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 <cppuhelper/interfacecontainer.h>
  24 #include <comphelper/guarding.hxx>
  25
  26 #include <map>
  27 #include <limits>
  28
  29 using namespace ::com::sun::star::uno;
  30 using namespace ::com::sun::star::lang;
  31 using namespace ::com::sun::star::accessibility;
  32 using namespace ::comphelper;
  33
  34 namespace
  35 {
  36     typedef ::std::pair< AccessibleEventNotifier::TClientId,
  37             AccessibleEventObject > ClientEvent;
  38
  39     typedef ::std::map< AccessibleEventNotifier::TClientId,
  40                 ::cppu::OInterfaceContainerHelper*,
  41                 ::std::less< AccessibleEventNotifier::TClientId > > ClientMap;
  42
  43     /// key is the end of the interval, value is the start of the interval
  44     typedef ::std::map<AccessibleEventNotifier::TClientId,
  45                 AccessibleEventNotifier::TClientId> IntervalMap;
  46
  47     struct lclMutex
  48         : public rtl::Static< ::osl::Mutex, lclMutex > {};
  49     struct Clients
  50         : public rtl::Static< ClientMap, Clients > {};
  51     struct FreeIntervals
  52         : public rtl::StaticWithInit<IntervalMap, FreeIntervals> {
  53             IntervalMap operator() () {
  54                 IntervalMap map;
  55                 map.insert(::std::make_pair(
  56                     ::std::numeric_limits<AccessibleEventNotifier::TClientId>::max(), 1));
  57                 return map;
  58             }
  59         };
  60
  61     static void releaseId(AccessibleEventNotifier::TClientId const nId)
  62     {
  63         IntervalMap & rFreeIntervals(FreeIntervals::get());
  64         IntervalMap::iterator const upper(rFreeIntervals.upper_bound(nId));
  65         assert(upper != rFreeIntervals.end());
  66         assert(nId < upper->second); // second is start of the interval!
  67         if (nId + 1 == upper->second)
  68         {
  69             --upper->second; // add nId to existing interval
  70         }
  71         else
  72         {
  73             IntervalMap::iterator const lower(rFreeIntervals.lower_bound(nId));
  74             if (lower != rFreeIntervals.end() && lower->first == nId - 1)
  75             {
  76                 // add nId by replacing lower with new merged entry
  77                 rFreeIntervals.insert(::std::make_pair(nId, lower->second));
  78                 rFreeIntervals.erase(lower);
  79             }
  80             else // otherwise just add new 1-element interval
  81             {
  82                 rFreeIntervals.insert(::std::make_pair(nId, nId));
  83             }
  84         }
  85         // currently it's not checked whether intervals can be merged now
  86         // hopefully that won't be a problem in practice
  87     }
  88
  89     /// generates a new client id
  90     static AccessibleEventNotifier::TClientId generateId()
  91     {
  92         IntervalMap & rFreeIntervals(FreeIntervals::get());
  93         assert(!rFreeIntervals.empty());
  94         IntervalMap::iterator const iter(rFreeIntervals.begin());
  95         AccessibleEventNotifier::TClientId const nFirst = iter->first;
  96         AccessibleEventNotifier::TClientId const nFreeId = iter->second;
  97         assert(nFreeId <= nFirst);
  98         if (nFreeId != nFirst)
  99         {
 100             ++iter->second; // remove nFreeId from interval
 101         }
 102         else
 103         {
 104             rFreeIntervals.erase(iter); // remove 1-element interval
 105         }
 106
 107         assert(Clients::get().end() == Clients::get().find(nFreeId));
 108
 109         return nFreeId;
 110     }
 111
 112     /** looks up a client in our client map, asserts if it cannot find it or
 113         no event thread is present
 114
 115         @precond
 116             to be called with our mutex locked
 117
 118         @param nClient
 119             the id of the client to loopup
 120         @param rPos
 121             out-parameter for the position of the client in the client map
 122
 123         @return
 124             <TRUE/> if and only if the client could be found and
 125             <arg>rPos</arg> has been filled with it's position
 126     */
 127     static bool implLookupClient(
 128             const AccessibleEventNotifier::TClientId nClient,
 129             ClientMap::iterator& rPos )
 130     {
 131         // look up this client
 132         ClientMap &rClients = Clients::get();
 133         rPos = rClients.find( nClient );
 134         OSL_ENSURE( rClients.end() != rPos,
 135             "AccessibleEventNotifier::implLookupClient: invalid client id "
 136             "(did you register your client?)!" );
 137
 138         return ( rClients.end() != rPos );
 139     }
 140 }
 141
 142
 143 namespace comphelper
 144 {
 145
 146
 147
 148     AccessibleEventNotifier::TClientId AccessibleEventNotifier::registerClient( )
 149     {
 150         ::osl::MutexGuard aGuard( lclMutex::get() );
 151
 152         // generate a new client id
 153         TClientId nNewClientId = generateId( );
 154
 155         // the event listeners for the new client
 156         ::cppu::OInterfaceContainerHelper *const pNewListeners =
 157             new ::cppu::OInterfaceContainerHelper( lclMutex::get() );
 158             // note that we're using our own mutex here, so the listener containers for all
 159             // our clients share this same mutex.
 160             // this is a reminiscense to the days where the notifier was asynchronous. Today this is
 161             // completely nonsense, and potentially slowing down the Office me thinks ...
 162
 163         // add the client
 164         Clients::get().insert( ClientMap::value_type( nNewClientId, pNewListeners ) );
 165
 166         // outta here
 167         return nNewClientId;
 168     }
 169
 170
 171     void AccessibleEventNotifier::revokeClient( const TClientId _nClient )
 172     {
 173         ::osl::MutexGuard aGuard( lclMutex::get() );
 174
 175         ClientMap::iterator aClientPos;
 176         if ( !implLookupClient( _nClient, aClientPos ) )
 177             // already asserted in implLookupClient
 178             return;
 179
 180         // remove it from the clients map
 181         delete aClientPos->second;
 182         Clients::get().erase( aClientPos );
 183         releaseId(_nClient);
 184     }
 185
 186
 187     void AccessibleEventNotifier::revokeClientNotifyDisposing( const TClientId _nClient,
 188             const Reference< XInterface >& _rxEventSource )
 189     {
 190         ::cppu::OInterfaceContainerHelper* pListeners(0);
 191
 192         {
 193             // rhbz#1001768 drop the mutex before calling disposeAndClear
 194             ::osl::MutexGuard aGuard( lclMutex::get() );
 195
 196             ClientMap::iterator aClientPos;
 197             if (!implLookupClient(_nClient, aClientPos))
 198                 // already asserted in implLookupClient
 199                 return;
 200
 201             // notify the listeners
 202             pListeners = aClientPos->second;
 203
 204             // we do not need the entry in the clients map anymore
 205             // (do this before actually notifying, because some client
 206             // implementations have re-entrance problems and call into
 207             // revokeClient while we are notifying from here)
 208             Clients::get().erase(aClientPos);
 209             releaseId(_nClient);
 210         }
 211
 212         // notify the "disposing" event for this client
 213         EventObject aDisposalEvent;
 214         aDisposalEvent.Source = _rxEventSource;
 215
 216         // now really do the notification
 217         pListeners->disposeAndClear( aDisposalEvent );
 218         delete pListeners;
 219     }
 220
 221
 222     sal_Int32 AccessibleEventNotifier::addEventListener(
 223         const TClientId _nClient, const Reference< XAccessibleEventListener >& _rxListener )
 224     {
 225         ::osl::MutexGuard aGuard( lclMutex::get() );
 226
 227         ClientMap::iterator aClientPos;
 228         if ( !implLookupClient( _nClient, aClientPos ) )
 229             // already asserted in implLookupClient
 230             return 0;
 231
 232         if ( _rxListener.is() )
 233             aClientPos->second->addInterface( _rxListener );
 234
 235         return aClientPos->second->getLength();
 236     }
 237
 238
 239     sal_Int32 AccessibleEventNotifier::removeEventListener(
 240         const TClientId _nClient, const Reference< XAccessibleEventListener >& _rxListener )
 241     {
 242         ::osl::MutexGuard aGuard( lclMutex::get() );
 243
 244         ClientMap::iterator aClientPos;
 245         if ( !implLookupClient( _nClient, aClientPos ) )
 246             // already asserted in implLookupClient
 247             return 0;
 248
 249         if ( _rxListener.is() )
 250             aClientPos->second->removeInterface( _rxListener );
 251
 252         return aClientPos->second->getLength();
 253     }
 254
 255
 256     void AccessibleEventNotifier::addEvent( const TClientId _nClient, const AccessibleEventObject& _rEvent )
 257     {
 258         Sequence< Reference< XInterface > > aListeners;
 259
 260         // --- <mutex lock> -------------------------------
 261         {
 262             ::osl::MutexGuard aGuard( lclMutex::get() );
 263
 264             ClientMap::iterator aClientPos;
 265             if ( !implLookupClient( _nClient, aClientPos ) )
 266                 // already asserted in implLookupClient
 267                 return;
 268
 269             // since we're synchronous, again, we want to notify immediately
 270             aListeners = aClientPos->second->getElements();
 271         }
 272         // --- </mutex lock> ------------------------------
 273
 274             // default handling: loop through all listeners, and notify them
 275         const Reference< XInterface >* pListeners = aListeners.getConstArray();
 276         const Reference< XInterface >* pListenersEnd = pListeners + aListeners.getLength();
 277         while ( pListeners != pListenersEnd )
 278         {
 279             try
 280             {
 281                 static_cast< XAccessibleEventListener* >( pListeners->get() )->notifyEvent( _rEvent );
 282             }
 283             catch( const Exception& )
 284             {
 285                 // no assertion, because a broken access remote bridge or something like this
 286                 // can cause this exception
 287             }
 288             ++pListeners;
 289         }
 290     }
 291
 292
 293 }   // namespace comphelper
 294
 295
 296 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */