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