/*

* Copyright (c) 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:  Class declaration for DiagFwInternal::CStateMachine

*

*/

#ifndef DIAGENGINESTATEMACHINE_H

#define DIAGENGINESTATEMACHINE_H

// system include

#include <e32base.h>

// user include

#include "diagenginestates.h"   // DiagFwInternal::TState

#include "diagengineevents.h"   // DiagFwInternal::TEvent

namespace DiagFwInternal

    {

// forward declaration

class CEventBasic;

class MStateMachineObserver;

/**

*  Diagnostics Framework Engine State Machine

*

*  This class implements state machine for CDiagEngine.

*

*/

NONSHARABLE_CLASS( CStateMachine ) : public CActive

    {

public:

    /**

    * Two-phased constructor.

    * 

    * @param aObserver     Engine observer.

    * @return New instance of CStateMachine

    */

    static CStateMachine* NewL( MStateMachineObserver& aObserver );

    static CStateMachine* NewLC( MStateMachineObserver& aObserver );

    /**

    * Queue a new event into event queue. 

    * 

    * @param aEvent  New event. CStateMachine will own

    *              the object from this point on.

    *              It will be freed by CStateMachine when

    *              the event is processed.

    */

    void AddEventL( CEventBasic* aEvent );

    /**

    * Queue a new event into event queue.

    * 

    * @param aEventId  Event Id of new event. CEventBasic will be created.

    */

    void AddEventL( TEvent aEventId );

    /**

    * Current State.

    * 

    * @return Current state.

    */

    TState CurrentState() const;

    /**

    * Handle error. This should be called when an abnormal error

    * occurs (e.g. leave that cannot be handled.)

    * 

    * @param aError - Error number.

    */

    void HandleError( TInt aError );

    /**

    * State Name. 

    * Debugging purpose only. In release build, this function will

    * return empty string.

    * 

    * @param aState - a state 

    * @return Name of the state

    */

    const TDesC& StateName( TState aState ) const;

    /**

    * C++ Destructor

    */

    ~CStateMachine();

protected: // from CActive

    /**

    * @see CActive::RunL

    */

    virtual void RunL();

    /**

    * @see CActive::DoCancel

    */

    virtual void DoCancel();

    /**

    * @see CActive::RunError

    */

    virtual TInt RunError( TInt aError );

private:    // private constructors

    /**

    * C++ constructor

    */

    CStateMachine( MStateMachineObserver& iObserver );

    /**

    * 2nd phase constructor

    *

    */

    virtual void ConstructL();

private:    // private functions

    /**

    * Match states in state table.

    */

    TState CheckStateTable( TState aCurrState, TEvent aEvent ) const;

    /**

    * Complete request and set itself to be active so that the next

    * item in the queue can be executed.

    */

    void ReactivateQueue();

private: // private data

    /**

    * iObserver - Observer.

    */

    MStateMachineObserver&          iObserver;      

    /**

    * iEventQueue - array of events to process.

    */

    RPointerArray<CEventBasic>      iEventQueue;

    /**

    * iState - Current state.

    */

    TState                          iState;

    };

    } // end of namespace DiagFwInternal

#endif // DIAGENGINESTATEMACHINE_H

// End of File