Coalescer#

Fully qualified name: usd_optimize::Coalescer

class Coalescer#

Class to coalesce events.

An instance of the class is created with a callback function and a delay in milliseconds. The instance can then be triggered, which will schedule the callback to run after the delay.

If the instance is subsequently triggered again before the delay has expired, then the callback is rescheduled. This continues until no more triggers have been made within the delay, at which point the callback will be executed.

It can be used to respond to events where you may have a high frequency of similar events and only want to respond when the last one completes, for example responding after a user has been interactively manipulating the transform of an object which fires a lot of interim events, and you don’t necessarily want to respond to all of them.

The callback function, when executed, will be called on an arbitrary thread. The intention is to allow triggering an instance of this class from the main thread and not blocking.

Public Types

using CallbackFn = std::function<void()>#

Callback typedef.

Public Functions

Coalescer(
const CallbackFn &callback,
const std::chrono::milliseconds &delay,
)#

Constructor.

Parameters:

  • callback – The callback function to execute

  • delay – The delay to wait before executing the callback function

virtual ~Coalescer()#

Destructor.

When this object is destroyed it will Coalescer::wait on any active thread to ensure that the object is still alive if a callback was scheduled to trigger. This means that destruction may block for a brief delay. If you prefer to avoid this you can manually wait.

void trigger()#

Trigger the callback to be scheduled.

This function can be called repeatedly, and the callback timer will be reset until it stops being called. Once the configured delay passes without this function being called again, the callback will be executed.

bool isActive()#

Return whether there is a callback currently scheduled.

If a callback has been scheduled but has not yet executed this function will return true. If there is no scheduled callback, it will return false.

Returns:

Whether a callback is scheduled

void cancel()#

Cancel any active callback and invalidate.

This function will mark this object cancelled. No new triggers will be accepted, and any scheduled callback will not execute. There may however still be an active thread running that requires this object to exist, so it is not safe to delete until either Coalescer::isActive returns false or Coalescer::wait has been called.

void wait()#

Wait for any internal thread to finish.

Blocks and waits for any scheduled internal thread to complete. This function can be used prior to deleting the object in order to safely destroy it.