/*

* Copyright (c) 2004-2007 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 class implements the SI Controller Plugin database.

*

*/

#ifndef SIDATABASE_H

#define SIDATABASE_H

//  INCLUDES

#include <d32dbms.h>

#include <e32svr.h>

#include <sysutil.h> // Critical Level check

#include <f32file.h>

class CNssBackupObserver;

// CLASS DECLARATION

/**

*  This class is the base class for all SI Controller Plugin DB classes.

*  It provides the common functionality for the DB classes.

*

*  @lib SIControllerPlugin.lib

*  @since 2.8

*/

class CSIDatabase : public CBase

    {

    public:  // Constructors and destructor

        /**

        * Two-phased constructor.

        */

        static CSIDatabase* NewL(TFileName aDatabaseFileName);

 		/**

        * Destructor.

        */

        virtual ~CSIDatabase();

    public: // New functions

        /**

        * Begins a database transaction if not already.

        * @since 2.8

        * @return	Reference to the database.

        */

		void BeginTransactionL();

        /**

        * Commits all changes to the database.

        * @since 2.8

        */

		void CommitChangesL( TBool aCompact );

        /**

        * Rollback all changes to the database.

        * @since 2.8

        */

		void Rollback();

        /**

        * Checks to see if ID tables exist.

        * @since 2.8

        * @return	ETrue if ID tables exist; EFalse otherwise.

        */

		TBool DoIDTablesExistL();

        /**

        * @todo Add comments

        */

        TBool DoesLockTableExistL();

        /**

        * @todo Add comments

        */

        TBool DoesModelBankTableExistL();

        /**

        * @todo Add comments

        */

        TBool DoesLexiconTableExistL();

        /**

        * @todo Add comments

        */

        TBool DoesGrammarTableExistL();

        /**

        * Returns a reference to the database.

        * @since 2.8

        * @return	Reference to the database.

        */

		RDbNamedDatabase& SIDatabase();

        /**

        * Returns a reference to DB session.

        * @since 2.8

        * @return	Reference to the database.

        */

		RDbs& DbSession();

        /**

        * Returns a drive for DB file.

        * @since 2.8

        * @return	Reference to the session.

        */

		TInt DbDrive();

        /**

        * Creates a small table to the database. Writing of this table is tried

        * when acquiring for a write lock.

        */

        void CreateLockTableL();

		/**

		* Permit transactions. Used when e.g. backup or restore begins 

		* @since 3.1

		*/

		void LockTransactionsL();

		/**

		* Allow transactions. Used when e.g. backup or restore ends 

		* @since 3.1

		*/

		void UnlockTransactionsL();

        /**

        * Opens a database session.  If database file doesn't exist, it creates one.

        * @since 2.8

        */

        void OpenDatabaseL();

        /**

	    * Close database.

	    * @since 3.1

	    * @return Symbian-wide error codes

	    */

		TInt  CloseDatabase();

     private:

        /**

        * C++ default constructor.

        */

        CSIDatabase(TFileName aDbFileName);

        /**

        * By default Symbian 2nd phase constructor is private.

        */

        void ConstructL();

        /**

        * Creates a new database file.

        * @since 2.8

        */

		void CreateDatabaseL();

    public:    // Data

		// Database session

		RDbs iDbSession;

		// Database

        RDbNamedDatabase iDb;

		// Indication for outstanding transaction by this client

		TBool iOpenTransaction;

		// Name of the database file	

		TFileName iDatabaseFileName;

        // drive for the database file

        TInt iDatabaseDrive;

        // Indication if database connection is open

        TBool iDatabaseOpen;

        // Mutex for DB write lock

        // Makes sure that only one process gets the DB lock

        RMutex iMutex; 

        // Critical section is used in locking transactions inside one object

        RCriticalSection iCriticalSection;

        // backup and restore observer

        CNssBackupObserver* iBackupObserver;

    };

#endif // SIDATABASE_H

// End of File