FileCache.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "Async/TaskGraphInterfaces.h"
#include "Containers/UnrealString.h"
#include "CoreMinimal.h"
#include "GenericPlatform/GenericPlatformFile.h"
#include "HAL/Platform.h"
#include "HAL/PlatformFile.h"
#include "Misc/MemoryReadStream.h"
 
class IAsyncReadFileHandle;
 
//
struct FFileCachePreloadEntry
{
    FFileCachePreloadEntry() : Offset(0), Size(0) {}
    FFileCachePreloadEntry(int64 InOffset, int64 InSize) : Offset(InOffset), Size(InSize) {}
 
    int64 Offset;
    int64 Size;
};
 
class IFileCacheHandle
{
public:
    CORE_API static void EvictAll();
 
    CORE_API static IFileCacheHandle* CreateFileCacheHandle(const TCHAR* InFileName, int64 InBaseOffset = 0);
 
    CORE_API static IFileCacheHandle* CreateFileCacheHandle(IAsyncReadFileHandle* FileHandle, int64 InBaseOffset = 0);
 
    virtual ~IFileCacheHandle() {};
 
    CORE_API static int64 GetFileCacheSize();
 
    virtual IMemoryReadStreamRef ReadData(FGraphEventArray& OutCompletionEvents, int64 Offset, int64 BytesToRead, EAsyncIOPriorityAndFlags Priority) = 0;
 
    virtual FGraphEventRef PreloadData(const FFileCachePreloadEntry* PreloadEntries, int32 NumEntries, EAsyncIOPriorityAndFlags Priority) = 0;
 
    virtual void WaitAll() = 0;
};
 
#if !UE_BUILD_SHIPPING
//
// Called by the IoStore system to inform the FileCache of used compression block sizes,
// for usage warning purposes. (FFileIoStoreReader::ReadContainerHeader)
//
void CORE_API FileCache_PostIoStoreCompressionBlockSize(uint32 InCompressionBlockSize, FString const& InContainerFilePath);
#endif // !UE_BUILD_SHIPPING