Implement input source switching

Instead of calling out to gnome-settings-daemon we'll just implement
the switching logic ourselves and use mutter APIs that allow this
functionality to work both in X sessions and when we're a Wayland
compositor.

Switching IBus engines is done transparently as well just like g-s-d
used to do.

https://bugzilla.gnome.org/show_bug.cgi?id=736435

js/misc/keyboardManager.js

@@ -1,11 +1,16 @@
 // -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
 
-const Gio = imports.gi.Gio;
+const GLib = imports.gi.GLib;
 const GnomeDesktop = imports.gi.GnomeDesktop;
 const Lang = imports.lang;
+const Meta = imports.gi.Meta;
 
 const Main = imports.ui.main;
 
+const DEFAULT_LOCALE = 'en_US';
+const DEFAULT_LAYOUT = 'us';
+const DEFAULT_VARIANT = '';
+
 let _xkbInfo = null;
 
 function getXkbInfo() {
@@ -36,36 +41,113 @@ function holdKeyboard() {
 const KeyboardManager = new Lang.Class({
     Name: 'KeyboardManager',
 
-    // This is the longest we'll keep the keyboard frozen until an input
-    // source is active.
-    _MAX_INPUT_SOURCE_ACTIVATION_TIME: 4000, // ms
-
-    _BUS_NAME: 'org.gnome.SettingsDaemon.Keyboard',
-    _OBJECT_PATH: '/org/gnome/SettingsDaemon/Keyboard',
-
-    _INTERFACE: '\
-        <node> \
-        <interface name="org.gnome.SettingsDaemon.Keyboard"> \
-            <method name="SetInputSource"> \
-                <arg type="u" direction="in" /> \
-            </method> \
-        </interface> \
-        </node>',
+    // The XKB protocol doesn't allow for more that 4 layouts in a
+    // keymap. Wayland doesn't impose this limit and libxkbcommon can
+    // handle up to 32 layouts but since we need to support X clients
+    // even as a Wayland compositor, we can't bump this.
+    MAX_LAYOUTS_PER_GROUP: 4,
 
     _init: function() {
-        let Proxy = Gio.DBusProxy.makeProxyWrapper(this._INTERFACE);
-        this._proxy = new Proxy(Gio.DBus.session,
-                                this._BUS_NAME,
-                                this._OBJECT_PATH,
-                                function(proxy, error) {
-                                    if (error)
-                                        log(error.message);
-                                });
-        this._proxy.g_default_timeout = this._MAX_INPUT_SOURCE_ACTIVATION_TIME;
+        this._xkbInfo = getXkbInfo();
+        this._current = null;
+        this._localeLayoutInfo = this._getLocaleLayout();
+        this._layoutInfos = {};
     },
 
-    SetInputSource: function(is) {
-        holdKeyboard();
-        this._proxy.SetInputSourceRemote(is.index, releaseKeyboard);
+    _applyLayoutGroup: function(group) {
+        let options = this._buildOptionsString();
+        let [layouts, variants] = this._buildGroupStrings(group);
+        Meta.get_backend().set_keymap(layouts, variants, options);
+    },
+
+    _applyLayoutGroupIndex: function(idx) {
+        Meta.get_backend().lock_layout_group(idx);
+    },
+
+    apply: function(id) {
+        let info = this._layoutInfos[id];
+        if (!info)
+            return;
+
+        if (this._current && this._current.group == info.group) {
+            if (this._current.groupIndex != info.groupIndex)
+                this._applyLayoutGroupIndex(info.groupIndex);
+        } else {
+            this._applyLayoutGroup(info.group);
+            this._applyLayoutGroupIndex(info.groupIndex);
+        }
+
+        this._current = info;
+    },
+
+    reapply: function() {
+        if (!this._current)
+            return;
+
+        this._applyLayoutGroup(this._current.group);
+        this._applyLayoutGroupIndex(this._current.groupIndex);
+    },
+
+    setUserLayouts: function(ids) {
+        this._current = null;
+        this._layoutInfos = {};
+
+        for (let i = 0; i < ids.length; ++i) {
+            let [found, , , _layout, _variant] = this._xkbInfo.get_layout_info(ids[i]);
+            if (found)
+                this._layoutInfos[ids[i]] = { id: ids[i], layout: _layout, variant: _variant };
+        }
+
+        let i = 0;
+        let group = [];
+        for (let id in this._layoutInfos) {
+            // We need to leave one slot on each group free so that we
+            // can add a layout containing the symbols for the
+            // language used in UI strings to ensure that toolkits can
+            // handle mnemonics like Alt+Ф even if the user is
+            // actually typing in a different layout.
+            let groupIndex = i % (this.MAX_LAYOUTS_PER_GROUP - 1);
+            if (groupIndex == 0)
+                group = [];
+
+            let info = this._layoutInfos[id];
+            group[groupIndex] = info;
+            info.group = group;
+            info.groupIndex = groupIndex;
+
+            i += 1;
+        }
+    },
+
+    _getLocaleLayout: function() {
+        let locale = GLib.get_language_names()[0];
+        if (locale.indexOf('_') == -1)
+            locale = DEFAULT_LOCALE;
+
+        let [found, , id] = GnomeDesktop.get_input_source_from_locale(locale);
+        if (!found)
+            [, , id] = GnomeDesktop.get_input_source_from_locale(DEFAULT_LOCALE);
+
+        let [found, , , _layout, _variant] = this._xkbInfo.get_layout_info(id);
+        if (found)
+            return { layout: _layout, variant: _variant };
+        else
+            return { layout: DEFAULT_LAYOUT, variant: DEFAULT_VARIANT };
+    },
+
+    _buildGroupStrings: function(_group) {
+        let group = _group.concat(this._localeLayoutInfo);
+        let layouts = group.map(function(g) { return g.layout; }).join(',');
+        let variants = group.map(function(g) { return g.variant; }).join(',');
+        return [layouts, variants];
+    },
+
+    setKeyboardOptions: function(options) {
+        this._xkbOptions = options;
+    },
+
+    _buildOptionsString: function() {
+        let options = this._xkbOptions.join(',');
+        return options;
     }
 });