toolkit/source/helper/accessibilityclient.cxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  *
   9  * This file incorporates work covered by the following license notice:
  10  *
  11  *   Licensed to the Apache Software Foundation (ASF) under one or more
  12  *   contributor license agreements. See the NOTICE file distributed
  13  *   with this work for additional information regarding copyright
  14  *   ownership. The ASF licenses this file to you under the Apache
  15  *   License, Version 2.0 (the "License"); you may not use this file
  16  *   except in compliance with the License. You may obtain a copy of
  17  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  18  */
  19
  20 #include <toolkit/helper/accessibilityclient.hxx>
  21 #include <toolkit/helper/accessiblefactory.hxx>
  22 #include <osl/module.h>
  23 #include <osl/diagnose.h>
  24 #include <tools/solar.h>
  25
  26 // #define UNLOAD_ON_LAST_CLIENT_DYING
  27     // this is not recommended currently. If enabled, the implementation will log
  28     // the number of active clients, and unload the acc library when the last client
  29     // goes away.
  30     // Sounds like a good idea, unfortunately, there's no guarantee that all objects
  31     // implemented in this library are already dead.
  32     // Iow, just because an object implementing an XAccessible (implemented in this lib
  33     // here) died, it's not said that everybody released all references to the
  34     // XAccessibleContext used by this component, and implemented in the acc lib.
  35     // So we cannot really unload the lib.
  36     //
  37     // Alternatively, if the lib would us own "usage counting", i.e. every component
  38     // implemented therein would affect a static ref count, the acc lib could care
  39     // for unloading itself.
  40
  41 //........................................................................
  42 namespace toolkit
  43 {
  44 //........................................................................
  45
  46     using namespace ::com::sun::star::uno;
  47     using namespace ::com::sun::star::accessibility;
  48
  49     namespace
  50     {
  51 #ifdef UNLOAD_ON_LAST_CLIENT_DYING
  52         static oslInterlockedCount                      s_nAccessibilityClients = 0;
  53 #endif // UNLOAD_ON_LAST_CLIENT_DYING
  54 #ifndef DISABLE_DYNLOADING
  55         static oslModule                                s_hAccessibleImplementationModule = NULL;
  56 #endif
  57         static GetStandardAccComponentFactory           s_pAccessibleFactoryFunc = NULL;
  58         static ::rtl::Reference< IAccessibleFactory >   s_pFactory;
  59     }
  60
  61     //====================================================================
  62     //= AccessibleDummyFactory
  63     //====================================================================
  64     class AccessibleDummyFactory : public IAccessibleFactory
  65     {
  66     public:
  67         AccessibleDummyFactory();
  68
  69     protected:
  70         virtual ~AccessibleDummyFactory();
  71
  72     private:
  73         AccessibleDummyFactory( const AccessibleDummyFactory& );            // never implemented
  74         AccessibleDummyFactory& operator=( const AccessibleDummyFactory& ); // never implemented
  75
  76         oslInterlockedCount m_refCount;
  77
  78     public:
  79         // IReference
  80         virtual oslInterlockedCount SAL_CALL acquire();
  81         virtual oslInterlockedCount SAL_CALL release();
  82
  83         // IAccessibleFactory
  84         ::com::sun::star::uno::Reference< ::com::sun::star::accessibility::XAccessibleContext >
  85                 createAccessibleContext( VCLXButton* /*_pXWindow*/ )
  86         {
  87             return NULL;
  88         }
  89         ::com::sun::star::uno::Reference< ::com::sun::star::accessibility::XAccessibleContext >
  90                 createAccessibleContext( VCLXCheckBox* /*_pXWindow*/ )
  91         {
  92             return NULL;
  93         }
  94         ::com::sun::star::uno::Reference< ::com::sun::star::accessibility::XAccessibleContext >
  95                 createAccessibleContext( VCLXRadioButton* /*_pXWindow*/ )
  96         {
  97             return NULL;
  98         }
  99         ::com::sun::star::uno::Reference< ::com::sun::star::accessibility::XAccessibleContext >
 100                 createAccessibleContext( VCLXListBox* /*_pXWindow*/ )
 101         {
 102             return NULL;
 103         }
 104         ::com::sun::star::uno::Reference< ::com::sun::star::accessibility::XAccessibleContext >
 105                 createAccessibleContext( VCLXFixedHyperlink* /*_pXWindow*/ )
 106         {
 107             return NULL;
 108         }
 109         ::com::sun::star::uno::Reference< ::com::sun::star::accessibility::XAccessibleContext >
 110                 createAccessibleContext( VCLXFixedText* /*_pXWindow*/ )
 111         {
 112             return NULL;
 113         }
 114         ::com::sun::star::uno::Reference< ::com::sun::star::accessibility::XAccessibleContext >
 115                 createAccessibleContext( VCLXScrollBar* /*_pXWindow*/ )
 116         {
 117             return NULL;
 118         }
 119         ::com::sun::star::uno::Reference< ::com::sun::star::accessibility::XAccessibleContext >
 120                 createAccessibleContext( VCLXEdit* /*_pXWindow*/ )
 121         {
 122             return NULL;
 123         }
 124         ::com::sun::star::uno::Reference< ::com::sun::star::accessibility::XAccessibleContext >
 125                 createAccessibleContext( VCLXComboBox* /*_pXWindow*/ )
 126         {
 127             return NULL;
 128         }
 129         ::com::sun::star::uno::Reference< ::com::sun::star::accessibility::XAccessibleContext >
 130                 createAccessibleContext( VCLXToolBox* /*_pXWindow*/ )
 131         {
 132             return NULL;
 133         }
 134         ::com::sun::star::uno::Reference< ::com::sun::star::accessibility::XAccessibleContext >
 135                 createAccessibleContext( VCLXWindow* /*_pXWindow*/ )
 136         {
 137             return NULL;
 138         }
 139         ::com::sun::star::uno::Reference< ::com::sun::star::accessibility::XAccessible >
 140                 createAccessible( Menu* /*_pMenu*/, sal_Bool /*_bIsMenuBar*/ )
 141         {
 142             return NULL;
 143         }
 144     };
 145
 146     //--------------------------------------------------------------------
 147     AccessibleDummyFactory::AccessibleDummyFactory()
 148         : m_refCount(0)
 149     {
 150     }
 151
 152     //--------------------------------------------------------------------
 153     AccessibleDummyFactory::~AccessibleDummyFactory()
 154     {
 155     }
 156
 157     //--------------------------------------------------------------------
 158     oslInterlockedCount SAL_CALL AccessibleDummyFactory::acquire()
 159     {
 160         return osl_atomic_increment( &m_refCount );
 161     }
 162
 163     //--------------------------------------------------------------------
 164     oslInterlockedCount SAL_CALL AccessibleDummyFactory::release()
 165     {
 166         if ( 0 == osl_atomic_decrement( &m_refCount ) )
 167         {
 168             delete this;
 169             return 0;
 170         }
 171         return m_refCount;
 172     }
 173
 174     //====================================================================
 175     //= AccessibilityClient
 176     //====================================================================
 177     //--------------------------------------------------------------------
 178     AccessibilityClient::AccessibilityClient()
 179         :m_bInitialized( false )
 180     {
 181     }
 182
 183     //--------------------------------------------------------------------
 184 #ifndef DISABLE_DYNLOADING
 185     extern "C" { static void SAL_CALL thisModule() {} }
 186 #else
 187     extern "C" void *getStandardAccessibleFactory();
 188 #endif
 189
 190     void AccessibilityClient::ensureInitialized()
 191     {
 192         if ( m_bInitialized )
 193             return;
 194
 195         ::osl::MutexGuard aGuard( ::osl::Mutex::getGlobalMutex() );
 196
 197 #ifdef UNLOAD_ON_LAST_CLIENT_DYING
 198         if ( 1 == osl_atomic_increment( &s_nAccessibilityClients ) )
 199         {   // the first client
 200 #endif // UNLOAD_ON_LAST_CLIENT_DYING
 201             // load the library implementing the factory
 202             if ( !s_pFactory.get() )
 203             {
 204 #ifndef DISABLE_DYNLOADING
 205                 const OUString sModuleName( SVLIBRARY( "acc" ) );
 206                 s_hAccessibleImplementationModule = osl_loadModuleRelative( &thisModule, sModuleName.pData, 0 );
 207                 if ( s_hAccessibleImplementationModule != NULL )
 208                 {
 209                     const OUString sFactoryCreationFunc =
 210                         OUString("getStandardAccessibleFactory");
 211                     s_pAccessibleFactoryFunc = (GetStandardAccComponentFactory)
 212                         osl_getFunctionSymbol( s_hAccessibleImplementationModule, sFactoryCreationFunc.pData );
 213
 214                 }
 215                 OSL_ENSURE( s_pAccessibleFactoryFunc, "AccessibilityClient::ensureInitialized: could not load the library, or not retrieve the needed symbol!" );
 216 #else
 217                 s_pAccessibleFactoryFunc = getStandardAccessibleFactory;
 218 #endif
 219
 220                 // get a factory instance
 221                 if ( s_pAccessibleFactoryFunc )
 222                 {
 223                     IAccessibleFactory* pFactory = static_cast< IAccessibleFactory* >( (*s_pAccessibleFactoryFunc)() );
 224                     OSL_ENSURE( pFactory, "AccessibilityClient::ensureInitialized: no factory provided by the A11Y lib!" );
 225                     if ( pFactory )
 226                     {
 227                         s_pFactory = pFactory;
 228                         pFactory->release();
 229                     }
 230                 }
 231             }
 232
 233             if ( !s_pFactory.get() )
 234                 // the attempt to load the lib, or to create the factory, failed
 235                 // -> fall back to a dummy factory
 236                 s_pFactory = new AccessibleDummyFactory;
 237 #ifdef UNLOAD_ON_LAST_CLIENT_DYING
 238         }
 239 #endif
 240
 241         m_bInitialized = true;
 242     }
 243
 244     //--------------------------------------------------------------------
 245     AccessibilityClient::~AccessibilityClient()
 246     {
 247         if ( m_bInitialized )
 248         {
 249             ::osl::MutexGuard aGuard( ::osl::Mutex::getGlobalMutex() );
 250
 251 #ifdef UNLOAD_ON_LAST_CLIENT_DYING
 252             if( 0 == osl_atomic_decrement( &s_nAccessibilityClients ) )
 253             {
 254                 s_pFactory = NULL;
 255                 s_pAccessibleFactoryFunc = NULL;
 256                 if ( s_hAccessibleImplementationModule )
 257                 {
 258                     osl_unloadModule( s_hAccessibleImplementationModule );
 259                     s_hAccessibleImplementationModule = NULL;
 260                 }
 261             }
 262 #endif // UNLOAD_ON_LAST_CLIENT_DYING
 263         }
 264     }
 265
 266     //--------------------------------------------------------------------
 267     IAccessibleFactory& AccessibilityClient::getFactory()
 268     {
 269         ensureInitialized();
 270         OSL_ENSURE( s_pFactory.is(), "AccessibilityClient::getFactory: at least a dummy factory should have been created!" );
 271         return *s_pFactory;
 272     }
 273
 274 //........................................................................
 275 }   // namespace toolkit
 276 //........................................................................
 277
 278 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */