/*

* 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 singleton

*

*/

#ifndef CMPXBACKSTEPPINGUTILITYIMP_H

#define CMPXBACKSTEPPINGUTILITYIMP_H

// INCLUDES

#include <e32base.h>

#include <mpxbacksteppingutility.h>

// FORWARD DECLARATIONS

class MLiwInterface;

class CLiwGenericParamList;

class CLiwServiceHandler;

// CLASS DECLARATION

/**

*  Music Player common utility class

 *

 *  @lib mpxbacksteppingutility.lib

 *  @since S60 v3.2

*/

NONSHARABLE_CLASS( CMPXBackSteppingUtilityImp )

    : public CBase

    , public 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 3.2

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

     */

    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 3.2

     */

    void Close();

    /**

     * Forwards activation event

     *

     * @since S60 v3.2

     * @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

     */

    TInt ForwardActivationEventL(

        const TDesC8& aState,

        const TBool aEnter );

    /**

     * Handles back command

     *

     * @since S60 v3.2

     * @param aState state of application like view ids

     * @return result code retutned by BS Service interface

     * @leave leaves from HandleResultL are propagated

     */

    TInt HandleBackCommandL( const TDesC8& aState );

    /**

     * Initializes BS Service

     * @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)

     */

    void InitializeL( const TUid aUid );

private:

    /**

    * C++ constructor

    */

    CMPXBackSteppingUtilityImp();

    /**

    *  Destuctor

    */ 

    virtual ~CMPXBackSteppingUtilityImp();

    /**

     * 2nd phase constructor

     */

    void ConstructL();

    /**

    *  Two phased contructor

    */ 

    static CMPXBackSteppingUtilityImp* NewL(); 

    static CMPXBackSteppingUtilityImp* NewLC(); 

    /**

     * Store utility to TLS.

     *

     * @param aUtility Utility object. Ownership not transferred.

     */

    static void StoreUtility( MMPXBackSteppingUtility* aUtility );

    /**

     * Handles the result of a LIW command

     * @return result code retutned by BS Service interface

     * @leave KErrNotSupported or KErrArgument 

     *        (if arguments passed to BS Service are incorrect)

     *        KErrNotFound (if there was no return value)

     */

    TInt HandleResultL();

private: // data

    /**

     * Reference count.

     */

    TInt iRefCount;

    /**

     * AIW Service Handler

     * Own.

     */

    CLiwServiceHandler* iServiceHandler;

    /**

     * BS Service interface returned by LIW

     * Own.

     */

    MLiwInterface* iBSInterface;

    /**

     * In param list

     * Not own.

     */

    CLiwGenericParamList* iInParamList;

    /**

     * Out param list

     * Not own.

     */

    CLiwGenericParamList* iOutParamList;

    };

#endif  // CMPXBACKSTEPPINGUTILITYIMP_H

// End of File