1 /*

     2 * Copyright (c) 2006 Nokia Corporation and/or its subsidiary(-ies).

     3 * All rights reserved.

     4 * This component and the accompanying materials are made available

     5 * under the terms of "Eclipse Public License v1.0"

     6 * which accompanies this distribution, and is available

     7 * at the URL "http://www.eclipse.org/legal/epl-v10.html".

     8 *

     9 * Initial Contributors:

    10 * Nokia Corporation - initial contribution.

    11 *

    12 * Contributors:

    13 *

    14 * Description:   Contains MNcdNodePreview

    15 *

    16 */

    17 

    18 

    19 #ifndef M_NCD_NODE_PREVIEW_H

    20 #define M_NCD_NODE_PREVIEW_H

    21 

    22 

    23 #include <e32cmn.h>

    24 

    25 #include "catalogsbase.h"

    26 #include "ncdinterfaceids.h"

    27 

    28 

    29 class MNcdDownloadOperation;

    30 class MNcdDownloadOperationObserver;

    31 class RFile;

    32 

    33 /**

    34  *  This interface is provided if the node contains preview content.

    35  *  One node may contain multiple preview items.

    36  *

    37  *  

    38  */

    39 class MNcdNodePreview : public virtual MCatalogsBase

    40     {

    41 

    42 public:

    43 

    44     /**

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

    46      *

    47      * 

    48      */

    49     enum { KInterfaceUid = ENcdNodePreviewUid };

    50 

    51 

    52     /**

    53      * Gives the number of previews of the node.

    54      *

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

    56      * that informs how many previews are available. So, the information

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

    58      * data of the wanted preview, LoadPreviewL has to be called.

    59      *

    60      * @return The number of preview items.

    61      */

    62     virtual TInt PreviewCount() const = 0;

    63 

    64 

    65     /**

    66      * IsPreviewLoadedL informs if the preview has already been loaded for the

    67      * node. Then, call of LoadPreviewL is not necessary.

    68      *

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

    70      * @return ETrue if the preview has already been loaded, EFalse otherwise.

    71      * @exception Panic ENcdPanicIndexOutOfRange Array index out of range.

    72      */

    73     virtual TBool IsPreviewLoadedL( TInt aIndex ) const = 0;

    74 

    75 

    76     /**

    77      * Gives the mime type of the preview data.

    78      *

    79      * This mime type is set according to the information gotten

    80      * from the protocol if any. So, this information is available before 

    81      * calling LoadPreviewL for the preview item of the given index. 

    82      *

    83      * @note If the mime type is not received in protocol responses, it is

    84      * taken from Content-Type HTTP header after the preview has been downloaded

    85      * successfully

    86      *

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

    88      * @return The mime type of the preview data. The type is

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

    90      * Ownership is transferred. If the protocol has not defined

    91      * any value, KNullDesC is returned.

    92      * @exception Panic ENcdPanicIndexOutOfRange Array index out of range.

    93      */

    94     virtual const TDesC& PreviewMimeType( TInt aIndex ) const = 0;

    95 

    96 

    97     /**

    98      * Loads the preview data from the internet.

    99      *

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

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

   102      * is not needed anymore.

   103      *

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

   105      * @param aObserver Observer for the operation.

   106      * @return Pointer to an operation object that handles

   107      *  the preview data downloading. This operation can be used

   108      *  to check the progressing of the preview download. Counted, Release() must

   109      *  be called after use.

   110      * @exception Leave System wide error codes.

   111      *  KNcdErrorParallelOperationNotAllowed if a parallel client is running

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

   113      * @exception Panic ENcdPanicIndexOutOfRange Array index out of range.

   114      */

   115     virtual MNcdDownloadOperation* LoadPreviewL( TInt aIndex,

   116         MNcdDownloadOperationObserver* aObserver ) = 0;

   117 

   118 

   119     /**

   120      * Gives the preview data file.

   121      *

   122      * @note RFile handle can be used to get the unifying id for example

   123      * using RFile::FullName.

   124      * @note The MIME type of the preview may be found automatically

   125      * from the preview data by Symbian methods.

   126      *

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

   128      * @return Handle to a file containing the preview data. Ownership is transferred.

   129      *  So, the user has to call Close when the file is not needed anymore.

   130      * @exception KErrNotFound if the corresponding preview data 

   131      *  has not been downloaded for the specified preview item.

   132      * @exception Leave System wide error codes.

   133      * @exception Panic ENcdPanicIndexOutOfRange Array index out of range.

   134      */

   135     virtual RFile PreviewFileL( TInt aIndex ) const = 0;

   136 

   137 

   138 protected:

   139 

   140     /**

   141      * Destructor.

   142      * 

   143      * @see MCatalogsBase::~MCatalogsBase()

   144      */

   145     virtual ~MNcdNodePreview() {}

   146 

   147     };

   148 

   149 

   150 #endif // M_NCD_NODE_PREVIEW_H