Track XKB group configuration change

Since GNOME 3.6, switching XKB layouts changes the group
configuration, while libcaribou assumes that the configuration is
fixed during the session.

This patch tries to track group configuration changes and allow
clients to reconstruct keyboard UI through two new signals:
KeyboardModel::group-added and KeyboardModel::group-removed.

https://bugzilla.gnome.org/show_bug.cgi?id=694011

2 files changed, 44 insertions, 14 deletions

diff --git a/libcaribou/keyboard-model.vala b/libcaribou/keyboard-model.vala
index 785a668..be00b5c 100644
--- a/libcaribou/keyboard-model.vala
+++ b/libcaribou/keyboard-model.vala
@@ -15,39 +15,63 @@ namespace Caribou {
         private KeyModel last_activated_key;
         private Gee.HashSet<KeyModel> active_mod_keys;
 
-        construct {
-            uint grpid;
-            string group, variant;
-            string[] grps, variants;
-            int i;
+        public signal void group_added (string name);
+        public signal void group_removed (string name);
 
+        construct {
             assert (keyboard_type != null);
 
             xadapter = XAdapter.get_default ();
             xadapter.group_changed.connect (on_group_changed);
+            xadapter.config_changed.connect (on_config_changed);
+
+            groups = new Gee.HashMap<string, GroupModel> ();
+            on_config_changed ();
 
+            active_mod_keys = new Gee.HashSet<KeyModel> ();
+        }
+
+        private void on_config_changed () {
+            string[] grps, variants;
             xadapter.get_groups (out grps, out variants);
 
-            groups = new Gee.HashMap<string, GroupModel> ();
+            var group_names = new Gee.HashSet<string> ();
+            for (var i = 0; i < grps.length; i++) {
+                var group_name = GroupModel.create_group_name (grps[i],
+                                                               variants[i]);
+                group_names.add (group_name);
+                if (!groups.has_key (group_name)) {
+                    var grp = populate_group (grps[i], variants[i]);
+                    if (grp != null) {
+                        groups.set (group_name, grp);
+                        group_added (group_name);
+                    }
+                }
+            }
 
-            for (i=0;i<grps.length;i++)
-                populate_group (grps[i], variants[i]);
+            var iter = groups.map_iterator ();
+            while (iter.next ()) {
+                var group_name = iter.get_key ();
+                if (!group_names.contains (group_name)) {
+                    iter.unset ();
+                    group_removed (group_name);
+                }
+            }
 
-            grpid = xadapter.get_current_group (out group, out variant);
+            string group, variant;
+            var grpid = xadapter.get_current_group (out group, out variant);
             on_group_changed (grpid, group, variant);
-
-            active_mod_keys = new Gee.HashSet<KeyModel> ();
         }
 
-        private void populate_group (string group, string variant) {
+        private GroupModel? populate_group (string group, string variant) {
             GroupModel grp = XmlDeserializer.load_group (keyboard_type,
-                                                          group, variant);
+                                                         group, variant);
             if (grp != null) {
-                groups.set (GroupModel.create_group_name (group, variant), grp);
                 grp.key_clicked.connect (on_key_clicked);
                 grp.key_pressed.connect (on_key_pressed);
                 grp.key_released.connect (on_key_released);
             }
+            return grp;
         }
 
         private void on_key_clicked (KeyModel key) {
diff --git a/libcaribou/xadapter.vala b/libcaribou/xadapter.vala
index 49aeb68..dbc34f9 100644
--- a/libcaribou/xadapter.vala
+++ b/libcaribou/xadapter.vala
@@ -7,6 +7,7 @@ namespace Caribou {
         /* Signals */
         public signal void modifiers_changed (uint modifiers);
         public signal void group_changed (uint gid, string group, string variant);
+        public signal void config_changed ();
 
         /* Private properties */
         static XAdapter instance;
@@ -47,6 +48,7 @@ namespace Caribou {
             xkl_state = this.xkl_engine.get_current_state ();
             this.group = (uchar) xkl_state.group;
             xkl_engine.X_state_changed.connect_after (xkl_state_changed);
+            xkl_engine.X_config_changed.connect_after (xkl_config_changed);
 
             Xkb.get_state (this.xdisplay, Xkb.UseCoreKbd, out xkb_state);
             this.modifiers = xkb_state.mods;
@@ -137,6 +139,10 @@ namespace Caribou {
             group_changed (this.group, group_name, variant_name);
         }
 
+        private void xkl_config_changed () {
+            config_changed ();
+        }
+
         private uchar keysym_to_modifier (uint keyval) {
             for (int i = xkbdesc.min_key_code; i <= xkbdesc.max_key_code; i++) {
                 unowned Xkb.SymMap symmap = xkbdesc.map.key_sym_map[i];