/*

* 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:  

*  Version     : 2 << Don't touch! Updated by Synergy at check-out.

*

*/

#ifndef MMITEMSDATACACHE_H

#define MMITEMSDATACACHE_H

#include <e32base.h>

#include <e32cmn.h>

class CMmCacheForItem;

/**

 * Provides a cache of data needed to draw every item in grid or list view.

 * This class is only used by CMmListBoxItemDrawer.

 */

NONSHARABLE_CLASS( CMmItemsDataCache ): public CBase

    {

public:

    /**

     * Creates new CMmItemsDataCache object. 

     */

    static CMmItemsDataCache* NewLC();

    /**

     * Creates new CMmItemsDataCache object.

     */

    static CMmItemsDataCache* NewL();

    /**

     * Returns item cache object for an item at specified index.

     * 

     * @param aItemIndex Item index

     * @return Item cache object.

     */

    CMmCacheForItem* GetItemCacheL( TInt aItemIndex );

    /**

     * Gets an integer identifier of a template of given name.

     * The identifier is guaranteed to be unique among other

     * identifiers obtained from this instance of CMmItemsDataCache

     * object.

     * Such identifier can be used to perform fast template

     * comparisons in the CMmListBoxItemDrawer code.

     * @c TMmSubcellsSetupCode code assumes that the template

     * identifier will not exceed 255. Assumption will be met unless

     * there are more that 256 different templates used in one suite

     * which is extremely unlikely.

     * 

     * @param aTemplateName Name of a template.

     * @return Template identifier based on template name.

     */

    TInt GetTemplateIdentifierL( const TDesC8& aTemplateName );

    /**

     * Translates a template identifier obtained from @c GetTemplateIdentifierL

     * into a regular string containing template name.

     * 

     * @param aTemplateIdentifier Template identifier from GetTemplateIdentifierL.

     * @return Template name.

     */

    const TDesC8& GetTemplateNameByIdentifier( TInt aTemplateIdentifier ) const;

    /**

     * Marks the whole data in cache as outdated so that

     * it cannot possibly be used until it is updated by

     * setting up subcells in normal (non-cached) mode.

     */

    void Invalidate();

    /**

     * Reduces the number of cache entries to given number.

     * If there are less entries than aItemCount then nothing

     * is done.

     * 

     * @param aItemCount number of items to store cached data for

     */

    void Trim( TInt aItemCount );

    /**

     * Standard C++ virtual destructor. 

     */

    ~CMmItemsDataCache();

protected:

    /**

     * Standard C++ constructor.

     */

    CMmItemsDataCache();

    /**

     * 2nd phase constructor.

     */

    void ConstructL();

protected: // data

    /**

     * Array of cache objects for individual items.

     * Own.

     */

    RPointerArray<CMmCacheForItem> iItemCacheArr;

    /**

     * Array of template names used by @c GetTemplateIdentifierL and

     * @c GetTemplateNameByIdentifier methods. Template identifiers

     * that @c GetTemplateIdentifierL returns are in fact indices in

     * this array.

     * Own. Contents of the array owned too.

     */

    RPointerArray<HBufC8> iTemplateNames;

    };

#endif // MMITEMSDATACACHE_H