xsettings: Adopt code to look up GTK IM module

Right now, gsd-keyboard and gsd-xsettings have a strange relation
where the first sets the gtk-im-module dconf setting for the latter
to read the setting and forward it through XSettings.

Since this detection is highly X11 specific, make it happen in the
Xsettings daemon itself, from the relevant setting and device presence.

This makes users still able to shoot themselves in the foot by changing
the setting, X11 clients able to be told to switch to ibus if it turns
out necessary, and Wayland clients unaffected otherwise.

Related: https://gitlab.gnome.org/GNOME/gtk/-/issues/4443

2 files changed, 152 insertions, 147 deletions

diff --git a/plugins/keyboard/gsd-keyboard-manager.c b/plugins/keyboard/gsd-keyboard-manager.c
index 6e2465bc..d41393bc 100644
--- a/plugins/keyboard/gsd-keyboard-manager.c
+++ b/plugins/keyboard/gsd-keyboard-manager.c
@@ -57,10 +57,6 @@
 
 #define GNOME_DESKTOP_INTERFACE_DIR "org.gnome.desktop.interface"
 
-#define KEY_GTK_IM_MODULE    "gtk-im-module"
-#define GTK_IM_MODULE_SIMPLE "gtk-im-context-simple"
-#define GTK_IM_MODULE_IBUS   "ibus"
-
 #define GNOME_DESKTOP_INPUT_SOURCES_DIR "org.gnome.desktop.input-sources"
 
 #define KEY_INPUT_SOURCES        "sources"
@@ -71,9 +67,6 @@
 
 #define DEFAULT_LAYOUT "us"
 
-#define GNOME_A11Y_APPLICATIONS_INTERFACE_DIR "org.gnome.desktop.a11y.applications"
-#define KEY_OSK_ENABLED "screen-keyboard-enabled"
-
 struct _GsdKeyboardManager
 {
         GObject    parent;
@@ -81,21 +74,14 @@ struct _GsdKeyboardManager
         guint      start_idle_id;
         GSettings *settings;
         GSettings *input_sources_settings;
-        GSettings *a11y_settings;
         GDBusProxy *localed;
         GCancellable *cancellable;
-
-        GdkSeat *user_seat;
-        guint device_added_id;
-        guint device_removed_id;
 };
 
 static void     gsd_keyboard_manager_class_init  (GsdKeyboardManagerClass *klass);
 static void     gsd_keyboard_manager_init        (GsdKeyboardManager      *keyboard_manager);
 static void     gsd_keyboard_manager_finalize    (GObject                 *object);
 
-static void     update_gtk_im_module (GsdKeyboardManager *manager);
-
 G_DEFINE_TYPE (GsdKeyboardManager, gsd_keyboard_manager, G_TYPE_OBJECT)
 
 static gpointer manager_object = NULL;
@@ -219,121 +205,6 @@ settings_changed (GSettings          *settings,
 }
 
 static void
-device_added_cb (GdkSeat            *user_seat,
-                 GdkDevice          *device,
-                 GsdKeyboardManager *manager)
-{
-        GdkInputSource source;
-
-        source = gdk_device_get_source (device);
-        if (source == GDK_SOURCE_TOUCHSCREEN) {
-                update_gtk_im_module (manager);
-        }
-}
-
-static void
-device_removed_cb (GdkSeat            *user_seat,
-                   GdkDevice          *device,
-                   GsdKeyboardManager *manager)
-{
-        GdkInputSource source;
-
-        source = gdk_device_get_source (device);
-        if (source == GDK_SOURCE_TOUCHSCREEN)
-                update_gtk_im_module (manager);
-}
-
-static void
-set_devicepresence_handler (GsdKeyboardManager *manager)
-{
-        GdkSeat *user_seat;
-
-        if (gnome_settings_is_wayland ())
-                return;
-
-        user_seat = gdk_display_get_default_seat (gdk_display_get_default ());
-
-        manager->device_added_id = g_signal_connect (G_OBJECT (user_seat), "device-added",
-                                                     G_CALLBACK (device_added_cb), manager);
-        manager->device_removed_id = g_signal_connect (G_OBJECT (user_seat), "device-removed",
-                                                       G_CALLBACK (device_removed_cb), manager);
-        manager->user_seat = user_seat;
-}
-
-static gboolean
-need_ibus (GVariant *sources)
-{
-        GVariantIter iter;
-        const gchar *type;
-
-        g_variant_iter_init (&iter, sources);
-        while (g_variant_iter_next (&iter, "(&s&s)", &type, NULL))
-                if (g_str_equal (type, INPUT_SOURCE_TYPE_IBUS))
-                        return TRUE;
-
-        return FALSE;
-}
-
-static gboolean
-need_osk (GsdKeyboardManager *manager)
-{
-        gboolean has_touchscreen = FALSE;
-        GList *devices;
-        GdkSeat *seat;
-
-        if (g_settings_get_boolean (manager->a11y_settings,
-                                    KEY_OSK_ENABLED))
-                return TRUE;
-
-        seat = gdk_display_get_default_seat (gdk_display_get_default ());
-        devices = gdk_seat_get_slaves (seat, GDK_SEAT_CAPABILITY_TOUCH);
-
-        has_touchscreen = devices != NULL;
-
-        g_list_free (devices);
-
-        return has_touchscreen;
-}
-
-static void
-set_gtk_im_module (GsdKeyboardManager *manager,
-                   GSettings          *settings,
-                   GVariant           *sources)
-{
-        const gchar *new_module;
-        gchar *current_module;
-
-        if (need_ibus (sources) || need_osk (manager))
-                new_module = GTK_IM_MODULE_IBUS;
-        else
-                new_module = GTK_IM_MODULE_SIMPLE;
-
-        current_module = g_settings_get_string (settings, KEY_GTK_IM_MODULE);
-        if (!g_str_equal (current_module, new_module))
-                g_settings_set_string (settings, KEY_GTK_IM_MODULE, new_module);
-        g_free (current_module);
-}
-
-static void
-update_gtk_im_module (GsdKeyboardManager *manager)
-{
-        GSettings *interface_settings;
-        GVariant *sources;
-
-        /* Gtk+ uses the IM module advertised in XSETTINGS so, if we
-         * have IBus input sources, we want it to load that
-         * module. Otherwise we can use the default "simple" module
-         * which is builtin gtk+
-         */
-        interface_settings = g_settings_new (GNOME_DESKTOP_INTERFACE_DIR);
-        sources = g_settings_get_value (manager->input_sources_settings,
-                                        KEY_INPUT_SOURCES);
-        set_gtk_im_module (manager, interface_settings, sources);
-        g_object_unref (interface_settings);
-        g_variant_unref (sources);
-}
-
-static void
 get_sources_from_xkb_config (GsdKeyboardManager *manager)
 {
         GVariantBuilder builder;
@@ -580,18 +451,7 @@ start_keyboard_idle_cb (GsdKeyboardManager *manager)
 
         manager->settings = g_settings_new (GSD_KEYBOARD_DIR);
 
-	set_devicepresence_handler (manager);
-
         manager->input_sources_settings = g_settings_new (GNOME_DESKTOP_INPUT_SOURCES_DIR);
-        g_signal_connect_swapped (manager->input_sources_settings,
-                                  "changed::" KEY_INPUT_SOURCES,
-                                  G_CALLBACK (update_gtk_im_module), manager);
-
-        manager->a11y_settings = g_settings_new (GNOME_A11Y_APPLICATIONS_INTERFACE_DIR);
-        g_signal_connect_swapped (manager->a11y_settings,
-                                  "changed::" KEY_OSK_ENABLED,
-                                  G_CALLBACK (update_gtk_im_module), manager);
-        update_gtk_im_module (manager);
 
         manager->cancellable = g_cancellable_new ();
 
@@ -645,14 +505,7 @@ gsd_keyboard_manager_stop (GsdKeyboardManager *manager)
 
         g_clear_object (&manager->settings);
         g_clear_object (&manager->input_sources_settings);
-        g_clear_object (&manager->a11y_settings);
         g_clear_object (&manager->localed);
-
-        if (manager->user_seat != NULL) {
-                g_signal_handler_disconnect (manager->user_seat, manager->device_added_id);
-                g_signal_handler_disconnect (manager->user_seat, manager->device_removed_id);
-                manager->user_seat = NULL;
-        }
 }
 
 static void
diff --git a/plugins/xsettings/gsd-xsettings-manager.c b/plugins/xsettings/gsd-xsettings-manager.c
index 7e5b1021..7258c9cd 100644
--- a/plugins/xsettings/gsd-xsettings-manager.c
+++ b/plugins/xsettings/gsd-xsettings-manager.c
@@ -57,6 +57,8 @@
 #define WM_SETTINGS_SCHEMA        "org.gnome.desktop.wm.preferences"
 #define A11Y_SCHEMA               "org.gnome.desktop.a11y"
 #define A11Y_INTERFACE_SCHEMA     "org.gnome.desktop.a11y.interface"
+#define A11Y_APPLICATIONS_SCHEMA   "org.gnome.desktop.a11y.applications"
+#define INPUT_SOURCES_SCHEMA       "org.gnome.desktop.input-sources"
 #define CLASSIC_WM_SETTINGS_SCHEMA "org.gnome.shell.extensions.classic-overrides"
 
 #define XSETTINGS_PLUGIN_SCHEMA "org.gnome.settings-daemon.plugins.xsettings"
@@ -75,9 +77,18 @@
 
 #define HIGH_CONTRAST_KEY "high-contrast"
 
+#define INPUT_SOURCES_KEY      "sources"
+#define OSK_ENABLED_KEY        "screen-keyboard-enabled"
+#define GTK_IM_MODULE_KEY      "gtk-im-module"
+
 #define GTK_SETTINGS_DBUS_PATH "/org/gtk/Settings"
 #define GTK_SETTINGS_DBUS_NAME "org.gtk.Settings"
 
+#define INPUT_SOURCE_TYPE_IBUS "ibus"
+
+#define GTK_IM_MODULE_SIMPLE "gtk-im-context-simple"
+#define GTK_IM_MODULE_IBUS   "ibus"
+
 static const gchar introspection_xml[] =
 "<node name='/org/gtk/Settings'>"
 "  <interface name='org.gtk.Settings'>"
@@ -280,6 +291,11 @@ struct _GsdXSettingsManager
         FcMonitor         *fontconfig_monitor;
         gint64             fontconfig_timestamp;
 
+        GSettings         *interface_settings;
+        GSettings         *input_sources_settings;
+        GSettings         *a11y_settings;
+        GdkSeat           *user_seat;
+
         GsdXSettingsGtk   *gtk;
 
         guint              introspect_properties_changed_id;
@@ -289,6 +305,9 @@ struct _GsdXSettingsManager
         guint              display_config_watch_id;
         guint              monitors_changed_id;
 
+        guint              device_added_id;
+        guint              device_removed_id;
+
         guint              shell_name_watch_id;
         gboolean           have_shell;
 
@@ -1323,6 +1342,112 @@ migrate_settings (void)
                                     mouse_entries, G_N_ELEMENTS (mouse_entries));
 }
 
+static gboolean
+need_ibus (GsdXSettingsManager *manager)
+{
+        GVariant *sources;
+        GVariantIter iter;
+        const gchar *type;
+        gboolean needs_ibus = FALSE;
+
+        sources = g_settings_get_value (manager->input_sources_settings,
+                                        INPUT_SOURCES_KEY);
+
+        g_variant_iter_init (&iter, sources);
+        while (g_variant_iter_next (&iter, "(&s&s)", &type, NULL)) {
+                if (g_str_equal (type, INPUT_SOURCE_TYPE_IBUS)) {
+                        needs_ibus = TRUE;
+                        break;
+                }
+        }
+
+        g_variant_unref (sources);
+
+        return needs_ibus;
+}
+
+static gboolean
+need_osk (GsdXSettingsManager *manager)
+{
+        gboolean has_touchscreen = FALSE;
+        GList *devices;
+        GdkSeat *seat;
+
+        if (g_settings_get_boolean (manager->a11y_settings,
+                                    OSK_ENABLED_KEY))
+                return TRUE;
+
+        seat = gdk_display_get_default_seat (gdk_display_get_default ());
+        devices = gdk_seat_get_slaves (seat, GDK_SEAT_CAPABILITY_TOUCH);
+
+        has_touchscreen = devices != NULL;
+
+        g_list_free (devices);
+
+        return has_touchscreen;
+}
+
+static void
+update_gtk_im_module (GsdXSettingsManager *manager)
+{
+        const gchar *module;
+        gchar *setting;
+
+        setting = g_settings_get_string (manager->interface_settings,
+                                         GTK_IM_MODULE_KEY);
+        if (setting && *setting)
+                module = setting;
+        else if (need_ibus (manager) || need_osk (manager))
+                module = GTK_IM_MODULE_IBUS;
+        else
+                module = GTK_IM_MODULE_SIMPLE;
+
+        xsettings_manager_set_string (manager->manager, "Gtk/IMModule", module);
+        g_free (setting);
+}
+
+static void
+device_added_cb (GdkSeat             *user_seat,
+                 GdkDevice           *device,
+                 GsdXSettingsManager *manager)
+{
+        GdkInputSource source;
+
+        source = gdk_device_get_source (device);
+        if (source == GDK_SOURCE_TOUCHSCREEN) {
+                update_gtk_im_module (manager);
+        }
+}
+
+static void
+device_removed_cb (GdkSeat             *user_seat,
+                   GdkDevice           *device,
+                   GsdXSettingsManager *manager)
+{
+        GdkInputSource source;
+
+        source = gdk_device_get_source (device);
+        if (source == GDK_SOURCE_TOUCHSCREEN)
+                update_gtk_im_module (manager);
+}
+
+static void
+set_devicepresence_handler (GsdXSettingsManager *manager)
+{
+        GdkSeat *user_seat;
+
+        if (gnome_settings_is_wayland ())
+                return;
+
+        user_seat = gdk_display_get_default_seat (gdk_display_get_default ());
+
+        manager->device_added_id = g_signal_connect (G_OBJECT (user_seat), "device-added",
+                                                     G_CALLBACK (device_added_cb), manager);
+        manager->device_removed_id = g_signal_connect (G_OBJECT (user_seat), "device-removed",
+                                                       G_CALLBACK (device_removed_cb), manager);
+        manager->user_seat = user_seat;
+}
+
 gboolean
 gsd_xsettings_manager_start (GsdXSettingsManager *manager,
                              GError             **error)
@@ -1344,6 +1469,23 @@ gsd_xsettings_manager_start (GsdXSettingsManager *manager,
                 return FALSE;
         }
 
+	set_devicepresence_handler (manager);
+        manager->interface_settings = g_settings_new (INTERFACE_SETTINGS_SCHEMA);
+        g_signal_connect_swapped (manager->interface_settings,
+                                  "changed::" GTK_IM_MODULE_KEY,
+                                  G_CALLBACK (update_gtk_im_module), manager);
+
+        manager->input_sources_settings = g_settings_new (INPUT_SOURCES_SCHEMA);
+        g_signal_connect_swapped (manager->input_sources_settings,
+                                  "changed::" INPUT_SOURCES_KEY,
+                                  G_CALLBACK (update_gtk_im_module), manager);
+
+        manager->a11y_settings = g_settings_new (A11Y_APPLICATIONS_SCHEMA);
+        g_signal_connect_swapped (manager->a11y_settings,
+                                  "changed::" OSK_ENABLED_KEY,
+                                  G_CALLBACK (update_gtk_im_module), manager);
+        update_gtk_im_module (manager);
+
         manager->monitors_changed_id =
                 g_dbus_connection_signal_subscribe (manager->dbus_connection,
                                                     "org.gnome.Mutter.DisplayConfig",
@@ -1541,6 +1683,16 @@ gsd_xsettings_manager_stop (GsdXSettingsManager *manager)
                 g_object_unref (manager->gtk);
                 manager->gtk = NULL;
         }
+
+        if (manager->user_seat != NULL) {
+                g_signal_handler_disconnect (manager->user_seat, manager->device_added_id);
+                g_signal_handler_disconnect (manager->user_seat, manager->device_removed_id);
+                manager->user_seat = NULL;
+        }
+
+        g_clear_object (&manager->a11y_settings);
+        g_clear_object (&manager->input_sources_settings);
+        g_clear_object (&manager->interface_settings);
 }
 
 static void