/*

* Copyright (c) 2002 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 CPbkThumbnailManager implementation classes.

*

*/

#ifndef __CPbkThumbnailReaderBase_H__

#define __CPbkThumbnailReaderBase_H__

//  INCLUDES

#include <e32base.h>

#include "CPbkThumbnailManagerImpl.h"

#include "MPbkImageReaderObserver.h"

//  FORWARD DECLARATIONS

class MPbkThumbnailGetObserver;

class CPbkImageReader;

class MPbkThumbnailGetImageObserver;

class MPbkImageData;

class CPbkImageDataWithInfo;

class TPbkImageLoadParameters;

// CLASS DECLARATION

/**

 * Implementation base class for thumbnail readers.

 */

NONSHARABLE_CLASS(CPbkThumbnailReaderBase) : 

        public CBase, 

        public MPbkThumbnailReader,

        private MPbkImageReaderObserver

    {

    protected: // interface

        /**

         * Constructor.

		 * @param aObserver thumbnail get observer

         */

        CPbkThumbnailReaderBase(MPbkThumbnailGetObserver& aObserver);

        /**

         * Second phase constructor.

         */

        void ConstructL();

        /**

         * Destructor. Cancels any previously executing read operation and

         * destroys this object.

         */

        ~CPbkThumbnailReaderBase();

        /**

         * Returns the image reader.

         */

        CPbkImageReader& ImageReader()

			{

			return *iImageReader;

			}

    public:  // from MPbkThumbnailReader

        void CancelRead();

    private:  // from MPbkImageReaderObserver

        void ImageReadComplete(CPbkImageReader& aReader, CFbsBitmap* aBitmap);

        void ImageReadFailed(CPbkImageReader& aReader, TInt aError);

    private: // data members

        /// Ref: observer

        MPbkThumbnailGetObserver& iObserver;

        /// Own: image reader

        CPbkImageReader* iImageReader;

    };

/**

 * Implementation base class for thumbnail image readers.

 */

NONSHARABLE_CLASS(CPbkThumbnailImageReaderBase) : 

        public CBase, 

        public MPbkThumbnailReader,

        private MPbkImageReaderObserver

    {

    protected: // Interface

        /**

         * Constructor.

         * @param aObserver observer to notify about progress of this 

         *        operation

         */

        CPbkThumbnailImageReaderBase

            (MPbkThumbnailGetImageObserver& aObserver);

        /**

         * Second phase constructor.

         */

        void ConstructL();

        /**

         * Destructor. Cancels any previously executing read operation and

         * destroys this object.

         */

        ~CPbkThumbnailImageReaderBase();

        /**

         * Returns the image reader.

         */

        CPbkImageReader& ImageReader()

			{

			return *iImageReader;

			}

    private:  // Abstract interface for derived classes

        /**

         * Starts image reader.

         * 

         * @param aParameters  Optional parameters for resulting thumbnail

         */

        virtual void DoStartReadL

			(const TPbkImageLoadParameters* aParameters = NULL) =0;

        /**

         * Creates and returns an image data object.

         */

        virtual MPbkImageData* CreateImageDataLC() =0;

    public:  // From MPbkThumbnailReader

        void StartReadL(const TPbkImageLoadParameters* aParameters = NULL);

        void CancelRead();

    private:  // From MPbkImageReaderObserver

        void ImageReadComplete

            (CPbkImageReader& aReader, CFbsBitmap* aBitmap);

        void ImageReadFailed(CPbkImageReader& aReader, TInt aError);

        void ImageOpenComplete(CPbkImageReader& aReader);

    private: // Implementation

        void HandleImageOpenCompleteL();

    private: // data members

        /// Ref: observer

        MPbkThumbnailGetImageObserver& iObserver;

        /// Own: image reader

        CPbkImageReader* iImageReader;

        /// Own: image data

        CPbkImageDataWithInfo* iImageData;

    };

#endif // __CPbkThumbnailReaderBase_H__

// End of File