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