/*

* Copyright (c) 2005-2006 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:  Active Idle content observer interface.

*

*/

#ifndef M_AICONTENTOBSERVER_H

#define M_AICONTENTOBSERVER_H

#include <e32std.h>

class MAiPropertyExtension;

class RFile;

class TDesC8;

class TDesC16;

struct TAiPublisherInfo;

/**

 *  Used by AI Plug-in to give notification about modifications in

 *  content and/or internal state.

 *

 *  @since S60 3.2

 */

class MAiContentObserver

    {

public:  // New functions

    /**

     * Invoked by the plug-in to inform that it initiates content publishing

     * transaction.

     *

     * @param  aTxId - transaction Id

     * @return - Possible return values:

     *         - KErrNone - transaction is started.

     *         - KErrNotSupported - UI Controller does not support transactions,

     *         meaning that content will be rendered every time when Publish

     *         is called.

     */

    virtual TInt StartTransaction( TInt aTxId ) = 0;

    /**

     * Invoked by the plug-in to request framework that content publishing

     * transaction must be finalized and content should be rendered to the

     * screen.

     *

     * @param  aTxId - transaction Id

     * @return - Possible return values:

     *         - KErrNone - transaction is over.

     *         - KErrNotSupported - UI Controller does not support transactions,

     *         meaning that content will be rendered every time when Publish

     *         is called.

     *         - KErrNotFound - transaction with matching id has not been 

     *         started.

     *         - Any of the system-wide error codes in case of resource allocation failure.

     */

    virtual TInt Commit( TInt aTxId ) = 0;

    /**

     * Invoked by plug-in to indicate that content publishing transaction

     * must be cancelled.

     *

     * @param  aTxId - transaction Id

     * @return - Possible return values:

     *         - KErrNone - transaction is cancelled.

     *         - KErrNotSupported - UI Controller does not support transactions,

     *         meaning that content will be rendered every time when Publish

     *         is called.

     *         - KErrNotFound - transaction with matching id has not been 

     *         started.

     */

    virtual TInt CancelTransaction( TInt aTxId ) = 0;

    /**

     * Invoked by plug-in to test if the specified content can be published.

     *

     * @param  aPlugin - Plug-in property extension interface implementation.

     * @param  aContent - identification of content selector, MUST correspond

     *         single content selector supported by plug-in. The framework

     *         utilizes the selector id to match for cid and MIME type.

     * @param  aIndex - index of the content item.

     * @return ETrue - if content could be published; EFalse otherwise.

     */

    virtual TBool CanPublish( MAiPropertyExtension& aPlugin, TInt aContent, TInt aIndex ) = 0;

    /**

     * Invoked by the plug-in to inform that content identified by reference

     * aResource must be published to UI control\element identified by selector

     * aContent.

     *

     * @param  aPlugin - Plug-in property extension interface implementation.

     * @param  aContent - identification of content selector, MUST correspond

     *         single content selector supported by plug-in. The framework

     *         utilizes the selector id to match for cid and MIME type.

     * @param  aResource - identification of content reference, MUST correspond

     *         single content reference supported by plug-in. The framework

     *         utilizes the reference if to match for cid and MIME type of the

     *         content supplied with in UI definition.

     * @param  aIndex - index of the content item.

     * @return - Possible return values:

     *         - KErrNone - if content is published.

     *         - KErrNotSupported - if content selector is not supported by

     *         current UI definition.

     *         - KErrNotFound - if content reference is not found in current

     *         UI definition.

     */

    virtual TInt Publish( MAiPropertyExtension& aPlugin, TInt aContent, TInt aResource, TInt aIndex ) = 0;

    /**

     * Invoked by the plug-in to inform that textual content provided within 

     * parameter aText must be published to UI control\element identified by 

     * selector aContent.

     *

     * @param  aPlugin - Plug-in property extension interface implementation.

     * @param  aContent - identification of content selector, MUST correspond

     *         single content selector supported by plug-in. The framework

     *         utilizes the selector id to match for cid and MIME type.

     * @param  aText - Textual content in UNICODE.

     * @param  aIndex - index of the content item.

     * @return - Possible return values:

     *         - KErrNone - if content is published.

     *         - KErrNotSupported - if content selector is not supported by

     *         current UI definition.

     *         - KErrNotFound - if content reference is not found in current

     *         UI definition.

     *         - KErrArgument - if content cannot be published to UI element,

     *         e.g. MIME type mismatch.

     */

    virtual TInt Publish( MAiPropertyExtension& aPlugin, TInt aContent, const TDesC16& aText, TInt aIndex ) = 0;

    /**

     * Invoked by the plug-in to inform that content provided within buffer

     * aBuf must be published to UI control\element identified by selector

     * aContent.

     *

     * @param  aPlugin - Plug-in property extension interface implementation.

     * @param  aContent - identification of content selector, MUST correspond

     *         single content selector supported by plug-in. The framework

     *         utilizes the selector id to match for cid and MIME type.

     * @param  aBuf - instance of content.

     * @param  aIndex - index of the content item.

     * @return - Possible return values:

     *         - KErrNone - if content is published.

     *         - KErrNotSupported - if content selector is not supported by

     *         current UI definition.

     *         - KErrNotFound - if content reference is not found in current

     *         UI definition.

     *         - KErrArgument - if content cannot be published to UI element,

     *         e.g. MIME type mismatch.

     */ 

    virtual TInt Publish( MAiPropertyExtension& aPlugin, TInt aContent, const TDesC8& aBuf, TInt aIndex ) = 0;

    /**

     * Invoked by the plug-in to inform that an object provided by pointer aPtr

     * must be published to UI control\element identified by selector aContent.

     * The implementation packages the pointer to a buffer and delegates to 

     * buffer publishing method Publish(MAiPropertyExtension&, TInt, const TDesC8&, TInt).

     *

     * @param  aPlugin - Plug-in property extension interface implementation.

     * @param  aContent - identification of content selector, MUST correspond

     *         single content selector supported by plug-in. The framework

     *         utilizes the selector id to match for cid and MIME type.

     * @param  aPtr - pointer to the content object. The actual type of the 

     *         pointer is deduced based on the MIME type of the content item 

     *         identified by aContent.

     * @param  aIndex - index of the content item.

     * @return - Possible return values:

     *         - KErrNone - if content is published.

     *         - KErrNotSupported - if content selector is not supported by

     *         current UI definition.

     *         - KErrNotFound - if content reference is not found in current

     *         UI definition.

     *         - KErrArgument - if content cannot be published to UI element,

     *         e.g. MIME type mismatch.

     * @see KAiContentTypeBitmap

     */ 

    inline TInt PublishPtr( MAiPropertyExtension& aPlugin, TInt aContent, TAny* aPtr, TInt aIndex );

    /**

     * Helper function for unpacking a pointer that has been published with

     * MAiContentObserver::PublishPtr.

     *

     * @see MAiContentObserver::PublishPtr

     */

    template<class PtrT> inline static PtrT* UnpackPtr( const TDesC8& aBuf );

    /**

     * Invoked by the plug-in to inform that content from file handle aFile

     * must be published to UI control\element identified by selector aContent.

     *

     * @param  aPlugin - Plug-in property extension interface implementation.

     * @param  aContent - identification of content selector, MUST correspond

     *         single content selector supported by plug-in. The framework

     *         utilizes the selector id to match for cid and MIME type.

     * @param  aFile - file handle from where content can be obtained by UI

     *         framework.

     * @param  aIndex - index of the content item.

     * @return - Possible return values:

     *         - KErrNone - if content is published.

     *         - KErrNotSupported - if content selector is not supported by

     *         current UI definition.

     *         - KErrNotFound - if content reference is not found in current

     *         UI definition.

     *         - KErrArgument - if content cannot be published to UI element,

     *         e.g. MIME type mismatch.

     */

    virtual TInt Publish( MAiPropertyExtension& aPlugin, TInt aContent, RFile& aFile, TInt aIndex ) = 0;

    /**

     * Invoked by the plug-in to inform that content must be cleaned in UI

     * control\element identified by selector aContent.

     *

     * @param  aPlugin - Plug-in property extension interface implementation.

     * @param  aContent - identification of content selector, MUST correspond

     *         single content selector supported by plug-in. The framework

     *         utilizes the selector id to match for cid and MIME type.

     * @param  aIndex - index of the content item.

     * @return - Possible return values:

     *         - KErrNone - if content is published.

     *         - KErrNotSupported - if content selector is not supported by

     *         current UI definition.

     *         - KErrNotFound - if content reference is not found in current

     *         UI definition.

     */

    virtual TInt Clean( MAiPropertyExtension& aPlugin, TInt aContent, TInt aIndex ) = 0;

    /**

     * Returns interface extension. Not used in S60 3.2 release.

     *

     * @param  aUid - UID of the extension interface to access.

     * @return the extension interface. Actual type depends on the passed aUid 

     *         argument.

     */

    virtual TAny* Extension( TUid aUid ) = 0;

    /**

	 * Invoked by the plugin factory

	 *

	 * @param aPublsiherInfo Publisher which requires subscription

	 * @return ETrue if subsription is needed, EFalse otherwise

	 */	

    virtual TBool RequiresSubscription( const TAiPublisherInfo& aPublisherInfo ) const = 0;	    

protected:

    /**

     * Protected destructor prevents deletion through this interface.

     */

    ~MAiContentObserver() { }

    };

#include <aicontentobserver.inl>

#endif // M_AICONTENTOBSERVER_H