/*

* Copyright (c) 2006 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:   Contains MNcdNodeScreenshot interface

*

*/

#ifndef M_NCD_NODE_SCREENSHOT_H

#define M_NCD_NODE_SCREENSHOT_H

#include <e32cmn.h>

#include "catalogsbase.h"

#include "ncdinterfaceids.h"

class MNcdDownloadOperation;

class MNcdDownloadOperationObserver;

/**

 *  This interface is provided for the node if it contains screenshots.

 *  The node may contains multiple screenshots.

 *

 *  

 */

class MNcdNodeScreenshot : public virtual MCatalogsBase

    {

public:

    /**

     * Unique identifier for the interface, required for all MCatalogsBase interfaces.

     *

     * 

     */

    enum { KInterfaceUid = ENcdNodeScreenshotUid };

    /**

     * Gives the number of the screenshots for the node.

     * 

     * @note This count is given according to the protocol information

     * that informs how many screenshots for the node are available. So, the information

     * can be asked before calling LoadScreenshotL. But, to get the

     * data of the wanted screenshot, LoadScreenshotL has to be called.

     *

     * 

     * @return The number of screenshots.

     */

     virtual TInt ScreenshotCount() const = 0;

    /**

     * Gives the mime type of the screenshot data.

     *

     * @note This mime type is set according to the information gotten

     * from the protocol. So, this information is available before calling

     * LoadScreenshotL for the screenshot item of the given index.

     *

     * @note Current servers do not send mime types for screenshots so

     * this always returns KNullDesC

     * 

     * @param aIndex tells which one of the screenshots is wanted.

     * @return The mime type of the screenshot data. The type is

     *  given as a text according to the standards that define MIME types.

     *  If the protocol has not defined

     *  any value, an empty string is returned.

     * @exception Panic ENcdPanicIndexOutOfRange Index out of range.

     */

    virtual const TDesC& ScreenshotMimeType( TInt aIndex ) const = 0;

    /**

     * Downloads the screenshot file. The screenshot is not handled by the engine,

     * the screenshot data should be handled by the user of this interface as it

     * sees fit.

     *

     * @note The reference count of the operation object is increased by one. 

     * So, Release() function of the operation should be called when the operation 

     * is not needed anymore.

     *

     * @note If a download operation has already been started for the specified

     *  screenshot, the already existing operation object is returned.

     *

     * 

     * @param aIndex Index of the screenshot that should be loaded.

     * @param aObserver Observer for the operation.

     * @return Pointer to an operation object that can 

     *  be used to check the progressing of the screenshot loading. Counted,

     *  Release() must be called after use.

     * @exception Leave System wide error codes.

     *  Leave with KNcdErrorParallelOperationNotAllowed if a parallel client is running

     *  an operation for the same metadata. See MNcdOperation for full explanation.

     * @exception Panic ENcdPanicIndexOutOfRange Index out of range.

     */ 

     virtual MNcdDownloadOperation* LoadScreenshotL( TInt aIndex,

         MNcdDownloadOperationObserver* aObserver ) = 0;

    /**

     * Gives the data of the loaded screenshot.

     *

     *  The MIME type of the screenshot may be found automatically

     *  from the screenshot data by Symbian methods.

     *

     * 

     * @param aIndex is the index of the screenshot.

     * @return Data of the loaded screenshot. Ownership is

     *  transferred. NULL if the data has not been loaded.

     * @exception Leave System wide error codes.

     * @exception Panic ENcdPanicIndexOutOfRange Index out of range.

     */

     virtual HBufC8* ScreenshotDataL( TInt aIndex ) const = 0;

protected:

    /**

    * Destructor.

    *

    * @see MCatalogsBase::~MCatalogsBase

    */

    virtual ~MNcdNodeScreenshot() {}

    };

#endif // M_NCD_NODE_SCREENSHOT_H