metadataengine/server/inc/mdsobjectlocklist.h
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     1 /*
       
     2 * Copyright (c) 2005-2009 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:  Object locking features*
       
    15 */
       
    16 
       
    17 #ifndef __MDSOBJECTLOCKLIST_H__
       
    18 #define __MDSOBJECTLOCKLIST_H__
       
    19 
       
    20 #include <e32base.h>
       
    21 
       
    22 #include "mdscommoninternal.h"
       
    23 
       
    24 class TMdSLockEntry;
       
    25 class CMdSServerSession;
       
    26 class CMdsNamespaceDef;
       
    27 
       
    28 /**
       
    29 * Metadata object locking.
       
    30 * When opening objects for modifications, objects
       
    31 * is locked so that no other session can modify the
       
    32 * same object at same time.
       
    33 */
       
    34 class CMdSObjectLockList : public CBase
       
    35     {
       
    36     public: // Constructors and destructor
       
    37 
       
    38         virtual ~CMdSObjectLockList();
       
    39 
       
    40         static CMdSObjectLockList* NewL();
       
    41         static CMdSObjectLockList* NewLC();
       
    42 
       
    43     private: // Private constructors
       
    44 
       
    45         void ConstructL();
       
    46 
       
    47     public: // Public functions
       
    48         /**
       
    49         * Locks object for modifying.
       
    50         * @param aSession   Session where object is being modified.
       
    51         * @param aNamespace Object's owner namespace
       
    52         * @param aObjId     Object id that is being modified.
       
    53         * @return           Returns whether object could be locked or not.
       
    54         */
       
    55         void LockObjectL( const CMdSServerSession& aSession, 
       
    56         		const CMdsNamespaceDef& aNamespace, const TItemId aObjectId );
       
    57 
       
    58         /**
       
    59         * Unlocks all locked objects of particular session.
       
    60         * @param aSession   Session which locked objects are to be released.
       
    61         */
       
    62         void UnlockBySession( const CMdSServerSession& aSession );
       
    63 
       
    64         /**
       
    65         * Unlocks locked object by Id.
       
    66         * @param aNamespace Object's owner namespace
       
    67         * @param aObjId     Object id that is being modified.
       
    68         */
       
    69         void UnlockById( const CMdsNamespaceDef& aNamespace, 
       
    70         		const TItemId aObjectId );
       
    71 
       
    72         /**
       
    73         * Checks if object is locked for modifying.
       
    74         * @param aNamespace Object's owner namespace
       
    75         * @param aObjId     An objects id which is going to be checked.
       
    76         * @return           <code>ETrue</code> if locked.
       
    77         *                   <code>EFalse</code> if not.
       
    78         */
       
    79         TBool IsLocked( const CMdsNamespaceDef& aNamespace, 
       
    80         		const TItemId aObjectId ) const;
       
    81 
       
    82     	/**
       
    83     	 * Empties the object lock list.
       
    84     	 */
       
    85         void Reset();
       
    86 
       
    87 	protected:
       
    88 		TInt Find( const CMdsNamespaceDef& aNamespace, 
       
    89 				const TItemId aObjectId ) const;
       
    90 
       
    91     private:
       
    92         /**
       
    93          * Array which have the locked objects.
       
    94          */
       
    95         RArray<TMdSLockEntry> iLockListArray;
       
    96     };
       
    97 
       
    98 /**
       
    99  * Internal data structure for storing information about locked objects.
       
   100  */
       
   101 class TMdSLockEntry
       
   102     {
       
   103     public:
       
   104         /**
       
   105     	* Constructs a new lock list object.
       
   106         *
       
   107     	* @param aSession   session to which object id belongs
       
   108         * @param aNamespace Object's owner namespace
       
   109     	* @param aId        object id being modified
       
   110     	*/
       
   111     	TMdSLockEntry( const CMdSServerSession* aSession, 
       
   112     			const CMdsNamespaceDef& aNamespace, const TItemId aId )
       
   113     	: iSession( aSession ) , iNamespace( aNamespace ), iId( aId )
       
   114     	    {}
       
   115 
       
   116 		static TInt Compare( const TMdSLockEntry& aFirst, 
       
   117 				const TMdSLockEntry& aSecond );
       
   118     public:
       
   119         /* Session where object is being modified */
       
   120         const CMdSServerSession* iSession;
       
   121 
       
   122         /* Object's owner namespace */
       
   123         const CMdsNamespaceDef& iNamespace;
       
   124 
       
   125         /* Object's id which is being modified */
       
   126         TItemId iId;
       
   127     };
       
   128 
       
   129 #endif  // __MDSOBJECTLOCKLIST_H__