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     #include "wx/stopwatch.h"   // for wxMilliClock_t
  32 #endif //WX_PRECOMP
  33
  34 // ----------------------------------------------------------------------------
  35 // globals
  36 // ----------------------------------------------------------------------------
  37
  38 wxEventLoopBase *wxEventLoopBase::ms_activeLoop = NULL;
  39
  40 // wxEventLoopManual is unused in the other ports
  41 #if defined(__WXMSW__) || defined(__WXMAC__) || defined(__WXDFB__) || (defined(__UNIX__) && wxUSE_BASE)
  42
  43 // ============================================================================
  44 // wxEventLoopManual implementation
  45 // ============================================================================
  46
  47 wxEventLoopManual::wxEventLoopManual()
  48 {
  49     m_exitcode = 0;
  50     m_shouldExit = false;
  51 }
  52
  53 int wxEventLoopManual::Run()
  54 {
  55     // event loops are not recursive, you need to create another loop!
  56     wxCHECK_MSG( !IsRunning(), -1, _T("can't reenter a message loop") );
  57
  58     // ProcessIdle() and Dispatch() below may throw so the code here should
  59     // be exception-safe, hence we must use local objects for all actions we
  60     // should undo
  61     wxEventLoopActivator activate(this);
  62
  63     // we must ensure that OnExit() is called even if an exception is thrown
  64     // from inside Dispatch() but we must call it from Exit() in normal
  65     // situations because it is supposed to be called synchronously,
  66     // wxModalEventLoop depends on this (so we can't just use ON_BLOCK_EXIT or
  67     // something similar here)
  68 #if wxUSE_EXCEPTIONS
  69     for ( ;; )
  70     {
  71         try
  72         {
  73 #endif // wxUSE_EXCEPTIONS
  74
  75             // this is the event loop itself
  76             for ( ;; )
  77             {
  78                 // give them the possibility to do whatever they want
  79                 OnNextIteration();
  80
  81                 // generate and process idle events for as long as we don't
  82                 // have anything else to do
  83                 while ( !Pending() && (wxTheApp && wxTheApp->ProcessIdle()) )
  84                     ;
  85
  86                 // if the "should exit" flag is set, the loop should terminate
  87                 // but not before processing any remaining messages so while
  88                 // Pending() returns true, do process them
  89                 if ( m_shouldExit )
  90                 {
  91                     while ( Pending() )
  92                         Dispatch();
  93
  94                     break;
  95                 }
  96
  97                 // a message came or no more idle processing to do, sit in
  98                 // Dispatch() waiting for the next message
  99                 if ( !Dispatch() )
 100                 {
 101                     // we got WM_QUIT
 102                     break;
 103                 }
 104             }
 105
 106 #if wxUSE_EXCEPTIONS
 107             // exit the outer loop as well
 108             break;
 109         }
 110         catch ( ... )
 111         {
 112             try
 113             {
 114                 if ( !wxTheApp || !wxTheApp->OnExceptionInMainLoop() )
 115                 {
 116                     OnExit();
 117                     break;
 118                 }
 119                 //else: continue running the event loop
 120             }
 121             catch ( ... )
 122             {
 123                 // OnException() throwed, possibly rethrowing the same
 124                 // exception again: very good, but we still need OnExit() to
 125                 // be called
 126                 OnExit();
 127                 throw;
 128             }
 129         }
 130     }
 131 #endif // wxUSE_EXCEPTIONS
 132
 133     return m_exitcode;
 134 }
 135
 136 void wxEventLoopManual::Exit(int rc)
 137 {
 138     wxCHECK_RET( IsRunning(), _T("can't call Exit() if not running") );
 139
 140     m_exitcode = rc;
 141     m_shouldExit = true;
 142
 143     OnExit();
 144
 145     // all we have to do to exit from the loop is to (maybe) wake it up so that
 146     // it can notice that Exit() had been called
 147     //
 148     // in particular, do *not* use here calls such as PostQuitMessage() (under
 149     // MSW) which terminate the current event loop here because we're not sure
 150     // that it is going to be processed by the correct event loop: it would be
 151     // possible that another one is started and terminated by mistake if we do
 152     // this
 153     WakeUp();
 154 }
 155
 156 #endif // __WXMSW__ || __WXMAC__ || __WXDFB__
 157
 158 #ifdef wxNEEDS_GENERIC_DISPATCH_TIMEOUT
 159
 160 int wxGUIEventLoop::DispatchTimeout(unsigned long timeout)
 161 {
 162     // TODO: this is, of course, horribly inefficient and a proper wait with
 163     //       timeout should be implemented for all ports natively...
 164     const wxMilliClock_t timeEnd = wxGetLocalTimeMillis() + timeout;
 165     for ( ;; )
 166     {
 167         if ( Pending() )
 168             return Dispatch();
 169
 170         if ( wxGetLocalTimeMillis() >= timeEnd )
 171             return -1;
 172     }
 173 }
 174
 175 #endif // wxNEEDS_GENERIC_DISPATCH_TIMEOUT
 176