src/msw/evtloopconsole.cpp

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/msw/evtloopconsole.cpp
   3 // Purpose:     wxConsoleEventLoop class for Windows
   4 // Author:      Vadim Zeitlin
   5 // Modified by:
   6 // Created:     01.06.01
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) 2001 Vadim Zeitlin <zeitlin@dptmaths.ens-cachan.fr>
   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 // wxMSWEventLoopBase implementation
  31 // ============================================================================
  32
  33 // ----------------------------------------------------------------------------
  34 // ctor/dtor
  35 // ----------------------------------------------------------------------------
  36
  37 wxMSWEventLoopBase::wxMSWEventLoopBase()
  38 {
  39     m_shouldExit = false;
  40     m_exitcode = 0;
  41 }
  42
  43 // ----------------------------------------------------------------------------
  44 // wxEventLoop message processing dispatching
  45 // ----------------------------------------------------------------------------
  46
  47 bool wxMSWEventLoopBase::Pending() const
  48 {
  49     MSG msg;
  50     return ::PeekMessage(&msg, 0, 0, 0, PM_NOREMOVE) != 0;
  51 }
  52
  53 bool wxMSWEventLoopBase::GetNextMessage(WXMSG* msg)
  54 {
  55     const BOOL rc = ::GetMessage(msg, NULL, 0, 0);
  56
  57     if ( rc == 0 )
  58     {
  59         // got WM_QUIT
  60         return false;
  61     }
  62
  63     if ( rc == -1 )
  64     {
  65         // should never happen, but let's test for it nevertheless
  66         wxLogLastError(wxT("GetMessage"));
  67
  68         // still break from the loop
  69         return false;
  70     }
  71
  72     return true;
  73 }
  74
  75 int wxMSWEventLoopBase::GetNextMessageTimeout(WXMSG *msg, unsigned long timeout)
  76 {
  77     // MsgWaitForMultipleObjects() won't notice any input which was already
  78     // examined (e.g. using PeekMessage()) but not yet removed from the queue
  79     // so we need to remove any immediately messages manually
  80     //
  81     // NB: using MsgWaitForMultipleObjectsEx() could simplify the code here but
  82     //     it is not available in very old Windows versions
  83     if ( !::PeekMessage(msg, 0, 0, 0, PM_REMOVE) )
  84     {
  85         // we use this function just in order to not block longer than the
  86         // given timeout, so we don't pass any handles to it at all
  87         DWORD rc = ::MsgWaitForMultipleObjects
  88                      (
  89                         0, NULL,
  90                         FALSE,
  91                         timeout,
  92                         QS_ALLINPUT
  93                      );
  94
  95         switch ( rc )
  96         {
  97             default:
  98                 wxLogDebug("unexpected MsgWaitForMultipleObjects() return "
  99                            "value %lu", rc);
 100                 // fall through
 101
 102             case WAIT_TIMEOUT:
 103                 return -1;
 104
 105             case WAIT_OBJECT_0:
 106                 if ( !::PeekMessage(msg, 0, 0, 0, PM_REMOVE) )
 107                 {
 108                     // somehow it may happen that MsgWaitForMultipleObjects()
 109                     // returns true but there are no messages -- just treat it
 110                     // the same as timeout then
 111                     return -1;
 112                 }
 113                 break;
 114         }
 115     }
 116
 117     return msg->message != WM_QUIT;
 118 }
 119
 120 // ============================================================================
 121 // wxConsoleEventLoop implementation
 122 // ============================================================================
 123
 124 #if wxUSE_CONSOLE_EVENTLOOP
 125
 126 void wxConsoleEventLoop::WakeUp()
 127 {
 128 #if wxUSE_THREADS
 129     wxWakeUpMainThread();
 130 #endif
 131 }
 132
 133 void wxConsoleEventLoop::ProcessMessage(WXMSG *msg)
 134 {
 135     ::DispatchMessage(msg);
 136 }
 137
 138 bool wxConsoleEventLoop::Dispatch()
 139 {
 140     MSG msg;
 141     if ( !GetNextMessage(&msg) )
 142         return false;
 143
 144     ProcessMessage(&msg);
 145
 146     return !m_shouldExit;
 147 }
 148
 149 int wxConsoleEventLoop::DispatchTimeout(unsigned long timeout)
 150 {
 151     MSG msg;
 152     int rc = GetNextMessageTimeout(&msg, timeout);
 153     if ( rc != 1 )
 154         return rc;
 155
 156     ProcessMessage(&msg);
 157
 158     return !m_shouldExit;
 159 }
 160
 161 #endif // wxUSE_CONSOLE_EVENTLOOP