Struct DispatcherOperation 

pub struct DispatcherOperation<R = ()> { /* private fields */ }

Represents an object used to interact with a job that has been posted to the Dispatcher queue.

The handle can be cloned and sent to other threads. It is also a Future that resolves when the operation has completed (Ok(result)) or has been aborted (Err(OperationCanceledError)).

A panic raised by the callback is the equivalent of an exception in the reference implementation: it is captured when the callback runs and re-raised by wait, result and when the future is polled.

Implementations

impl<R: 'static> DispatcherOperation<R>

pub fn status(&self) -> DispatcherOperationStatus

The current status of the operation.

pub fn dispatcher(&self) -> &Arc<Dispatcher>

The dispatcher the operation was queued on.

pub fn priority(&self) -> DispatcherPriority

pub fn set_priority(&self, value: DispatcherPriority)

Changes the priority of the operation. A queued operation keeps its position relative to the other operations of the new priority.

pub fn aborted( &self, handler: impl Fn() + Send + Sync + 'static, ) -> Rc<dyn IDisposable>

An event that is raised when the operation is aborted or canceled.

The handler runs on the thread that aborts the operation.

pub fn completed( &self, handler: impl Fn() + Send + Sync + 'static, ) -> Rc<dyn IDisposable>

An event that is raised when the operation completes.

The handler runs on the dispatcher thread.

pub fn abort(&self) -> bool

Removes a pending operation from the queue. Returns false when the operation is no longer pending.

pub fn wait(&self) -> Result<(), OperationCanceledError>

Waits for this operation to complete.

On the dispatcher thread this pumps the queue (nesting a frame when the operation has a background priority and the platform supports run loops). On any other thread it blocks.

Returns Err when the operation was aborted.

Panics

Re-raises the panic of the callback. Panics when called on the dispatcher thread for the operation that is currently executing.

pub fn wait_with_timeout( &self, timeout: Duration, ) -> Result<bool, OperationCanceledError>

Waits for this operation to complete, for at most timeout.

Returns Ok(true) when the operation completed in time, Ok(false) when it is still pending or executing after timeout, and Err when it was aborted.

On the dispatcher thread this pumps the queue like wait and measures the timeout with the dispatcher clock; a nested frame (background priorities, where the platform supports run loops) is left by a dispatcher timer. On any other thread it blocks. A zero timeout only reports the current state.

Panics

Re-raises the panic of the callback. Panics when called on the dispatcher thread for the operation that is currently executing.

pub fn result(&self) -> Result<R, OperationCanceledError>

Takes the result of the operation.

When the operation has not finished yet this blocks, which is only supported on non-dispatcher threads.

Panics

Re-raises the panic of the callback. Panics when the operation is not finished and the calling thread is the dispatcher thread, when the result has already been taken, and when the result of a local operation is requested from another thread.

Trait Implementations

impl<R> Clone for DispatcherOperation<R>

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<R> Debug for DispatcherOperation<R>

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

Formats the value using the given formatter.

impl<R: 'static> Future for DispatcherOperation<R>

type Output = Result<R, OperationCanceledError>

The type of value produced on completion.

fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output>

Attempts to resolve the future to a final value, registering the current task for wakeup if the value is not yet available.