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 // ============================================================================
  13 // declarations
  14 // ============================================================================
  15
  16 // ----------------------------------------------------------------------------
  17 // headers
  18 // ----------------------------------------------------------------------------
  19
  20 // for compilers that support precompilation, includes "wx.h".
  21 #include "wx/wxprec.h"
  22
  23 #ifdef __BORLANDC__
  24     #pragma hdrstop
  25 #endif
  26
  27 #include "wx/evtloop.h"
  28
  29 #ifndef WX_PRECOMP
  30     #include "wx/app.h"
  31 #endif //WX_PRECOMP
  32
  33 // ----------------------------------------------------------------------------
  34 // globals
  35 // ----------------------------------------------------------------------------
  36
  37 wxEventLoop *wxEventLoopBase::ms_activeLoop = NULL;
  38
  39 // wxEventLoopManual is unused in the other ports
  40 #if defined(__WXMSW__) || defined(__WXMAC__) || defined(__WXDFB__) || (defined(__UNIX__) && !wxUSE_GUI)
  41
  42 // ============================================================================
  43 // wxEventLoopManual implementation
  44 // ============================================================================
  45
  46 wxEventLoopManual::wxEventLoopManual()
  47 {
  48     m_exitcode = 0;
  49     m_shouldExit = false;
  50 }
  51
  52 int wxEventLoopManual::Run()
  53 {
  54     // event loops are not recursive, you need to create another loop!
  55     wxCHECK_MSG( !IsRunning(), -1, _T("can't reenter a message loop") );
  56
  57     // ProcessIdle() and Dispatch() below may throw so the code here should
  58     // be exception-safe, hence we must use local objects for all actions we
  59     // should undo
  60     wxEventLoopActivator activate(this);
  61
  62     // we must ensure that OnExit() is called even if an exception is thrown
  63     // from inside Dispatch() but we must call it from Exit() in normal
  64     // situations because it is supposed to be called synchronously,
  65     // wxModalEventLoop depends on this (so we can't just use ON_BLOCK_EXIT or
  66     // something similar here)
  67 #if wxUSE_EXCEPTIONS
  68     for ( ;; )
  69     {
  70         try
  71         {
  72 #endif // wxUSE_EXCEPTIONS
  73
  74             // this is the event loop itself
  75             for ( ;; )
  76             {
  77                 // give them the possibility to do whatever they want
  78                 OnNextIteration();
  79
  80                 // generate and process idle events for as long as we don't
  81                 // have anything else to do
  82                 while ( !Pending() && (wxTheApp && wxTheApp->ProcessIdle()) )
  83                     ;
  84
  85                 // if the "should exit" flag is set, the loop should terminate
  86                 // but not before processing any remaining messages so while
  87                 // Pending() returns true, do process them
  88                 if ( m_shouldExit )
  89                 {
  90                     while ( Pending() )
  91                         Dispatch();
  92
  93                     break;
  94                 }
  95
  96                 // a message came or no more idle processing to do, sit in
  97                 // Dispatch() waiting for the next message
  98                 if ( !Dispatch() )
  99                 {
 100                     // we got WM_QUIT
 101                     break;
 102                 }
 103             }
 104
 105 #if wxUSE_EXCEPTIONS
 106             // exit the outer loop as well
 107             break;
 108         }
 109         catch ( ... )
 110         {
 111             try
 112             {
 113                 if ( !wxTheApp || !wxTheApp->OnExceptionInMainLoop() )
 114                 {
 115                     OnExit();
 116                     break;
 117                 }
 118                 //else: continue running the event loop
 119             }
 120             catch ( ... )
 121             {
 122                 // OnException() throwed, possibly rethrowing the same
 123                 // exception again: very good, but we still need OnExit() to
 124                 // be called
 125                 OnExit();
 126                 throw;
 127             }
 128         }
 129     }
 130 #endif // wxUSE_EXCEPTIONS
 131
 132     return m_exitcode;
 133 }
 134
 135 void wxEventLoopManual::Exit(int rc)
 136 {
 137     wxCHECK_RET( IsRunning(), _T("can't call Exit() if not running") );
 138
 139     m_exitcode = rc;
 140     m_shouldExit = true;
 141
 142     OnExit();
 143
 144     // all we have to do to exit from the loop is to (maybe) wake it up so that
 145     // it can notice that Exit() had been called
 146     //
 147     // in particular, do *not* use here calls such as PostQuitMessage() (under
 148     // MSW) which terminate the current event loop here because we're not sure
 149     // that it is going to be processed by the correct event loop: it would be
 150     // possible that another one is started and terminated by mistake if we do
 151     // this
 152     WakeUp();
 153 }
 154
 155 #endif // __WXMSW__ || __WXMAC__ || __WXDFB__