src/common/evtloopcmn.cpp

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/common/evtloopcmn.cpp
   3 // Purpose:     common wxEventLoop-related stuff
   4 // Author:      Vadim Zeitlin
   5 // Modified by:
   6 // Created:     2006-01-12
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) 2006 Vadim Zeitlin <vadim@wxwindows.org>
   9 // Licence:     wxWindows licence
  10 ///////////////////////////////////////////////////////////////////////////////
  11
  12 // for compilers that support precompilation, includes "wx.h".
  13 #include "wx/wxprec.h"
  14
  15 #ifdef __BORLANDC__
  16     #pragma hdrstop
  17 #endif
  18
  19 #include "wx/evtloop.h"
  20
  21 #ifndef WX_PRECOMP
  22     #include "wx/app.h"
  23 #endif //WX_PRECOMP
  24
  25 // ----------------------------------------------------------------------------
  26 // wxEventLoopBase
  27 // ----------------------------------------------------------------------------
  28
  29 wxEventLoopBase *wxEventLoopBase::ms_activeLoop = NULL;
  30
  31 wxEventLoopBase::wxEventLoopBase()
  32 {
  33     m_isInsideYield = false;
  34     m_eventsToProcessInsideYield = wxEVT_CATEGORY_ALL;
  35 }
  36
  37 void wxEventLoopBase::DelayPendingEventHandler(wxEvtHandler* toDelay)
  38 {
  39     wxENTER_CRIT_SECT(m_handlersWithPendingEventsLocker);
  40
  41     // move the handler from the list of handlers with processable pending events
  42     // to the list of handlers with pending events which needs to be processed later
  43     m_handlersWithPendingEvents.Remove(toDelay);
  44
  45     if (m_handlersWithPendingDelayedEvents.Index(toDelay) == wxNOT_FOUND)
  46         m_handlersWithPendingDelayedEvents.Add(toDelay);
  47
  48     wxLEAVE_CRIT_SECT(m_handlersWithPendingEventsLocker);
  49 }
  50
  51 void wxEventLoopBase::RemovePendingEventHandler(wxEvtHandler* toRemove)
  52 {
  53     wxENTER_CRIT_SECT(m_handlersWithPendingEventsLocker);
  54
  55     if (m_handlersWithPendingEvents.Index(toRemove) != wxNOT_FOUND)
  56     {
  57         m_handlersWithPendingEvents.Remove(toRemove);
  58
  59         // check that the handler was present only once in the list
  60         wxASSERT_MSG( m_handlersWithPendingEvents.Index(toRemove) == wxNOT_FOUND,
  61                         "Handler occurs twice in the m_handlersWithPendingEvents list!" );
  62     }
  63     //else: it wasn't in this list at all, it's ok
  64
  65     if (m_handlersWithPendingDelayedEvents.Index(toRemove) != wxNOT_FOUND)
  66     {
  67         m_handlersWithPendingDelayedEvents.Remove(toRemove);
  68
  69         // check that the handler was present only once in the list
  70         wxASSERT_MSG( m_handlersWithPendingDelayedEvents.Index(toRemove) == wxNOT_FOUND,
  71                         "Handler occurs twice in m_handlersWithPendingDelayedEvents list!" );
  72     }
  73     //else: it wasn't in this list at all, it's ok
  74
  75     wxLEAVE_CRIT_SECT(m_handlersWithPendingEventsLocker);
  76 }
  77
  78 void wxEventLoopBase::AppendPendingEventHandler(wxEvtHandler* toAppend)
  79 {
  80     wxENTER_CRIT_SECT(m_handlersWithPendingEventsLocker);
  81
  82     if ( m_handlersWithPendingEvents.Index(toAppend) == wxNOT_FOUND )
  83         m_handlersWithPendingEvents.Add(toAppend);
  84
  85     wxLEAVE_CRIT_SECT(m_handlersWithPendingEventsLocker);
  86 }
  87
  88 bool wxEventLoopBase::HasPendingEvents() const
  89 {
  90     wxENTER_CRIT_SECT(const_cast<wxEventLoopBase*>(this)->m_handlersWithPendingEventsLocker);
  91
  92     bool has = !m_handlersWithPendingEvents.IsEmpty();
  93
  94     wxLEAVE_CRIT_SECT(const_cast<wxEventLoopBase*>(this)->m_handlersWithPendingEventsLocker);
  95
  96     return has;
  97 }
  98
  99 void wxEventLoopBase::SuspendProcessingOfPendingEvents()
 100 {
 101     wxENTER_CRIT_SECT(m_handlersWithPendingEventsLocker);
 102 }
 103
 104 void wxEventLoopBase::ResumeProcessingOfPendingEvents()
 105 {
 106     wxLEAVE_CRIT_SECT(m_handlersWithPendingEventsLocker);
 107 }
 108
 109 void wxEventLoopBase::ProcessPendingEvents()
 110 {
 111     wxENTER_CRIT_SECT(m_handlersWithPendingEventsLocker);
 112
 113     wxCHECK_RET( m_handlersWithPendingDelayedEvents.IsEmpty(),
 114                  "this helper list should be empty" );
 115
 116     // iterate until the list becomes empty: the handlers remove themselves
 117     // from it when they don't have any more pending events
 118     while (!m_handlersWithPendingEvents.IsEmpty())
 119     {
 120         // In ProcessPendingEvents(), new handlers might be added
 121         // and we can safely leave the critical section here.
 122         wxLEAVE_CRIT_SECT(m_handlersWithPendingEventsLocker);
 123
 124         // NOTE: we always call ProcessPendingEvents() on the first event handler
 125         //       with pending events because handlers auto-remove themselves
 126         //       from this list (see RemovePendingEventHandler) if they have no
 127         //       more pending events.
 128         m_handlersWithPendingEvents[0]->ProcessPendingEvents();
 129
 130         wxENTER_CRIT_SECT(m_handlersWithPendingEventsLocker);
 131     }
 132
 133     // now the wxHandlersWithPendingEvents is surely empty; however some event
 134     // handlers may have moved themselves into wxHandlersWithPendingDelayedEvents
 135     // because of a selective wxYield call in progress.
 136     // Now we need to move them back to wxHandlersWithPendingEvents so the next
 137     // call to this function has the chance of processing them:
 138     if (!m_handlersWithPendingDelayedEvents.IsEmpty())
 139     {
 140         WX_APPEND_ARRAY(m_handlersWithPendingEvents, m_handlersWithPendingDelayedEvents);
 141         m_handlersWithPendingDelayedEvents.Clear();
 142     }
 143
 144     wxLEAVE_CRIT_SECT(m_handlersWithPendingEventsLocker);
 145 }
 146
 147 void wxEventLoopBase::WakeUpIdle()
 148 {
 149     WakeUp();
 150 }
 151
 152 bool wxEventLoopBase::ProcessIdle()
 153 {
 154     // process pending wx events before sending idle events
 155     ProcessPendingEvents();
 156
 157     wxIdleEvent event;
 158
 159     event.SetEventObject(wxTheApp);
 160     wxTheApp->ProcessEvent(event);
 161     return event.MoreRequested();
 162 }
 163
 164 bool wxEventLoopBase::Yield(bool onlyIfNeeded)
 165 {
 166     if ( m_isInsideYield )
 167     {
 168         if ( !onlyIfNeeded )
 169         {
 170             wxFAIL_MSG( wxT("wxYield called recursively" ) );
 171         }
 172
 173         return false;
 174     }
 175
 176     return YieldFor(wxEVT_CATEGORY_ALL);
 177 }
 178
 179 // wxEventLoopManual is unused in the other ports
 180 #if defined(__WXMSW__) || defined(__WXMAC__) || defined(__WXDFB__) || (defined(__UNIX__) && wxUSE_BASE)
 181
 182 // ============================================================================
 183 // wxEventLoopManual implementation
 184 // ============================================================================
 185
 186 wxEventLoopManual::wxEventLoopManual()
 187 {
 188     m_exitcode = 0;
 189     m_shouldExit = false;
 190 }
 191
 192 int wxEventLoopManual::Run()
 193 {
 194     // event loops are not recursive, you need to create another loop!
 195     wxCHECK_MSG( !IsRunning(), -1, _T("can't reenter a message loop") );
 196
 197     // ProcessIdle() and Dispatch() below may throw so the code here should
 198     // be exception-safe, hence we must use local objects for all actions we
 199     // should undo
 200     wxEventLoopActivator activate(this);
 201
 202     // we must ensure that OnExit() is called even if an exception is thrown
 203     // from inside Dispatch() but we must call it from Exit() in normal
 204     // situations because it is supposed to be called synchronously,
 205     // wxModalEventLoop depends on this (so we can't just use ON_BLOCK_EXIT or
 206     // something similar here)
 207 #if wxUSE_EXCEPTIONS
 208     for ( ;; )
 209     {
 210         try
 211         {
 212 #endif // wxUSE_EXCEPTIONS
 213
 214             // this is the event loop itself
 215             for ( ;; )
 216             {
 217                 // give them the possibility to do whatever they want
 218                 OnNextIteration();
 219
 220                 // generate and process idle events for as long as we don't
 221                 // have anything else to do
 222                 while ( !Pending() && (wxTheApp && wxTheApp->ProcessIdle()) )
 223                     ;
 224
 225                 // if the "should exit" flag is set, the loop should terminate
 226                 // but not before processing any remaining messages so while
 227                 // Pending() returns true, do process them
 228                 if ( m_shouldExit )
 229                 {
 230                     while ( Pending() )
 231                         Dispatch();
 232
 233                     break;
 234                 }
 235
 236                 // a message came or no more idle processing to do, sit in
 237                 // Dispatch() waiting for the next message
 238                 if ( !Dispatch() )
 239                 {
 240                     // we got WM_QUIT
 241                     break;
 242                 }
 243             }
 244
 245 #if wxUSE_EXCEPTIONS
 246             // exit the outer loop as well
 247             break;
 248         }
 249         catch ( ... )
 250         {
 251             try
 252             {
 253                 if ( !wxTheApp || !wxTheApp->OnExceptionInMainLoop() )
 254                 {
 255                     OnExit();
 256                     break;
 257                 }
 258                 //else: continue running the event loop
 259             }
 260             catch ( ... )
 261             {
 262                 // OnException() throwed, possibly rethrowing the same
 263                 // exception again: very good, but we still need OnExit() to
 264                 // be called
 265                 OnExit();
 266                 throw;
 267             }
 268         }
 269     }
 270 #endif // wxUSE_EXCEPTIONS
 271
 272     return m_exitcode;
 273 }
 274
 275 void wxEventLoopManual::Exit(int rc)
 276 {
 277     wxCHECK_RET( IsRunning(), _T("can't call Exit() if not running") );
 278
 279     m_exitcode = rc;
 280     m_shouldExit = true;
 281
 282     OnExit();
 283
 284     // all we have to do to exit from the loop is to (maybe) wake it up so that
 285     // it can notice that Exit() had been called
 286     //
 287     // in particular, do *not* use here calls such as PostQuitMessage() (under
 288     // MSW) which terminate the current event loop here because we're not sure
 289     // that it is going to be processed by the correct event loop: it would be
 290     // possible that another one is started and terminated by mistake if we do
 291     // this
 292     WakeUp();
 293 }
 294
 295 #endif // __WXMSW__ || __WXMAC__ || __WXDFB__
 296