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 * const wndThis = wxGetWindowFromHWND((WXHWND)hwnd);
 128     wxWindow *wnd;
 129
 130     // this may happen if the event occurred in a standard modeless dialog (the
 131     // only example of which I know of is the find/replace dialog) - then call
 132     // IsDialogMessage() to make TAB navigation in it work
 133     if ( !wndThis )
 134     {
 135         // we need to find the dialog containing this control as
 136         // IsDialogMessage() just eats all the messages (i.e. returns true for
 137         // them) if we call it for the control itself
 138         while ( hwnd && ::GetWindowLong(hwnd, GWL_STYLE) & WS_CHILD )
 139         {
 140             hwnd = ::GetParent(hwnd);
 141         }
 142
 143         return hwnd && ::IsDialogMessage(hwnd, msg) != 0;
 144     }
 145
 146     if ( !AllowProcessing(wndThis) )
 147     {
 148         // not a child of critical window, so we eat the event but take care to
 149         // stop an endless stream of WM_PAINTs which would have resulted if we
 150         // didn't validate the invalidated part of the window
 151         if ( msg->message == WM_PAINT )
 152             ::ValidateRect(hwnd, NULL);
 153
 154         return true;
 155     }
 156
 157 #if wxUSE_TOOLTIPS
 158     // we must relay WM_MOUSEMOVE events to the tooltip ctrl if we want it to
 159     // popup the tooltip bubbles
 160     if ( msg->message == WM_MOUSEMOVE )
 161     {
 162         wxToolTip *tt = wndThis->GetToolTip();
 163         if ( tt )
 164         {
 165             tt->RelayEvent((WXMSG *)msg);
 166         }
 167     }
 168 #endif // wxUSE_TOOLTIPS
 169
 170     // allow the window to prevent certain messages from being
 171     // translated/processed (this is currently used by wxTextCtrl to always
 172     // grab Ctrl-C/V/X, even if they are also accelerators in some parent)
 173     if ( !wndThis->MSWShouldPreProcessMessage((WXMSG *)msg) )
 174     {
 175         return false;
 176     }
 177
 178     // try translations first: the accelerators override everything
 179     for ( wnd = wndThis; wnd; wnd = wnd->GetParent() )
 180     {
 181         if ( wnd->MSWTranslateMessage((WXMSG *)msg))
 182             return true;
 183
 184         // stop at first top level window, i.e. don't try to process the key
 185         // strokes originating in a dialog using the accelerators of the parent
 186         // frame - this doesn't make much sense
 187         if ( wnd->IsTopLevel() )
 188             break;
 189     }
 190
 191     // now try the other hooks (kbd navigation is handled here)
 192     for ( wnd = wndThis; wnd; wnd = wnd->GetParent() )
 193     {
 194         if (wnd != wndThis) // Skip the first since wndThis->MSWProcessMessage() was called above
 195         {
 196             if ( wnd->MSWProcessMessage((WXMSG *)msg) )
 197                 return true;
 198         }
 199
 200         // Stop at first top level window (as per comment above).
 201         // If we don't do this, pressing ESC on a modal dialog shown as child of a modal
 202         // dialog with wxID_CANCEL will cause the parent dialog to be closed, for example
 203         if (wnd->IsTopLevel())
 204             break;
 205     }
 206
 207     // no special preprocessing for this message, dispatch it normally
 208     return false;
 209 }
 210
 211 // ----------------------------------------------------------------------------
 212 // wxEventLoop running and exiting
 213 // ----------------------------------------------------------------------------
 214
 215 bool wxEventLoop::IsRunning() const
 216 {
 217     return ms_activeLoop == this;
 218 }
 219
 220 int wxEventLoop::Run()
 221 {
 222     // event loops are not recursive, you need to create another loop!
 223     wxCHECK_MSG( !IsRunning(), -1, _T("can't reenter a message loop") );
 224
 225     // ProcessIdle() and Dispatch() below may throw so the code here should
 226     // be exception-safe, hence we must use local objects for all actions we
 227     // should undo
 228     wxEventLoopActivator activate(&ms_activeLoop, this);
 229
 230     // we must ensure that OnExit() is called even if an exception is thrown
 231     // from inside Dispatch() but we must call it from Exit() in normal
 232     // situations because it is supposed to be called synchronously,
 233     // wxModalEventLoop depends on this (so we can't just use ON_BLOCK_EXIT or
 234     // something similar here)
 235 #if wxUSE_EXCEPTIONS
 236     for ( ;; )
 237     {
 238         try
 239         {
 240 #endif // wxUSE_EXCEPTIONS
 241
 242             // this is the event loop itself
 243             for ( ;; )
 244             {
 245                 #if wxUSE_THREADS
 246                     wxMutexGuiLeaveOrEnter();
 247                 #endif // wxUSE_THREADS
 248
 249                 // generate and process idle events for as long as we don't
 250                 // have anything else to do
 251                 while ( !Pending() && (wxTheApp && wxTheApp->ProcessIdle()) )
 252                     ;
 253
 254                 // if the "should exit" flag is set, the loop should terminate
 255                 // but not before processing any remaining messages so while
 256                 // Pending() returns true, do process them
 257                 if ( m_shouldExit )
 258                 {
 259                     while ( Pending() )
 260                         Dispatch();
 261
 262                     break;
 263                 }
 264
 265                 // a message came or no more idle processing to do, sit in
 266                 // Dispatch() waiting for the next message
 267                 if ( !Dispatch() )
 268                 {
 269                     // we got WM_QUIT
 270                     break;
 271                 }
 272             }
 273
 274 #if wxUSE_EXCEPTIONS
 275             // exit the outer loop as well
 276             break;
 277         }
 278         catch ( ... )
 279         {
 280             try
 281             {
 282                 if ( !wxTheApp || !wxTheApp->OnExceptionInMainLoop() )
 283                 {
 284                     OnExit();
 285                     break;
 286                 }
 287                 //else: continue running the event loop
 288             }
 289             catch ( ... )
 290             {
 291                 // OnException() throwed, possibly rethrowing the same
 292                 // exception again: very good, but we still need OnExit() to
 293                 // be called
 294                 OnExit();
 295                 throw;
 296             }
 297         }
 298     }
 299 #endif // wxUSE_EXCEPTIONS
 300
 301     return m_exitcode;
 302 }
 303
 304 void wxEventLoop::Exit(int rc)
 305 {
 306     wxCHECK_RET( IsRunning(), _T("can't call Exit() if not running") );
 307
 308     m_exitcode = rc;
 309     m_shouldExit = true;
 310
 311     OnExit();
 312
 313     // all we have to do to exit from the loop is to (maybe) wake it up so that
 314     // it can notice that Exit() had been called
 315     //
 316     // in particular, we do *not* use PostQuitMessage() here because we're not
 317     // sure that WM_QUIT is going to be processed by the correct event loop: it
 318     // is possible that another one is started before this one has a chance to
 319     // process WM_QUIT
 320     ::PostMessage(NULL, WM_NULL, 0, 0);
 321 }
 322
 323 // ----------------------------------------------------------------------------
 324 // wxEventLoop message processing dispatching
 325 // ----------------------------------------------------------------------------
 326
 327 bool wxEventLoop::Pending() const
 328 {
 329     MSG msg;
 330     return ::PeekMessage(&msg, 0, 0, 0, PM_NOREMOVE) != 0;
 331 }
 332
 333 bool wxEventLoop::Dispatch()
 334 {
 335     wxCHECK_MSG( IsRunning(), false, _T("can't call Dispatch() if not running") );
 336
 337     MSG msg;
 338     BOOL rc = ::GetMessage(&msg, (HWND) NULL, 0, 0);
 339
 340     if ( rc == 0 )
 341     {
 342         // got WM_QUIT
 343         return false;
 344     }
 345
 346     if ( rc == -1 )
 347     {
 348         // should never happen, but let's test for it nevertheless
 349         wxLogLastError(wxT("GetMessage"));
 350
 351         // still break from the loop
 352         return false;
 353     }
 354
 355 #if wxUSE_THREADS
 356     wxASSERT_MSG( wxThread::IsMain(),
 357                   wxT("only the main thread can process Windows messages") );
 358
 359     static bool s_hadGuiLock = true;
 360     static wxMsgList s_aSavedMessages;
 361
 362     // if a secondary thread owning the mutex is doing GUI calls, save all
 363     // messages for later processing - we can't process them right now because
 364     // it will lead to recursive library calls (and we're not reentrant)
 365     if ( !wxGuiOwnedByMainThread() )
 366     {
 367         s_hadGuiLock = false;
 368
 369         // leave out WM_COMMAND messages: too dangerous, sometimes
 370         // the message will be processed twice
 371         if ( !wxIsWaitingForThread() || msg.message != WM_COMMAND )
 372         {
 373             MSG* pMsg = new MSG(msg);
 374             s_aSavedMessages.Append(pMsg);
 375         }
 376
 377         return true;
 378     }
 379     else
 380     {
 381         // have we just regained the GUI lock? if so, post all of the saved
 382         // messages
 383         //
 384         // FIXME of course, it's not _exactly_ the same as processing the
 385         //       messages normally - expect some things to break...
 386         if ( !s_hadGuiLock )
 387         {
 388             s_hadGuiLock = true;
 389
 390             wxMsgList::compatibility_iterator node = s_aSavedMessages.GetFirst();
 391             while (node)
 392             {
 393                 MSG* pMsg = node->GetData();
 394                 s_aSavedMessages.Erase(node);
 395
 396                 ProcessMessage(pMsg);
 397                 delete pMsg;
 398
 399                 node = s_aSavedMessages.GetFirst();
 400             }
 401         }
 402     }
 403 #endif // wxUSE_THREADS
 404
 405     ProcessMessage(&msg);
 406
 407     return true;
 408 }
 409