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 // Copyright:   (c) 2001 Vadim Zeitlin <zeitlin@dptmaths.ens-cachan.fr>
   8 // Licence:     wxWindows licence
   9 ///////////////////////////////////////////////////////////////////////////////
  10
  11 // ============================================================================
  12 // declarations
  13 // ============================================================================
  14
  15 // ----------------------------------------------------------------------------
  16 // headers
  17 // ----------------------------------------------------------------------------
  18
  19 // For compilers that support precompilation, includes "wx.h".
  20 #include "wx/wxprec.h"
  21
  22 #ifdef __BORLANDC__
  23     #pragma hdrstop
  24 #endif
  25
  26 #ifndef WX_PRECOMP
  27     #include "wx/log.h"
  28     #include "wx/msw/wrapwin.h"
  29 #endif //WX_PRECOMP
  30
  31 #include "wx/evtloop.h"
  32
  33 // ============================================================================
  34 // wxMSWEventLoopBase implementation
  35 // ============================================================================
  36
  37 // ----------------------------------------------------------------------------
  38 // ctor/dtor
  39 // ----------------------------------------------------------------------------
  40
  41 wxMSWEventLoopBase::wxMSWEventLoopBase()
  42 {
  43     m_shouldExit = false;
  44     m_exitcode = 0;
  45 }
  46
  47 // ----------------------------------------------------------------------------
  48 // wxEventLoop message processing dispatching
  49 // ----------------------------------------------------------------------------
  50
  51 bool wxMSWEventLoopBase::Pending() const
  52 {
  53     MSG msg;
  54     return ::PeekMessage(&msg, 0, 0, 0, PM_NOREMOVE) != 0;
  55 }
  56
  57 bool wxMSWEventLoopBase::GetNextMessage(WXMSG* msg)
  58 {
  59     const BOOL rc = ::GetMessage(msg, NULL, 0, 0);
  60
  61     if ( rc == 0 )
  62     {
  63         // got WM_QUIT
  64         return false;
  65     }
  66
  67     if ( rc == -1 )
  68     {
  69         // should never happen, but let's test for it nevertheless
  70         wxLogLastError(wxT("GetMessage"));
  71
  72         // still break from the loop
  73         return false;
  74     }
  75
  76     return true;
  77 }
  78
  79 int wxMSWEventLoopBase::GetNextMessageTimeout(WXMSG *msg, unsigned long timeout)
  80 {
  81     // MsgWaitForMultipleObjects() won't notice any input which was already
  82     // examined (e.g. using PeekMessage()) but not yet removed from the queue
  83     // so we need to remove any immediately messages manually
  84     //
  85     // NB: using MsgWaitForMultipleObjectsEx() could simplify the code here but
  86     //     it is not available in very old Windows versions
  87     if ( !::PeekMessage(msg, 0, 0, 0, PM_REMOVE) )
  88     {
  89         // we use this function just in order to not block longer than the
  90         // given timeout, so we don't pass any handles to it at all
  91         DWORD rc = ::MsgWaitForMultipleObjects
  92                      (
  93                         0, NULL,
  94                         FALSE,
  95                         timeout,
  96                         QS_ALLINPUT
  97                      );
  98
  99         switch ( rc )
 100         {
 101             default:
 102                 wxLogDebug("unexpected MsgWaitForMultipleObjects() return "
 103                            "value %lu", rc);
 104                 // fall through
 105
 106             case WAIT_TIMEOUT:
 107                 return -1;
 108
 109             case WAIT_OBJECT_0:
 110                 if ( !::PeekMessage(msg, 0, 0, 0, PM_REMOVE) )
 111                 {
 112                     // somehow it may happen that MsgWaitForMultipleObjects()
 113                     // returns true but there are no messages -- just treat it
 114                     // the same as timeout then
 115                     return -1;
 116                 }
 117                 break;
 118         }
 119     }
 120
 121     return msg->message != WM_QUIT;
 122 }
 123
 124 // ============================================================================
 125 // wxConsoleEventLoop implementation
 126 // ============================================================================
 127
 128 #if wxUSE_CONSOLE_EVENTLOOP
 129
 130 void wxConsoleEventLoop::WakeUp()
 131 {
 132 #if wxUSE_THREADS
 133     wxWakeUpMainThread();
 134 #endif
 135 }
 136
 137 void wxConsoleEventLoop::ProcessMessage(WXMSG *msg)
 138 {
 139     ::DispatchMessage(msg);
 140 }
 141
 142 bool wxConsoleEventLoop::Dispatch()
 143 {
 144     MSG msg;
 145     if ( !GetNextMessage(&msg) )
 146         return false;
 147
 148     ProcessMessage(&msg);
 149
 150     return !m_shouldExit;
 151 }
 152
 153 int wxConsoleEventLoop::DispatchTimeout(unsigned long timeout)
 154 {
 155     MSG msg;
 156     int rc = GetNextMessageTimeout(&msg, timeout);
 157     if ( rc != 1 )
 158         return rc;
 159
 160     ProcessMessage(&msg);
 161
 162     return !m_shouldExit;
 163 }
 164
 165 #endif // wxUSE_CONSOLE_EVENTLOOP