/*

* Copyright (c) 2007-2008 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:  CCFCount class declaration.

*

*/

#ifndef C_CFCOUNT_H

#define C_CFCOUNT_H

// INCLUDES

#include "cfcontextoperation.h"

// FORWARD DECLARATIONS

class CCFContextObject;

// CLASS DECLARATION

/**

*  This class implements count -operation on Context Framework Scripts.

*

*  @lib CFScriptEngine

*  @since S60 v5.0

*/

NONSHARABLE_CLASS( CCFCount ): public CCFContextOperation

    {

public: // Public types

    /** Count types. */

    enum TCountType {

        ECountTypeRemain, /** Count value remains true after operation is evaluated to true. */

        ECountTypeChange, /** Count value is changed back from true to false after receiving the next counted context. */

        ECountTypeTrigger /** Count triggers one evaluation when count's value is true, after which count changes it's value back to false. */

    };

public: // Constructors and destructor

    /**

    * Creates and parses a CCFCount instance from an xml node.

    * @param aServices is the operation services interface for nodes.

    * @param aParent is the parent of this node or NULL if this is a root.

    *   The ownership of the parent is not transferred.

    * @param aNode is the node to be parsed.

    * @return a pointer to the created instance of CCFCount, or NULL if the node

    *   is not this count node. May leave with any system wide error code.

    */

    static CCFCount* ParseL( MCFOperationServices& aServices,

            CCFOperationNode* aParent,

            CMDXMLNode& aNode );

    /**

    * Destructor.

    */

    ~CCFCount();

public: // From CCFOperationNode

    /**

    * Internalizes operation.

    * @param aStream Read stream.

    * @return None.

    */

    void InternalizeL( RReadStream& aStream );

    /**

    * Externalizes operation.

    * @param aStream Write stream.

    * @return None.

    */

    void ExternalizeL( RWriteStream& aStream );

    /**

    * Cleanup deletes possible persistent data file.

    * This is called by the context framework when the script is uninstalled

    * from the system.

    * @return None.

    */ 

    void Cleanup();

protected: // From CCFContextOperation

    /**

    * Tests if this listener requires notification of all contexts.

    * Count type trigger requires all contexts, other types do not.

    * @returns ETrue if this listener is interested in all contexts,

    *   EFalse otherwise.

    */

    TBool IsAllRequired() const;

    /**

    * Evaluates a node with a context.

    * @param aContext is the context for evaluation.

    * @param aContextLevelDelay contains the context level delay defined by

    *  contextRef after the call.

    * @return ETrue if the operation was evaluated, EFalse otherwise.

    */

    TBool Evaluate( const CCFContextObject& aContext,

            TInt& aContextLevelDelay );

protected: // From CCFOperationNode

    /**

    * Activates this node by subscribing to a context.

    * Overrides base class implementation because count must discard the

    * possible cached context used to pre-evaluate operations during subscribe

    * context. Otherwise count might be increased based on the cached context.

    * @return None.

    */

    void ActivateL();

    /**

    * Deactivates this node by removing context subscription.

    * @return None.

    */

    void Deactivate();

protected:

    /**

    * C++ default constructor.

    */

    CCFCount( MCFOperationServices& aServices,

            CCFOperationNode* aParent,

            HBufC* aName,

            HBufC* aSource,

            const CCFContextOperation::TCmpType aType,

            const TUint aCount,

            const TCountType aCountType );

    /**

    * By default Symbian 2nd phase constructor is private.

    */

    void ConstructL( const TDesC& aCmpVal );

private: // New functions

    /**

    * Evaluates a node with a context.

    * @param aContext is the context for evaluation.

    * @return ETrue if the operation was evaluated, EFalse otherwise.

    */

    TBool DoEvaluateL( const CCFContextObject& aContext );

    /**

    * Counts a context if appropriate.

    * @param aContext is the context for counting.

    * @return ETrue if the context was counted, otherwise EFalse.

    */

    TBool CountContextL( const CCFContextObject& aContext );

protected: // Data

    CCFContextOperation::TCmpType iType;

    TUint                         iCurrentCount;

    TBool                         iActive;

    TBool                         iFinished;

    TUint                         iCmpCount;

    TCountType                    iCountType;

    HBufC*                        iCmpValue;

    HBufC*                        iPersistencyFile;

    TBool                         iReEvaluateFromNextContext;

    };

#endif // C_CFCOUNT_H