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
  35 //= AccessibleEventNotifier
  36
  37
  38 namespace
  39 {
  40     typedef ::std::pair< AccessibleEventNotifier::TClientId,
  41             AccessibleEventObject > ClientEvent;
  42
  43     typedef ::std::map< AccessibleEventNotifier::TClientId,
  44                 ::cppu::OInterfaceContainerHelper*,
  45                 ::std::less< AccessibleEventNotifier::TClientId > > ClientMap;
  46
  47     /// key is the end of the interval, value is the start of the interval
  48     typedef ::std::map<AccessibleEventNotifier::TClientId,
  49                 AccessibleEventNotifier::TClientId> IntervalMap;
  50
  51     struct lclMutex
  52         : public rtl::Static< ::osl::Mutex, lclMutex > {};
  53     struct Clients
  54         : public rtl::Static< ClientMap, Clients > {};
  55     struct FreeIntervals
  56         : public rtl::StaticWithInit<IntervalMap, FreeIntervals> {
  57             IntervalMap operator() () {
  58                 IntervalMap map;
  59                 map.insert(::std::make_pair(
  60                     ::std::numeric_limits<AccessibleEventNotifier::TClientId>::max(), 1));
  61                 return map;
  62             }
  63         };
  64
  65     static void releaseId(AccessibleEventNotifier::TClientId const nId)
  66     {
  67         IntervalMap & rFreeIntervals(FreeIntervals::get());
  68         IntervalMap::iterator const upper(rFreeIntervals.upper_bound(nId));
  69         assert(upper != rFreeIntervals.end());
  70         assert(nId < upper->second); // second is start of the interval!
  71         if (nId + 1 == upper->second)
  72         {
  73             --upper->second; // add nId to existing interval
  74         }
  75         else
  76         {
  77             IntervalMap::iterator const lower(rFreeIntervals.lower_bound(nId));
  78             if (lower != rFreeIntervals.end() && lower->first == nId - 1)
  79             {
  80                 // add nId by replacing lower with new merged entry
  81                 rFreeIntervals.insert(::std::make_pair(nId, lower->second));
  82                 rFreeIntervals.erase(lower);
  83             }
  84             else // otherwise just add new 1-element interval
  85             {
  86                 rFreeIntervals.insert(::std::make_pair(nId, nId));
  87             }
  88         }
  89         // currently it's not checked whether intervals can be merged now
  90         // hopefully that won't be a problem in practice
  91     }
  92
  93     /// generates a new client id
  94     static AccessibleEventNotifier::TClientId generateId()
  95     {
  96         IntervalMap & rFreeIntervals(FreeIntervals::get());
  97         assert(!rFreeIntervals.empty());
  98         IntervalMap::iterator const iter(rFreeIntervals.begin());
  99         AccessibleEventNotifier::TClientId const nFirst = iter->first;
 100         AccessibleEventNotifier::TClientId const nFreeId = iter->second;
 101         assert(nFreeId <= nFirst);
 102         if (nFreeId != nFirst)
 103         {
 104             ++iter->second; // remove nFreeId from interval
 105         }
 106         else
 107         {
 108             rFreeIntervals.erase(iter); // remove 1-element interval
 109         }
 110
 111         assert(Clients::get().end() == Clients::get().find(nFreeId));
 112
 113         return nFreeId;
 114     }
 115
 116     /** looks up a client in our client map, asserts if it cannot find it or
 117         no event thread is present
 118
 119         @precond
 120             to be called with our mutex locked
 121
 122         @param nClient
 123             the id of the client to loopup
 124         @param rPos
 125             out-parameter for the position of the client in the client map
 126
 127         @return
 128             <TRUE/> if and only if the client could be found and
 129             <arg>rPos</arg> has been filled with it's position
 130     */
 131     static bool implLookupClient(
 132             const AccessibleEventNotifier::TClientId nClient,
 133             ClientMap::iterator& rPos )
 134     {
 135         // look up this client
 136         ClientMap &rClients = Clients::get();
 137         rPos = rClients.find( nClient );
 138         OSL_ENSURE( rClients.end() != rPos,
 139             "AccessibleEventNotifier::implLookupClient: invalid client id "
 140             "(did you register your client?)!" );
 141
 142         return ( rClients.end() != rPos );
 143     }
 144 }
 145
 146
 147 namespace comphelper
 148 {
 149
 150
 151
 152     AccessibleEventNotifier::TClientId AccessibleEventNotifier::registerClient( )
 153     {
 154         ::osl::MutexGuard aGuard( lclMutex::get() );
 155
 156         // generate a new client id
 157         TClientId nNewClientId = generateId( );
 158
 159         // the event listeners for the new client
 160         ::cppu::OInterfaceContainerHelper *const pNewListeners =
 161             new ::cppu::OInterfaceContainerHelper( lclMutex::get() );
 162             // note that we're using our own mutex here, so the listener containers for all
 163             // our clients share this same mutex.
 164             // this is a reminiscense to the days where the notifier was asynchronous. Today this is
 165             // completely nonsense, and potentially slowing down the Office me thinks ...
 166
 167         // add the client
 168         Clients::get().insert( ClientMap::value_type( nNewClientId, pNewListeners ) );
 169
 170         // outta here
 171         return nNewClientId;
 172     }
 173
 174
 175     void AccessibleEventNotifier::revokeClient( const TClientId _nClient )
 176     {
 177         ::osl::MutexGuard aGuard( lclMutex::get() );
 178
 179         ClientMap::iterator aClientPos;
 180         if ( !implLookupClient( _nClient, aClientPos ) )
 181             // already asserted in implLookupClient
 182             return;
 183
 184         // remove it from the clients map
 185         delete aClientPos->second;
 186         Clients::get().erase( aClientPos );
 187         releaseId(_nClient);
 188     }
 189
 190
 191     void AccessibleEventNotifier::revokeClientNotifyDisposing( const TClientId _nClient,
 192             const Reference< XInterface >& _rxEventSource ) SAL_THROW( ( ) )
 193     {
 194         ::cppu::OInterfaceContainerHelper* pListeners(0);
 195
 196         {
 197             // rhbz#1001768 drop the mutex before calling disposeAndClear
 198             ::osl::MutexGuard aGuard( lclMutex::get() );
 199
 200             ClientMap::iterator aClientPos;
 201             if (!implLookupClient(_nClient, aClientPos))
 202                 // already asserted in implLookupClient
 203                 return;
 204
 205             // notify the listeners
 206             pListeners = aClientPos->second;
 207
 208             // we do not need the entry in the clients map anymore
 209             // (do this before actually notifying, because some client
 210             // implementations have re-entrance problems and call into
 211             // revokeClient while we are notifying from here)
 212             Clients::get().erase(aClientPos);
 213             releaseId(_nClient);
 214         }
 215
 216         // notify the "disposing" event for this client
 217         EventObject aDisposalEvent;
 218         aDisposalEvent.Source = _rxEventSource;
 219
 220         // now really do the notification
 221         pListeners->disposeAndClear( aDisposalEvent );
 222         delete pListeners;
 223     }
 224
 225
 226     sal_Int32 AccessibleEventNotifier::addEventListener(
 227         const TClientId _nClient, const Reference< XAccessibleEventListener >& _rxListener ) SAL_THROW( ( ) )
 228     {
 229         ::osl::MutexGuard aGuard( lclMutex::get() );
 230
 231         ClientMap::iterator aClientPos;
 232         if ( !implLookupClient( _nClient, aClientPos ) )
 233             // already asserted in implLookupClient
 234             return 0;
 235
 236         if ( _rxListener.is() )
 237             aClientPos->second->addInterface( _rxListener );
 238
 239         return aClientPos->second->getLength();
 240     }
 241
 242
 243     sal_Int32 AccessibleEventNotifier::removeEventListener(
 244         const TClientId _nClient, const Reference< XAccessibleEventListener >& _rxListener ) SAL_THROW( ( ) )
 245     {
 246         ::osl::MutexGuard aGuard( lclMutex::get() );
 247
 248         ClientMap::iterator aClientPos;
 249         if ( !implLookupClient( _nClient, aClientPos ) )
 250             // already asserted in implLookupClient
 251             return 0;
 252
 253         if ( _rxListener.is() )
 254             aClientPos->second->removeInterface( _rxListener );
 255
 256         return aClientPos->second->getLength();
 257     }
 258
 259
 260     void AccessibleEventNotifier::addEvent( const TClientId _nClient, const AccessibleEventObject& _rEvent ) SAL_THROW( ( ) )
 261     {
 262         Sequence< Reference< XInterface > > aListeners;
 263
 264         // --- <mutex lock> -------------------------------
 265         {
 266             ::osl::MutexGuard aGuard( lclMutex::get() );
 267
 268             ClientMap::iterator aClientPos;
 269             if ( !implLookupClient( _nClient, aClientPos ) )
 270                 // already asserted in implLookupClient
 271                 return;
 272
 273             // since we're synchronous, again, we want to notify immediately
 274             aListeners = aClientPos->second->getElements();
 275         }
 276         // --- </mutex lock> ------------------------------
 277
 278             // default handling: loop through all listeners, and notify them
 279         const Reference< XInterface >* pListeners = aListeners.getConstArray();
 280         const Reference< XInterface >* pListenersEnd = pListeners + aListeners.getLength();
 281         while ( pListeners != pListenersEnd )
 282         {
 283             try
 284             {
 285                 static_cast< XAccessibleEventListener* >( pListeners->get() )->notifyEvent( _rEvent );
 286             }
 287             catch( const Exception& )
 288             {
 289                 // no assertion, because a broken access remote bridge or something like this
 290                 // can cause this exception
 291             }
 292             ++pListeners;
 293         }
 294     }
 295
 296
 297 }   // namespace comphelper
 298
 299
 300 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */