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 bool wxEventLoopBase::IsMain() const
  38 {
  39     if (wxTheApp)
  40         return wxTheApp->GetMainLoop() == this;
  41     return false;
  42 }
  43
  44 /* static */
  45 void wxEventLoopBase::SetActive(wxEventLoopBase* loop)
  46 {
  47     ms_activeLoop = loop;
  48
  49     if (wxTheApp)
  50         wxTheApp->OnEventLoopEnter(loop);
  51 }
  52
  53 void wxEventLoopBase::OnExit()
  54 {
  55     if (wxTheApp)
  56         wxTheApp->OnEventLoopExit(this);
  57
  58 #if wxUSE_EVENTLOOP_SOURCE
  59     // unregister all sources
  60     (void) RemoveAllSources();
  61 #endif
  62 }
  63
  64 void wxEventLoopBase::WakeUpIdle()
  65 {
  66     WakeUp();
  67 }
  68
  69 bool wxEventLoopBase::ProcessIdle()
  70 {
  71     return wxTheApp && wxTheApp->ProcessIdle();
  72 }
  73
  74 bool wxEventLoopBase::Yield(bool onlyIfNeeded)
  75 {
  76     if ( m_isInsideYield )
  77     {
  78         if ( !onlyIfNeeded )
  79         {
  80             wxFAIL_MSG( wxT("wxYield called recursively" ) );
  81         }
  82
  83         return false;
  84     }
  85
  86     return YieldFor(wxEVT_CATEGORY_ALL);
  87 }
  88
  89 // wxEventLoopManual is unused in the other ports
  90 #if defined(__WXMSW__) || defined(__WXMAC__) || defined(__WXDFB__) || (defined(__UNIX__) && wxUSE_BASE)
  91
  92 // ============================================================================
  93 // wxEventLoopManual implementation
  94 // ============================================================================
  95
  96 wxEventLoopManual::wxEventLoopManual()
  97 {
  98     m_exitcode = 0;
  99     m_shouldExit = false;
 100 }
 101
 102 bool wxEventLoopManual::ProcessEvents()
 103 {
 104     // process pending wx events first as they correspond to low-level events
 105     // which happened before, i.e. typically pending events were queued by a
 106     // previous call to Dispatch() and if we didn't process them now the next
 107     // call to it might enqueue them again (as happens with e.g. socket events
 108     // which would be generated as long as there is input available on socket
 109     // and this input is only removed from it when pending event handlers are
 110     // executed)
 111     if ( wxTheApp )
 112         wxTheApp->ProcessPendingEvents();
 113
 114     return Dispatch();
 115 }
 116
 117 int wxEventLoopManual::Run()
 118 {
 119     // event loops are not recursive, you need to create another loop!
 120     wxCHECK_MSG( !IsRunning(), -1, wxT("can't reenter a message loop") );
 121
 122     // ProcessIdle() and ProcessEvents() below may throw so the code here should
 123     // be exception-safe, hence we must use local objects for all actions we
 124     // should undo
 125     wxEventLoopActivator activate(this);
 126
 127     // we must ensure that OnExit() is called even if an exception is thrown
 128     // from inside ProcessEvents() but we must call it from Exit() in normal
 129     // situations because it is supposed to be called synchronously,
 130     // wxModalEventLoop depends on this (so we can't just use ON_BLOCK_EXIT or
 131     // something similar here)
 132 #if wxUSE_EXCEPTIONS
 133     for ( ;; )
 134     {
 135         try
 136         {
 137 #endif // wxUSE_EXCEPTIONS
 138
 139             // this is the event loop itself
 140             for ( ;; )
 141             {
 142                 // give them the possibility to do whatever they want
 143                 OnNextIteration();
 144
 145                 // generate and process idle events for as long as we don't
 146                 // have anything else to do
 147                 while ( !Pending() && ProcessIdle() )
 148                     ;
 149
 150                 // if the "should exit" flag is set, the loop should terminate
 151                 // but not before processing any remaining messages so while
 152                 // Pending() returns true, do process them
 153                 if ( m_shouldExit )
 154                 {
 155                     while ( Pending() )
 156                         ProcessEvents();
 157
 158                     break;
 159                 }
 160
 161                 // a message came or no more idle processing to do, dispatch
 162                 // all the pending events and call Dispatch() to wait for the
 163                 // next message
 164                 if ( !ProcessEvents() )
 165                 {
 166                     // we got WM_QUIT
 167                     break;
 168                 }
 169             }
 170
 171 #if wxUSE_EXCEPTIONS
 172             // exit the outer loop as well
 173             break;
 174         }
 175         catch ( ... )
 176         {
 177             try
 178             {
 179                 if ( !wxTheApp || !wxTheApp->OnExceptionInMainLoop() )
 180                 {
 181                     OnExit();
 182                     break;
 183                 }
 184                 //else: continue running the event loop
 185             }
 186             catch ( ... )
 187             {
 188                 // OnException() throwed, possibly rethrowing the same
 189                 // exception again: very good, but we still need OnExit() to
 190                 // be called
 191                 OnExit();
 192                 throw;
 193             }
 194         }
 195     }
 196 #endif // wxUSE_EXCEPTIONS
 197
 198     return m_exitcode;
 199 }
 200
 201 void wxEventLoopManual::Exit(int rc)
 202 {
 203     wxCHECK_RET( IsRunning(), wxT("can't call Exit() if not running") );
 204
 205     m_exitcode = rc;
 206     m_shouldExit = true;
 207
 208     OnExit();
 209
 210     // all we have to do to exit from the loop is to (maybe) wake it up so that
 211     // it can notice that Exit() had been called
 212     //
 213     // in particular, do *not* use here calls such as PostQuitMessage() (under
 214     // MSW) which terminate the current event loop here because we're not sure
 215     // that it is going to be processed by the correct event loop: it would be
 216     // possible that another one is started and terminated by mistake if we do
 217     // this
 218     WakeUp();
 219 }
 220
 221 #endif // __WXMSW__ || __WXMAC__ || __WXDFB__
 222