75 lines
1.4 KiB
C++
75 lines
1.4 KiB
C++
// Copyright Epic Games, Inc. All Rights Reserved.
|
|
|
|
#pragma once
|
|
|
|
#include "Delegates/Delegate.h"
|
|
|
|
namespace UE::CurveEditor
|
|
{
|
|
/**
|
|
* Wraps a simple multicast delegate with a counter.
|
|
*
|
|
* While the counter is positive, the event cannot be broadcast.
|
|
* Once the counter reaches 0, the event is broadcast.
|
|
*
|
|
* This is a reusable optimization that is useful to change-type events.
|
|
*/
|
|
class FSuppressibleEventBroadcaster
|
|
{
|
|
public:
|
|
|
|
void IncrementSuppressionCount()
|
|
{
|
|
++SuppressionCount;
|
|
}
|
|
|
|
void DecrementSuppressionCount()
|
|
{
|
|
if (!ensure(SuppressionCount > 0))
|
|
{
|
|
return;
|
|
}
|
|
|
|
--SuppressionCount;
|
|
|
|
if (SuppressionCount == 0 && bWasEventSuppressed)
|
|
{
|
|
bWasEventSuppressed = false;
|
|
Broadcast();
|
|
}
|
|
}
|
|
|
|
void Broadcast()
|
|
{
|
|
if (SuppressionCount == 0)
|
|
{
|
|
bWasEventSuppressed = false;
|
|
Event.Broadcast();
|
|
}
|
|
else
|
|
{
|
|
bWasEventSuppressed = true;
|
|
}
|
|
}
|
|
|
|
/** @return The event that is broadcast. This exists only for convenience: by design, you're NOT supposed to call Broadcast on this directly. */
|
|
FSimpleMulticastDelegate& OnChanged() { return Event; }
|
|
|
|
private:
|
|
|
|
/** When 0, the event can be broadcast. */
|
|
int32 SuppressionCount = 0;
|
|
|
|
/**
|
|
* This is set to true when Broadcast is called while SuppressionCount > 0.
|
|
* If true, then DecrementSuppressionCount will broadcast the event when count reaches 0.
|
|
*/
|
|
bool bWasEventSuppressed = false;
|
|
|
|
/** The event to broadcast */
|
|
FSimpleMulticastDelegate Event;
|
|
};
|
|
}
|
|
|
|
|