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