/*

* Copyright (c) 2006 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:  header of EventNotifier class.

*

*/

#ifndef EVENTNOTIFIER_H

#define EVENTNOTIFIER_H

#include <e32base.h>

#include <Events.h>

namespace multimedia

    {

    class MControlObserver;

    class CEventBase;

    class MControl;

    class CObserverManager : public CBase

        {

        public:

            static CObserverManager* NewL();

            ~CObserverManager();

            // Adds observer to list

            TInt AddObserver( const MControlObserver& aObserver );

            // Marks observer as inactive in the list

            TInt RemoveObserver( const MControlObserver& aObserver );

            // Moves the pointer to element before the first in list

            void Init();

            // Returns true and moves pointer to next active observer.

            TBool Next();

            // aObserver will contain pointer to current observer

            void Observer( MControlObserver*& aObserver );

            // Returns the count of active observers

            TInt Count();

            // Purge inactive observers in the list

            void Purge();

            // Resets the list

            void Reset();

        private:

            CObserverManager();

            void ConstructL();

        private:

            TInt    iObserverCount;

            TInt    iCurrentObserverIndex;

            // For now we maintain 2 RPointerArray lists

            // better option is to merge into one data structure

            RPointerArray<MControlObserver> iObserversList;

            RArray<TInt>                    iActiveList;

        };

    class CEventQueueItem : public CBase

        {

        public:

            static CEventQueueItem* NewL( MControl* aControl, TUint aEvent, CEventBase* aEventObject );

            ~CEventQueueItem();

        TUint EventType();

        CEventBase* EventObject();

        MControl* ControlObject();

            TAny* GetInterface();

        private:

            CEventQueueItem( MControl* aControl,TUint aEvent, CEventBase* aEventObject );

            void ConstructL();

        public:

            // next item

            TSglQueLink* iLink;

        private:

            TUint  iEvent;

            CEventBase*       iEventObject;

            MControl* iControl;

        };

    class CEventNotifier : public CActive

        {

        public:

            static CEventNotifier* NewL();

            ~CEventNotifier();

            // Adds observer

            TInt AddObserver( const MControlObserver& aObserver );

            // Remove observer

            TInt RemoveObserver( const MControlObserver& aObserver );

            // Send notification to observers. If another event is

            // being processed, this will add event to pending events

            // and observers will be notified later.

            // Takes ownership of aEventObject

            TInt Event( MControl* aControl, TUint aEvent, CEventBase* aEventObject );

            // From CActive

            void RunL();

            void DoCancel();

            TInt RunError(TInt aError);

        private:

            CEventNotifier();

            void ConstructL();

            // Signals to continue processing.

            void KickSignal();

            // Signals the event has been notified to all observers

            void EventNotified();

            void EmptyQueue();

        private:

            // Pointer to observer manager

            CObserverManager* iObserverManager;

            // List holding events to be notified

            TSglQue<CEventQueueItem>* iEventQueue;

        };

    } // namespace multimedia

#endif // EVENTNOTIFIER_H

    // End of file