/*

* 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:    

*

*/

#ifndef C_STUNASYNCCALLBACK_H

#define C_STUNASYNCCALLBACK_H

// INCLUDES

#include <e32base.h>

#include "tstunplugincallbackinfo.h"

// FORWARD DECLARATIONS

class MNATFWPluginObserver;

// CLASS DECLARATION

/**

 * CStunAsyncCallback is an active object used to guarantee that when the

 * function calls to the MNATFWPluginObserver are made, the upper layer 

 * can delete any STUN plugin related object it owns.

 */

class CStunAsyncCallback : public CActive

    {

    friend class UT_CNATFWStunConnectionHandler;

public: // Constructor and destructor

    /**

     * Two-phased constructor.

     * @param aStunPlugin The STUN plugin instance

     * @param aObserver Observer implementing the callback functions

     */

    static CStunAsyncCallback* NewL( 

        const CNATFWPluginApi& aStunPlugin, 

        MNATFWPluginObserver& aObserver );

    /**     

     * Frees the resources of CStunAsyncCallback. Any issued callback 

     * request that have not yet been executed, are discarded.

     *

     * @since   s60 3.2

     */

    ~CStunAsyncCallback();

public: // New functions

    /**

     * Orders a specified callback function to be called, and provides all

     * necessary parameters.

     *

     * @since   s60 3.2     

     * @param   aFunction Identifies the function of MNATFWPluginObserver to 

     *          use

     * @param   aStreamId   Stream ID

     * @param   aErrorCode  Error reason

     * @param   aEventData  Event data

     */

    void MakeCallbackL( TStunPluginCallbackInfo::TFunction aFunction,

                        TUint aStreamId,

                        TInt aErrorCode,

                        TAny* aEventData );

    /**

     * Removes all pending callbacks, which have the specified stream id as a

     * parameter.

     *

     * @since   s60 3.2

     * @param   aStreamId   Stream ID

     */

    void CancelCallback( TUint aStreamId );

protected: // From CActive

    /**

     * from CActive

     */

    void DoCancel();

    /**

     * from CActive

     */

    void RunL();

    /**

     * from CActive

     */

    TInt RunError( TInt aError );

private: // Constructors

    CStunAsyncCallback();

    CStunAsyncCallback( const CNATFWPluginApi& aStunPlugin, 

        MNATFWPluginObserver& aObserver );

    CStunAsyncCallback( const CStunAsyncCallback& aAsyncCallback );

private: // New functions, for internal use

    /**

     * Starts waiting for MakeCallbackL events.

     *

     * @since   s60 3.2

     */

    void WaitForRequestsL();

    /**

     * Wakes system up.

     *

     * @since   s60 3.2

     */

    void Wakeup();

    /**

     * Calls the oldest callback entry, if any.

     *

     * @since   s60 3.2

     */

    void ExecuteFirstCallback();

private: // Data

    /**

     * STUN plugin instance

     */

    const CNATFWPluginApi& iStunPlugin;

    /**

     * Implements the callback functions

     */

    MNATFWPluginObserver& iObserver;

    /**

     * Callback requests that have not yet been executed

     */

    TSglQue<TStunPluginCallbackInfo> iPendingCallbacks;

    };

#endif // C_STUNASYNCCALLBACK_H