check in the 'selective yield' patch (see ticket #10320):

- implements YieldFor() with event filtering for wxMSW and wxGTK,
  adds TODO markers in other ports;
- replaces wxYield() in GTK's clipboard code with a wxTheApp->YieldFor() call, thus fixing possible reentrancies 
(and modifies clipboard sample to test synchronous IsSupported calls)
- replaces wxYieldIfNeeded() calls in wxProgressDialog with wxTheApp->YieldFor() calls, so that it processes only 
UI/user-input events, thus fixing the race condition visible in the "thread" sample
- documents the new functions


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@58654 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/gtk/app.cpp

@@ -49,12 +49,13 @@
 //-----------------------------------------------------------------------------
 
 static GtkWidget *gs_RootWindow = NULL;
+static wxArrayPtrVoid g_arrGdkEvents;
 
 //-----------------------------------------------------------------------------
 // wxYield
 //-----------------------------------------------------------------------------
 
-bool wxApp::Yield(bool onlyIfNeeded)
+bool wxApp::DoYield(bool onlyIfNeeded, long eventsToProcess)
 {
     if ( m_isInsideYield )
     {
@@ -75,6 +76,7 @@ bool wxApp::Yield(bool onlyIfNeeded)
 #endif // wxUSE_THREADS
 
     m_isInsideYield = true;
+    m_eventsToProcessInsideYield = eventsToProcess;
 
 #if wxUSE_LOG
     // disable log flushing from here because a call to wxYield() shouldn't
@@ -82,16 +84,116 @@ bool wxApp::Yield(bool onlyIfNeeded)
     wxLog::Suspend();
 #endif
 
-    while (EventsPending())
-        gtk_main_iteration();
+    // NOTE: gtk_main_iteration() doesn't allow us to filter events, so we
+    //       rather use gtk_main_do_event() after filtering the events at
+    //       GDK level
 
-    // It's necessary to call ProcessIdle() to update the frames sizes which
-    // might have been changed (it also will update other things set from
-    // OnUpdateUI() which is a nice (and desired) side effect). But we
-    // call ProcessIdle() only once since this is not meant for longish
-    // background jobs (controlled by wxIdleEvent::RequestMore() and the
-    // return value of Processidle().
-    ProcessIdle();
+    GdkDisplay* disp = gtk_widget_get_display(gs_RootWindow);
+
+    // gdk_display_get_event() will transform X11 events into GDK events
+    // and will queue all of them in the display (private) structure;
+    // finally it will "unqueue" the last one and return it to us
+    GdkEvent* event = gdk_display_get_event(disp);
+    while (event)
+    {
+        // categorize the GDK event according to wxEventCategory.
+        // See http://library.gnome.org/devel/gdk/unstable/gdk-Events.html#GdkEventType
+        // for more info.
+
+        wxEventCategory cat = wxEVT_CATEGORY_UNKNOWN;
+        switch (event->type)
+        {
+        case GDK_SELECTION_REQUEST:
+        case GDK_SELECTION_NOTIFY:
+        case GDK_SELECTION_CLEAR:
+        case GDK_OWNER_CHANGE:
+            cat = wxEVT_CATEGORY_CLIPBOARD;
+            break;
+
+
+        case GDK_KEY_PRESS:
+        case GDK_KEY_RELEASE:
+        case GDK_BUTTON_PRESS:
+        case GDK_2BUTTON_PRESS:
+        case GDK_3BUTTON_PRESS:
+        case GDK_BUTTON_RELEASE:
+        case GDK_SCROLL:        // generated from mouse buttons
+        case GDK_CLIENT_EVENT:
+            cat = wxEVT_CATEGORY_USER_INPUT;
+            break;
+
+
+        case GDK_PROXIMITY_IN:
+        case GDK_PROXIMITY_OUT:
+
+        case GDK_MOTION_NOTIFY:
+        case GDK_ENTER_NOTIFY:
+        case GDK_LEAVE_NOTIFY:
+        case GDK_VISIBILITY_NOTIFY:
+        case GDK_PROPERTY_NOTIFY:
+
+        case GDK_FOCUS_CHANGE:
+        case GDK_CONFIGURE:
+        case GDK_WINDOW_STATE:
+        case GDK_SETTING:
+        case GDK_DELETE:
+        case GDK_DESTROY:
+
+        case GDK_EXPOSE:
+        case GDK_NO_EXPOSE:
+        case GDK_MAP:
+        case GDK_UNMAP:
+        //case GDK_DAMAGE:
+
+        case GDK_DRAG_ENTER:
+        case GDK_DRAG_LEAVE:
+        case GDK_DRAG_MOTION:
+        case GDK_DRAG_STATUS:
+        case GDK_DROP_START:
+        case GDK_DROP_FINISHED:
+        case GDK_GRAB_BROKEN:
+            cat = wxEVT_CATEGORY_UI;
+            break;
+
+        default:
+            cat = wxEVT_CATEGORY_UNKNOWN;
+            break;
+        }
+
+        if (eventsToProcess & cat)
+            gtk_main_do_event(event);       // process it now
+        else
+            g_arrGdkEvents.Add(event);      // process it later
+
+        // get next event
+        event = gdk_display_get_event(disp);
+    }
+
+    if (eventsToProcess != wxEVT_CATEGORY_CLIPBOARD)
+    {
+        // It's necessary to call ProcessIdle() to update the frames sizes which
+        // might have been changed (it also will update other things set from
+        // OnUpdateUI() which is a nice (and desired) side effect). But we
+        // call ProcessIdle() only once since this is not meant for longish
+        // background jobs (controlled by wxIdleEvent::RequestMore() and the
+        // return value of Processidle().
+        ProcessIdle();      // ProcessIdle() also calls ProcessPendingEvents()
+    }
+    //else: if we are inside ~wxClipboardSync() and we call ProcessIdle() and
+    //      the user app contains an UI update handler which calls wxClipboard::IsSupported,
+    //      then we fall into a never-ending loop...
+
+    // put all unprocessed GDK events back in the queue
+    for (size_t i=0; i<g_arrGdkEvents.GetCount(); i++)
+    {
+        GdkEvent* ev = (GdkEvent*)g_arrGdkEvents[i];
+
+        // NOTE: gdk_display_put_event makes a copy of the event passed to it
+        gdk_display_put_event(disp, ev);
+        gdk_event_free(ev);
+    }
+
+    g_arrGdkEvents.Clear();
 
 #if wxUSE_LOG
     // let the logs be flashed again