1 /*

     2 * Copyright (c) 2006 Nokia Corporation and/or its subsidiary(-ies).

     3 * All rights reserved.

     4 * This component and the accompanying materials are made available

     5 * under the terms of "Eclipse Public License v1.0"

     6 * which accompanies this distribution, and is available

     7 * at the URL "http://www.eclipse.org/legal/epl-v10.html".

     8 *

     9 * Initial Contributors:

    10 * Nokia Corporation - initial contribution.

    11 *

    12 * Contributors:

    13 *

    14 * Description:  Command handler interface of the engine.

    15 *

    16 */

    17 

    18 

    19 

    20 #ifndef MVTENGCOMMANDHANDLER_H

    21 #define MVTENGCOMMANDHANDLER_H

    22 

    23 //  INCLUDES

    24 #include <e32base.h>

    25 #include "vtengcommands.h"

    26 

    27 // CONSTANTS

    28 

    29 // MACROS

    30 

    31 // DATA TYPES

    32 

    33 // FUNCTION PROTOTYPES

    34 

    35 // FORWARD DECLARATIONS

    36 

    37 class MVtEngCommandObserver;

    38 

    39 // CLASS DECLARATION

    40 

    41 /**

    42 *  Handler for commands from client.

    43 *

    44 *  @lib videoteleng

    45 *  @since 2.6

    46 */

    47 class MVtEngCommandHandler

    48     {

    49     public:        

    50 

    51         /**

    52         * EAttribAsync

    53         *  command is asynchronous. 

    54         * EAttribEnabled

    55         *  Command can be executed at the moment.

    56         * EAttribSupported

    57         *  Command is supported by the engine.

    58         */

    59         enum TCommandCaps 

    60             { 

    61             EAttribAsync      = 0x00000001,

    62             EAttribEnabled    = 0x00000002,

    63             EAttribSupported  = 0x00000004

    64             };

    65 

    66         /**

    67         * Excecutes a command. This function leaves KErrNotReady

    68         * if engine is in such a state that command cannot be

    69         * executed.

    70         * 

    71         * @param aCommandId command to be executed.

    72         * @param aParams command parameters, NULL if command

    73         * does not require any.

    74         */

    75         virtual void ExecuteL( 

    76             const TVtEngCommandId aCommandId,

    77             TDesC8* aParams ) = 0;

    78 

    79         /**

    80         * Cancels a command.

    81         * @param aCommandId command to cancel. 

    82         * @return KErrNotFound if command is not pending.

    83         */

    84         virtual TInt CancelCommand( const TVtEngCommandId aCommandId ) = 0;

    85 

    86         /**

    87         * Returns capabilities of a command.

    88         * @return command caps

    89         */

    90         virtual TInt GetCommandCaps( 

    91             const TVtEngCommandId aCommand ) = 0;

    92 

    93         /**

    94         * Returns pending command.

    95         * @return pending command

    96         */

    97         virtual TVtEngCommandId PendingCommand() = 0;

    98 

    99         /**

   100         * Sets command observer. First call on this is guaranteed

   101         * to succeed.

   102         * @param aObserver command observer.

   103         */

   104         virtual void AddObserverL( MVtEngCommandObserver& aObserver ) = 0;

   105 

   106         /**

   107         * Removes a command observer or if non-op if specified observer

   108         * is not found.

   109         * @param aObserver command observer to be removed.

   110         */

   111         virtual void RemoveObserver( MVtEngCommandObserver& aObserver ) = 0;

   112     };

   113 

   114 #endif //MVTENGCOMMANDHANDLER_H

   115 

   116 // End of File