/*

* Copyright (c) 2002-2005 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:A local representation of the operation class assigned for operations that

* modifies the database.

*

*/

#ifndef CPOSLMLOCALMODIFYOP_H

#define CPOSLMLOCALMODIFYOP_H

#include <epos_cposlmlocaloperation.h>

#include <epos_cposlmcompactdatabase.h>

class CPosLmLocalDatabase;

/**

* A local representation of the operation class assigned for operations that

* modifies the database. It provides an interface for operations that are

* performed in small synchronous steps.

*/

NONSHARABLE_CLASS(CPosLmLocalModifyOp) : public CPosLmLocalOperation

    {

    public:  // Constructors and destructor

        /**

        * Destructor.

        */

        virtual ~CPosLmLocalModifyOp();

    public: // New functions

        /**

        * Performs a step of the operation. Before this is called, this class

        * has begun a transaction.

        *

        * @param[out] aProgress The current progress.

        */

        virtual void DoNextStepPreL( TReal32& aProgress ) = 0;

        /**

        * Performs actions after a transaction commit.

        *

        * @param[out] aProgress The current progress.

        * @return The sub class should return ETrue if it wants the base class

        *   to begin a new transaction. EFalse otherwise.

        */

        virtual TBool DoNextStepPostL( TReal32& aProgress ) = 0;

        /**

        * Returns the current progress step size. This is the value of how much

        * the progress increases between each step.

        *

        * @return Current step size.

        */

        virtual TReal32 Step() = 0;

        /**

        * Panics if the number of sub operations is invalid.

        *

        * @param aResourceId A resource id.

        * @param aNoOfSubOperations A number of sub operations.

        */

        virtual void CheckResourceValue( TInt aResourceId, TInt aNrOfSubOperations ) = 0;

    public: // From base classes

        /**

        * From CPosLmLocalOperation.

        *

        * @param[out] aProgress Will be set to the progress of the operation when

        * the step has finished.

        * @return @p KPosLmOperationNotComplete if the step has completed but

        *   more steps are needed before the operation has finished,

        *   @p KErrNone if the operation has finished successfully.

        */

        TInt NextStepL( TReal32& aProgress );

    protected:

        /**

        * C++ default constructor.

        *

        * @param[in] aDb A local database.

        */

        CPosLmLocalModifyOp( CPosLmLocalDatabase& aDb );

        /**

        * Symbian 2nd phase constructor.

        */

        void BaseConstructL();

        /**

        * Reads information about number of suboperations for asynchronous

        * operations from a resource file.

        * @param aResourceId The id of the resource to read.

        */

        void ReadInfoFromResourceFileL( TInt aResourceId );

        /**

        * The transaction is rolled back if needed.

        */

        void RollbackIfNeeded();

        /**

        * Tells whether in compacting state or not.

        * @return @p ETrue if in compacting state, @p EFalse otherwise.

        */

        TBool IsInCompactingState();

    private:

        /**

        * Calculates the progress when a compacting operation is used as a

        * sub operation to another operation.

        *

        * @param aProgressStep The progress step for the operation (i.e. 0.1 if

        *   the operation takes 10 steps).

        * @param aCompactProgress The current progress of the compact operation.

        * @return A progress to add to the current operation progress. The

        *   operation progress should be constant during the sub operation.

        *   This means that the operation progress should be saved before

        *   starting the sub operation [i.e. iCurrentProgress = iSavedProgress +

        *   CalculateSubOperationProgress(step, compactProgress)].

        */

        TReal32 CalculateSubOperationProgress(

            TReal32 aProgressStep,

            TReal32 aCompactProgress );

        /**

        * Recalculates the progress if the compacting sub operation should be

        * performed.

        *

        * @param[in,out] aProgress An operation progress.

        * @param[in] aProgressStep The progress step for the operation (i.e. 0.1 if

        *   the operation takes 10 steps).

        */

        void RecalculateProgressDueToCompact(

            TReal32& aProgress,

            TReal32 aProgressStep );

        // By default, prohibit copy constructor

        CPosLmLocalModifyOp( const CPosLmLocalModifyOp& );

        // Prohibit assigment operator

        CPosLmLocalModifyOp& operator= ( const CPosLmLocalModifyOp& );

    private:  // Data types

        enum TPosSubOperationState

            {

            ECompactSubOperationOn = 0,

            ECompactSubOperationOff

            };

    protected:  // Data

        // Status flag. Holding the current status.

        TInt iStatusFlag;

        // Number of suboperations in each transaction.

        TInt iNoOfSubOperations;

        // Whether this operation uses server-side data,

        // which needs transactions

        TBool iUsesServerData;

    private:    // Data

        // Compact sub operation

        TPosSubOperationState iCompactState;

        CPosLmCompactDatabase* iCompactSubOp;

        TReal32 iSavedProgress;

    };

#endif      // CPOSLMLOCALMODIFYOP_H