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         EventListeners * pListeners(0);
 137
 138         {
 139             // rhbz#1001768 drop the mutex before calling disposeAndClear
 140             ::osl::MutexGuard aGuard( lclMutex::get() );
 141
 142             ClientMap::iterator aClientPos;
 143             if (!implLookupClient(_nClient, aClientPos))
 144                 // already asserted in implLookupClient
 145                 return;
 146
 147             // notify the listeners
 148             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
 152             // implementations have re-entrance problems and call into
 153             // revokeClient while we are notifying from here)
 154             Clients::get().erase(aClientPos);
 155         }
 156
 157         // notify the "disposing" event for this client
 158         EventObject aDisposalEvent;
 159         aDisposalEvent.Source = _rxEventSource;
 160
 161         // now really do the notification
 162         pListeners->disposeAndClear( aDisposalEvent );
 163         delete pListeners;
 164     }
 165
 166     //---------------------------------------------------------------------
 167     sal_Int32 AccessibleEventNotifier::addEventListener(
 168         const TClientId _nClient, const Reference< XAccessibleEventListener >& _rxListener ) SAL_THROW( ( ) )
 169     {
 170         ::osl::MutexGuard aGuard( lclMutex::get() );
 171
 172         ClientMap::iterator aClientPos;
 173         if ( !implLookupClient( _nClient, aClientPos ) )
 174             // already asserted in implLookupClient
 175             return 0;
 176
 177         if ( _rxListener.is() )
 178             aClientPos->second->addInterface( _rxListener );
 179
 180         return aClientPos->second->getLength();
 181     }
 182
 183     //---------------------------------------------------------------------
 184     sal_Int32 AccessibleEventNotifier::removeEventListener(
 185         const TClientId _nClient, const Reference< XAccessibleEventListener >& _rxListener ) SAL_THROW( ( ) )
 186     {
 187         ::osl::MutexGuard aGuard( lclMutex::get() );
 188
 189         ClientMap::iterator aClientPos;
 190         if ( !implLookupClient( _nClient, aClientPos ) )
 191             // already asserted in implLookupClient
 192             return 0;
 193
 194         if ( _rxListener.is() )
 195             aClientPos->second->removeInterface( _rxListener );
 196
 197         return aClientPos->second->getLength();
 198     }
 199
 200     //---------------------------------------------------------------------
 201     void AccessibleEventNotifier::addEvent( const TClientId _nClient, const AccessibleEventObject& _rEvent ) SAL_THROW( ( ) )
 202     {
 203         Sequence< Reference< XInterface > > aListeners;
 204
 205         // --- <mutex lock> -------------------------------
 206         {
 207             ::osl::MutexGuard aGuard( lclMutex::get() );
 208
 209             ClientMap::iterator aClientPos;
 210             if ( !implLookupClient( _nClient, aClientPos ) )
 211                 // already asserted in implLookupClient
 212                 return;
 213
 214             // since we're synchronous, again, we want to notify immediately
 215             aListeners = aClientPos->second->getElements();
 216         }
 217         // --- </mutex lock> ------------------------------
 218
 219             // default handling: loop through all listeners, and notify them
 220         const Reference< XInterface >* pListeners = aListeners.getConstArray();
 221         const Reference< XInterface >* pListenersEnd = pListeners + aListeners.getLength();
 222         while ( pListeners != pListenersEnd )
 223         {
 224             try
 225             {
 226                 static_cast< XAccessibleEventListener* >( pListeners->get() )->notifyEvent( _rEvent );
 227             }
 228             catch( const Exception& )
 229             {
 230                 // no assertion, because a broken access remote bridge or something like this
 231                 // can cause this exception
 232             }
 233             ++pListeners;
 234         }
 235     }
 236
 237 //.........................................................................
 238 }   // namespace comphelper
 239 //.........................................................................
 240
 241 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */