src/msw/evtloop.cpp

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // Name:        msw/evtloop.cpp
   3 // Purpose:     implements wxEventLoop for MSW
   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 // License:     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/window.h"
  29     #include "wx/app.h"
  30 #endif //WX_PRECOMP
  31
  32 #include "wx/evtloop.h"
  33
  34 #include "wx/tooltip.h"
  35 #include "wx/except.h"
  36 #include "wx/ptr_scpd.h"
  37
  38 #include "wx/msw/private.h"
  39
  40 #if wxUSE_THREADS
  41     #include "wx/thread.h"
  42
  43     // define the list of MSG strutures
  44     WX_DECLARE_LIST(MSG, wxMsgList);
  45
  46     #include "wx/listimpl.cpp"
  47
  48     WX_DEFINE_LIST(wxMsgList)
  49 #endif // wxUSE_THREADS
  50
  51 // ----------------------------------------------------------------------------
  52 // helper class
  53 // ----------------------------------------------------------------------------
  54
  55 // this object sets the wxEventLoop given to the ctor as the currently active
  56 // one and unsets it in its dtor
  57 class wxEventLoopActivator
  58 {
  59 public:
  60     wxEventLoopActivator(wxEventLoop **pActive,
  61                          wxEventLoop *evtLoop)
  62     {
  63         m_pActive = pActive;
  64         m_evtLoopOld = *pActive;
  65         *pActive = evtLoop;
  66     }
  67
  68     ~wxEventLoopActivator()
  69     {
  70         // restore the previously active event loop
  71         *m_pActive = m_evtLoopOld;
  72     }
  73
  74 private:
  75     wxEventLoop *m_evtLoopOld;
  76     wxEventLoop **m_pActive;
  77 };
  78
  79 // ============================================================================
  80 // wxEventLoop implementation
  81 // ============================================================================
  82
  83 wxEventLoop *wxEventLoopBase::ms_activeLoop = NULL;
  84 wxWindowMSW *wxEventLoop::ms_winCritical = NULL;
  85
  86 // ----------------------------------------------------------------------------
  87 // ctor/dtor
  88 // ----------------------------------------------------------------------------
  89
  90 wxEventLoop::wxEventLoop()
  91 {
  92     m_shouldExit = false;
  93     m_exitcode = 0;
  94 }
  95
  96 // ----------------------------------------------------------------------------
  97 // wxEventLoop message processing
  98 // ----------------------------------------------------------------------------
  99
 100 void wxEventLoop::ProcessMessage(WXMSG *msg)
 101 {
 102     // give us the chance to preprocess the message first
 103     if ( !PreProcessMessage(msg) )
 104     {
 105         // if it wasn't done, dispatch it to the corresponding window
 106         ::TranslateMessage(msg);
 107         ::DispatchMessage(msg);
 108     }
 109 }
 110
 111 bool wxEventLoop::IsChildOfCriticalWindow(wxWindowMSW *win)
 112 {
 113     while ( win )
 114     {
 115         if ( win == ms_winCritical )
 116             return true;
 117
 118         win = win->GetParent();
 119     }
 120
 121     return false;
 122 }
 123
 124 bool wxEventLoop::PreProcessMessage(WXMSG *msg)
 125 {
 126     HWND hwnd = msg->hwnd;
 127     wxWindow *wndThis = wxGetWindowFromHWND((WXHWND)hwnd);
 128     wxWindow *wnd;
 129
 130     // this might happen if we're in a modeless dialog, or if a wx control has
 131     // children which themselves were not created by wx (i.e. wxActiveX control children)
 132     if ( !wndThis )
 133     {
 134         while ( hwnd && (::GetWindowLong(hwnd, GWL_STYLE) & WS_CHILD ))
 135         {
 136             hwnd = ::GetParent(hwnd);
 137
 138             // If the control has a wx parent, break and give the parent a chance
 139             // to process the window message
 140             wndThis = wxGetWindowFromHWND((WXHWND)hwnd);
 141             if (wndThis != NULL)
 142                 break;
 143         }
 144
 145         if ( !wndThis )
 146         {
 147             // this may happen if the event occurred in a standard modeless dialog (the
 148             // only example of which I know of is the find/replace dialog) - then call
 149             // IsDialogMessage() to make TAB navigation in it work
 150
 151             // NOTE: IsDialogMessage() just eats all the messages (i.e. returns true for
 152             // them) if we call it for the control itself
 153             return hwnd && ::IsDialogMessage(hwnd, msg) != 0;
 154         }
 155     }
 156
 157     if ( !AllowProcessing(wndThis) )
 158     {
 159         // not a child of critical window, so we eat the event but take care to
 160         // stop an endless stream of WM_PAINTs which would have resulted if we
 161         // didn't validate the invalidated part of the window
 162         if ( msg->message == WM_PAINT )
 163             ::ValidateRect(hwnd, NULL);
 164
 165         return true;
 166     }
 167
 168 #if wxUSE_TOOLTIPS
 169     // we must relay WM_MOUSEMOVE events to the tooltip ctrl if we want it to
 170     // popup the tooltip bubbles
 171     if ( msg->message == WM_MOUSEMOVE )
 172     {
 173         wxToolTip *tt = wndThis->GetToolTip();
 174         if ( tt )
 175         {
 176             tt->RelayEvent((WXMSG *)msg);
 177         }
 178     }
 179 #endif // wxUSE_TOOLTIPS
 180
 181     // allow the window to prevent certain messages from being
 182     // translated/processed (this is currently used by wxTextCtrl to always
 183     // grab Ctrl-C/V/X, even if they are also accelerators in some parent)
 184     if ( !wndThis->MSWShouldPreProcessMessage((WXMSG *)msg) )
 185     {
 186         return false;
 187     }
 188
 189     // try translations first: the accelerators override everything
 190     for ( wnd = wndThis; wnd; wnd = wnd->GetParent() )
 191     {
 192         if ( wnd->MSWTranslateMessage((WXMSG *)msg))
 193             return true;
 194
 195         // stop at first top level window, i.e. don't try to process the key
 196         // strokes originating in a dialog using the accelerators of the parent
 197         // frame - this doesn't make much sense
 198         if ( wnd->IsTopLevel() )
 199             break;
 200     }
 201
 202     // now try the other hooks (kbd navigation is handled here)
 203     for ( wnd = wndThis; wnd; wnd = wnd->GetParent() )
 204     {
 205         if (wnd != wndThis) // Skip the first since wndThis->MSWProcessMessage() was called above
 206         {
 207             if ( wnd->MSWProcessMessage((WXMSG *)msg) )
 208                 return true;
 209         }
 210
 211         // Stop at first top level window (as per comment above).
 212         // If we don't do this, pressing ESC on a modal dialog shown as child of a modal
 213         // dialog with wxID_CANCEL will cause the parent dialog to be closed, for example
 214         if (wnd->IsTopLevel())
 215             break;
 216     }
 217
 218     // no special preprocessing for this message, dispatch it normally
 219     return false;
 220 }
 221
 222 // ----------------------------------------------------------------------------
 223 // wxEventLoop running and exiting
 224 // ----------------------------------------------------------------------------
 225
 226 bool wxEventLoop::IsRunning() const
 227 {
 228     return ms_activeLoop == this;
 229 }
 230
 231 int wxEventLoop::Run()
 232 {
 233     // event loops are not recursive, you need to create another loop!
 234     wxCHECK_MSG( !IsRunning(), -1, _T("can't reenter a message loop") );
 235
 236     // ProcessIdle() and Dispatch() below may throw so the code here should
 237     // be exception-safe, hence we must use local objects for all actions we
 238     // should undo
 239     wxEventLoopActivator activate(&ms_activeLoop, this);
 240
 241     // we must ensure that OnExit() is called even if an exception is thrown
 242     // from inside Dispatch() but we must call it from Exit() in normal
 243     // situations because it is supposed to be called synchronously,
 244     // wxModalEventLoop depends on this (so we can't just use ON_BLOCK_EXIT or
 245     // something similar here)
 246 #if wxUSE_EXCEPTIONS
 247     for ( ;; )
 248     {
 249         try
 250         {
 251 #endif // wxUSE_EXCEPTIONS
 252
 253             // this is the event loop itself
 254             for ( ;; )
 255             {
 256                 #if wxUSE_THREADS
 257                     wxMutexGuiLeaveOrEnter();
 258                 #endif // wxUSE_THREADS
 259
 260                 // generate and process idle events for as long as we don't
 261                 // have anything else to do
 262                 while ( !Pending() && (wxTheApp && wxTheApp->ProcessIdle()) )
 263                     ;
 264
 265                 // if the "should exit" flag is set, the loop should terminate
 266                 // but not before processing any remaining messages so while
 267                 // Pending() returns true, do process them
 268                 if ( m_shouldExit )
 269                 {
 270                     while ( Pending() )
 271                         Dispatch();
 272
 273                     break;
 274                 }
 275
 276                 // a message came or no more idle processing to do, sit in
 277                 // Dispatch() waiting for the next message
 278                 if ( !Dispatch() )
 279                 {
 280                     // we got WM_QUIT
 281                     break;
 282                 }
 283             }
 284
 285 #if wxUSE_EXCEPTIONS
 286             // exit the outer loop as well
 287             break;
 288         }
 289         catch ( ... )
 290         {
 291             try
 292             {
 293                 if ( !wxTheApp || !wxTheApp->OnExceptionInMainLoop() )
 294                 {
 295                     OnExit();
 296                     break;
 297                 }
 298                 //else: continue running the event loop
 299             }
 300             catch ( ... )
 301             {
 302                 // OnException() throwed, possibly rethrowing the same
 303                 // exception again: very good, but we still need OnExit() to
 304                 // be called
 305                 OnExit();
 306                 throw;
 307             }
 308         }
 309     }
 310 #endif // wxUSE_EXCEPTIONS
 311
 312     return m_exitcode;
 313 }
 314
 315 void wxEventLoop::Exit(int rc)
 316 {
 317     wxCHECK_RET( IsRunning(), _T("can't call Exit() if not running") );
 318
 319     m_exitcode = rc;
 320     m_shouldExit = true;
 321
 322     OnExit();
 323
 324     // all we have to do to exit from the loop is to (maybe) wake it up so that
 325     // it can notice that Exit() had been called
 326     //
 327     // in particular, we do *not* use PostQuitMessage() here because we're not
 328     // sure that WM_QUIT is going to be processed by the correct event loop: it
 329     // is possible that another one is started before this one has a chance to
 330     // process WM_QUIT
 331     ::PostMessage(NULL, WM_NULL, 0, 0);
 332 }
 333
 334 // ----------------------------------------------------------------------------
 335 // wxEventLoop message processing dispatching
 336 // ----------------------------------------------------------------------------
 337
 338 bool wxEventLoop::Pending() const
 339 {
 340     MSG msg;
 341     return ::PeekMessage(&msg, 0, 0, 0, PM_NOREMOVE) != 0;
 342 }
 343
 344 bool wxEventLoop::Dispatch()
 345 {
 346     wxCHECK_MSG( IsRunning(), false, _T("can't call Dispatch() if not running") );
 347
 348     MSG msg;
 349     BOOL rc = ::GetMessage(&msg, (HWND) NULL, 0, 0);
 350
 351     if ( rc == 0 )
 352     {
 353         // got WM_QUIT
 354         return false;
 355     }
 356
 357     if ( rc == -1 )
 358     {
 359         // should never happen, but let's test for it nevertheless
 360         wxLogLastError(wxT("GetMessage"));
 361
 362         // still break from the loop
 363         return false;
 364     }
 365
 366 #if wxUSE_THREADS
 367     wxASSERT_MSG( wxThread::IsMain(),
 368                   wxT("only the main thread can process Windows messages") );
 369
 370     static bool s_hadGuiLock = true;
 371     static wxMsgList s_aSavedMessages;
 372
 373     // if a secondary thread owning the mutex is doing GUI calls, save all
 374     // messages for later processing - we can't process them right now because
 375     // it will lead to recursive library calls (and we're not reentrant)
 376     if ( !wxGuiOwnedByMainThread() )
 377     {
 378         s_hadGuiLock = false;
 379
 380         // leave out WM_COMMAND messages: too dangerous, sometimes
 381         // the message will be processed twice
 382         if ( !wxIsWaitingForThread() || msg.message != WM_COMMAND )
 383         {
 384             MSG* pMsg = new MSG(msg);
 385             s_aSavedMessages.Append(pMsg);
 386         }
 387
 388         return true;
 389     }
 390     else
 391     {
 392         // have we just regained the GUI lock? if so, post all of the saved
 393         // messages
 394         //
 395         // FIXME of course, it's not _exactly_ the same as processing the
 396         //       messages normally - expect some things to break...
 397         if ( !s_hadGuiLock )
 398         {
 399             s_hadGuiLock = true;
 400
 401             wxMsgList::compatibility_iterator node = s_aSavedMessages.GetFirst();
 402             while (node)
 403             {
 404                 MSG* pMsg = node->GetData();
 405                 s_aSavedMessages.Erase(node);
 406
 407                 ProcessMessage(pMsg);
 408                 delete pMsg;
 409
 410                 node = s_aSavedMessages.GetFirst();
 411             }
 412         }
 413     }
 414 #endif // wxUSE_THREADS
 415
 416     ProcessMessage(&msg);
 417
 418     return true;
 419 }
 420