[mutter/wip/carlosg/input-thread: 91/96] backends/native: Seal MetaKeymapNative xkb usage

[Carlos Garnacho <carlosg src gnome org>]

commit 8dcba95e0a9defaf741bde3eef9f83f7a795d4f6
Author: Carlos Garnacho <carlosg gnome org>
Date:   Wed Aug 12 11:16:39 2020 +0200

    backends/native: Seal MetaKeymapNative xkb usage
    
    Don't let the vfuncs (meant to be called from the UI thread) deal with
    xkb state itself. Instead store the current state in struct fields, which
    is then fetched in vfuncs.
    
    This makes the keymap able to be used from the UI thread, while being
    maintained by the input thread. Same caveats apply than
    clutter_seat_query_state(), you are asking for the most up-to-date state,
    but it still may be changing under your feet.
    
    https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1403

 src/backends/native/meta-keymap-native.c | 45 +++++++++++++++++++-------------
 src/backends/native/meta-keymap-native.h |  1 +
 src/backends/native/meta-seat-impl.c     |  3 +++
 3 files changed, 31 insertions(+), 18 deletions(-)
---
diff --git a/src/backends/native/meta-keymap-native.c b/src/backends/native/meta-keymap-native.c
index 034f1e6f4c..e0b09a13bd 100644
--- a/src/backends/native/meta-keymap-native.c
+++ b/src/backends/native/meta-keymap-native.c
@@ -36,6 +36,8 @@ struct _MetaKeymapNative
   ClutterKeymap parent_instance;
 
   struct xkb_keymap *keymap;
+  gboolean num_lock;
+  gboolean caps_lock;
 };
 
 G_DEFINE_TYPE (MetaKeymapNative, meta_keymap_native,
@@ -54,31 +56,17 @@ meta_keymap_native_finalize (GObject *object)
 static gboolean
 meta_keymap_native_get_num_lock_state (ClutterKeymap *keymap)
 {
-  struct xkb_state *xkb_state;
-  ClutterSeat *seat;
-
-  seat = clutter_backend_get_default_seat (clutter_get_default_backend ());
-  xkb_state = meta_seat_impl_get_xkb_state (META_SEAT_NATIVE (seat)->impl);
+  MetaKeymapNative *keymap_native = META_KEYMAP_NATIVE (keymap);
 
-  return xkb_state_mod_name_is_active (xkb_state,
-                                       XKB_MOD_NAME_NUM,
-                                       XKB_STATE_MODS_LATCHED |
-                                       XKB_STATE_MODS_LOCKED);
+  return keymap_native->num_lock;
 }
 
 static gboolean
 meta_keymap_native_get_caps_lock_state (ClutterKeymap *keymap)
 {
-  struct xkb_state *xkb_state;
-  ClutterSeat *seat;
-
-  seat = clutter_backend_get_default_seat (clutter_get_default_backend ());
-  xkb_state = meta_seat_impl_get_xkb_state (META_SEAT_NATIVE (seat)->impl);
+  MetaKeymapNative *keymap_native = META_KEYMAP_NATIVE (keymap);
 
-  return xkb_state_mod_name_is_active (xkb_state,
-                                       XKB_MOD_NAME_CAPS,
-                                       XKB_STATE_MODS_LATCHED |
-                                       XKB_STATE_MODS_LOCKED);
+  return keymap_native->caps_lock;
 }
 
 static PangoDirection
@@ -132,3 +120,24 @@ meta_keymap_native_get_keyboard_map (MetaKeymapNative *keymap)
 {
   return keymap->keymap;
 }
+
+void
+meta_keymap_native_update (MetaKeymapNative *keymap)
+{
+  struct xkb_state *xkb_state;
+  ClutterSeat *seat;
+
+  seat = clutter_backend_get_default_seat (clutter_get_default_backend ());
+  xkb_state = meta_seat_impl_get_xkb_state (META_SEAT_NATIVE (seat)->impl);
+
+  keymap->num_lock =
+    xkb_state_mod_name_is_active (xkb_state,
+                                  XKB_MOD_NAME_NUM,
+                                  XKB_STATE_MODS_LATCHED |
+                                  XKB_STATE_MODS_LOCKED);
+  keymap->caps_lock =
+    xkb_state_mod_name_is_active (xkb_state,
+                                  XKB_MOD_NAME_CAPS,
+                                  XKB_STATE_MODS_LATCHED |
+                                  XKB_STATE_MODS_LOCKED);
+}
diff --git a/src/backends/native/meta-keymap-native.h b/src/backends/native/meta-keymap-native.h
index 27364984ce..8b276df5d6 100644
--- a/src/backends/native/meta-keymap-native.h
+++ b/src/backends/native/meta-keymap-native.h
@@ -32,5 +32,6 @@ G_DECLARE_FINAL_TYPE (MetaKeymapNative, meta_keymap_native,
 void                meta_keymap_native_set_keyboard_map (MetaKeymapNative  *keymap,
                                                          struct xkb_keymap *xkb_keymap);
 struct xkb_keymap * meta_keymap_native_get_keyboard_map (MetaKeymapNative *keymap);
+void                meta_keymap_native_update           (MetaKeymapNative *keymap);
 
 #endif /* META_KEYMAP_NATIVE_H */
diff --git a/src/backends/native/meta-seat-impl.c b/src/backends/native/meta-seat-impl.c
index ab9c714e76..6f1ddc8594 100644
--- a/src/backends/native/meta-seat-impl.c
+++ b/src/backends/native/meta-seat-impl.c
@@ -2863,6 +2863,7 @@ meta_seat_impl_update_xkb_state (MetaSeatImpl *seat)
   seat->scroll_lock_led = xkb_keymap_led_get_index (xkb_keymap, XKB_LED_NAME_SCROLL);
 
   meta_seat_impl_sync_leds (seat);
+  meta_keymap_native_update (seat->keymap);
 
   g_rw_lock_writer_unlock (&seat->state_lock);
 }
@@ -3034,6 +3035,7 @@ meta_seat_impl_set_keyboard_layout_index (MetaSeatImpl       *seat,
   locked_mods = xkb_state_serialize_mods (state, XKB_STATE_MODS_LOCKED);
 
   xkb_state_update_mask (state, depressed_mods, latched_mods, locked_mods, 0, 0, idx);
+  meta_keymap_native_update (seat->keymap);
 
   seat->layout_idx = idx;
 
@@ -3095,6 +3097,7 @@ meta_seat_impl_set_keyboard_numlock (MetaSeatImpl *seat,
                          group_mods);
 
   meta_seat_impl_sync_leds (seat);
+  meta_keymap_native_update (seat->keymap);
 
   g_rw_lock_writer_unlock (&seat->state_lock);
 }