BackgroundHttpManagerImpl.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "BackgroundHttpFileHashHelper.h"
#include "Containers/Array.h"
#include "Containers/Ticker.h"
#include "Containers/UnrealString.h"
#include "HAL/CriticalSection.h"
#include "HAL/Platform.h"
#include "Interfaces/IBackgroundHttpManager.h"
#include "Interfaces/IBackgroundHttpRequest.h"
#include "Interfaces/IBackgroundHttpResponse.h"
#include "Logging/LogMacros.h"
#include "Templates/Atomic.h"
 
DECLARE_LOG_CATEGORY_EXTERN(LogBackgroundHttpManager, Log, All)
 
class FBackgroundHttpFileHashHelper;
 
class FBackgroundHttpManagerImpl 
    : public IBackgroundHttpManager
    , public FTSTickerObjectBase
{
public:
    BACKGROUNDHTTP_API FBackgroundHttpManagerImpl();
    BACKGROUNDHTTP_API virtual ~FBackgroundHttpManagerImpl();
 
    BACKGROUNDHTTP_API virtual void AddRequest(const FBackgroundHttpRequestPtr Request) override;
    BACKGROUNDHTTP_API virtual void RemoveRequest(const FBackgroundHttpRequestPtr Request) override;
 
    BACKGROUNDHTTP_API virtual void Initialize() override;
    BACKGROUNDHTTP_API virtual void Shutdown() override;
 
    BACKGROUNDHTTP_API virtual void DeleteAllTemporaryFiles() override;
    
    BACKGROUNDHTTP_API virtual int GetMaxActiveDownloads() const override;
    BACKGROUNDHTTP_API virtual void SetMaxActiveDownloads(int MaxActiveDownloads) override;
 
    
    BACKGROUNDHTTP_API virtual FString GetTempFileLocationForURL(const FString& URL) override;
    
    BACKGROUNDHTTP_API virtual void CleanUpDataAfterCompletingRequest(const FBackgroundHttpRequestPtr Request) override;
    virtual void SetCellularPreference(int32 Value) override {}
    
    //FTSTickerObjectBase implementation
    BACKGROUNDHTTP_API virtual bool Tick(float DeltaTime) override;
    
protected:
    BACKGROUNDHTTP_API virtual bool AssociateWithAnyExistingRequest(const FBackgroundHttpRequestPtr Request) override;
 
    BACKGROUNDHTTP_API virtual bool CheckForExistingCompletedDownload(const FBackgroundHttpRequestPtr Request, FString& ExistingFilePathOut, int64& ExistingFileSizeOut);
    BACKGROUNDHTTP_API virtual void ActivatePendingRequests();
    
    //Different from DeleteAllTemporaryFiles as this doesn't delete all files but rather cleans up specific bad files that have gone stale
    BACKGROUNDHTTP_API virtual void DeleteStaleTempFiles();
    
    //Gets a list of full filenames for all temp files.
    BACKGROUNDHTTP_API virtual void GatherAllTempFilenames(TArray<FString>& OutAllTempFilenames, bool bOutputAsFullPaths = false) const;
    
    //Helper function that converts the supplied list of Temp folder filenames to a list that is always all full paths.
    BACKGROUNDHTTP_API virtual void ConvertAllTempFilenamesToFullPaths(TArray<FString>& OutFilenamesAsFullPaths, const TArray<FString>& FilenamesToConvertToFullPaths) const;
    
    //Gather a list of any temp files that have timed out of our BackgroundHTTP settings.
    //SecondsToConsiderOld should be a double representing how many seconds old a temp file needs to be to be returned by this function
    //If OptionalFileListToCheck is empty will check all temp files in the backgroundhttp temp file folder. If supplied only the given file paths are checked
    BACKGROUNDHTTP_API virtual void GatherTempFilesOlderThen(TArray<FString>& OutTimedOutTempFilenames,double SecondsToConsiderOld, TArray<FString>* OptionalFileList = nullptr) const;
    
    //Gather a list of any temp files that have no corresponding URL Mapping entry
    //If OptionalFileListToCheck is empty will check all temp files in the backgroundhttp temp file folder. If supplied only the given file paths are checked
    BACKGROUNDHTTP_API virtual void GatherTempFilesWithoutURLMappings(TArray<FString>& OutTempFilesMissingURLMappings, TArray<FString>* OptionalFileList = nullptr) const;
    
    //Gets our FileHashHelper to compute temp file mappings
    virtual BackgroundHttpFileHashHelperRef GetFileHashHelper(){ return FileHashHelper; }
    virtual const BackgroundHttpFileHashHelperRef GetFileHashHelper() const { return FileHashHelper; }
    
protected:
    TArray<FBackgroundHttpRequestPtr> PendingStartRequests;
    FRWLock PendingRequestLock;
 
    TArray<FBackgroundHttpRequestPtr> ActiveRequests;
    FRWLock ActiveRequestLock;
 
    volatile int NumCurrentlyActiveRequests;
    TAtomic<int> MaxActiveDownloads;
    
private:
    BackgroundHttpFileHashHelperRef FileHashHelper;
};