Struct OperationQueue 

pub struct OperationQueue { /* private fields */ }

A queue that performs asynchronous operations in order.

Implementations

impl OperationQueue

pub fn new( spawn_task: fn(fut: Pin<Box<dyn Future<Output = ()>>>), ) -> OperationQueue

Creates a new operation queue.

The function provided as argument is used when spawning new runners, e.g. tokio::task::spawn_local. It must not be blocking.

pub fn start(&self, runners: u32) -> Result<(), Error>

Starts the given number of runners that consume new items pushed to the queue.

A runner loops infinitely, performing operations as they get queued.

An error can be returned if the queue has previously been stopped.

pub async fn enqueue( &self, op: Box<dyn ErasedQueuedOperation>, ) -> Result<(), Error>

Pushes an operation to the back of the queue.

This function can be used with any type that implements QueuedOperation, since ErasedQueuedOperation is automatically implemented for all such implementations.

An error can be returned if the queue has been stopped.

pub async fn stop(&self)

Stops the queue.

Operations that have already been queued up will still be performed, but any call to start or enqueue following a call to stop will fail.

pub fn running(&self) -> bool

Checks whether one or more runner(s) is currently active.

If a runner has been created but isn’t running yet, it is still included in this count. Thus a runner being active means it’s in any state other than fully stopped.

This method also returns false if there aren’t any runners (e.g. if the queue hasn’t been started yet, or it has been stopped).

pub fn idle(&self) -> bool

Checks whether all runners are currently waiting for a new operation to perform.