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From 7f81445b3e6613d14f64253506a309095a37c8d7 Mon Sep 17 00:00:00 2001
From: fujiwarat <takao.fujiwara1@gmail.com>
Date: Mon, 20 Jun 2011 19:04:42 +0900
Subject: [PATCH] Reload preload engines until users customize the list.

The idea is, if users don't customize the preload_engines with ibus-setup,
users would prefer to load the system default engines again by login.
The gconf value 'preload_engine_mode' is
IBUS_PRELOAD_ENGINE_MODE_USER by default but set
IBUS_PRELOAD_ENGINE_MODE_LANG_RELATIVE for the initial login.
If preload_engine_mode is IBUS_PRELOAD_ENGINE_MODE_LANG_RELATIVE,
ibus-daemon loads the system preload engines by langs.
If preload_engine_mode is IBUS_PRELOAD_ENGINE_MODE_USER,
ibus-daemon do not update the gconf value preload_engines.
On the other hand, if users enable the customized engine checkbutton
on ibus-setup, ibus-setup sets 'preload_engine_mode' as
IBUS_PRELOAD_ENGINE_MODE_USER and users can customize the value
'preload_engines'.
---
 bus/ibusimpl.c       |  402 +++++++++++++++++++++++++++++++++++++++-----------
 data/ibus.schemas.in |   13 ++
 ibus/common.py       |    6 +
 setup/main.py        |   70 ++++++++-
 setup/setup.ui       |   21 +++-
 src/ibustypes.h      |   10 ++
 6 files changed, 427 insertions(+), 95 deletions(-)

diff --git a/bus/ibusimpl.c b/bus/ibusimpl.c
index a7ae52b..bb4b8ae 100644
--- a/bus/ibusimpl.c
+++ b/bus/ibusimpl.c
@@ -144,6 +144,9 @@ static void     bus_ibus_impl_set_previous_engine
 static void     bus_ibus_impl_set_preload_engines
                                                 (BusIBusImpl        *ibus,
                                                  GVariant           *value);
+static void     bus_ibus_impl_set_preload_engine_mode
+                                                (BusIBusImpl        *ibus,
+                                                 GVariant           *value);
 static void     bus_ibus_impl_set_use_sys_layout
                                                 (BusIBusImpl        *ibus,
                                                  GVariant           *value);
@@ -285,6 +288,259 @@ _panel_destroy_cb (BusPanelProxy *panel,
 }
 
 static void
+_config_set_value_done (GObject      *object,
+                        GAsyncResult *res,
+                        gpointer      user_data)
+{
+    IBusConfig *config = (IBusConfig *) object;
+    GVariant *value = (GVariant *) user_data;
+    GError *error = NULL;
+
+    g_assert (IBUS_IS_CONFIG (config));
+
+    if (!ibus_config_set_value_async_finish (config, res, &error)) {
+        if (error) {
+            g_error_free (error);
+        }
+    }
+    g_variant_unref (value);
+}
+
+#ifndef OS_CHROMEOS
+static gint
+_engine_desc_cmp (IBusEngineDesc *desc1,
+                  IBusEngineDesc *desc2)
+{
+    return - ((gint) ibus_engine_desc_get_rank (desc1)) +
+              ((gint) ibus_engine_desc_get_rank (desc2));
+}
+#endif
+
+#ifndef OS_CHROMEOS
+static gint
+_get_config_preload_engine_mode (BusIBusImpl *ibus)
+{
+    GVariant *variant = NULL;
+    gint preload_engine_mode = IBUS_PRELOAD_ENGINE_MODE_USER;
+
+    g_assert (BUS_IS_IBUS_IMPL (ibus));
+
+    if (ibus->config == NULL) {
+        return preload_engine_mode;
+    }
+
+    variant = ibus_config_get_value (ibus->config, "general",
+                                     "preload_engines");
+    if (variant == NULL) {
+        /* Set LANG_RELATIVE mode for the initial login */
+        preload_engine_mode = IBUS_PRELOAD_ENGINE_MODE_LANG_RELATIVE;
+        variant = g_variant_ref_sink (g_variant_new ("i", preload_engine_mode));
+        ibus_config_set_value_async (ibus->config, "general",
+                                     "preload_engine_mode", variant,
+                                     -1,
+                                     NULL,
+                                     _config_set_value_done,
+                                     variant);
+        return preload_engine_mode;
+    } else {
+        g_variant_unref (variant);
+    }
+
+    variant = ibus_config_get_value (ibus->config, "general",
+                                     "preload_engine_mode");
+    if (variant != NULL) {
+        if (g_variant_classify (variant) == G_VARIANT_CLASS_INT32) {
+            preload_engine_mode = g_variant_get_int32 (variant);
+        }
+        g_variant_unref (variant);
+    }
+
+    return preload_engine_mode;
+}
+#endif
+
+static int
+_compare_engine_list_value (GVariant *value_a, GVariant *value_b)
+{
+    GVariant *value;
+    GVariantIter iter;
+    const gchar *engine_name = NULL;
+    gchar *concat_engine_names;
+    gchar *concat_engine_names_a = NULL;
+    gchar *concat_engine_names_b = NULL;
+    int retval = 0;
+
+    value = value_a;
+    concat_engine_names = NULL;
+    if (value != NULL && g_variant_classify (value) == G_VARIANT_CLASS_ARRAY) {
+        g_variant_iter_init (&iter, value);
+        while (g_variant_iter_loop (&iter, "&s", &engine_name)) {
+            gchar *tmp = g_strdup_printf ("%s::%s",
+                                          concat_engine_names ? concat_engine_names : "",
+                                          engine_name ? engine_name : "");
+            g_free (concat_engine_names);
+            concat_engine_names = tmp;
+        }
+    }
+    concat_engine_names_a = concat_engine_names;
+
+    value = value_b;
+    concat_engine_names = NULL;
+    if (value != NULL && g_variant_classify (value) == G_VARIANT_CLASS_ARRAY) {
+        g_variant_iter_init (&iter, value);
+        while (g_variant_iter_loop (&iter, "&s", &engine_name)) {
+            gchar *tmp = g_strdup_printf ("%s::%s",
+                                          concat_engine_names ? concat_engine_names : "",
+                                          engine_name ? engine_name : "");
+            g_free (concat_engine_names);
+            concat_engine_names = tmp;
+        }
+    }
+    concat_engine_names_b = concat_engine_names;
+
+    retval = g_strcmp0 (concat_engine_names_a, concat_engine_names_b);
+    g_free (concat_engine_names_a);
+    g_free (concat_engine_names_b);
+    return retval;
+}
+
+static void
+_preload_engines_config_get_value_done (GObject      *object,
+                                        GAsyncResult *res,
+                                        gpointer      user_data)
+{
+    IBusConfig *config = (IBusConfig *) object;
+    GVariant *new_value = (GVariant *) user_data;
+    GVariant *value = NULL;
+    GError *error = NULL;
+
+    g_assert (IBUS_IS_CONFIG (config));
+
+    value = ibus_config_get_value_async_finish (config, res, &error);
+    if (error) {
+        g_error_free (error);
+    }
+    if (_compare_engine_list_value (value, new_value) != 0) {
+        ibus_config_set_value_async (config, "general",
+                                     "preload_engines", new_value,
+                                     -1,
+                                     NULL,
+                                     _config_set_value_done,
+                                     new_value);
+    } else if (new_value) {
+        g_variant_unref (new_value);
+    }
+    if (value) {
+        g_variant_unref (value);
+    }
+}
+
+static void
+_set_preload_engines (BusIBusImpl *ibus,
+                      GVariant    *value)
+{
+    GList *engine_list = NULL;
+
+    g_assert (BUS_IS_IBUS_IMPL (ibus));
+
+    g_list_foreach (ibus->engine_list, (GFunc) g_object_unref, NULL);
+    g_list_free (ibus->engine_list);
+
+    if (value != NULL && g_variant_classify (value) == G_VARIANT_CLASS_ARRAY) {
+        GVariantIter iter;
+        g_variant_iter_init (&iter, value);
+        const gchar *engine_name = NULL;
+        while (g_variant_iter_loop (&iter, "&s", &engine_name)) {
+            IBusEngineDesc *engine = bus_registry_find_engine_by_name (ibus->registry, engine_name);
+            if (engine == NULL || g_list_find (engine_list, engine) != NULL)
+                continue;
+            engine_list = g_list_append (engine_list, engine);
+        }
+
+        if (engine_list != NULL &&
+            ibus->config != NULL) {
+            /* sync function will effects the startup performance.
+             * We'd always like to save the value so that ibus-setup
+             * get the updated engine list. */
+            ibus_config_get_value_async (ibus->config, "general",
+                                         "preload_engines",
+                                         -1,
+                                         NULL,
+                                         _preload_engines_config_get_value_done,
+                                         g_variant_ref_sink (value));
+        } else {
+            /* We don't update preload_engines with an empty string for safety.
+             * Just unref the floating value. */
+            g_variant_unref (value);
+        }
+    } else if (value != NULL) {
+        g_variant_unref (value);
+    }
+
+    g_list_foreach (engine_list, (GFunc) g_object_ref, NULL);
+    ibus->engine_list = engine_list;
+
+    if (ibus->engine_list) {
+        BusComponent *component = bus_component_from_engine_desc ((IBusEngineDesc *) ibus->engine_list->data);
+        if (component && !bus_component_is_running (component)) {
+            bus_component_start (component, g_verbose);
+        }
+    }
+
+    bus_ibus_impl_check_global_engine (ibus);
+    bus_ibus_impl_update_engines_hotkey_profile (ibus);
+}
+
+#ifndef OS_CHROMEOS
+static void
+_set_language_relative_preload_engines (BusIBusImpl *ibus)
+{
+    gchar *lang = NULL;
+    gchar *p = NULL;
+    GList *engines = NULL;
+    GList *list;
+    GVariantBuilder builder;
+
+    g_assert (BUS_IS_IBUS_IMPL (ibus));
+
+    /* The setlocale call first checks LC_ALL. If it's not available, checks
+     * LC_CTYPE. If it's also not available, checks LANG. */
+    lang = g_strdup (setlocale (LC_CTYPE, NULL));
+    if (lang == NULL) {
+        return;
+    }
+
+    p = index (lang, '.');
+    if (p) {
+        *p = '\0';
+    }
+
+    engines = bus_registry_get_engines_by_language (ibus->registry, lang);
+    if (engines == NULL) {
+        p = index (lang, '_');
+        if (p) {
+            *p = '\0';
+            engines = bus_registry_get_engines_by_language (ibus->registry, lang);
+        }
+    }
+    g_free (lang);
+
+    /* sort engines by rank */
+    engines = g_list_sort (engines, (GCompareFunc) _engine_desc_cmp);
+
+    g_variant_builder_init (&builder, G_VARIANT_TYPE ("as"));
+    for (list = engines; list != NULL; list = list->next) {
+        IBusEngineDesc *desc = (IBusEngineDesc *)list->data;
+        /* ignore engines with rank <== 0 */
+        if (ibus_engine_desc_get_rank (desc) > 0)
+            g_variant_builder_add (&builder, "s", ibus_engine_desc_get_name (desc));
+    }
+    _set_preload_engines (ibus, g_variant_builder_end (&builder));
+    g_list_free (engines);
+}
+#endif
+
+static void
 bus_ibus_impl_set_hotkey (BusIBusImpl *ibus,
                           GQuark       hotkey,
                           GVariant    *value)
@@ -394,35 +650,50 @@ static void
 bus_ibus_impl_set_preload_engines (BusIBusImpl *ibus,
                                    GVariant    *value)
 {
-    GList *engine_list = NULL;
-
-    g_list_foreach (ibus->engine_list, (GFunc) g_object_unref, NULL);
-    g_list_free (ibus->engine_list);
+#ifndef OS_CHROMEOS
+    gint preload_engine_mode = _get_config_preload_engine_mode (ibus);
 
-    if (value != NULL && g_variant_classify (value) == G_VARIANT_CLASS_ARRAY) {
-        GVariantIter iter;
-        g_variant_iter_init (&iter, value);
-        const gchar *engine_name = NULL;
-        while (g_variant_iter_loop (&iter, "&s", &engine_name)) {
-            IBusEngineDesc *engine = bus_registry_find_engine_by_name (ibus->registry, engine_name);
-            if (engine == NULL || g_list_find (engine_list, engine) != NULL)
-                continue;
-            engine_list = g_list_append (engine_list, engine);
+    if (preload_engine_mode == IBUS_PRELOAD_ENGINE_MODE_USER) {
+        if (value == NULL) {
+            _set_language_relative_preload_engines (ibus);
+        } else {
+            _set_preload_engines (ibus, value);
         }
     }
+#else
+    _set_preload_engines (ibus, value);
+#endif
+}
 
-    g_list_foreach (engine_list, (GFunc) g_object_ref, NULL);
-    ibus->engine_list = engine_list;
+/**
+ * bus_ibus_impl_set_preload_engine_mode:
+ *
+ * A function to be called when "preload_engine_mode" config is updated.
+ */
+static void
+bus_ibus_impl_set_preload_engine_mode (BusIBusImpl *ibus,
+                                       GVariant    *value)
+{
+#ifndef OS_CHROMEOS
+    gint preload_engine_mode = IBUS_PRELOAD_ENGINE_MODE_USER;
 
-    if (ibus->engine_list) {
-        BusComponent *component = bus_component_from_engine_desc ((IBusEngineDesc *) ibus->engine_list->data);
-        if (component && !bus_component_is_running (component)) {
-            bus_component_start (component, g_verbose);
-        }
+    /* bus_ibus_impl_reload_config() sets value = NULL.
+     * bus_ibus_impl_reload_config() is always called when
+     * RequestName signal is sent so it is good to get the gconf value
+     * again when value == NULL.
+     */
+    if (value != NULL && g_variant_classify (value) == G_VARIANT_CLASS_INT32) {
+        preload_engine_mode = g_variant_get_int32 (value);
+    } else {
+        preload_engine_mode = _get_config_preload_engine_mode (ibus);
     }
 
-    bus_ibus_impl_check_global_engine (ibus);
-    bus_ibus_impl_update_engines_hotkey_profile (ibus);
+    if (preload_engine_mode == IBUS_PRELOAD_ENGINE_MODE_USER) {
+        return;
+    }
+
+    _set_language_relative_preload_engines (ibus);
+#endif
 }
 
 /**
@@ -503,89 +774,47 @@ bus_ibus_impl_set_use_global_engine (BusIBusImpl *ibus,
     }
 }
 
-#ifndef OS_CHROMEOS
-static gint
-_engine_desc_cmp (IBusEngineDesc *desc1,
-                  IBusEngineDesc *desc2)
-{
-    return - ((gint) ibus_engine_desc_get_rank (desc1)) +
-              ((gint) ibus_engine_desc_get_rank (desc2));
-}
-#endif
-
 /**
  * bus_ibus_impl_set_default_preload_engines:
  *
- * If the "preload_engines" config variable is not set yet, set the default value which is determined based on a current locale.
+ * bus_ibus_impl_set_default_preload_engines handles the gconf value
+ * /desktop/ibus/general/preload_engines and preload_engine_mode.
+ * The idea is, if users don't customize the preload_engines with ibus-setup,
+ * users would prefer to load the system default engines again by login.
+ * The gconf value 'preload_engine_mode' is
+ * IBUS_PRELOAD_ENGINE_MODE_USER by default but set
+ * IBUS_PRELOAD_ENGINE_MODE_LANG_RELATIVE for the initial login.
+ * If preload_engine_mode is IBUS_PRELOAD_ENGINE_MODE_LANG_RELATIVE,
+ * ibus-daemon loads the system preload engines by langs.
+ * If preload_engine_mode is IBUS_PRELOAD_ENGINE_MODE_USER,
+ * ibus-daemon do not update the gconf value preload_engines.
+ * On the other hand, if users enable the customized engine checkbutton
+ * on ibus-setup, ibus-setup sets 'preload_engine_mode' as
+ * IBUS_PRELOAD_ENGINE_MODE_USER and users can customize the value
+ * 'preload_engines'.
  */
 static void
 bus_ibus_impl_set_default_preload_engines (BusIBusImpl *ibus)
 {
 #ifndef OS_CHROMEOS
-    g_assert (BUS_IS_IBUS_IMPL (ibus));
-
     static gboolean done = FALSE;
+    gint preload_engine_mode = IBUS_PRELOAD_ENGINE_MODE_USER;
+
+    g_assert (BUS_IS_IBUS_IMPL (ibus));
 
     if (done || ibus->config == NULL) {
         return;
     }
 
-    GVariant *variant = ibus_config_get_value (ibus->config, "general", "preload_engines");
-    if (variant != NULL) {
+    preload_engine_mode = _get_config_preload_engine_mode (ibus);
+
+    if (preload_engine_mode == IBUS_PRELOAD_ENGINE_MODE_USER) {
         done = TRUE;
-        g_variant_unref (variant);
         return;
     }
 
     done = TRUE;
-
-    /* The setlocale call first checks LC_ALL. If it's not available, checks
-     * LC_CTYPE. If it's also not available, checks LANG. */
-    gchar *lang = g_strdup (setlocale (LC_CTYPE, NULL));
-    if (lang == NULL) {
-        return;
-    }
-
-    gchar *p = index (lang, '.');
-    if (p) {
-        *p = '\0';
-    }
-
-    GList *engines = bus_registry_get_engines_by_language (ibus->registry, lang);
-    if (engines == NULL) {
-        p = index (lang, '_');
-        if (p) {
-            *p = '\0';
-            engines = bus_registry_get_engines_by_language (ibus->registry, lang);
-        }
-    }
-    g_free (lang);
-
-    /* sort engines by rank */
-    engines = g_list_sort (engines, (GCompareFunc) _engine_desc_cmp);
-
-    GVariantBuilder builder;
-    g_variant_builder_init (&builder, G_VARIANT_TYPE ("as"));
-    GList *list;
-    for (list = engines; list != NULL; list = list->next) {
-        IBusEngineDesc *desc = (IBusEngineDesc *) list->data;
-        /* ignore engines with rank <= 0 */
-        if (ibus_engine_desc_get_rank (desc) > 0)
-            g_variant_builder_add (&builder, "s", ibus_engine_desc_get_name (desc));
-    }
-
-    GVariant *value = g_variant_builder_end (&builder);
-    if (value != NULL) {
-        if (g_variant_n_children (value) > 0) {
-            ibus_config_set_value (ibus->config,
-                                   "general", "preload_engines", value);
-        } else {
-            /* We don't update preload_engines with an empty string for safety.
-             * Just unref the floating value. */
-            g_variant_unref (value);
-        }
-    }
-    g_list_free (engines);
+    _set_language_relative_preload_engines (ibus);
 #endif
 }
 
@@ -601,6 +830,7 @@ const static struct {
     { "general/hotkey", "next_engine_in_menu",   bus_ibus_impl_set_next_engine_in_menu },
     { "general/hotkey", "previous_engine",       bus_ibus_impl_set_previous_engine },
     { "general", "preload_engines",              bus_ibus_impl_set_preload_engines },
+    { "general", "preload_engine_mode",          bus_ibus_impl_set_preload_engine_mode },
     { "general", "use_system_keyboard_layout",   bus_ibus_impl_set_use_sys_layout },
     { "general", "use_global_engine",            bus_ibus_impl_set_use_global_engine },
     { "general", "embed_preedit_text",           bus_ibus_impl_set_embed_preedit_text },
diff --git a/data/ibus.schemas.in b/data/ibus.schemas.in
index 7ca4899..d4334e1 100644
--- a/data/ibus.schemas.in
+++ b/data/ibus.schemas.in
@@ -13,6 +13,19 @@
       </locale>
     </schema>
     <schema>
+      <key>/schemas/desktop/ibus/general/preload_engine_mode</key>
+      <applyto>/desktop/ibus/general/preload_engine_mode</applyto>
+      <owner>ibus</owner>
+      <type>int</type>
+      <default>0</default>
+      <locale name="C">
+        <short>Preload engine mode</short>
+           <long>Preload engines are loaded with this mode.
+                 0 = user customized engines.
+                 1 = language related engines.</long>
+      </locale>
+    </schema>
+    <schema>
       <key>/schemas/desktop/ibus/general/hotkey/trigger</key>
       <applyto>/desktop/ibus/general/hotkey/trigger</applyto>
       <owner>ibus</owner>
diff --git a/ibus/common.py b/ibus/common.py
index 6483aae..127ed93 100644
--- a/ibus/common.py
+++ b/ibus/common.py
@@ -40,6 +40,8 @@ __all__ = (
         "BUS_REQUEST_NAME_REPLY_IN_QUEUE",
         "BUS_REQUEST_NAME_REPLY_EXISTS",
         "BUS_REQUEST_NAME_REPLY_ALREADY_OWNER",
+        "PRELOAD_ENGINE_MODE_USER",
+        "PRELOAD_ENGINE_MODE_LANG_RELATIVE",
         "default_reply_handler",
         "default_error_handler",
         "DEFAULT_ASYNC_HANDLERS",
@@ -150,6 +152,10 @@ BUS_REQUEST_NAME_REPLY_IN_QUEUE      = 2
 BUS_REQUEST_NAME_REPLY_EXISTS        = 3
 BUS_REQUEST_NAME_REPLY_ALREADY_OWNER = 4
 
+# define preload engine mode
+PRELOAD_ENGINE_MODE_USER          = 0
+PRELOAD_ENGINE_MODE_LANG_RELATIVE = 1
+
 def default_reply_handler( *args):
     pass
 
diff --git a/setup/main.py b/setup/main.py
index 7f4a040..192fb88 100644
--- a/setup/main.py
+++ b/setup/main.py
@@ -92,6 +92,7 @@ class Setup(object):
         # keyboard shortcut
         # trigger
         self.__config = self.__bus.get_config()
+        self.__config.connect("value-changed", self.__config_value_changed_cb)
         shortcuts = self.__config.get_value(
                         "general/hotkey", "trigger",
                         ibus.CONFIG_GENERAL_SHORTCUT_TRIGGER_DEFAULT)
@@ -213,15 +214,22 @@ class Setup(object):
         self.__checkbutton_use_global_engine.connect("toggled", self.__checkbutton_use_global_engine_toggled_cb)
 
         # init engine page
+        preload_engine_mode = self.__config.get_value("general",
+                                                      "preload_engine_mode",
+                                                      ibus.common.PRELOAD_ENGINE_MODE_USER)
+        button = self.__builder.get_object("checkbutton_preload_engine_mode")
+        if preload_engine_mode == ibus.common.PRELOAD_ENGINE_MODE_USER:
+            button.set_active(True)
+            self.__builder.get_object("hbox_customize_active_input_methods").set_sensitive(True)
+        else:
+            button.set_active(False)
+            self.__builder.get_object("hbox_customize_active_input_methods").set_sensitive(False)
+        button.connect("toggled", self.__checkbutton_preload_engine_mode_toggled_cb)
         self.__engines = self.__bus.list_engines()
         self.__combobox = self.__builder.get_object("combobox_engines")
         self.__combobox.set_engines(self.__engines)
 
-        tmp_dict = {}
-        for e in self.__engines:
-            tmp_dict[e.name] = e
-        engine_names = self.__config.get_value("general", "preload_engines", [])
-        engines = [tmp_dict[name] for name in engine_names if name in tmp_dict]
+        engines = self.__bus.list_active_engines()
 
         self.__treeview = self.__builder.get_object("treeview_engines")
         self.__treeview.set_engines(engines)
@@ -265,6 +273,26 @@ class Setup(object):
             engine_names = map(lambda e: e.name, engines)
             self.__config.set_list("general", "preload_engines", engine_names, "s")
 
+    def __get_engine_descs_from_names(self, engine_names):
+        tmp_dict = {}
+        for e in self.__engines:
+            tmp_dict[e.name] = e
+        engines = [tmp_dict[name] for name in engine_names if name in tmp_dict]
+        return engines
+
+    def __compare_descs(self, engines_a, engines_b):
+        engines = engines_a
+        concat_engine_names = ""
+        for engine in engines:
+            concat_engine_names = "%s::%s" % (concat_engine_names, engine.name)
+        concat_engine_names_a = concat_engine_names
+        engines = engines_b
+        concat_engine_names = ""
+        for engine in engines:
+            concat_engine_names = "%s::%s" % (concat_engine_names, engine.name)
+        concat_engine_names_b = concat_engine_names
+        return concat_engine_names_a == concat_engine_names_b
+
     def __button_engine_add_cb(self, button):
         engine = self.__combobox.get_active_engine()
         self.__treeview.append_engine(engine)
@@ -276,6 +304,32 @@ class Setup(object):
             about.run()
             about.destroy()
 
+    def __checkbutton_preload_engine_mode_toggled_cb(self, button):
+        if button.get_active():
+            self.__config.set_value("general",
+                                    "preload_engine_mode",
+                                    ibus.common.PRELOAD_ENGINE_MODE_USER)
+            self.__builder.get_object("hbox_customize_active_input_methods").set_sensitive(True)
+            self.__treeview.notify("engines")
+        else:
+            message = _("The list of your saved input methods will be " \
+                        "cleared immediately and the list will be " \
+                        "configured by the login language every time. " \
+                        "Do you agree with this?")
+            dlg = gtk.MessageDialog(type = gtk.MESSAGE_QUESTION,
+                    buttons = gtk.BUTTONS_YES_NO,
+                    message_format = message)
+            id = dlg.run()
+            dlg.destroy()
+            self.__flush_gtk_events()
+            if id != gtk.RESPONSE_YES:
+                button.set_active(True)
+                return
+            self.__config.set_value("general",
+                                    "preload_engine_mode",
+                                    ibus.common.PRELOAD_ENGINE_MODE_LANG_RELATIVE)
+            self.__builder.get_object("hbox_customize_active_input_methods").set_sensitive(False)
+
     def __init_bus(self):
         try:
             self.__bus = ibus.Bus()
@@ -466,7 +520,11 @@ class Setup(object):
         self.__config.set_value("general", "use_global_engine", value)
 
     def __config_value_changed_cb(self, bus, section, name, value):
-        pass
+        if section == 'general' and name == 'preload_engines':
+            engines = self.__get_engine_descs_from_names(value)
+            current_engines = self.__treeview.get_engines()
+            if self.__compare_descs(engines, current_engines) == False:
+                self.__treeview.set_engines(engines)
 
     def __config_reloaded_cb(self, bus):
         pass
diff --git a/setup/setup.ui b/setup/setup.ui
index f1e6d0b..562c091 100644
--- a/setup/setup.ui
+++ b/setup/setup.ui
@@ -582,7 +582,22 @@
                     <property name="visible">True</property>
                     <property name="orientation">vertical</property>
                     <child>
-                      <object class="GtkHBox" id="hbox1">
+                      <object class="GtkCheckButton" id="checkbutton_preload_engine_mode">
+                        <property name="visible">True</property>
+                        <property name="label" translatable="yes">Customize active input _methods</property>
+                        <property name="use_underline">True</property>
+                        <property name="can_focus">True</property>
+                        <property name="receives_default">False</property>
+                        <property name="tooltip_text" translatable="yes">Customize active input methods</property>
+                        <property name="draw_indicator">True</property>
+                      </object>
+                      <packing>
+                        <property name="expand">False</property>
+                        <property name="position">0</property>
+                      </packing>
+                    </child>
+                    <child>
+                      <object class="GtkHBox" id="hbox_customize_active_input_methods">
                         <property name="visible">True</property>
                         <child>
                           <object class="GtkAlignment" id="alignment6">
@@ -733,7 +748,7 @@
                         </child>
                       </object>
                       <packing>
-                        <property name="position">0</property>
+                        <property name="position">1</property>
                       </packing>
                     </child>
                     <child>
@@ -772,7 +787,7 @@ You may use up/down buttons to change it.&lt;/i&gt;&lt;/small&gt;</property>
                       </object>
                       <packing>
                         <property name="expand">False</property>
-                        <property name="position">1</property>
+                        <property name="position">2</property>
                       </packing>
                     </child>
                   </object>
diff --git a/src/ibustypes.h b/src/ibustypes.h
index 6a31847..14b44fc 100644
--- a/src/ibustypes.h
+++ b/src/ibustypes.h
@@ -186,6 +186,16 @@ typedef enum {
 } IBusError;
 
 /**
+ * IBusPreloadEngineMode:
+ * @IBUS_PRELOAD_ENGINE_MODE_USER: user custimized engines
+ * @IBUS_PRELOAD_ENGINE_MODE_LANG_RELATIVE: language related engines.
+ */
+typedef enum {
+    IBUS_PRELOAD_ENGINE_MODE_USER          = 0,
+    IBUS_PRELOAD_ENGINE_MODE_LANG_RELATIVE = 1,
+} IBusPreloadEngineMode;
+
+/**
  * IBusRectangle:
  * @x: x coordinate.
  * @y: y coordinate.
-- 
1.7.4.4