StackTracker.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "Containers/Array.h"
#include "Containers/Map.h"
#include "Containers/UnrealString.h"
#include "CoreTypes.h"
#include "Math/NumericLimits.h"
 
class FOutputDevice;
class FString;
 
 
struct FStackTracker
{
public:
    static constexpr int32 MAX_BACKTRACE_DEPTH = 50;
    struct FCallStack
    {
        int64 StackCount;
        uint64 Addresses[MAX_BACKTRACE_DEPTH];
        void* UserData;
    };
 
    typedef void (*StackTrackerUpdateFn)( const FCallStack& CallStack, void* UserData);
    typedef void (*StackTrackerReportFn)( const FCallStack& CallStack, uint64 TotalStackCount, FOutputDevice& Ar );
    typedef void (*StackTrackerDeleteUserDataFn)(void*);
 
    static void DefaultDeleteUserDataFn(void* UserData);
 
    [[nodiscard]] CORE_API FStackTracker(StackTrackerUpdateFn InUpdateFn = nullptr, StackTrackerReportFn InReportFn = nullptr, StackTrackerDeleteUserDataFn InDeleteUserDataFn = nullptr, bool bInIsEnabled = false);
 
    CORE_API void CaptureStackTrace(int32 EntriesToIgnore = 2, void* UserData = nullptr, int32 StackLen = MAX_int32, bool bLookupStringsForAliasRemoval = false);
 
    CORE_API void DumpStackTraces(int32 StackThreshold, FOutputDevice& Ar, float SampleCountCorrectionFactor = 1.0);
 
    CORE_API void ResetTracking();
 
    CORE_API void ToggleTracking();
    CORE_API void ToggleTracking(bool bEnable, bool bSilent);
 
private:
 
    TArray<FCallStack> CallStacks;
    TMap<uint32,int32> CRCToCallStackIndexMap;
    TMap<uint64,uint64> AliasMap;
    TMap<FString,uint64> StringAliasMap;
    bool bAvoidCapturing;
    bool bIsEnabled;
    uint64 StartFrameCounter;
    uint64 StopFrameCounter;
 
    StackTrackerUpdateFn UpdateFn;
    StackTrackerReportFn ReportFn;
    StackTrackerDeleteUserDataFn DeleteUserDataFn;
};