Fixes: NB#203650 - displayEntered() not emitted when switching between two windows in the same app

RevBy: Antti Kervinen

Details: Listen only to synthetic visibility events if mcompositor is running.

3 files changed, 81 insertions, 21 deletions

diff --git a/src/corelib/core/mapplication.cpp b/src/corelib/core/mapplication.cpp
index eb35c5f9..2b5cba4b 100644
--- a/src/corelib/core/mapplication.cpp
+++ b/src/corelib/core/mapplication.cpp
@@ -405,36 +405,35 @@ bool MApplication::x11EventFilter(XEvent *event)
 
 void MApplicationPrivate::handleXVisibilityEvent(XVisibilityEvent *xevent)
 {
-    switch (xevent->state) {
-    case VisibilityFullyObscured:
-        // Listen only to synthetic events by compositor
-        if (xevent->send_event)
-        {
-            MWindow * window = MApplicationPrivate::windowForId(xevent->window);
+    static const bool wmRunning = MComponentData::isMeeGoWindowManagerRunning();
+
+    // Listen only to synthetic events if window
+    // manager is running.
+    if (xevent->send_event || !wmRunning) {
+
+        MWindow * window = MApplicationPrivate::windowForId(xevent->window);
+
+        switch (xevent->state) {
+        case VisibilityFullyObscured:
             if (window) {
                 window->d_ptr->fullyObscured = true;
                 if (!window->d_ptr->visibleInSwitcher) {
                     setWindowVisibility(window, false);
                 }
             }
-        }
-        break;
-
-        // Always listen to these events, because if compositor is not running
-        // we are not getting any synthetic events at all and the window would never get
-        // the display entered signal.
-    case VisibilityUnobscured:
-    case VisibilityPartiallyObscured:
-        {
-            MWindow * window = MApplicationPrivate::windowForId(xevent->window);
+            break;
+
+        case VisibilityUnobscured:
+        case VisibilityPartiallyObscured:
             if (window) {
                 window->d_ptr->fullyObscured = false;
                 setWindowVisibility(window, true);
             }
+            break;
+
+        default:
+            break;
         }
-        break;
-    default:
-        break;
     }
 }
 
diff --git a/src/corelib/core/mcomponentdata.cpp b/src/corelib/core/mcomponentdata.cpp
index 3ed19820..4a174c17 100644
--- a/src/corelib/core/mcomponentdata.cpp
+++ b/src/corelib/core/mcomponentdata.cpp
@@ -56,10 +56,12 @@
 #include "mgraphicssystemhelper.h"
 
 #ifdef Q_WS_X11
-#ifdef HAVE_XDAMAGE
 #include <QX11Info>
+#include <X11/Xlib.h>
+#include <X11/Xatom.h>
+#ifdef HAVE_XDAMAGE
 #include <X11/extensions/Xfixes.h>
-#endif // HAVE_XFIXES
+#endif // HAVE_XDAMAGE
 #endif // Q_WS_X11
 
 namespace
@@ -1172,6 +1174,62 @@ bool MComponentData::isOrientationForced()
 }
 
 #ifdef Q_WS_X11
+static int handleXError(Display *, XErrorEvent *)
+{
+    return 0;
+}
+#endif // Q_WS_X11
+
+bool MComponentData::isMeeGoWindowManagerRunning()
+{
+    bool retValue = false;
+
+#ifdef Q_WS_X11
+
+    Display       *dpy = QX11Info::display();
+    Window         rootw = RootWindow(dpy, XDefaultScreen(dpy));
+    Atom           wmSupportAtom = XInternAtom(dpy, "_NET_SUPPORTING_WM_CHECK", False);
+    Atom           type;
+    int            format;
+    unsigned long  numItems;
+    unsigned long  bytesAfter;
+    unsigned char *data = 0;
+
+    if (XGetWindowProperty(dpy, rootw, wmSupportAtom, 0, 1, False, XA_WINDOW,
+                           &type, &format, &numItems, &bytesAfter, &data) == Success) {
+        if (data) {
+
+            Window wid = *(reinterpret_cast<Window *>(data));
+            XFree(data);
+            data = 0;
+
+            Atom wmNameAtom = XInternAtom(dpy, "WM_NAME", False);
+
+            // Set error handler because window wid we got might not exist and
+            // the following name query would fail.
+            int (*previousHandler)(Display *, XErrorEvent *) = XSetErrorHandler(handleXError);
+
+            if (XGetWindowProperty(dpy, wid, wmNameAtom, 0, 16, False, XA_STRING,
+                                   &type, &format, &numItems, &bytesAfter, &data) == Success) {
+                if (data) {
+                    if (strcmp(reinterpret_cast<const char *>(data), "MCompositor") == 0) {
+                        retValue = true;
+                    }
+
+                    XFree(data);
+                    data = 0;
+                }
+            }
+
+            XSetErrorHandler(previousHandler);
+        }
+    }
+#endif  // Q_WS_X11
+
+    return retValue;
+}
+
+#ifdef Q_WS_X11
 QStack<MComponentData::ChainData> MComponentDataPrivate::chainData;
 
 void MComponentData::pushChainData(const ChainData &newChainData)
diff --git a/src/corelib/core/mcomponentdata.h b/src/corelib/core/mcomponentdata.h
index 8441698c..589470d8 100644
--- a/src/corelib/core/mcomponentdata.h
+++ b/src/corelib/core/mcomponentdata.h
@@ -186,6 +186,9 @@ public:
     //! Sets whether MComponentData should automatically load m input context
     static void setLoadMInputContext(bool enable);
 
+    //! Returns whether MCompositor is present
+    static bool isMeeGoWindowManagerRunning();
+
     //! \internal
     static M::OrientationAngle forcedOrientationAngle();