backends: Handle numlock saving/restoring directly in backends

Simplify the handling of numlock state, so it can be entirely handled
within the input thread. Since the saving/restoring is triggered inside
each backend code, there's no need anymore for meta_backend_set_numlock().

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1403>

11 files changed, 111 insertions, 152 deletions

diff --git a/src/backends/meta-backend-private.h b/src/backends/meta-backend-private.h
index 3d32f05a3..b4dc5de10 100644
--- a/src/backends/meta-backend-private.h
+++ b/src/backends/meta-backend-private.h
@@ -100,9 +100,6 @@ struct _MetaBackendClass
   void (* update_screen_size) (MetaBackend *backend, int width, int height);
   void (* select_stage_events) (MetaBackend *backend);
 
-  void (* set_numlock) (MetaBackend *backend,
-                        gboolean     numlock_state);
-
   void (* set_pointer_constraint) (MetaBackend           *backend,
                                    MetaPointerConstraint *constraint);
 };
diff --git a/src/backends/meta-backend.c b/src/backends/meta-backend.c
index ba964c58b..fb05e078c 100644
--- a/src/backends/meta-backend.c
+++ b/src/backends/meta-backend.c
@@ -157,7 +157,6 @@ struct _MetaBackendPrivate
   gboolean is_pointer_position_initialized;
 
   guint device_update_idle_id;
-  gulong keymap_state_changed_id;
 
   GHashTable *device_monitors;
 
@@ -198,16 +197,6 @@ meta_backend_finalize (GObject *object)
   MetaBackend *backend = META_BACKEND (object);
   MetaBackendPrivate *priv = meta_backend_get_instance_private (backend);
 
-  if (priv->keymap_state_changed_id)
-    {
-      ClutterSeat *seat;
-      ClutterKeymap *keymap;
-
-      seat = clutter_backend_get_default_seat (priv->clutter_backend);
-      keymap = clutter_seat_get_keymap (seat);
-      g_clear_signal_handler (&priv->keymap_state_changed_id, keymap);
-    }
-
   g_list_free_full (priv->gpus, g_object_unref);
 
   g_clear_object (&priv->current_device);
@@ -579,7 +568,6 @@ meta_backend_real_post_init (MetaBackend *backend)
 {
   MetaBackendPrivate *priv = meta_backend_get_instance_private (backend);
   ClutterSeat *seat = clutter_backend_get_default_seat (priv->clutter_backend);
-  ClutterKeymap *keymap = clutter_seat_get_keymap (seat);
 
   priv->stage = meta_stage_new (backend);
   clutter_actor_realize (priv->stage);
@@ -602,15 +590,6 @@ meta_backend_real_post_init (MetaBackend *backend)
 
   priv->input_settings = meta_backend_create_input_settings (backend);
 
-  if (priv->input_settings)
-    {
-      priv->keymap_state_changed_id =
-        g_signal_connect_swapped (keymap, "state-changed",
-                                  G_CALLBACK (meta_input_settings_maybe_save_numlock_state),
-                                  priv->input_settings);
-      meta_input_settings_maybe_restore_numlock_state (priv->input_settings);
-    }
-
   priv->input_mapper = meta_input_mapper_new ();
   g_signal_connect (priv->input_mapper, "device-mapped",
                     G_CALLBACK (input_mapper_device_mapped_cb), backend);
@@ -1357,14 +1336,6 @@ meta_backend_lock_layout_group (MetaBackend *backend,
   META_BACKEND_GET_CLASS (backend)->lock_layout_group (backend, idx);
 }
 
-void
-meta_backend_set_numlock (MetaBackend *backend,
-                          gboolean     numlock_state)
-{
-  META_BACKEND_GET_CLASS (backend)->set_numlock (backend, numlock_state);
-}
-
-
 /**
  * meta_backend_get_stage:
  * @backend: A #MetaBackend
diff --git a/src/backends/meta-input-settings-private.h b/src/backends/meta-input-settings-private.h
index 639bede22..10de61d78 100644
--- a/src/backends/meta-input-settings-private.h
+++ b/src/backends/meta-input-settings-private.h
@@ -173,8 +173,9 @@ struct _MetaInputSettingsClass
                                     ClutterInputDevice *device);
 };
 
-void meta_input_settings_maybe_save_numlock_state    (MetaInputSettings *input_settings);
-void meta_input_settings_maybe_restore_numlock_state (MetaInputSettings *input_settings);
+void meta_input_settings_maybe_save_numlock_state (MetaInputSettings *input_settings,
+                                                   gboolean           numlock_state);
+gboolean meta_input_settings_maybe_restore_numlock_state (MetaInputSettings *input_settings);
 
 void meta_input_settings_set_device_matrix (MetaInputSettings  *input_settings,
                                             ClutterInputDevice *device,
diff --git a/src/backends/meta-input-settings.c b/src/backends/meta-input-settings.c
index 0b70681ae..5780fb9de 100644
--- a/src/backends/meta-input-settings.c
+++ b/src/backends/meta-input-settings.c
@@ -1161,8 +1161,6 @@ meta_input_settings_changed_cb (GSettings  *settings,
           strcmp (key, "repeat-interval") == 0 ||
           strcmp (key, "delay") == 0)
         update_keyboard_repeat (input_settings);
-      else if (strcmp (key, "remember-numlock-state") == 0)
-        meta_input_settings_maybe_save_numlock_state (input_settings);
     }
 }
 
@@ -1838,41 +1836,34 @@ meta_input_settings_init (MetaInputSettings *settings)
 }
 
 void
-meta_input_settings_maybe_save_numlock_state (MetaInputSettings *input_settings)
+meta_input_settings_maybe_save_numlock_state (MetaInputSettings *input_settings,
+                                              gboolean           numlock_state)
 {
   MetaInputSettingsPrivate *priv;
-  ClutterSeat *seat;
-  ClutterKeymap *keymap;
-  gboolean numlock_state;
 
   priv = meta_input_settings_get_instance_private (input_settings);
 
   if (!g_settings_get_boolean (priv->keyboard_settings, "remember-numlock-state"))
     return;
 
-  seat = clutter_backend_get_default_seat (clutter_get_default_backend ());
-  keymap = clutter_seat_get_keymap (seat);
-  numlock_state = clutter_keymap_get_num_lock_state (keymap);
-
   if (numlock_state == g_settings_get_boolean (priv->keyboard_settings, "numlock-state"))
     return;
 
   g_settings_set_boolean (priv->keyboard_settings, "numlock-state", numlock_state);
 }
 
-void
+gboolean
 meta_input_settings_maybe_restore_numlock_state (MetaInputSettings *input_settings)
 {
   MetaInputSettingsPrivate *priv;
-  gboolean numlock_state;
+  gboolean numlock_state = FALSE;
 
   priv = meta_input_settings_get_instance_private (input_settings);
 
-  if (!g_settings_get_boolean (priv->keyboard_settings, "remember-numlock-state"))
-    return;
+  if (g_settings_get_boolean (priv->keyboard_settings, "remember-numlock-state"))
+    numlock_state = g_settings_get_boolean (priv->keyboard_settings, "numlock-state");
 
-  numlock_state = g_settings_get_boolean (priv->keyboard_settings, "numlock-state");
-  meta_backend_set_numlock (meta_get_backend (), numlock_state);
+  return numlock_state;
 }
 
 void
diff --git a/src/backends/native/meta-backend-native.c b/src/backends/native/meta-backend-native.c
index c7809a8b5..a78c0866f 100644
--- a/src/backends/native/meta-backend-native.c
+++ b/src/backends/native/meta-backend-native.c
@@ -333,18 +333,6 @@ meta_backend_native_lock_layout_group (MetaBackend *backend,
 }
 
 static void
-meta_backend_native_set_numlock (MetaBackend *backend,
-                                 gboolean     numlock_state)
-{
-  ClutterBackend *clutter_backend = meta_backend_get_clutter_backend (backend);
-  ClutterSeat *seat;
-
-  seat = clutter_backend_get_default_seat (clutter_backend);
-  meta_seat_native_set_keyboard_numlock (META_SEAT_NATIVE (seat),
-                                         numlock_state);
-}
-
-static void
 meta_backend_native_set_pointer_constraint (MetaBackend           *backend,
                                             MetaPointerConstraint *constraint)
 {
@@ -576,7 +564,6 @@ meta_backend_native_class_init (MetaBackendNativeClass *klass)
   backend_class->get_keymap_layout_group = meta_backend_native_get_keymap_layout_group;
   backend_class->lock_layout_group = meta_backend_native_lock_layout_group;
   backend_class->update_screen_size = meta_backend_native_update_screen_size;
-  backend_class->set_numlock = meta_backend_native_set_numlock;
 
   backend_class->set_pointer_constraint = meta_backend_native_set_pointer_constraint;
 }
diff --git a/src/backends/native/meta-seat-impl.c b/src/backends/native/meta-seat-impl.c
index df53e55f5..a3cfef9d1 100644
--- a/src/backends/native/meta-seat-impl.c
+++ b/src/backends/native/meta-seat-impl.c
@@ -344,9 +344,18 @@ meta_seat_impl_notify_key (MetaSeatImpl       *seat_impl,
   if (update_keys && (changed_state & XKB_STATE_LEDS))
     {
       MetaInputDeviceNative *keyboard_native;
+      gboolean numlock_active;
 
       g_signal_emit (seat_impl, signals[MODS_STATE_CHANGED], 0);
       meta_seat_impl_sync_leds (seat_impl);
+
+      numlock_active =
+        xkb_state_mod_name_is_active (seat_impl->xkb, XKB_MOD_NAME_NUM,
+                                      XKB_STATE_MODS_LATCHED |
+                                      XKB_STATE_MODS_LOCKED);
+      meta_input_settings_maybe_save_numlock_state (seat_impl->input_settings,
+                                                    numlock_active);
+
       keyboard_native = META_INPUT_DEVICE_NATIVE (seat_impl->core_keyboard);
       meta_input_device_native_a11y_maybe_notify_toggle_keys (keyboard_native);
     }
@@ -2466,6 +2475,48 @@ static const struct libinput_interface libinput_interface = {
 };
 
 static void
+meta_seat_impl_set_keyboard_numlock (MetaSeatImpl *seat_impl,
+                                     gboolean      numlock_state)
+{
+  xkb_mod_mask_t depressed_mods;
+  xkb_mod_mask_t latched_mods;
+  xkb_mod_mask_t locked_mods;
+  xkb_mod_mask_t group_mods;
+  xkb_mod_mask_t numlock;
+  struct xkb_keymap *xkb_keymap;
+  MetaKeymapNative *keymap;
+
+  keymap = seat_impl->keymap;
+  xkb_keymap = meta_keymap_native_get_keyboard_map (keymap);
+
+  numlock = (1 << xkb_keymap_mod_get_index (xkb_keymap, "Mod2"));
+
+  depressed_mods =
+    xkb_state_serialize_mods (seat_impl->xkb, XKB_STATE_MODS_DEPRESSED);
+  latched_mods =
+    xkb_state_serialize_mods (seat_impl->xkb, XKB_STATE_MODS_LATCHED);
+  locked_mods =
+    xkb_state_serialize_mods (seat_impl->xkb, XKB_STATE_MODS_LOCKED);
+  group_mods =
+    xkb_state_serialize_layout (seat_impl->xkb, XKB_STATE_LAYOUT_EFFECTIVE);
+
+  if (numlock_state)
+    locked_mods |= numlock;
+  else
+    locked_mods &= ~numlock;
+
+  xkb_state_update_mask (seat_impl->xkb,
+                         depressed_mods,
+                         latched_mods,
+                         locked_mods,
+                         0, 0,
+                         group_mods);
+
+  meta_seat_impl_sync_leds (seat_impl);
+  meta_keymap_native_update (seat_impl->keymap);
+}
+
+static void
 meta_seat_impl_constructed (GObject *object)
 {
   MetaSeatImpl *seat_impl = META_SEAT_IMPL (object);
@@ -2536,6 +2587,9 @@ meta_seat_impl_constructed (GObject *object)
         xkb_keymap_led_get_index (xkb_keymap, XKB_LED_NAME_SCROLL);
     }
 
+  if (meta_input_settings_maybe_restore_numlock_state (seat_impl->input_settings))
+    meta_seat_impl_set_keyboard_numlock (seat_impl, TRUE);
+
   seat_impl->has_touchscreen = has_touchscreen (seat_impl);
   seat_impl->has_tablet_switch = has_tablet_switch (seat_impl);
   update_touch_mode (seat_impl);
@@ -2604,6 +2658,7 @@ static void
 meta_seat_impl_finalize (GObject *object)
 {
   MetaSeatImpl *seat_impl = META_SEAT_IMPL (object);
+  gboolean numlock_active;
   GSList *iter;
 
   for (iter = seat_impl->devices; iter; iter = g_slist_next (iter))
@@ -2621,6 +2676,13 @@ meta_seat_impl_finalize (GObject *object)
 
   meta_event_source_free (seat_impl->event_source);
 
+  numlock_active =
+    xkb_state_mod_name_is_active (seat_impl->xkb, XKB_MOD_NAME_NUM,
+                                  XKB_STATE_MODS_LATCHED |
+                                  XKB_STATE_MODS_LOCKED);
+  meta_input_settings_maybe_save_numlock_state (seat_impl->input_settings,
+                                                numlock_active);
+
   xkb_state_unref (seat_impl->xkb);
 
   meta_seat_impl_clear_repeat_timer (seat_impl);
@@ -2979,61 +3041,6 @@ meta_seat_impl_set_keyboard_layout_index (MetaSeatImpl       *seat_impl,
 }
 
 /**
- * meta_seat_impl_set_keyboard_numlock: (skip)
- * @seat: the #ClutterSeat created by the evdev backend
- * @numlock_set: TRUE to set NumLock ON, FALSE otherwise.
- *
- * Sets the NumLock state on the backend's #xkb_state .
- */
-void
-meta_seat_impl_set_keyboard_numlock (MetaSeatImpl *seat_impl,
-                                     gboolean      numlock_state)
-{
-  xkb_mod_mask_t depressed_mods;
-  xkb_mod_mask_t latched_mods;
-  xkb_mod_mask_t locked_mods;
-  xkb_mod_mask_t group_mods;
-  xkb_mod_mask_t numlock;
-  struct xkb_keymap *xkb_keymap;
-  MetaKeymapNative *keymap;
-
-  g_return_if_fail (META_IS_SEAT_IMPL (seat_impl));
-
-  g_rw_lock_writer_lock (&seat_impl->state_lock);
-
-  keymap = seat_impl->keymap;
-  xkb_keymap = meta_keymap_native_get_keyboard_map (keymap);
-
-  numlock = (1 << xkb_keymap_mod_get_index (xkb_keymap, "Mod2"));
-
-  depressed_mods =
-    xkb_state_serialize_mods (seat_impl->xkb, XKB_STATE_MODS_DEPRESSED);
-  latched_mods =
-    xkb_state_serialize_mods (seat_impl->xkb, XKB_STATE_MODS_LATCHED);
-  locked_mods =
-    xkb_state_serialize_mods (seat_impl->xkb, XKB_STATE_MODS_LOCKED);
-  group_mods =
-    xkb_state_serialize_layout (seat_impl->xkb, XKB_STATE_LAYOUT_EFFECTIVE);
-
-  if (numlock_state)
-    locked_mods |= numlock;
-  else
-    locked_mods &= ~numlock;
-
-  xkb_state_update_mask (seat_impl->xkb,
-                         depressed_mods,
-                         latched_mods,
-                         locked_mods,
-                         0, 0,
-                         group_mods);
-
-  meta_seat_impl_sync_leds (seat_impl);
-  meta_keymap_native_update (seat_impl->keymap);
-
-  g_rw_lock_writer_unlock (&seat_impl->state_lock);
-}
-
-/**
  * meta_seat_impl_set_keyboard_repeat:
  * @seat: the #ClutterSeat created by the evdev backend
  * @repeat: whether to enable or disable keyboard repeat events
diff --git a/src/backends/native/meta-seat-impl.h b/src/backends/native/meta-seat-impl.h
index a62af83f5..92d97b732 100644
--- a/src/backends/native/meta-seat-impl.h
+++ b/src/backends/native/meta-seat-impl.h
@@ -209,9 +209,6 @@ void               meta_seat_impl_set_keyboard_map   (MetaSeatImpl      *seat_im
 void meta_seat_impl_set_keyboard_layout_index (MetaSeatImpl       *seat_impl,
                                                xkb_layout_index_t  idx);
 
-void meta_seat_impl_set_keyboard_numlock (MetaSeatImpl *seat_impl,
-                                          gboolean      numlock_state);
-
 void meta_seat_impl_set_keyboard_repeat (MetaSeatImpl *seat_impl,
                                          gboolean      repeat,
                                          uint32_t      delay,
diff --git a/src/backends/native/meta-seat-native.c b/src/backends/native/meta-seat-native.c
index 88654f7b5..432b0fc00 100644
--- a/src/backends/native/meta-seat-native.c
+++ b/src/backends/native/meta-seat-native.c
@@ -612,20 +612,6 @@ meta_seat_native_get_keyboard_layout_index (MetaSeatNative *seat)
   return seat->xkb_layout_index;
 }
 
-/**
- * meta_seat_native_set_keyboard_numlock: (skip)
- * @seat: the #ClutterSeat created by the evdev backend
- * @numlock_set: TRUE to set NumLock ON, FALSE otherwise.
- *
- * Sets the NumLock state on the backend's #xkb_state .
- */
-void
-meta_seat_native_set_keyboard_numlock (MetaSeatNative *seat,
-                                       gboolean        numlock_state)
-{
-  meta_seat_impl_set_keyboard_numlock (seat->impl, numlock_state);
-}
-
 MetaBarrierManagerNative *
 meta_seat_native_get_barrier_manager (MetaSeatNative *seat)
 {
diff --git a/src/backends/native/meta-seat-native.h b/src/backends/native/meta-seat-native.h
index 787b2cc2b..4f7c30e46 100644
--- a/src/backends/native/meta-seat-native.h
+++ b/src/backends/native/meta-seat-native.h
@@ -107,9 +107,6 @@ void meta_seat_native_set_keyboard_layout_index (MetaSeatNative     *seat,
 
 xkb_layout_index_t meta_seat_native_get_keyboard_layout_index (MetaSeatNative *seat);
 
-void meta_seat_native_set_keyboard_numlock (MetaSeatNative *seat,
-                                            gboolean        numlock_state);
-
 void meta_seat_native_set_keyboard_repeat (MetaSeatNative *seat,
                                            gboolean        repeat,
                                            uint32_t        delay,
diff --git a/src/backends/x11/meta-backend-x11.c b/src/backends/x11/meta-backend-x11.c
index 068f138c6..94a13e7cd 100644
--- a/src/backends/x11/meta-backend-x11.c
+++ b/src/backends/x11/meta-backend-x11.c
@@ -82,6 +82,8 @@ struct _MetaBackendX11Private
   uint8_t xkb_event_base;
   uint8_t xkb_error_base;
 
+  gulong keymap_state_changed_id;
+
   struct xkb_keymap *keymap;
   xkb_layout_index_t keymap_layout_group;
 
@@ -605,6 +607,14 @@ meta_backend_x11_post_init (MetaBackend *backend)
       g_signal_connect_object (meta_backend_get_input_settings (backend),
                                "kbd-a11y-changed",
                                G_CALLBACK (on_kbd_a11y_changed), backend, 0);
+
+      if (meta_input_settings_maybe_restore_numlock_state (input_settings))
+        {
+          unsigned int num_mask;
+
+          num_mask = XkbKeysymToModifiers (priv->xdisplay, XK_Num_Lock);
+          XkbLockModifiers (priv->xdisplay, XkbUseCoreKbd, num_mask, num_mask);
+        }
     }
 }
 
@@ -758,19 +768,6 @@ meta_backend_x11_get_keymap_layout_group (MetaBackend *backend)
   return priv->keymap_layout_group;
 }
 
-static void
-meta_backend_x11_set_numlock (MetaBackend *backend,
-                              gboolean     numlock_state)
-{
-  MetaBackendX11 *x11 = META_BACKEND_X11 (backend);
-  MetaBackendX11Private *priv = meta_backend_x11_get_instance_private (x11);
-  unsigned int num_mask;
-
-  num_mask = XkbKeysymToModifiers (priv->xdisplay, XK_Num_Lock);
-  XkbLockModifiers (priv->xdisplay, XkbUseCoreKbd, num_mask,
-                    numlock_state ? num_mask : 0);
-}
-
 void
 meta_backend_x11_handle_event (MetaBackendX11 *x11,
                                XEvent      *xevent)
@@ -853,9 +850,21 @@ initable_iface_init (GInitableIface *initable_iface)
 static void
 meta_backend_x11_finalize (GObject *object)
 {
+  MetaBackend *backend = META_BACKEND (object);
   MetaBackendX11 *x11 = META_BACKEND_X11 (object);
   MetaBackendX11Private *priv = meta_backend_x11_get_instance_private (x11);
 
+  if (priv->keymap_state_changed_id)
+    {
+      ClutterBackend *clutter_backend = meta_backend_get_clutter_backend (backend);
+      ClutterSeat *seat = clutter_backend_get_default_seat (clutter_backend);
+      ClutterKeymap *keymap;
+
+      seat = clutter_backend_get_default_seat (clutter_backend);
+      keymap = clutter_seat_get_keymap (seat);
+      g_clear_signal_handler (&priv->keymap_state_changed_id, keymap);
+    }
+
   if (priv->user_active_alarm != None)
     {
       XSyncDestroyAlarm (priv->xdisplay, priv->user_active_alarm);
@@ -880,7 +889,6 @@ meta_backend_x11_class_init (MetaBackendX11Class *klass)
   backend_class->get_current_logical_monitor = meta_backend_x11_get_current_logical_monitor;
   backend_class->get_keymap = meta_backend_x11_get_keymap;
   backend_class->get_keymap_layout_group = meta_backend_x11_get_keymap_layout_group;
-  backend_class->set_numlock = meta_backend_x11_set_numlock;
 }
 
 static void
diff --git a/src/backends/x11/meta-keymap-x11.c b/src/backends/x11/meta-keymap-x11.c
index ac2b1d787..d30b46e98 100644
--- a/src/backends/x11/meta-keymap-x11.c
+++ b/src/backends/x11/meta-keymap-x11.c
@@ -26,6 +26,8 @@
 #include <X11/Xatom.h>
 #include <X11/XKBlib.h>
 
+#include "backends/meta-backend-private.h"
+#include "backends/meta-input-settings-private.h"
 #include "backends/x11/meta-keymap-x11.h"
 #include "clutter/clutter.h"
 #include "clutter/clutter-mutter.h"
@@ -218,6 +220,21 @@ update_locked_mods (MetaKeymapX11 *keymap_x11,
   if ((keymap_x11->caps_lock_state != old_caps_lock_state) ||
       (keymap_x11->num_lock_state != old_num_lock_state))
     g_signal_emit_by_name (keymap_x11, "state-changed");
+
+  if (keymap_x11->num_lock_state != old_num_lock_state)
+    {
+      MetaBackend *backend;
+      MetaInputSettings *input_settings;
+
+      backend = meta_get_backend ();
+      input_settings = meta_backend_get_input_settings (backend);
+
+      if (input_settings)
+        {
+          meta_input_settings_maybe_save_numlock_state (input_settings,
+                                                        keymap_x11->num_lock_state);
+        }
+    }
 }
 
 /* the code to retrieve the keymap direction and cache it