/*

* Copyright (c) 2004 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of the License "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: 

*      Declaration of class RFavouritesBuf.

*      

*

*/

#ifndef FAVOURITES_BUF_H

#define FAVOURITES_BUF_H

//  INCLUDES

#include <e32base.h>

#include <s32buf.h>

#include <FavouritesHandle.h>

// CONSTANTS

/// Stream buffer size.

LOCAL_D const TInt KFavouritesStreamBufSize = 512;

// FORWARD DECLARATION

class RFavouritesSession;

// CLASS DECLARATION

/**

* Client side stream buffer data container.

*/

NONSHARABLE_CLASS(TFavouritesBuf)

    {

    public:     // Data

        TInt iLen;                              ///< Data length.

        TUint8 iData[KFavouritesStreamBufSize]; ///< Data buffer.

    };

/**

* Client side stream buffer. Not seekable.

*/

NONSHARABLE_CLASS(RFavouritesBuf): public RFavouritesHandle, public TStreamBuf

    {

    public:     // Constructors and destructor

        /**

        * Open the object (initially empty).

        * @param aSess Session to be used.

        * @return Error code.

        */

        TInt Open( RFavouritesSession& aSess );

        /**

        * Open this object using other object.

        * @param aHandle Handle used to open this object.

        * @param aFunction Function.

        * @param aArgs Arguments. Arg 3 used here.

        * @return Error code.

        */

        TInt Open

            ( RFavouritesHandle& aHandle, TInt aFunction, TIpcArgs& aArgs );

        /**

        * Close the object.

        */

        void Close();

    private:    // from TStreamBuf

        /**

        * Re-fill the intermediate buffer and reset the start and end points

        * of the read area.

        * @param aMaxLength The maximum amount of data required.

        * @return The amount of data available.

        */

        TInt UnderflowL( TInt aMaxLength );

        /**

        * Empty the intermediate buffer and resets the start and end points

        * of the write area.

        */

        void OverflowL();

        /**

        * Synchronise the stream buffer with the stream. In effect, this

        * ensures that buffered data is delivered to the stream.

        * Write lag flushed.

        * Read lag leaves with KErrNotSupported.

        */

        void DoSynchL();

    private:    // New methods

        /**

        * Read data from server.

        * @return The number of bytes read.

        */

        TInt IpcReadL();

        /**

        * Write data to server.

        */

        void IpcWriteL();

        /**

        * Get read lag (number of bytes transferred from server side but not

        * yet read).

        * @return Read lag.

        */

        inline TInt Lag( TRead aArea ) const;

        /**

        * Get write lag (number of bytes written but not yet transferred to

        * server side).

        * @return Write lag.

        */

        inline TInt Lag( TWrite aArea ) const;

    private:    // Data

       TFavouritesBuf iBuf; ///< Data buffer.

    };

#include "FavouritesBuf.inl"

#endif

// End of File