/*

* Copyright (c) 2007 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:  MPX back stepping utility interface definition

*

*/

#ifndef MMPXBACKSTEPPINGUTILITY_H

#define MMPXBACKSTEPPINGUTILITY_H

// INCLUDES

#include <e32base.h>

const TInt KMPXBackSteppingNotConsumed = 0;

const TInt KMPXBackSteppingConsumed = 1;

// CLASS DECLARATION

/**

 *  Music Player common utility interface

 *

 *  @lib mpxbacksteppingutility.lib

 */

NONSHARABLE_CLASS( MMPXBackSteppingUtility )

    {

public: 

    /**

     * Retrieve a back stepping utility of this thread.  All clients in this thread

     * shares the same utility (singleton)

     * Call Close() when this object is not needed anymore.

     *

     * @since S60 3.2

     * @return Pointer to backstepping utility. Ownership not transferred.

     */

    IMPORT_C static MMPXBackSteppingUtility* UtilityL();

    /**

     * This method must be called when this object can be freed. This object 

     * will be destroyed when no one is using it.

     *

     * @since S60 3.2

     */

    virtual void Close() = 0;

    /**

     * Forwards activation event.

     *

     * @since S60 3.2

     * @param aState state of application like view ids

     * @param aEnter indicate if it is entry/exit activation

     * @return result code retutned by BS Service interface

     * @leave leaves from HandleResultL are propagated

     */

    virtual TInt ForwardActivationEventL(

        const TDesC8& aState,

        const TBool aEnter ) = 0;

    /**

     * Handles back command.

     *

     * @since S60 3.2

     * @param aState state of application like view ids

     * @return result code retutned by BS Service interface

     * @leave leaves from HandleResultL are propagated

     */

    virtual TInt HandleBackCommandL( const TDesC8& aState ) = 0;

    /**

     * Initializes Backstepping Service.

     *

     * @since S60 3.2

     * @param aUid client application UID

     * @leave KErrNotSupported or KErrArgument 

     *        (if arguments passed to BS Service are incorrect 

     *        or could not initialize BS)

     *        KErrNotFound (if there was no return value)

     */

    virtual void InitializeL( const TUid aUid ) = 0;

    };

#endif  // MMPXBACKSTEPPINGUTILITY_H

// End of File