/*

* 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:  Stream component async state class description.

*

*/

#ifndef NSPNATFWASYNCSTATE_H

#define NSPNATFWASYNCSTATE_H

#include <e32base.h>

/**

 *  NAT FW stream state.

 *

 *  Class objects depict an async state of NAT FW stream, stream component

 *  stores/changes the state whenever it makes async call to NAT FW.

 *

 *  @lib natfwsdpprovider.dll

 *  @since S60 3.2

 */

class CNSPNATFWAsyncState : public CBase

    {

public: // Enums

    /**

     * External events that can change the state of this object.

     */

    enum TNATFWEvent

        {

        ENATFWEventFetchCand,

        ENATFWEventPerformChecks,

        ENATFWEventRecvAct,

        ENATFWEventSendAct,

        ENATFWEventRecvDeAct,

        ENATFWEventSendDeAct

        };

private: // Enums

    /**

     * Internal state of this object.

     */

    enum TNATFWAsyncState

        {

        ENATFWIdle,

        ENATFWFetchCand,

        ENATFWCandChecks,

        ENATFWSend,

        ENATFWRecv,

        ENATFWSendRecv

        };    

public: // Constructors and destructor

    /**

     * A two-phase constructor.

     */

    static CNSPNATFWAsyncState* NewL();

    /**

     * A two-phase constructor.

     */

    static CNSPNATFWAsyncState* NewLC();

    /**

     * Copy constructor.

     */

    static CNSPNATFWAsyncState* NewL(

                const CNSPNATFWAsyncState& aState );

    /**

     * Copy constructor.

     */

    static CNSPNATFWAsyncState* NewLC(

                const CNSPNATFWAsyncState& aState );

    /**

     * Destructor.

     */

    virtual ~CNSPNATFWAsyncState();

private: // Constructors and destructor

    CNSPNATFWAsyncState();

    void Construct( const CNSPNATFWAsyncState& aState );

public: // New functions

    /**

     * This method is used to check if given event can be processed.

     *

     * @since       S60 3.2

     * @param       aEvent              Enumeration, external event.

     * @return      System wide error code.

     */

    TInt CheckState( TNATFWEvent aEvent ) const;

    /**

     * This method is used to check if given event can be processed.

     * Leave occurs if processing is not allowed.

     *

     * @since       S60 3.2

     * @param       aEvent              External event.

     */

    void CheckStateL( TNATFWEvent aEvent ) const;

    /**

     * This method is used to change to state. Use CheckState(L) 

     * method to first verify that event is acceptable. 

     *

     * @since       S60 3.2

     * @param       aEvent              External event.

     * @return      System wide error code.

     */

    TInt ChangeState( TNATFWEvent aEvent );

    /**

     * This method is used to change to state. Use CheckState(L) 

     * method to first verify that event is acceptable. 

     *

     * @since       S60 3.2

     * @param       aEvent              External event.

     */

    void ChangeStateL( TNATFWEvent aEvent );

    /**

     * This method is used to change to state, from async states

     * to idle, depending on current state.

     *

     * @since       S60 3.2

     * @return      ETrue if session state processing can continue.

     */

    TBool Continue();

private: // data

    /**

     * Current stream state is preserved.

     */

    TNATFWAsyncState iCurrentState;

    };

#endif // NSPNATFWASYNCSTATE_H

// end of file