WindowsD3D12DiskCache.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
// Implementation of D3D12 Disk caching functions to preserve state across runs
 
#pragma once
 
#include "HAL/Platform.h"
#include "Containers/UnrealString.h"
#include "Windows/WindowsHWrapper.h"
 
#define IL_MAX_SEMANTIC_NAME 255
 
class FDiskCacheInterface
{
    // Increment this if changes are made to the
    // disk caches so stale caches get updated correctly
    static const uint32 mCurrentHeaderVersion = 11;
    struct FDiskCacheHeader
    {
        uint32 mHeaderVersion;
        uint32 mNumPsos;
        size_t mSizeInBytes; // The number of bytes after the header
    };
 
private:
    FString mFileName;
    uint8*  mFileStart;
    HANDLE  mFile;
    HANDLE  mMemoryMap;
    HANDLE  mMapAddress;
    SIZE_T  mCurrentFileMapSize;
    SIZE_T  mCurrentOffset;
    bool    mCacheExists;
    bool    mInErrorState;
    bool    mEnableDiskCache;
    FDiskCacheHeader mHeader;
 
    // There is the potential for the file mapping to grow
    // in that case all of the pointers will be invalid. Back
    // some of the pointers we might read again (i.e. shade byte
    // code for PSO mapping) in persitent system memory.
    TArray<void*> mBackedMemory;
 
    static const SIZE_T mFileGrowSize = (1024 * 1024); // 1 megabyte;
 
    void GrowMapping(SIZE_T size, bool firstrun);
 
public:
    enum RESET_TYPE
    {
        RESET_TO_FIRST_OBJECT,
        RESET_TO_AFTER_LAST_OBJECT
    };
 
    bool AppendData(const void* pData, size_t size);
    bool SetPointerAndAdvanceFilePosition(void** pDest, size_t size, bool backWithSystemMemory = false);
    void Reset(RESET_TYPE type);
    void Init(FString &filename, bool bEnable = true);
    void Close(uint32 numberOfPSOs);
    void Flush(uint32 numberOfPSOs);
    void ClearDiskCache();
 
    void ClearAndReinitialize()
    {
        // Must call the normal Init() first.
        if (ensure(!mFileName.IsEmpty()))
        {
            ClearDiskCache();
            Init(mFileName, mEnableDiskCache);
        }
    }
 
    uint32 GetNumPSOs() const
    {
        return mHeader.mNumPsos;
    }
 
    uint32 GetSizeInBytes() const
    {
        return mHeader.mSizeInBytes;
    }
    
    FORCEINLINE_DEBUGGABLE bool IsInErrorState() const
    {
        return mInErrorState;
    }
 
    SIZE_T GetCurrentOffset() const { return mCurrentOffset; }
 
    void* GetDataAt(SIZE_T Offset) const;
    void* GetDataAtStart() const;
 
    ~FDiskCacheInterface()
    {
        for (void* memory : mBackedMemory)
        {
            if (memory)
            {
                FMemory::Free(memory);
            }
        }
    }
};