RuntimeAssetCacheBackend.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreMinimal.h"
#include "Templates/UnrealTemplate.h"
#include "UObject/NameTypes.h"
 
class FArchive;
class FCacheEntryMetadata;
class FRuntimeAssetCacheBucket;
 
class FCacheEntryMetadata;
class FRuntimeAssetCacheBucket;
 
class FRuntimeAssetCacheBackend : public FNoncopyable
{
public:
    static FRuntimeAssetCacheBackend& Get()
    {
        static FRuntimeAssetCacheBackend& Backend = *CreateBackend();
        return Backend;
    }
 
    FCacheEntryMetadata* GetCachedData(FName Bucket, const TCHAR* CacheKey, void*& OutData, int64& OutDataSize);
 
    bool PutCachedData(FName Bucket, const TCHAR* CacheKey, void* InData, int64 InDataSize, FCacheEntryMetadata* Metadata);
 
    virtual bool RemoveCacheEntry(FName Bucket, const TCHAR* CacheKey) = 0;
 
    virtual bool ClearCache() = 0;
 
    virtual bool ClearCache(FName Bucket) = 0;
 
    virtual FRuntimeAssetCacheBucket* PreLoadBucket(FName BucketName, int32 BucketSize) = 0;
 
protected:
    /*
    * Virtual destructor.
    */
    virtual ~FRuntimeAssetCacheBackend() { }
 
    /*
    * Creates archive to read data from.
    * @param Bucket Bucket containing cache entry.
    * @param CacheKey Key to cache entry.
    * @return Archive storing data.
    */
    virtual FArchive* CreateReadArchive(FName Bucket, const TCHAR* CacheKey) = 0;
 
    /*
    * Creates archive to write data into.
    * @param Bucket Bucket containing cache entry.
    * @param CacheKey Key to cache entry.
    * @return Archive storing data.
    */
    virtual FArchive* CreateWriteArchive(FName Bucket, const TCHAR* CacheKey) = 0;
 
    /*
    * Preloads metadata from archive.
    * @param Ar Archive to load metadata from
    * @return Metadata.
    */
    FCacheEntryMetadata* PreloadMetadata(FArchive* Ar);
 
private:
    static FRuntimeAssetCacheBackend* CreateBackend();
 
};