[mutter] wayland: Check serial on wp_tablet_pad.set_feedback

[Carlos Garnacho <carlosg src gnome org>]

commit b34fe72bb7b536f314803a7612e5f6218aeb8e61
Author: Carlos Garnacho <carlosg gnome org>
Date:   Wed Jun 29 18:31:24 2016 +0200

    wayland: Check serial on wp_tablet_pad.set_feedback
    
    We must lookup the mode switch serial for the group where the button
    belongs to. Also, avoid the changes if the client requests setting
    the feedback for buttons owned by the compositor.

 src/wayland/meta-wayland-tablet-pad.c |   31 ++++++++++++++++++++++++++++++-
 1 files changed, 30 insertions(+), 1 deletions(-)
---
diff --git a/src/wayland/meta-wayland-tablet-pad.c b/src/wayland/meta-wayland-tablet-pad.c
index 6f55729..9995692 100644
--- a/src/wayland/meta-wayland-tablet-pad.c
+++ b/src/wayland/meta-wayland-tablet-pad.c
@@ -217,6 +217,23 @@ meta_wayland_tablet_pad_free (MetaWaylandTabletPad *pad)
   g_slice_free (MetaWaylandTabletPad, pad);
 }
 
+static MetaWaylandTabletPadGroup *
+tablet_pad_lookup_button_group (MetaWaylandTabletPad *pad,
+                                guint                 button)
+{
+  GList *l;
+
+  for (l = pad->groups; l; l = l->next)
+    {
+      MetaWaylandTabletPadGroup *group = l->data;
+
+      if (meta_wayland_tablet_pad_group_has_button (group, button))
+        return group;
+    }
+
+  return NULL;
+}
+
 static void
 tablet_pad_set_feedback (struct wl_client   *client,
                          struct wl_resource *resource,
@@ -225,8 +242,20 @@ tablet_pad_set_feedback (struct wl_client   *client,
                          uint32_t            serial)
 {
   MetaWaylandTabletPad *pad = wl_resource_get_user_data (resource);
+  MetaWaylandTabletPadGroup *group = tablet_pad_lookup_button_group (pad, button);
+  MetaInputSettings *input_settings;
+
+  if (!group || group->mode_switch_serial != serial)
+    return;
+
+  input_settings = meta_backend_get_input_settings (meta_get_backend ());
 
-  /* FIXME: check serial */
+  if (input_settings &&
+      meta_input_settings_is_pad_button_grabbed (input_settings, pad->device, button))
+    return;
+
+  if (meta_wayland_tablet_pad_group_is_mode_switch_button (group, button))
+    return;
 
   g_hash_table_insert (pad->feedback, GUINT_TO_POINTER (button), g_strdup (str));
 }