/*

* Copyright (c) 2003 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:  This file contains the header file of the RCbsTopicMessages class

*    

*                Client-side subsession handling requests which regard 

*                CB messages.

*

*

*/

#ifndef     RCBSTOPICMESSAGES_H

#define     RCBSTOPICMESSAGES_H

// INCLUDES

#include <e32base.h>

#include "CbsCommon.h"

// FORWARD DECLARATIONS

class RCbs;

// CLASS DECLARATION 

// Client-side subsession handling requests regarding 

// CB messages.

//

class RCbsTopicMessages 

        : public RSubSessionBase

    {

    public:     // New functions

        /**

        *   Constructor.

        */

        RCbsTopicMessages();

        /**

        *   Creates a subsession to the server. Before using any other method 

        *   it must be called.

        *

        *   @param aServer      It is the cbs server.

        *   @return             Return code.

        */

        TInt Open( RCbs& aServer );

        /**

        *   Closes the subsession.

        *

        *   @return             Return code.

        */

        TInt Close();

        /**

        *   Returns the total amount of messages the topic contains.    

        *

        *   @param  aNumber     Topic number.

        *   @param  aCount      It will contain the total amount of 

        *                       messages.

        */

        TInt GetMessageCount( TCbsTopicNumber aNumber, TInt& aCount );

        /**

        *   Returns message information.

        *

        *   @param  aNumber     Topic number

        *   @param  aIndex      It is index to the message in topic. 

        *   @param  aMessage    It will contain the message information.

        *   @return             Return code.

        */

        TInt GetMessage( TCbsTopicNumber aNumber, TInt aIndex, 

            TCbsMessage& aMessage );

        /**

        *   Finds a message by given handle.

        *

        *   @param  aHandle     It is handle to the message.

        *   @param  aMessage    It will contain the message information.

        *   @return             Return code.

        */

        TInt FindMessageByHandle( const TCbsMessageHandle& aHandle, 

            TCbsMessage& aMessage );

        /**

        *   Returns the index of a message with given handle in topic.

        *

        *   Result code KErrNotFound indicates that no message was found with

        *   the given handle.

        *

        *   @param  aHandle     Handle of the message

        *   @param  aIndex      Return: index of the message in message topic

        *   @return             Result code

        */

        TInt GetMessageIndexByHandle( 

            const TCbsMessageHandle& aHandle, TInt& aIndex );

        /**

        *   Deletes an existing message.

        *

        *   Note that it does not care a lot about the status of the message.

        *   

        *   Check also the description of LockMessage method.

        *

        *   @param  aHandle     It is handle to the message.

        *   @return             Return code.

        */

        TInt DeleteMessage( const TCbsMessageHandle& aHandle );

        /**

        *   Saves a message (i.e., the saved message won't be deleted to make 

        *   room for new messages).

        *

        *   Return codes:

        *   KErrNone            Message is saved.

        *   KErrGeneral         Message not saved -- total maximum of saved 

        *                       messages reached.

        *

        *   @param  aHandle     Handle to the message to be saved.

        *   @return             Return code.

        */

        TInt SaveMessage( const TCbsMessageHandle& aHandle );

        /**

        *   Locks the message.

        *

        *   Note that a single topic messages subsession can have at most one 

        *   locked message. 

        *

        *   Message can be unlocked by trying to lock a null message. Locked 

        *   message will also be automatically unlocked when subsession is 

        *   closed. If a message is locked, then it will not be deleted from

        *   the database. Thus, deleting a message or trying to delete a 

        *   topic that contains such a message will fail.

        *

        *   Locking a message does not prevent to save the message nor read 

        *   the message.

        *

        *   @param  aHandle     It is handle to the message to be locked.

        *   @return             Return code.

        */

        TInt LockMessage( const TCbsMessageHandle& aHandle );

        /**

        *   Sets the message as read.

        *

        *   @param  aHandle     It is handle to the message to be set read.

        */

        TInt ReadMessage( const TCbsMessageHandle& aHandle );

        /**

        *   Returns the message contents.

        *

        *   @param  aHandle     It is handle to the message.

        *   @param  aBuffer     It will contain the contents (as much as it fits).

        *   @return             Return code.

        */

        TInt GetMessageContents( const TCbsMessageHandle& aHandle, 

            TDes& aBuffer );

        /**

        *   Returns the handles of messages that precede and succeed the 

        *   given message in server-side list of topic messages.

        *

        *   Topic is resolved from the given message handle

        *

        *   If the given handle specifies the first message in topic,

        *   aPosition has ECbsHead bit up. If the given handle specifies 

        *   the last message in topic, aPosition has ECbsTail bit up.

        *    

        *    Return code values:

        *    KErrNone       aPrevMsgHandle, aNextMsgHandle and aPosition

        *                   contain valid values.

        *    KErrNotFound	aCurrentMsgHandle specified a message that was not

        *			        found.

        *

        *    @param  aCurrentMsgHandle		Handle that specifies the message 

        *                                   whose surroundings are returned

        *    @param  aPrevMsgHandle		    Returns: handle of message 

        *                                   preceding the given message

        *    @param  aNextMsgHandle		    Returns: handle of message 

        *                                   succeeding the given topic

        *    @param  aPosition			    Returns: position of current topic 

        *                                   in list

        *    @return 				        Result code

        */

        IMPORT_C TInt GetNextAndPrevMessageHandle(

	        const TCbsMessageHandle& aCurrentMsgHandle,

	        TCbsMessageHandle& aPrevMsgHandle,

	        TCbsMessageHandle& aNextMsgHandle,

	        TInt& aPosition );

    };

#endif      //  RCBSTOPICMESSAGES_H   

// End of File