// Copyright (c) 2006-2009 Nokia Corporation and/or its subsidiary(-ies).

// All rights reserved.

// This component and the accompanying materials are made available

// under the terms of "Eclipse Public License v1.0"

// which accompanies this distribution, and is available

// at the URL "http://www.eclipse.org/legal/epl-v10.html".

//

// Initial Contributors:

// Nokia Corporation - initial contribution.

//

// Contributors:

//

// Description:

//

#ifndef ASYNCFILEWRITER_H

#include <e32base.h>

#define ASYNCFILEWRITER_H

/**

   @file

   @internalComponent

*/

#if defined(SYMBIAN_ENABLE_ENCODER_ASYNC_WRITES)

/**

	Callback interface which is used to notify a client that a buffer has been 

	written

*/

class MBufferWrittenObserver

    {

public:

    virtual void BufferWritten(const TPtrC8& aWritten, TInt aErrorCode)=0;

    };

class CBufferPool;

class RFile;

// can be used to emulate slow media on emulator

// for debugging/unittest purpose

#if ( defined(__WINS__) || defined(_DEBUG) )

# define WRITER_EMULATE_SLOW_MEDIA

#endif

#ifdef WRITER_EMULATE_SLOW_MEDIA

const TUid KUidIclTestEmulateSlowMedia = { 0x10273823 };

class CCallbackTimer;

#endif

/**

	Asynchronous file writer which manages memory buffers and provides with 

	asynchronous file writing service, which gives performance increase 

	in case of writing large files (> 64K) onto slow/high latency media

*/

class CAsyncFileWriter; //declared here

NONSHARABLE_CLASS( CAsyncFileWriter ): public CActive

    {

private:    

    enum

    	{

    	// defines maximum number of pending buffers which can be held in the Q, must be power of 2

    	KMaxNumOfBuffers = 4,

    	};

public:

    static CAsyncFileWriter* NewL(MBufferWrittenObserver& aObserver, RFile& aFile, TInt aBufferSize);

    ~CAsyncFileWriter();

    /**

        To check a buffer out of the buffer pool, 

        @return buffer pointer

    */

    void CheckBufferOut(TPtr8& aBuffer);

    /**

        To return a buffer back to the buffer pool, 

        @param  buffer pointer

    */    

    void CheckBufferIn(const TPtrC8& aBuffer);

    /**

        To put a buffer into file writing Q

    */

    void WriteBufferL(const TDesC8& aBuf, TInt aFilePos);

    /**

        To write all the pending buffers synchronously

    */

    TInt FlushBuffers();

private:

    CAsyncFileWriter(MBufferWrittenObserver& aObserver, RFile& aFile);

    void ConstructL(TInt aBufferSize);

    void RunL();

    void DoCancel();

    TInt WriteNextBuffer();

    TInt WaitForCurrentBuffer();

    void HandleBufferCompletion(TInt aError);

    TPtrC8 iBufPtr[KMaxNumOfBuffers];	// array of pending buffer pointers

    TInt iFilePos[KMaxNumOfBuffers];	// array of positions within the destination file

    TInt iCurrentBuf;					// index of the current buffer being written

    TInt iNumOfPendingBuffs;			// number of buffer pointer in the Q

    MBufferWrittenObserver& iObserver;	// observer interface pointer

    RFile* const iFile;					// destination file handle

    CBufferPool* iBufferPool;			// memory buffer manager

#ifdef WRITER_EMULATE_SLOW_MEDIA				// can be used to emulate slow media (for testing)

	static TInt TimerGate(TAny* aPtr);

	CCallbackTimer*	iCallbackTimer;

	TBool iDelayOff;

public:	

	TBool iEmulateSlowMedia;

#endif

    };

#endif // defined(SYMBIAN_ENABLE_ENCODER_ASYNC_WRITES)

#endif // ndef ASYNCFILEWRITER_H