InstanceCounter.h

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// Copyright Epic Games, Inc. All Rights Reserved.
#pragma once
 
#include "Containers/Map.h"
#include "Containers/UnrealString.h"
#include "CoreTypes.h"
#include "HAL/CriticalSection.h"
#include "HAL/PreprocessorHelpers.h"
#include "Misc/Build.h"
#include "UObject/NameTypes.h"
 
class FOutputDevice;
 
/*
    A helper object for counting instances of struct or classes for debugging
    purposes, e.g. to get an absolute count of the number of "Foo"'s in existence
 
    Suggested use
 
    class UFoo
    {
    public:
        // etc etc
 
    protected:
        COUNT_INSTANCES(FTypeIWantToCount)
    };
 
*/
class FInstanceCountingObject
{
public:
 
    CORE_API FInstanceCountingObject(const TCHAR* InName, bool InLogConstruction=false);
 
    CORE_API FInstanceCountingObject(const FInstanceCountingObject& RHS);
 
    CORE_API virtual ~FInstanceCountingObject();
 
    
    
protected:
 
    CORE_API void IncrementStats();
 
    CORE_API void DecrementStats();
 
protected:
    
    FName       Name;
 
    // Log increment/decrement?
    bool         DoLog;
 
    struct FGlobalVars
    {
        TMap<FName, int32>  InstanceCounts;
        FCriticalSection    Mutex;
    };
 
    static CORE_API FGlobalVars* Globals;
    static CORE_API FGlobalVars& GetGlobals();
};
 
 
#if !UE_BUILD_SHIPPING
 
    #define COUNT_INSTANCES(TypeName) \
        struct FCount##TypeName : FInstanceCountingObject { FCount##TypeName() : FInstanceCountingObject(TEXT(PREPROCESSOR_TO_STRING(TypeName))) {} }; FCount##TypeName TypeName##Count; 
 
    #define COUNT_INSTANCES_AND_LOG(TypeName) \
        struct FCount##TypeName : FInstanceCountingObject { FCount##TypeName() : FInstanceCountingObject(TEXT(PREPROCESSOR_TO_STRING(TypeName)), true) {} }; FCount##TypeName TypeName##Count;
 
 
#else
 
    #define COUNT_INSTANCES(TypeName)
    #define COUNT_INSTANCES_AND_LOG(TypeName)
 
#endif // SHIPPING