Struct tokio::runtime::io::registration::Registration

pub(crate) struct Registration {
    handle: Handle,
    shared: Arc<ScheduledIo>,
}

Associates an I/O resource with the reactor instance that drives it.

A registration represents an I/O resource registered with a Reactor such that it will receive task notifications on readiness. This is the lowest level API for integrating with a reactor.

The association between an I/O resource is made by calling new_with_interest_and_handle. Once the association is established, it remains established until the registration instance is dropped.

A registration instance represents two separate readiness streams. One for the read readiness and one for write readiness. These streams are independent and can be consumed from separate tasks.

Note: while Registration is Sync, the caller must ensure that there are at most two tasks that use a registration instance concurrently. One task for poll_read_ready and one task for poll_write_ready. While violating this requirement is “safe” from a Rust memory safety point of view, it will result in unexpected behavior in the form of lost notifications and tasks hanging.

Platform-specific events

Registration 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

handle: Handle

Handle to the associated runtime.

TODO: this can probably be moved into ScheduledIo.

shared: Arc<ScheduledIo>

Reference to state stored by the driver.

Implementations

impl Registration

pub(crate) fn new_with_interest_and_handle( io: &mut impl Source, interest: Interest, handle: Handle, ) -> Result<Registration>

Registers the I/O resource with the reactor for the provided handle, for a specific Interest. This does not add hup or error so if you are interested in those states, you will need to add them to the readiness state passed to this function.

Return

• Ok if the registration happened successfully
• Err if an error was encountered during registration

pub(crate) fn deregister(&mut self, io: &mut impl Source) -> Result<()>

Deregisters the I/O resource from the reactor it is associated with.

This function must be called before the I/O resource associated with the registration is dropped.

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.

Return

If the deregistration was successful, Ok is returned. Any calls to Reactor::turn that happen after a successful call to deregister will no longer result in notifications getting sent for this registration.

Err is returned if an error is encountered.

pub(crate) fn clear_readiness(&self, event: ReadyEvent)

pub(crate) fn poll_read_ready( &self, cx: &mut Context<'_>, ) -> Poll<Result<ReadyEvent>>

pub(crate) fn poll_write_ready( &self, cx: &mut Context<'_>, ) -> Poll<Result<ReadyEvent>>

pub(crate) fn poll_read_io<R>( &self, cx: &mut Context<'_>, f: impl FnMut() -> Result<R>, ) -> Poll<Result<R>>

pub(crate) fn poll_write_io<R>( &self, cx: &mut Context<'_>, f: impl FnMut() -> Result<R>, ) -> Poll<Result<R>>

fn poll_ready( &self, cx: &mut Context<'_>, direction: Direction, ) -> Poll<Result<ReadyEvent>>

Polls for events on the I/O resource’s direction readiness stream.

If called with a task context, notify the task when a new event is received.

fn poll_io<R>( &self, cx: &mut Context<'_>, direction: Direction, f: impl FnMut() -> Result<R>, ) -> Poll<Result<R>>

pub(crate) fn try_io<R>( &self, interest: Interest, f: impl FnOnce() -> Result<R>, ) -> Result<R>

pub(crate) async fn readiness(&self, interest: Interest) -> Result<ReadyEvent>

pub(crate) async fn async_io<R>( &self, interest: Interest, f: impl FnMut() -> Result<R>, ) -> Result<R>

fn handle(&self) -> &Handle

Trait Implementations

impl Debug for Registration

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

Formats the value using the given formatter.

impl Drop for Registration

fn drop(&mut self)

Executes the destructor for this type.

impl Send for Registration

impl Sync for Registration