CacheJournalSimple.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CacheJournal.h"
#include "Containers/Map.h"
#include "HAL/CriticalSection.h"
#include "Tasks/Task.h"
#include <atomic>
 
#if !UE_BUILD_SHIPPING
 
namespace StorageServer
{
    // Cross-platform cache journal implementation, baseline for platforms where platform specific implementation is not available.
    class FCacheJournalSimple : public ICacheJournal
    {
    public:
        FCacheJournalSimple(const TCHAR* FileName, const uint64 FlushAtWriteCount);
        virtual ~FCacheJournalSimple() override;
 
        virtual void Flush(bool bImmediate) override;
 
        virtual void InvalidateAll() override;
        virtual void Invalidate(const FIoChunkId& ChunkId) override;
 
        virtual bool SetChunkInfo(
            const FIoChunkId& ChunkId,
            const TOptional<uint64>& OptModTag,
            const TOptional<int64>& OptRawSize,
            const TOptional<int32>& OptRawBlockSize
        ) override;
        virtual bool TryGetChunkInfo(
            const FIoChunkId& ChunkId,
            FCacheChunkInfo& OutChunkInfo
        ) override;
 
        virtual bool AddEntry(
            const FIoChunkId& ChunkId,
            const FCacheEntry& Entry
        ) override;
        virtual bool TryGetEntry(
            const FIoChunkId& ChunkId,
            const uint64 ChunkOffset,
            const uint64 ChunkSize,
            FCacheEntry& OutEntry
        ) override;
 
        virtual void IterateChunkIds(
            TFunctionRef<void(const FIoChunkId& ChunkId, const FCacheChunkInfo& ChunkInfo)> Callback
        ) override;
        virtual void IterateCacheEntriesForChunkId(
            const FIoChunkId& ChunkId,
            TFunctionRef<void(const FCacheEntry& Entry)> Callback
        ) override;
        virtual void IterateCacheEntries(
            TFunctionRef<void(const FIoChunkId& ChunkId, const FCacheEntry& Entry)> Callback
        ) override;
 
    private:
        FCriticalSection DataLock, FlushTaskLock;
        FString FileName;
        UE::Tasks::TTask<void> FlushTask;
        uint64 FlushAtWriteCount;
        uint64 CurrentWriteCount;
        std::atomic<bool> bDirty;
 
        typedef TMap<TInterval<uint64>, FCacheEntry> FPerChunkCacheEntries;
        TMap<FIoChunkId, FCacheChunkInfo> ChunkInfos;
        TMap<FIoChunkId, FPerChunkCacheEntries> ChunkCacheEntries;
 
        void FlushImmediate();
    };
}
 
#endif