status/keyboard: Disregard the backwards flag for the popup switcher

This seems to cause more harm than good. It puzzles users looking at
the shortcuts list in g-c-c and it prevents otherwise valid shortcuts
like Shift+Hangul from working.

https://bugzilla.gnome.org/show_bug.cgi?id=695823

js/ui/status/keyboard.js

@@ -33,6 +33,36 @@ const KEY_INPUT_SOURCES = 'sources';
 const INPUT_SOURCE_TYPE_XKB = 'xkb';
 const INPUT_SOURCE_TYPE_IBUS = 'ibus';
 
+// This is longest we'll keep the keyboard frozen until an input
+// source is active.
+const MAX_INPUT_SOURCE_ACTIVATION_TIME = 2000; // ms
+
+const BUS_NAME = 'org.gnome.SettingsDaemon.Keyboard';
+const OBJECT_PATH = '/org/gnome/SettingsDaemon/Keyboard';
+
+const KeyboardManagerInterface =
+<interface name="org.gnome.SettingsDaemon.Keyboard">
+<method name="SetInputSource">
+    <arg type="u" direction="in" />
+</method>
+</interface>;
+
+const KeyboardManagerProxy = Gio.DBusProxy.makeProxyWrapper(KeyboardManagerInterface);
+
+function releaseKeyboard() {
+    if (Main.modalCount > 0)
+        global.display.unfreeze_keyboard(global.get_current_time());
+    else
+        global.display.ungrab_keyboard(global.get_current_time());
+}
+
+function holdKeyboard() {
+    if (Main.modalCount > 0)
+        global.display.freeze_keyboard(global.get_current_time());
+    else
+        global.display.grab_keyboard(global.get_current_time());
+}
+
 const IBusManager = new Lang.Class({
     Name: 'IBusManager',
 
@@ -230,6 +260,7 @@ const InputSource = new Lang.Class({
     },
 
     activate: function() {
+        holdKeyboard();
         this.emit('activate');
     },
 });
@@ -262,11 +293,11 @@ const InputSourcePopup = new Lang.Class({
         this._select(this._selectedIndex);
     },
 
-    _keyPressHandler: function(keysym, backwards, action) {
+    _keyPressHandler: function(keysym, _ignored, action) {
         if (action == this._action)
-            this._select(backwards ? this._previous() : this._next());
+            this._select(this._next());
         else if (action == this._actionBackward)
-            this._select(backwards ? this._next() : this._previous());
+            this._select(this._previous());
         else if (keysym == Clutter.Left)
             this._select(this._previous());
         else if (keysym == Clutter.Right)
@@ -336,15 +367,14 @@ const InputSourceIndicator = new Lang.Class({
         this._keybindingAction =
             Main.wm.addKeybinding('switch-input-source',
                                   new Gio.Settings({ schema: "org.gnome.desktop.wm.keybindings" }),
-                                  Meta.KeyBindingFlags.REVERSES,
-                                  Shell.KeyBindingMode.ALL & ~Shell.KeyBindingMode.MESSAGE_TRAY,
+                                  Meta.KeyBindingFlags.NONE,
+                                  Shell.KeyBindingMode.ALL,
                                   Lang.bind(this, this._switchInputSource));
         this._keybindingActionBackward =
             Main.wm.addKeybinding('switch-input-source-backward',
                                   new Gio.Settings({ schema: "org.gnome.desktop.wm.keybindings" }),
-                                  Meta.KeyBindingFlags.REVERSES |
-                                  Meta.KeyBindingFlags.REVERSED,
-                                  Shell.KeyBindingMode.ALL & ~Shell.KeyBindingMode.MESSAGE_TRAY,
+                                  Meta.KeyBindingFlags.NONE,
+                                  Shell.KeyBindingMode.ALL,
                                   Lang.bind(this, this._switchInputSource));
         this._settings = new Gio.Settings({ schema: DESKTOP_INPUT_SOURCES_SCHEMA });
         this._settings.connect('changed::' + KEY_CURRENT_INPUT_SOURCE, Lang.bind(this, this._currentInputSourceChanged));
@@ -364,6 +394,13 @@ const InputSourceIndicator = new Lang.Class({
         this._ibusManager.connect('property-updated', Lang.bind(this, this._ibusPropertyUpdated));
         this._inputSourcesChanged();
 
+        this._keyboardManager = new KeyboardManagerProxy(Gio.DBus.session, BUS_NAME, OBJECT_PATH,
+                                                         function(proxy, error) {
+                                                             if (error)
+                                                                 log(error.message);
+                                                         });
+        global.display.connect('modifiers-accelerator-activated', Lang.bind(this, this._modifiersSwitcher));
+
         this.menu.addMenuItem(new PopupMenu.PopupSeparatorMenuItem());
         this._showLayoutItem = this.menu.addAction(_("Show Keyboard Layout"), Lang.bind(this, this._showLayout));
 
@@ -397,13 +434,44 @@ const InputSourceIndicator = new Lang.Class({
         this._inputSourcesChanged();
     },
 
+    _modifiersSwitcher: function() {
+        let sourceIndexes = Object.keys(this._inputSources);
+        if (sourceIndexes.length == 0) {
+            releaseKeyboard();
+            return;
+        }
+
+        let is = this._currentSource;
+        if (!is)
+            is = this._inputSources[sourceIndexes[0]];
+
+        let nextIndex = is.index + 1;
+        if (nextIndex > sourceIndexes[sourceIndexes.length - 1])
+            nextIndex = 0;
+
+        while (!(is = this._inputSources[nextIndex]))
+            nextIndex += 1;
+
+        is.activate();
+    },
+
     _switchInputSource: function(display, screen, window, binding) {
         if (this._mruSources.length < 2)
             return;
 
+        // HACK: Fall back on simple input source switching since we
+        // can't show a popup switcher while the message tray is up
+        // without considerable work to consolidate the usage of
+        // pushModal/popModal and grabHelper. See
+        // https://bugzilla.gnome.org/show_bug.cgi?id=695143 .
+        if (Main.keybindingMode == Shell.KeyBindingMode.MESSAGE_TRAY) {
+            this._modifiersSwitcher();
+            return;
+        }
+
         let popup = new InputSourcePopup(this._mruSources, this._keybindingAction, this._keybindingActionBackward);
         let modifiers = binding.get_modifiers();
-        let backwards = modifiers & Meta.VirtualModifier.SHIFT_MASK;
+        let backwards = false;  // Not using this
         if (!popup.show(backwards, binding.get_name(), binding.get_mask()))
             popup.destroy();
     },
@@ -487,10 +555,10 @@ const InputSourceIndicator = new Lang.Class({
             let is = new InputSource(type, id, displayName, shortName, i);
 
             is.connect('activate', Lang.bind(this, function() {
-                if (this._currentSource && this._currentSource.index == is.index)
-                    return;
-                this._settings.set_value(KEY_CURRENT_INPUT_SOURCE,
-                                         GLib.Variant.new_uint32(is.index));
+                let inVariant = new GLib.Variant('(u)', [is.index]);
+                this._keyboardManager.call('SetInputSource', inVariant, 0,
+                                           MAX_INPUT_SOURCE_ACTIVATION_TIME,
+                                           null, releaseKeyboard);
             }));
 
             if (!(is.shortName in inputSourcesByShortName))