1 /*

     2 * Copyright (c) 2009 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:  Meeting Request calendar info object extension

    15 *

    16 */

    17 

    18 #ifndef CEMAILEXTENSIONBASE_H

    19 #define CEMAILEXTENSIONBASE_H

    20 

    21 #include <e32base.h>

    22 

    23 /**

    24 * Base class for extensions. Instances of subclasses are requested from

    25 * CExtendableEmail::ExtensionL() with specific extension UID.

    26 * When client has ended using an extension it must be released with

    27 * CExtendableEmail::ReleaseExtension().

    28 * @since s60 v5.0

    29 */

    30 class CEmailExtension : public CBase

    31 {

    32 

    33 public: 

    34     IMPORT_C ~CEmailExtension();

    35 protected:    

    36     IMPORT_C CEmailExtension( const TUid& aUid );

    37 public:

    38     

    39     /**         

    40     * returns extension uid

    41     * @return   uid of the extension.

    42     */

    43     IMPORT_C TUid Uid() const;

    44 

    45 public: // for internal use

    46                            

    47     /**

    48     * Decrement reference count.

    49     * @return new value of ref count

    50     */                           

    51     TUint DecRef();

    52     

    53     /**

    54     * Increment reference count.

    55     */                           

    56     void IncRef();

    57         

    58 private:

    59 

    60     

    61     // extension interface UID defined by specific interface.

    62     const TUid iUid;    

    63     

    64     // Reference count is needed because more than one client may request

    65     // same extension (e.g. UI and protocol plugin).

    66     TUint iRefCount;

    67 };

    68 

    69 /**

    70 * helper class for managing extensions. In most cases needed only

    71 * by CExtendableEmail when extensions are created/released. Proto

    72 * @since s60 v5.0

    73 */

    74 class TEmailExtensions

    75 {

    76 public:

    77 

    78     /**

    79      * c++ constructor

    80      */

    81     IMPORT_C TEmailExtensions();

    82     

    83     /**

    84      * Destructor

    85      */

    86     IMPORT_C ~TEmailExtensions();

    87                        

    88     /**

    89      * Returns extension index in iExtensions

    90      @ return extension index or KErrNotFound

    91      */

    92     IMPORT_C TInt FindExtension( const TUid& aUid ) const;

    93     

    94     /**

    95      * Returns extension by index or panics if invalid index is given

    96      * @param aIndex index in iExtensions

    97      * @panic EEmailExtensionIndexOutOfRange if index is out of range

    98      * @return extension

    99      */

   100     IMPORT_C CEmailExtension* Extension( const TInt aIndex ) const;

   101     

   102     /**

   103      * Adds extension to iExtensions array and increments its ref count by one.

   104      *

   105      * @param aExtenstion   extension to add

   106      * @leave KErrArgument  if aExtension is NULL

   107      */

   108     IMPORT_C void AddL( CEmailExtension* aExtension );

   109 

   110     /**

   111      * Removes extension from iExtensions

   112      * @param aExtenstion extension to remove

   113      */

   114     IMPORT_C void Remove( const CEmailExtension* aExtension );

   115     

   116 private:    

   117     // array of extensions

   118     RPointerArray<CEmailExtension> iExtensions;

   119 };

   120 

   121 /**                 

   122 * Classes that support email extension mechanism by returning extensions by

   123 * uid should have this as base class.

   124 *

   125 * @since s60 v5.0

   126 */                 

   127 class CExtendableEmail : public CBase

   128 {

   129 public:

   130     /**

   131     * Decrements extension reference count and deletes if count reaches 0.

   132     * Derived class must call this if it overrides this method.

   133     * @param aExtension extension to release

   134     */

   135     IMPORT_C virtual void ReleaseExtension( CEmailExtension* aExtension );

   136 

   137     /**

   138     * Requests extension. Default implementation performs lookup only and

   139     * derived class should implement actual instantiation because it knows

   140     * extensions it supports. Derived class must always call this to ensure

   141     * that extension is not created twice.

   142     *

   143     * @param aExtension extension to release

   144     */

   145     IMPORT_C virtual CEmailExtension* ExtensionL( const TUid& aInterfaceUid );

   146 

   147 protected:    

   148     // extension containment

   149     TEmailExtensions iExtensions;

   150 };

   151 

   152 #endif // CEMAILEXTENSIONBASE_H