[mutter] xwayland: Ignore selection request not meant to our internal window

[Carlos Garnacho <carlosg src gnome org>]

commit b3eac93c4cef1b3ca6748cd95544ac720ee40821
Author: Carlos Garnacho <carlosg gnome org>
Date:   Fri Oct 7 13:58:35 2016 +0200

    xwayland: Ignore selection request not meant to our internal window
    
    There may be other windows managing selection whose events are seen in
    our GDK event filter, like st-clipboard in gnome-shell, we should in
    that case not interfere on Selection/SelectionRequest events that are
    not meant for us.
    
    This fixes an odd feedback loop where requesting clipboard contents from
    wayland results in a XConvertRequest call and a SelectionRequest event
    that is interpreted by mutter as a request from another X11 client, so
    the current data source is poked for content, which happens to be the
    X11 bridge, which does a XConvertRequest to get contents... This is only
    broken after the many nested async operations create enough pipes and
    cancellables to run out of fds.
    
    Adding checks to ensure only events meant to our "selection owner"
    window are managed prevent this unintended loop to happen in the first
    place.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=760745

 src/wayland/meta-xwayland-selection.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)
---
diff --git a/src/wayland/meta-xwayland-selection.c b/src/wayland/meta-xwayland-selection.c
index 5735fe4..a8806f1 100644
--- a/src/wayland/meta-xwayland-selection.c
+++ b/src/wayland/meta-xwayland-selection.c
@@ -1129,6 +1129,9 @@ meta_xwayland_selection_handle_selection_notify (MetaWaylandCompositor *composit
   if (!selection)
     return FALSE;
 
+  if (selection->window != event->requestor)
+    return FALSE;
+
   /* convert selection failed */
   if (event->property == None)
     {
@@ -1261,6 +1264,9 @@ meta_xwayland_selection_handle_selection_request (MetaWaylandCompositor *composi
   if (!selection)
     return FALSE;
 
+  if (selection->window != event->owner)
+    return FALSE;
+
   /* We must fetch from the currently active source, not the Xwayland one */
   data_source = data_device_get_active_source_for_atom (&compositor->seat->data_device,
                                                         selection->selection_atom);