Better fix

[wxWidgets.git] / src / msw / app.cpp

diff --git a/src/msw/app.cpp b/src/msw/app.cpp
index 474e8e4839d96e626f744cc3cfcfa652144d34cf..04916f784b59ae248b3f36a6508103043b7869a8 100644 (file)
--- a/src/msw/app.cpp
+++ b/src/msw/app.cpp
@@ -355,8 +355,6 @@ bool wxApp::Initialize(int& argc, wxChar **argv)
 
     RegisterWindowClasses();
 
-    wxWinHandleHash = new wxWinHashTable(wxKEY_INTEGER, 100);
-
 #if !defined(__WXMICROWIN__) && !defined(__WXWINCE__)
     wxSetKeyboardHook(true);
 #endif
@@ -510,10 +508,10 @@ bool wxApp::UnregisterWindowClasses()
 
 void wxApp::CleanUp()
 {
-    // all objects pending for deletion must be deleted first, otherwise we
-    // would crash when they use wxWinHandleHash (and UnregisterWindowClasses()
-    // call wouldn't succeed as long as any windows still exist), so call the
-    // base class method first and only then do our clean up
+    // all objects pending for deletion must be deleted first, otherwise
+    // UnregisterWindowClasses() call wouldn't succeed (because windows
+    // using the classes being unregistered still exist), so call the base
+    // class method first and only then do our clean up
     wxAppBase::CleanUp();
 
 #if !defined(__WXMICROWIN__) && !defined(__WXWINCE__)
@@ -528,9 +526,6 @@ void wxApp::CleanUp()
     // unregister the classes now
     UnregisterWindowClasses();
 
-    delete wxWinHandleHash;
-    wxWinHandleHash = NULL;
-
 #ifdef __WXWINCE__
     free( wxCanvasClassName );
     free( wxCanvasClassNameNR );
@@ -571,13 +566,28 @@ void wxApp::WakeUpIdle()
     // start up again.  Doing it this way ensures that the idle handler
     // wakes up in the right thread (see also wxWakeUpMainThread() which does
     // the same for the main app thread only)
-    wxWindow *topWindow = wxTheApp->GetTopWindow();
+    wxWindow * const topWindow = wxTheApp->GetTopWindow();
     if ( topWindow )
     {
-        if ( !::PostMessage(GetHwndOf(topWindow), WM_NULL, 0, 0) )
+        HWND hwndTop = GetHwndOf(topWindow);
+
+        // Do not post WM_NULL if there's already a pending WM_NULL to avoid
+        // overflowing the message queue.
+        //
+        // Notice that due to a limitation of PeekMessage() API (which handles
+        // 0,0 range specially), we have to check the range from 0-1 instead.
+        // This still makes it possible to overflow the queue with WM_NULLs by
+        // interspersing the calles to WakeUpIdle() with windows creation but
+        // it should be rather hard to do it accidentally.
+        MSG msg;
+        if ( !::PeekMessage(&msg, hwndTop, 0, 1, PM_NOREMOVE) ||
+              ::PeekMessage(&msg, hwndTop, 1, 1, PM_NOREMOVE) )
         {
-            // should never happen
-            wxLogLastError(wxT("PostMessage(WM_NULL)"));
+            if ( !::PostMessage(hwndTop, WM_NULL, 0, 0) )
+            {
+                // should never happen
+                wxLogLastError(wxT("PostMessage(WM_NULL)"));
+            }
         }
     }
 }