more

Writes a signed 64 bit integer to the underlying writer. Read more

Writes an unsigned 128 bit integer to the underlying writer.

Writes a signed 128 bit integer to the underlying writer.

Writes an unsigned n-bytes integer to the underlying writer. Read more

Writes a signed n-bytes integer to the underlying writer. Read more

Writes an unsigned n-bytes integer to the underlying writer. Read more

Writes a signed n-bytes integer to the underlying writer. Read more

Writes a IEEE754 single-precision (4 bytes) floating point number to the underlying writer. Read more

Writes a IEEE754 double-precision (8 bytes) floating point number to the underlying writer. Read more