comphelper/source/misc/accessibleeventnotifier.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 <comphelper/accessibleeventnotifier.hxx>
  21 #include <osl/diagnose.h>
  22 #include <rtl/instance.hxx>
  23 #include <comphelper/guarding.hxx>
  24
  25 using namespace ::com::sun::star::uno;
  26 using namespace ::com::sun::star::lang;
  27 using namespace ::com::sun::star::accessibility;
  28 using namespace ::comphelper;
  29
  30 //=====================================================================
  31 //= AccessibleEventNotifier
  32 //=====================================================================
  33 //---------------------------------------------------------------------
  34 namespace
  35 {
  36     struct lclMutex
  37         : public rtl::Static< ::osl::Mutex, lclMutex > {};
  38     struct Clients
  39         : public rtl::Static< AccessibleEventNotifier::ClientMap, Clients > {};
  40 }
  41
  42 //.........................................................................
  43 namespace comphelper
  44 {
  45 //.........................................................................
  46
  47     //---------------------------------------------------------------------
  48     AccessibleEventNotifier::TClientId AccessibleEventNotifier::generateId()
  49     {
  50         TClientId nBiggestUsedId = 0;
  51         TClientId nFreeId = 0;
  52
  53         // look through all registered clients until we find a "gap" in the ids
  54
  55         // Note that the following relies on the fact the elements in the map are traveled with
  56         // ascending keys (aka client ids)
  57         AccessibleEventNotifier::ClientMap &rClients = Clients::get();
  58         for (   ClientMap::const_iterator aLookup = rClients.begin();
  59                 aLookup != rClients.end();
  60                 ++aLookup
  61             )
  62         {
  63             TClientId nCurrent = aLookup->first;
  64             OSL_ENSURE( nCurrent > nBiggestUsedId, "AccessibleEventNotifier::generateId: map is expected to be sorted ascending!" );
  65
  66             if ( nCurrent - nBiggestUsedId > 1 )
  67             {   // found a "gap"
  68                 nFreeId = nBiggestUsedId + 1;
  69                 break;
  70             }
  71
  72             nBiggestUsedId = nCurrent;
  73         }
  74
  75         if ( !nFreeId )
  76             nFreeId = nBiggestUsedId + 1;
  77
  78         OSL_ENSURE( rClients.end() == rClients.find( nFreeId ),
  79             "AccessibleEventNotifier::generateId: algorithm broken!" );
  80
  81         return nFreeId;
  82     }
  83
  84     //---------------------------------------------------------------------
  85     AccessibleEventNotifier::TClientId AccessibleEventNotifier::registerClient( )
  86     {
  87         ::osl::MutexGuard aGuard( lclMutex::get() );
  88
  89         // generate a new client id
  90         TClientId nNewClientId = generateId( );
  91
  92         // the event listeners for the new client
  93         EventListeners* pNewListeners = new EventListeners( lclMutex::get() );
  94             // note that we're using our own mutex here, so the listener containers for all
  95             // our clients share this same mutex.
  96             // this is a reminiscense to the days where the notifier was asynchronous. Today this is
  97             // completely nonsense, and potentially slowing down the Office me thinks ...
  98
  99         // add the client
 100         Clients::get().insert( ClientMap::value_type( nNewClientId, pNewListeners ) );
 101
 102         // outta here
 103         return nNewClientId;
 104     }
 105
 106     //---------------------------------------------------------------------
 107     sal_Bool AccessibleEventNotifier::implLookupClient( const TClientId _nClient, ClientMap::iterator& _rPos )
 108     {
 109         // look up this client
 110         AccessibleEventNotifier::ClientMap &rClients = Clients::get();
 111         _rPos = rClients.find( _nClient );
 112         OSL_ENSURE( rClients.end() != _rPos, "AccessibleEventNotifier::implLookupClient: invalid client id (did you register your client?)!" );
 113
 114         return ( rClients.end() != _rPos );
 115     }
 116
 117     //---------------------------------------------------------------------
 118     void AccessibleEventNotifier::revokeClient( const TClientId _nClient )
 119     {
 120         ::osl::MutexGuard aGuard( lclMutex::get() );
 121
 122         ClientMap::iterator aClientPos;
 123         if ( !implLookupClient( _nClient, aClientPos ) )
 124             // already asserted in implLookupClient
 125             return;
 126
 127         // remove it from the clients map
 128         delete aClientPos->second;
 129         Clients::get().erase( aClientPos );
 130     }
 131
 132     //---------------------------------------------------------------------
 133     void AccessibleEventNotifier::revokeClientNotifyDisposing( const TClientId _nClient,
 134             const Reference< XInterface >& _rxEventSource ) SAL_THROW( ( ) )
 135     {
 136         ::osl::MutexGuard aGuard( lclMutex::get() );
 137
 138         ClientMap::iterator aClientPos;
 139         if ( !implLookupClient( _nClient, aClientPos ) )
 140             // already asserted in implLookupClient
 141             return;
 142
 143         // notify the "disposing" event for this client
 144         EventObject aDisposalEvent;
 145         aDisposalEvent.Source = _rxEventSource;
 146
 147         // notify the listeners
 148         EventListeners* pListeners = aClientPos->second;
 149
 150         // we do not need the entry in the clients map anymore
 151         // (do this before actually notifying, because some client implementations have re-entrance
 152         // problems and call into revokeClient while we are notifying from hereing)
 153         Clients::get().erase( aClientPos );
 154
 155         // now really do the notification
 156         pListeners->disposeAndClear( aDisposalEvent );
 157         delete pListeners;
 158
 159     }
 160
 161     //---------------------------------------------------------------------
 162     sal_Int32 AccessibleEventNotifier::addEventListener(
 163         const TClientId _nClient, const Reference< XAccessibleEventListener >& _rxListener ) SAL_THROW( ( ) )
 164     {
 165         ::osl::MutexGuard aGuard( lclMutex::get() );
 166
 167         ClientMap::iterator aClientPos;
 168         if ( !implLookupClient( _nClient, aClientPos ) )
 169             // already asserted in implLookupClient
 170             return 0;
 171
 172         if ( _rxListener.is() )
 173             aClientPos->second->addInterface( _rxListener );
 174
 175         return aClientPos->second->getLength();
 176     }
 177
 178     //---------------------------------------------------------------------
 179     sal_Int32 AccessibleEventNotifier::removeEventListener(
 180         const TClientId _nClient, const Reference< XAccessibleEventListener >& _rxListener ) SAL_THROW( ( ) )
 181     {
 182         ::osl::MutexGuard aGuard( lclMutex::get() );
 183
 184         ClientMap::iterator aClientPos;
 185         if ( !implLookupClient( _nClient, aClientPos ) )
 186             // already asserted in implLookupClient
 187             return 0;
 188
 189         if ( _rxListener.is() )
 190             aClientPos->second->removeInterface( _rxListener );
 191
 192         return aClientPos->second->getLength();
 193     }
 194
 195     //---------------------------------------------------------------------
 196     void AccessibleEventNotifier::addEvent( const TClientId _nClient, const AccessibleEventObject& _rEvent ) SAL_THROW( ( ) )
 197     {
 198         Sequence< Reference< XInterface > > aListeners;
 199
 200         // --- <mutex lock> -------------------------------
 201         {
 202             ::osl::MutexGuard aGuard( lclMutex::get() );
 203
 204             ClientMap::iterator aClientPos;
 205             if ( !implLookupClient( _nClient, aClientPos ) )
 206                 // already asserted in implLookupClient
 207                 return;
 208
 209             // since we're synchronous, again, we want to notify immediately
 210             aListeners = aClientPos->second->getElements();
 211         }
 212         // --- </mutex lock> ------------------------------
 213
 214             // default handling: loop through all listeners, and notify them
 215         const Reference< XInterface >* pListeners = aListeners.getConstArray();
 216         const Reference< XInterface >* pListenersEnd = pListeners + aListeners.getLength();
 217         while ( pListeners != pListenersEnd )
 218         {
 219             try
 220             {
 221                 static_cast< XAccessibleEventListener* >( pListeners->get() )->notifyEvent( _rEvent );
 222             }
 223             catch( const Exception& )
 224             {
 225                 // no assertion, because a broken access remote bridge or something like this
 226                 // can cause this exception
 227             }
 228             ++pListeners;
 229         }
 230     }
 231
 232 //.........................................................................
 233 }   // namespace comphelper
 234 //.........................................................................
 235
 236 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */