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 #if defined(__GNUG__) && !defined(NO_GCC_PRAGMA)
  21     #pragma implementation "evtloop.h"
  22 #endif
  23
  24 // For compilers that support precompilation, includes "wx.h".
  25 #include "wx/wxprec.h"
  26
  27 #ifdef __BORLANDC__
  28     #pragma hdrstop
  29 #endif
  30
  31 #ifndef WX_PRECOMP
  32     #include "wx/window.h"
  33     #include "wx/app.h"
  34 #endif //WX_PRECOMP
  35
  36 #include "wx/evtloop.h"
  37
  38 #include "wx/tooltip.h"
  39 #include "wx/except.h"
  40 #include "wx/ptr_scpd.h"
  41
  42 #include "wx/msw/private.h"
  43
  44 #if wxUSE_THREADS
  45     #include "wx/thread.h"
  46
  47     // define the list of MSG strutures
  48     WX_DECLARE_LIST(MSG, wxMsgList);
  49
  50     #include "wx/listimpl.cpp"
  51
  52     WX_DEFINE_LIST(wxMsgList);
  53 #endif // wxUSE_THREADS
  54
  55 // ----------------------------------------------------------------------------
  56 // helper class
  57 // ----------------------------------------------------------------------------
  58
  59 // this object sets the wxEventLoop given to the ctor as the currently active
  60 // one and unsets it in its dtor
  61 class wxEventLoopActivator
  62 {
  63 public:
  64     wxEventLoopActivator(wxEventLoop **pActive,
  65                          wxEventLoop *evtLoop)
  66     {
  67         m_pActive = pActive;
  68         m_evtLoopOld = *pActive;
  69         *pActive = evtLoop;
  70     }
  71
  72     ~wxEventLoopActivator()
  73     {
  74         // restore the previously active event loop
  75         *m_pActive = m_evtLoopOld;
  76     }
  77
  78 private:
  79     wxEventLoop *m_evtLoopOld;
  80     wxEventLoop **m_pActive;
  81 };
  82
  83 // ============================================================================
  84 // wxEventLoop implementation
  85 // ============================================================================
  86
  87 wxEventLoop *wxEventLoopBase::ms_activeLoop = NULL;
  88
  89 // ----------------------------------------------------------------------------
  90 // ctor/dtor
  91 // ----------------------------------------------------------------------------
  92
  93 wxEventLoop::wxEventLoop()
  94 {
  95     m_shouldExit = false;
  96     m_exitcode = 0;
  97 }
  98
  99 // ----------------------------------------------------------------------------
 100 // wxEventLoop message processing
 101 // ----------------------------------------------------------------------------
 102
 103 void wxEventLoop::ProcessMessage(WXMSG *msg)
 104 {
 105     // give us the chance to preprocess the message first
 106     if ( !PreProcessMessage(msg) )
 107     {
 108         // if it wasn't done, dispatch it to the corresponding window
 109         ::TranslateMessage(msg);
 110         ::DispatchMessage(msg);
 111     }
 112 }
 113
 114 bool wxEventLoop::PreProcessMessage(WXMSG *msg)
 115 {
 116     HWND hwnd = msg->hwnd;
 117     wxWindow *wndThis = wxGetWindowFromHWND((WXHWND)hwnd);
 118
 119     // this may happen if the event occured in a standard modeless dialog (the
 120     // only example of which I know of is the find/replace dialog) - then call
 121     // IsDialogMessage() to make TAB navigation in it work
 122     if ( !wndThis )
 123     {
 124         // we need to find the dialog containing this control as
 125         // IsDialogMessage() just eats all the messages (i.e. returns true for
 126         // them) if we call it for the control itself
 127         while ( hwnd && ::GetWindowLong(hwnd, GWL_STYLE) & WS_CHILD )
 128         {
 129             hwnd = ::GetParent(hwnd);
 130         }
 131
 132         return hwnd && ::IsDialogMessage(hwnd, msg) != 0;
 133     }
 134
 135 #if wxUSE_TOOLTIPS
 136     // we must relay WM_MOUSEMOVE events to the tooltip ctrl if we want it to
 137     // popup the tooltip bubbles
 138     if ( msg->message == WM_MOUSEMOVE )
 139     {
 140         wxToolTip *tt = wndThis->GetToolTip();
 141         if ( tt )
 142         {
 143             tt->RelayEvent((WXMSG *)msg);
 144         }
 145     }
 146 #endif // wxUSE_TOOLTIPS
 147
 148     // allow the window to prevent certain messages from being
 149     // translated/processed (this is currently used by wxTextCtrl to always
 150     // grab Ctrl-C/V/X, even if they are also accelerators in some parent)
 151     if ( !wndThis->MSWShouldPreProcessMessage((WXMSG *)msg) )
 152     {
 153         return false;
 154     }
 155
 156     // try translations first: the accelerators override everything
 157     wxWindow *wnd;
 158
 159     for ( wnd = wndThis; wnd; wnd = wnd->GetParent() )
 160     {
 161         if ( wnd->MSWTranslateMessage((WXMSG *)msg))
 162             return true;
 163
 164         // stop at first top level window, i.e. don't try to process the key
 165         // strokes originating in a dialog using the accelerators of the parent
 166         // frame - this doesn't make much sense
 167         if ( wnd->IsTopLevel() )
 168             break;
 169     }
 170
 171     // now try the other hooks (kbd navigation is handled here)
 172     for ( wnd = wndThis; wnd; wnd = wnd->GetParent() )
 173     {
 174         if (wnd != wndThis) // Skip the first since wndThis->MSWProcessMessage() was called above
 175         {
 176             if ( wnd->MSWProcessMessage((WXMSG *)msg) )
 177                 return true;
 178         }
 179
 180         // Stop at first top level window (as per comment above).
 181         // If we don't do this, pressing ESC on a modal dialog shown as child of a modal
 182         // dialog with wxID_CANCEL will cause the parent dialog to be closed, for example
 183         if (wnd->IsTopLevel())
 184             break;
 185     }
 186
 187     // no special preprocessing for this message, dispatch it normally
 188     return false;
 189 }
 190
 191 // ----------------------------------------------------------------------------
 192 // wxEventLoop running and exiting
 193 // ----------------------------------------------------------------------------
 194
 195 bool wxEventLoop::IsRunning() const
 196 {
 197     return ms_activeLoop == this;
 198 }
 199
 200 int wxEventLoop::Run()
 201 {
 202     // event loops are not recursive, you need to create another loop!
 203     wxCHECK_MSG( !IsRunning(), -1, _T("can't reenter a message loop") );
 204
 205     // ProcessIdle() and Dispatch() below may throw so the code here should
 206     // be exception-safe, hence we must use local objects for all actions we
 207     // should undo
 208     wxEventLoopActivator activate(&ms_activeLoop, this);
 209
 210     // we must ensure that OnExit() is called even if an exception is thrown
 211     // from inside Dispatch() but we must call it from Exit() in normal
 212     // situations because it is supposed to be called synchronously,
 213     // wxModalEventLoop depends on this (so we can't just use ON_BLOCK_EXIT or
 214     // something similar here)
 215 #if wxUSE_EXCEPTIONS
 216     for ( ;; )
 217     {
 218         try
 219         {
 220 #endif // wxUSE_EXCEPTIONS
 221
 222             // this is the event loop itself
 223             for ( ;; )
 224             {
 225                 #if wxUSE_THREADS
 226                     wxMutexGuiLeaveOrEnter();
 227                 #endif // wxUSE_THREADS
 228
 229                 // generate and process idle events for as long as we don't
 230                 // have anything else to do
 231                 while ( !Pending() && (wxTheApp && wxTheApp->ProcessIdle()) )
 232                     ;
 233
 234                 // if the "should exit" flag is set, the loop should terminate
 235                 // but not before processing any remaining messages so while
 236                 // Pending() returns true, do process them
 237                 if ( m_shouldExit )
 238                 {
 239                     while ( Pending() )
 240                         Dispatch();
 241
 242                     break;
 243                 }
 244
 245                 // a message came or no more idle processing to do, sit in
 246                 // Dispatch() waiting for the next message
 247                 if ( !Dispatch() )
 248                 {
 249                     // we got WM_QUIT
 250                     break;
 251                 }
 252             }
 253
 254 #if wxUSE_EXCEPTIONS
 255             // exit the outer loop as well
 256             break;
 257         }
 258         catch ( ... )
 259         {
 260             try
 261             {
 262                 if ( !wxTheApp || !wxTheApp->OnExceptionInMainLoop() )
 263                 {
 264                     OnExit();
 265                     break;
 266                 }
 267                 //else: continue running the event loop
 268             }
 269             catch ( ... )
 270             {
 271                 // OnException() throwed, possibly rethrowing the same
 272                 // exception again: very good, but we still need OnExit() to
 273                 // be called
 274                 OnExit();
 275                 throw;
 276             }
 277         }
 278     }
 279 #endif // wxUSE_EXCEPTIONS
 280
 281     return m_exitcode;
 282 }
 283
 284 void wxEventLoop::Exit(int rc)
 285 {
 286     wxCHECK_RET( IsRunning(), _T("can't call Exit() if not running") );
 287
 288     m_exitcode = rc;
 289     m_shouldExit = true;
 290
 291     OnExit();
 292
 293     // all we have to do to exit from the loop is to (maybe) wake it up so that
 294     // it can notice that Exit() had been called
 295     //
 296     // in particular, we do *not* use PostQuitMessage() here because we're not
 297     // sure that WM_QUIT is going to be processed by the correct event loop: it
 298     // is possible that another one is started before this one has a chance to
 299     // process WM_QUIT
 300     ::PostMessage(NULL, WM_NULL, 0, 0);
 301 }
 302
 303 // ----------------------------------------------------------------------------
 304 // wxEventLoop message processing dispatching
 305 // ----------------------------------------------------------------------------
 306
 307 bool wxEventLoop::Pending() const
 308 {
 309     MSG msg;
 310     return ::PeekMessage(&msg, 0, 0, 0, PM_NOREMOVE) != 0;
 311 }
 312
 313 bool wxEventLoop::Dispatch()
 314 {
 315     wxCHECK_MSG( IsRunning(), false, _T("can't call Dispatch() if not running") );
 316
 317     MSG msg;
 318     BOOL rc = ::GetMessage(&msg, (HWND) NULL, 0, 0);
 319
 320     if ( rc == 0 )
 321     {
 322         // got WM_QUIT
 323         return false;
 324     }
 325
 326     if ( rc == -1 )
 327     {
 328         // should never happen, but let's test for it nevertheless
 329         wxLogLastError(wxT("GetMessage"));
 330
 331         // still break from the loop
 332         return false;
 333     }
 334
 335 #if wxUSE_THREADS
 336     wxASSERT_MSG( wxThread::IsMain(),
 337                   wxT("only the main thread can process Windows messages") );
 338
 339     static bool s_hadGuiLock = true;
 340     static wxMsgList s_aSavedMessages;
 341
 342     // if a secondary thread owning the mutex is doing GUI calls, save all
 343     // messages for later processing - we can't process them right now because
 344     // it will lead to recursive library calls (and we're not reentrant)
 345     if ( !wxGuiOwnedByMainThread() )
 346     {
 347         s_hadGuiLock = false;
 348
 349         // leave out WM_COMMAND messages: too dangerous, sometimes
 350         // the message will be processed twice
 351         if ( !wxIsWaitingForThread() || msg.message != WM_COMMAND )
 352         {
 353             MSG* pMsg = new MSG(msg);
 354             s_aSavedMessages.Append(pMsg);
 355         }
 356
 357         return true;
 358     }
 359     else
 360     {
 361         // have we just regained the GUI lock? if so, post all of the saved
 362         // messages
 363         //
 364         // FIXME of course, it's not _exactly_ the same as processing the
 365         //       messages normally - expect some things to break...
 366         if ( !s_hadGuiLock )
 367         {
 368             s_hadGuiLock = true;
 369
 370             wxMsgList::compatibility_iterator node = s_aSavedMessages.GetFirst();
 371             while (node)
 372             {
 373                 MSG* pMsg = node->GetData();
 374                 s_aSavedMessages.Erase(node);
 375
 376                 ProcessMessage(pMsg);
 377                 delete pMsg;
 378
 379                 node = s_aSavedMessages.GetFirst();
 380             }
 381         }
 382     }
 383 #endif // wxUSE_THREADS
 384
 385     ProcessMessage(&msg);
 386
 387     return true;
 388 }
 389