tray/na-xembed: Destroy socket window when ending the embedding

Currently when embedding a tray icon is ended we are leaving the X11
socket window around as we don't really destroy it, while we're just
listening for its child destruction.

So, when embedding is ending we need to make sure that:
 - If the plug window is still alive, move it back to its old parent
   (normally that's the root window, but we query for it, to be sure)
 - If the plug window has been already destroyed or reparented (by us or
   by something else), we've to just destroy the socket window

Fixes: https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/7614
Origin: https://gitlab.gnome.org/3v1n0/gnome-shell/-/commits/tray-offscreen-xwindows
Bug-Ubuntu: https://bugs.launchpad.net/bugs/2012388

Gbp-Pq: Topic tray-icons
Gbp-Pq: Name tray-na-xembed-Destroy-socket-window-when-ending-the-embe.patch

diff --git a/src/tray/na-xembed.c b/src/tray/na-xembed.c
index 4ef3666ab710d86f7df683a725edb5e3976190bb..588e0344e510d312bae61141dc50723e606f0a7e 100644 (file)
--- a/src/tray/na-xembed.c
+++ b/src/tray/na-xembed.c
@@ -36,6 +36,7 @@ struct _NaXembedPrivate
   MetaX11Display *x11_display;
   Window socket_window;
   Window plug_window;
+  Window old_parent;
 
   int root_x;
   int root_y;
@@ -139,7 +140,26 @@ na_xembed_end_embedding (NaXembed *xembed)
 {
   NaXembedPrivate *priv = na_xembed_get_instance_private (xembed);
 
+  if (priv->socket_window)
+    {
+      Display *xdisplay = meta_x11_display_get_xdisplay (priv->x11_display);
+
+      mtk_x11_error_trap_push (xdisplay);
+
+      if (priv->plug_window && priv->old_parent)
+        XReparentWindow (xdisplay,
+                         priv->plug_window,
+                         priv->old_parent,
+                         0, 0);
+
+      XDestroyWindow (xdisplay, priv->socket_window);
+      priv->socket_window = None;
+
+      mtk_x11_error_trap_pop (xdisplay);
+    }
+
   priv->plug_window = None;
+  priv->old_parent = None;
   priv->current_width = 0;
   priv->current_height = 0;
   priv->resize_count = 0;
@@ -413,6 +433,18 @@ na_xembed_add_window (NaXembed  *xembed,
                        &socket_attrs);
 
       XUnmapWindow (xdisplay, priv->plug_window); /* Shouldn't actually be necessary for XEMBED, but just in case */
+
+      if (!priv->old_parent)
+        {
+          g_autofree Window *children = NULL;
+          unsigned int n_children;
+          Window root;
+
+          if (!XQueryTree (xdisplay, priv->plug_window, &root, &priv->old_parent,
+                           &children, &n_children))
+            priv->old_parent = meta_x11_display_get_xroot (priv->x11_display);
+        }
+
       XReparentWindow (xdisplay,
                        priv->plug_window,
                        priv->socket_window,
@@ -563,10 +595,14 @@ xembed_filter_func (MetaX11Display *x11_display,
         /* Note that we get destroy notifies both from SubstructureNotify on
          * our window and StructureNotify on socket->plug_window
          */
+        if (priv->socket_window && xdwe->window == priv->socket_window)
+          priv->socket_window = None;
+
         if (priv->plug_window && (xdwe->window == priv->plug_window))
           {
             g_object_ref (xembed);
             g_signal_emit (xembed, signals[PLUG_REMOVED], 0);
+            priv->plug_window = None;
             na_xembed_end_embedding (xembed);
             g_object_unref (xembed);
           }
@@ -631,6 +667,7 @@ xembed_filter_func (MetaX11Display *x11_display,
           {
             g_object_ref (xembed);
             g_signal_emit (xembed, signals[PLUG_REMOVED], 0);
+            priv->old_parent = None;
             na_xembed_end_embedding (xembed);
             g_object_unref (xembed);
           }
@@ -696,7 +733,7 @@ na_xembed_finalize (GObject *object)
   if (priv->x11_display && priv->event_func_id)
     meta_x11_display_remove_event_func (priv->x11_display, priv->event_func_id);
 
-  if (priv->plug_window)
+  if (priv->plug_window || priv->socket_window)
     na_xembed_end_embedding (xembed);
 
   G_OBJECT_CLASS (na_xembed_parent_class)->finalize (object);