/*

* Copyright (c) 2008-2008 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:  Implements VBus observer

 *

*/

#ifndef C_USBVBUSOBSERVER_H

#define C_USBVBUSOBSERVER_H

#include <e32base.h>

#include <e32property.h>

/**

 * Observers of this class have to implement this interface

 * to get call back on VBus events

 */

NONSHARABLE_CLASS( MUsbVBusObserver)

    {

public:

    /**

     * VBus down event received

     */

    virtual void VBusDownL() = 0;

    /**

     * VBus up event received

     */

    virtual void VBusUpL() = 0;

    /**

     * error handler

     * @param aError error code

     */   

    virtual void VBusObserverErrorL(TInt aError)=0;

    };

/**

 *  Class observes VBUS property

 *

 */

NONSHARABLE_CLASS( CUsbVBusObserver ) : public CActive

    {

public:

    enum TState

        {

        EVBusDown = 0, EVBusUp = 1

        };

    /**

     * Two-phased constructor.

     */

    static CUsbVBusObserver* NewL();

    /**

     * Destructor.

     */

    virtual ~CUsbVBusObserver();

    /**

     * VBus state getter

     * @return VBus state

     */

    TState VBus() /* not const. read comment in impl*/;

    /**

     * Adds observer to a list

     * @param aObserver observer

     */

    void SubscribeL(MUsbVBusObserver* aObserver);

    /**

     * removes observer from list

     * @param aObserver observer

     */

    void UnsubscribeL(MUsbVBusObserver* aObserver);

private:

    // From CActive

    /**

     * Called when request completed

     *

     */

    void RunL();

    /**

     * Called when request is cancelled

     *

     */

    void DoCancel();

    /**

     * Called when RunL leaves

     * @param aError error code

     * @return error code

     *

     */

    TInt RunError(TInt aError);

private:

    /**

     * Default constructor

     */

    CUsbVBusObserver();

    /**

     * 2nd phase constructor

     */

    void ConstructL();

private:

    // data

    /**

     * The observer reports state changes to own observers

     * Own

     */

    RPointerArray<MUsbVBusObserver> iObservers;

    /**

     * The observer observes property change

     */

    RProperty iVBus;

    };

#endif //  C_USBVBUSOBSERVER_H