/*

* Copyright (c) 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 HGSCROLLBUFFERMANAGER_H_

#define HGSCROLLBUFFERMANAGER_H_

#include <e32base.h>

class MHgScrollBufferObserver;

class MHgBufferOwner;

NONSHARABLE_CLASS( CHgScrollBufferManager ) : public CActive

    {

public:

    static CHgScrollBufferManager* NewL( 

            MHgScrollBufferObserver& aObserver, 

            TInt aBufferSize,

            TInt aBufferTreshold,

            TInt aInitialPosition,

            TInt aTotalCount );

    virtual ~CHgScrollBufferManager();

protected: // From CActive

    void RunL();

    void DoCancel();

    TInt RunError( TInt aError );

public:

    void SetPosition( TInt aIndex );

    void ItemCountChanged( TInt aIndex, TBool aRemoved, TInt aNewTotalCount );

    void SetTotalCount( TInt aTotalCount );

    void SetBufferOwner( MHgBufferOwner& aOwner );

    void ResetBuffer( TInt aPosition, TInt aTotalCount);

protected:

    CHgScrollBufferManager(

            MHgScrollBufferObserver& aObserver, 

            TInt aBufferSize,

            TInt aBufferTreshold,

            TInt aInitialPosition,

            TInt aTotalCount );

    void ConstructL();

private:

    void NotifyObserver();

private:

    MHgScrollBufferObserver& iObserver; 

    MHgBufferOwner* iOwner;

    TInt iBufferSize;

    TInt iBufferTreshold;

    TInt iBufferPosition;

    TInt iDiff;

    TInt iTotalCount;

    TBool iResetOrdered;

    TInt iRequestStart;

    TInt iRequestCount;

    TInt iReleaseStart;

    TInt iReleaseCount;

    };

#endif /*HGSCROLLBUFFERMANAGER_H_*/