x11: Move focus sentinel to MetaX11Display

This focus sentinel is a mechanism to avoid some X11-specific race
conditions in focus-follows-pointer, using X11 mechanisms. Move it to
MetaX11Display altogether.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/420

1 files changed, 31 insertions, 0 deletions

diff --git a/src/x11/meta-x11-display.c b/src/x11/meta-x11-display.c
index af8ae7a8d..2aece19a8 100644
--- a/src/x11/meta-x11-display.c
+++ b/src/x11/meta-x11-display.c
@@ -2177,3 +2177,34 @@ prefs_changed_callback (MetaPreference pref,
       set_workspace_names (x11_display);
     }
 }
+
+void
+meta_x11_display_increment_focus_sentinel (MetaX11Display *x11_display)
+{
+  unsigned long data[1];
+
+  data[0] = meta_display_get_current_time (x11_display->display);
+
+  XChangeProperty (x11_display->xdisplay,
+                   x11_display->xroot,
+                   x11_display->atom__MUTTER_SENTINEL,
+                   XA_CARDINAL,
+                   32, PropModeReplace, (guchar*) data, 1);
+
+  x11_display->sentinel_counter += 1;
+}
+
+void
+meta_x11_display_decrement_focus_sentinel (MetaX11Display *x11_display)
+{
+  x11_display->sentinel_counter -= 1;
+
+  if (x11_display->sentinel_counter < 0)
+    x11_display->sentinel_counter = 0;
+}
+
+gboolean
+meta_x11_display_focus_sentinel_clear (MetaX11Display *x11_display)
+{
+  return (x11_display->sentinel_counter == 0);
+}