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     {
 149     }
 150
 151     //--------------------------------------------------------------------
 152     AccessibleDummyFactory::~AccessibleDummyFactory()
 153     {
 154     }
 155
 156     //--------------------------------------------------------------------
 157     oslInterlockedCount SAL_CALL AccessibleDummyFactory::acquire()
 158     {
 159         return osl_atomic_increment( &m_refCount );
 160     }
 161
 162     //--------------------------------------------------------------------
 163     oslInterlockedCount SAL_CALL AccessibleDummyFactory::release()
 164     {
 165         if ( 0 == osl_atomic_decrement( &m_refCount ) )
 166         {
 167             delete this;
 168             return 0;
 169         }
 170         return m_refCount;
 171     }
 172
 173     //====================================================================
 174     //= AccessibilityClient
 175     //====================================================================
 176     //--------------------------------------------------------------------
 177     AccessibilityClient::AccessibilityClient()
 178         :m_bInitialized( false )
 179     {
 180     }
 181
 182     //--------------------------------------------------------------------
 183 #ifndef DISABLE_DYNLOADING
 184     extern "C" { static void SAL_CALL thisModule() {} }
 185 #else
 186     extern "C" void *getStandardAccessibleFactory();
 187 #endif
 188
 189     void AccessibilityClient::ensureInitialized()
 190     {
 191         if ( m_bInitialized )
 192             return;
 193
 194         ::osl::MutexGuard aGuard( ::osl::Mutex::getGlobalMutex() );
 195
 196 #ifdef UNLOAD_ON_LAST_CLIENT_DYING
 197         if ( 1 == osl_atomic_increment( &s_nAccessibilityClients ) )
 198         {   // the first client
 199 #endif // UNLOAD_ON_LAST_CLIENT_DYING
 200             // load the library implementing the factory
 201             if ( !s_pFactory.get() )
 202             {
 203 #ifndef DISABLE_DYNLOADING
 204                 const ::rtl::OUString sModuleName( SVLIBRARY( "acc" ) );
 205                 s_hAccessibleImplementationModule = osl_loadModuleRelative( &thisModule, sModuleName.pData, 0 );
 206                 if ( s_hAccessibleImplementationModule != NULL )
 207                 {
 208                     const ::rtl::OUString sFactoryCreationFunc =
 209                         ::rtl::OUString("getStandardAccessibleFactory");
 210                     s_pAccessibleFactoryFunc = (GetStandardAccComponentFactory)
 211                         osl_getFunctionSymbol( s_hAccessibleImplementationModule, sFactoryCreationFunc.pData );
 212
 213                 }
 214                 OSL_ENSURE( s_pAccessibleFactoryFunc, "AccessibilityClient::ensureInitialized: could not load the library, or not retrieve the needed symbol!" );
 215 #else
 216                 s_pAccessibleFactoryFunc = getStandardAccessibleFactory;
 217 #endif
 218
 219                 // get a factory instance
 220                 if ( s_pAccessibleFactoryFunc )
 221                 {
 222                     IAccessibleFactory* pFactory = static_cast< IAccessibleFactory* >( (*s_pAccessibleFactoryFunc)() );
 223                     OSL_ENSURE( pFactory, "AccessibilityClient::ensureInitialized: no factory provided by the A11Y lib!" );
 224                     if ( pFactory )
 225                     {
 226                         s_pFactory = pFactory;
 227                         pFactory->release();
 228                     }
 229                 }
 230             }
 231
 232             if ( !s_pFactory.get() )
 233                 // the attempt to load the lib, or to create the factory, failed
 234                 // -> fall back to a dummy factory
 235                 s_pFactory = new AccessibleDummyFactory;
 236 #ifdef UNLOAD_ON_LAST_CLIENT_DYING
 237         }
 238 #endif
 239
 240         m_bInitialized = true;
 241     }
 242
 243     //--------------------------------------------------------------------
 244     AccessibilityClient::~AccessibilityClient()
 245     {
 246         if ( m_bInitialized )
 247         {
 248             ::osl::MutexGuard aGuard( ::osl::Mutex::getGlobalMutex() );
 249
 250 #ifdef UNLOAD_ON_LAST_CLIENT_DYING
 251             if( 0 == osl_atomic_decrement( &s_nAccessibilityClients ) )
 252             {
 253                 s_pFactory = NULL;
 254                 s_pAccessibleFactoryFunc = NULL;
 255                 if ( s_hAccessibleImplementationModule )
 256                 {
 257                     osl_unloadModule( s_hAccessibleImplementationModule );
 258                     s_hAccessibleImplementationModule = NULL;
 259                 }
 260             }
 261 #endif // UNLOAD_ON_LAST_CLIENT_DYING
 262         }
 263     }
 264
 265     //--------------------------------------------------------------------
 266     IAccessibleFactory& AccessibilityClient::getFactory()
 267     {
 268         ensureInitialized();
 269         OSL_ENSURE( s_pFactory.is(), "AccessibilityClient::getFactory: at least a dummy factory should have been created!" );
 270         return *s_pFactory;
 271     }
 272
 273 //........................................................................
 274 }   // namespace toolkit
 275 //........................................................................
 276
 277 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */