ScopedCallback.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreTypes.h"
 
 
/**
 * Helper object for batching callback requests and firing on destruction of the FScopedCallback object.
 * CallbackType is a class implementing a static method called FireCallback, which does the work.
 */
template< class CallbackType >
class TScopedCallback
{
public:
 
    TScopedCallback()
        :   Counter(0)
    { }
 
    /** Fires a callback if outstanding requests exist. */
    ~TScopedCallback()
    {
        if (HasRequests())
        {
            CallbackType::FireCallback();
        }
    }
 
    /** Request a callback. */
    void Request()
    {
        ++Counter;
    }
 
    /** Unrequest a callback. */
    void Unrequest()
    {
        --Counter;
    }
 
    /**
     * Checks whether this callback has outstanding requests.
     *
     * @return true if there are outstanding requests, false otherwise.
     */
    bool HasRequests() const
    {
        return Counter > 0;
    }
 
private:
 
    /** Counts callback requests. */
    int32   Counter;
};