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 #ifndef WX_PRECOMP
  28     #include "wx/log.h"
  29     #include "wx/msw/wrapwin.h"
  30 #endif //WX_PRECOMP
  31
  32 #include "wx/evtloop.h"
  33
  34 // ============================================================================
  35 // wxMSWEventLoopBase implementation
  36 // ============================================================================
  37
  38 // ----------------------------------------------------------------------------
  39 // ctor/dtor
  40 // ----------------------------------------------------------------------------
  41
  42 wxMSWEventLoopBase::wxMSWEventLoopBase()
  43 {
  44     m_shouldExit = false;
  45     m_exitcode = 0;
  46 }
  47
  48 // ----------------------------------------------------------------------------
  49 // wxEventLoop message processing dispatching
  50 // ----------------------------------------------------------------------------
  51
  52 bool wxMSWEventLoopBase::Pending() const
  53 {
  54     MSG msg;
  55     return ::PeekMessage(&msg, 0, 0, 0, PM_NOREMOVE) != 0;
  56 }
  57
  58 bool wxMSWEventLoopBase::GetNextMessage(WXMSG* msg)
  59 {
  60     const BOOL rc = ::GetMessage(msg, NULL, 0, 0);
  61
  62     if ( rc == 0 )
  63     {
  64         // got WM_QUIT
  65         return false;
  66     }
  67
  68     if ( rc == -1 )
  69     {
  70         // should never happen, but let's test for it nevertheless
  71         wxLogLastError(wxT("GetMessage"));
  72
  73         // still break from the loop
  74         return false;
  75     }
  76
  77     return true;
  78 }
  79
  80 int wxMSWEventLoopBase::GetNextMessageTimeout(WXMSG *msg, unsigned long timeout)
  81 {
  82     // MsgWaitForMultipleObjects() won't notice any input which was already
  83     // examined (e.g. using PeekMessage()) but not yet removed from the queue
  84     // so we need to remove any immediately messages manually
  85     //
  86     // NB: using MsgWaitForMultipleObjectsEx() could simplify the code here but
  87     //     it is not available in very old Windows versions
  88     if ( !::PeekMessage(msg, 0, 0, 0, PM_REMOVE) )
  89     {
  90         // we use this function just in order to not block longer than the
  91         // given timeout, so we don't pass any handles to it at all
  92         DWORD rc = ::MsgWaitForMultipleObjects
  93                      (
  94                         0, NULL,
  95                         FALSE,
  96                         timeout,
  97                         QS_ALLINPUT
  98                      );
  99
 100         switch ( rc )
 101         {
 102             default:
 103                 wxLogDebug("unexpected MsgWaitForMultipleObjects() return "
 104                            "value %lu", rc);
 105                 // fall through
 106
 107             case WAIT_TIMEOUT:
 108                 return -1;
 109
 110             case WAIT_OBJECT_0:
 111                 if ( !::PeekMessage(msg, 0, 0, 0, PM_REMOVE) )
 112                 {
 113                     // somehow it may happen that MsgWaitForMultipleObjects()
 114                     // returns true but there are no messages -- just treat it
 115                     // the same as timeout then
 116                     return -1;
 117                 }
 118                 break;
 119         }
 120     }
 121
 122     return msg->message != WM_QUIT;
 123 }
 124
 125 // ============================================================================
 126 // wxConsoleEventLoop implementation
 127 // ============================================================================
 128
 129 #if wxUSE_CONSOLE_EVENTLOOP
 130
 131 void wxConsoleEventLoop::WakeUp()
 132 {
 133 #if wxUSE_THREADS
 134     wxWakeUpMainThread();
 135 #endif
 136 }
 137
 138 void wxConsoleEventLoop::ProcessMessage(WXMSG *msg)
 139 {
 140     ::DispatchMessage(msg);
 141 }
 142
 143 bool wxConsoleEventLoop::Dispatch()
 144 {
 145     MSG msg;
 146     if ( !GetNextMessage(&msg) )
 147         return false;
 148
 149     ProcessMessage(&msg);
 150
 151     return !m_shouldExit;
 152 }
 153
 154 int wxConsoleEventLoop::DispatchTimeout(unsigned long timeout)
 155 {
 156     MSG msg;
 157     int rc = GetNextMessageTimeout(&msg, timeout);
 158     if ( rc != 1 )
 159         return rc;
 160
 161     ProcessMessage(&msg);
 162
 163     return !m_shouldExit;
 164 }
 165
 166 #endif // wxUSE_CONSOLE_EVENTLOOP