/*

* 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:  Command handler of the engine.

*

*/

#ifndef CVTENGCOMMANDHANDLER_H

#define CVTENGCOMMANDHANDLER_H

//  INCLUDES

#include <e32base.h>

#include "MVtEngCommandHandler.h"

#include "mvtengoperationobserver.h"

// FORWARD DECLARATIONS

class CVtEngHandlerContainer;

class CVtEngOperation;

// CLASS DECLARATION

/**

*  Handler for commands from client.

*

*  @lib videoteleng

*  @since 2.6

*/

NONSHARABLE_CLASS( CVtEngCommandHandler ) : public CBase,

    public MVtEngCommandHandler,

    public MVtEngOperationObserver

    {

    public: // constructor and destructors

        static CVtEngCommandHandler* NewL( 

            CVtEngHandlerContainer& aHandlers );

        virtual ~CVtEngCommandHandler();

    public: // from MVtEngCommandHandler

        /**

        * @see MVtEngCommandHandler

        */        

        virtual void ExecuteL( 

            const TVtEngCommandId aCommand,

            TDesC8* aParams );

        /**

        * @see MVtEngCommandHandler        

        */

        virtual TInt CancelCommand( const TVtEngCommandId aCommandId );

        /**

        * @see MVtEngCommandHandler        

        */

        virtual TInt GetCommandCaps( 

            const TVtEngCommandId aCommand );

        /**

        * @see MVtEngCommandHandler        

        */

        virtual TVtEngCommandId PendingCommand();

        /**

        * @see MVtEngCommandHandler        

        */

        virtual TVtEngCommandId InvalidCommand();

        /**

        * @see MVtEngCommandHandler        

        */

        virtual void AddObserverL( MVtEngCommandObserver& aObserver );

        /**

        * @see MVtEngCommandHandler        

        */

        virtual void RemoveObserver( MVtEngCommandObserver& aObserver );

    public: // from MVtEngOperationObserver

        /**

        * Handles command completion.

        * @param aCommand command id

        * @param aResult Symbian OS error code.

        */

        virtual void CommandCompleteL( 

            const TVtEngCommandId aCommand, 

            const TInt aResult );

        /**

        * Sets pending asynch operation

        * @param aActiveOp pending operation or NULL.

        */

        virtual void SetOperation( CVtEngOperation* aActiveOp );

    private: // constructors

        /**

        * Second phase constructor

        */

        void ConstructL();

        /**

        * c++ constructor

        */

        CVtEngCommandHandler( CVtEngHandlerContainer& aHandlers );

    private:

        void AddToPoolL( TVtEngCommandId aCommand );

        /**

        * Validates command

        */

        void ValidateL( 

            const TVtEngCommandId aCommandId,

            TDesC8* aParams );

        /**

        * Check if command is async.        

        */

        void CheckAsynchronity( 

            const TVtEngCommandId aCommandId, 

            TInt& aCaps );

        /**

        * Check if command is supported.

        */

        void CheckSupport( 

            const TVtEngCommandId aCommandId, 

            TInt& aCaps );

        /**

        * Check if command is applicable in current state.

        */

        void CheckState( 

            const TVtEngCommandId aCommandId, 

            TInt& aCaps );

    private: // command pool

        struct TVtOpItem

            {

            TVtEngCommandId  iId;

            CVtEngOperation* iOperation;

            };

        /**

        * Command pool for commands instantiated at construction

        * time to guarantee certain operations.

        */

        NONSHARABLE_CLASS( CVtEngCmdPool ): public CArrayPtrFlat<CVtEngOperation>

            {

            public: // constructor and destructor

                // Constructor

                CVtEngCmdPool( TInt aGranularity );

                // Destructor

                ~CVtEngCmdPool();

            public: // data structures

            public: // new methods

                /**

                * Returns operation stored in the pool.

                * @param aId command id

                * @return operation or NULL if not found.

                */

                CVtEngOperation* Get( const TVtEngCommandId aId );

            };

    private: // Data members

        RPointerArray<MVtEngCommandObserver> iObservers;

        CVtEngHandlerContainer&              iHandlers;

        CVtEngOperation*                     iActiveOp;

        CVtEngCmdPool*                       iCommandPool;

        TVtEngCommandId                      iInvalidCommandId;

    };

#endif //CVTENGCOMMANDHANDLER_H

// End of File