/*

* Copyright (c) 2006-2007 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:  Processor object for running thumbnail requests

*

*/

#ifndef THUMBNAILREQUESTQUEUE_H

#define THUMBNAILREQUESTQUEUE_H

#include <e32base.h>

#include "thumbnailmanager.h"

class CThumbnailRequestActive;

/**

 *  Processor object for running queued tasks.

 *

 *  @since S60 v5.0

 */

class CThumbnailRequestQueue: public CBase

    {

public:

    /**

     * Two-phased constructor.

     *

     * @since S60 v5.0

     * @return Instance of CThumbnailRequestQueue.

     */

    static CThumbnailRequestQueue* NewL();

    /**

     * Destructor

     *

     * @since S60 v5.0

     */

    virtual ~CThumbnailRequestQueue();

    /**

     * Activates next request if possible.

     *

     * @since S60 v5.0

     */

    void Process();

    /**

     * Adds new request to the queue.

     *

     * @since S60 v5.0

     * @param aRequest Request to be added to the queue.

     */

    void AddRequestL( CThumbnailRequestActive* aRequest );

    /**

     * Cancels request in the queue.

     *

     * @since S60 v5.0

     * @param aId Request to be canceled.

     * @return Error code.

     */

    TInt CancelRequest( const TThumbnailRequestId aId );

    /**

     * Change priority of a request.

     *

     * @since S60 v5.0

     * @param aId Request to be canceled.

     * @param aNewPriority New priority.

     * @return Error code.

     */

    TInt ChangePriority( const TThumbnailRequestId aId, const TInt aNewPriority );

    /**

     * Marks request complete.

     *

     * @since S60 v5.0

     */

    void RequestComplete(CThumbnailRequestActive* aRequestAO = NULL);

    /**

     * Removes completed requests.

     *

     * @since S60 v5.0

     */

	void RemoveCompleted(CThumbnailRequestActive* aRequestAO);

private:

    /**

     * C++ default constructor

     *

     * @since S60 v5.0

     * @return Instance of CThumbnailRequestQueue.

     */

    CThumbnailRequestQueue();

    /**

     * Symbian 2nd phase constructor can leave.

     *

     * @since S60 v5.0

     */

    void ConstructL();

private:

    /**

     * Array of active objects for each pending thumbnail request.

     */

    RPointerArray <CThumbnailRequestActive> iRequests;

    // number of currently active requests

    TInt iActiveRequests;

};

#endif // THUMBNAILREQUESTQUEUE_H