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