gdm: add AuthList control

Ultimately, we want to add support for GDM's need ChoiceList
PAM extension.  That extension allows PAM modules to present
a list of choices to the user. Before we can support that
extension, however, we need to have a list control in the
login-screen/unlock screen.  This commit adds that control.

For the most part, it's a copy-and-paste of the gdm userlist,
but with less features.  It lacks API specific to the users,
lacks the built in timed login indicator, etc.

js/gdm/authList.js

@@ -0,0 +1,190 @@
+// -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
+/*
+ * Copyright 2017 Red Hat, Inc
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+const Clutter = imports.gi.Clutter;
+const GObject = imports.gi.GObject;
+const Gtk = imports.gi.Gtk;
+const Lang = imports.lang;
+const Meta = imports.gi.Meta;
+const Signals = imports.signals;
+const St = imports.gi.St;
+
+const Tweener = imports.ui.tweener;
+
+const _SCROLL_ANIMATION_TIME = 0.5;
+
+const AuthListItem = new Lang.Class({
+    Name: 'AuthListItem',
+
+    _init: function(key, text) {
+        this.key = key;
+        let label = new St.Label({ style_class: 'auth-list-item-label',
+                                   y_align: Clutter.ActorAlign.CENTER });
+        label.text = text;
+
+        this.actor = new St.Button({ style_class: 'login-dialog-user-list-item',
+                                     button_mask: St.ButtonMask.ONE | St.ButtonMask.THREE,
+                                     can_focus: true,
+                                     child: label,
+                                     reactive: true,
+                                     x_align: St.Align.START,
+                                     x_fill: true });
+
+        this.actor.connect('key-focus-in', () => {
+            this._setSelected(true);
+        });
+        this.actor.connect('key-focus-out', () => {
+            this._setSelected(false);
+        });
+        this.actor.connect('notify::hover', () => {
+            this._setSelected(this.actor.hover);
+        });
+
+        this.actor.connect('clicked', Lang.bind(this, this._onClicked));
+    },
+
+    _onClicked: function() {
+        this.emit('activate');
+    },
+
+    _setSelected: function(selected) {
+        if (selected) {
+            this.actor.add_style_pseudo_class('selected');
+            this.actor.grab_key_focus();
+        } else {
+            this.actor.remove_style_pseudo_class('selected');
+        }
+    }
+});
+Signals.addSignalMethods(AuthListItem.prototype);
+
+const AuthList = new Lang.Class({
+    Name: 'AuthList',
+
+    _init: function() {
+        this.actor = new St.ScrollView({ style_class: 'login-dialog-user-list-view'});
+        this.actor.set_policy(Gtk.PolicyType.NEVER,
+                              Gtk.PolicyType.AUTOMATIC);
+
+        this._box = new St.BoxLayout({ vertical: true,
+                                       style_class: 'login-dialog-user-list',
+                                       pseudo_class: 'expanded' });
+
+        this.actor.add_actor(this._box);
+        this._items = {};
+
+        this.actor.connect('key-focus-in', Lang.bind(this, this._moveFocusToItems));
+    },
+
+    _moveFocusToItems: function() {
+        let hasItems = Object.keys(this._items).length > 0;
+
+        if (!hasItems)
+            return;
+
+        if (global.stage.get_key_focus() != this.actor)
+            return;
+
+        let focusSet = this.actor.navigate_focus(null, Gtk.DirectionType.TAB_FORWARD, false);
+        if (!focusSet) {
+            Meta.later_add(Meta.LaterType.BEFORE_REDRAW, Lang.bind(this, function() {
+                this._moveFocusToItems();
+                return false;
+            }));
+        }
+    },
+
+    _onItemActivated: function(activatedItem) {
+        this.emit('activate', activatedItem.key);
+    },
+
+    scrollToItem: function(item) {
+        let box = item.actor.get_allocation_box();
+
+        let adjustment = this.actor.get_vscroll_bar().get_adjustment();
+
+        let value = (box.y1 + adjustment.step_increment / 2.0) - (adjustment.page_size / 2.0);
+        Tweener.removeTweens(adjustment);
+        Tweener.addTween (adjustment,
+                          { value: value,
+                            time: _SCROLL_ANIMATION_TIME,
+                            transition: 'easeOutQuad' });
+    },
+
+    jumpToItem: function(item) {
+        let box = item.actor.get_allocation_box();
+
+        let adjustment = this.actor.get_vscroll_bar().get_adjustment();
+
+        let value = (box.y1 + adjustment.step_increment / 2.0) - (adjustment.page_size / 2.0);
+
+        adjustment.set_value(value);
+    },
+
+    getItem: function(key) {
+        let item = this._items[key];
+
+        if (!item)
+            return null;
+
+        return item;
+    },
+
+    addItem: function(key, text) {
+        this.removeItem(key);
+
+        let item = new AuthListItem(key, text);
+        this._box.add(item.actor, { x_fill: true });
+
+        this._items[key] = item;
+
+        item.connect('activate',
+                     Lang.bind(this, this._onItemActivated));
+
+        // Try to keep the focused item front-and-center
+        item.actor.connect('key-focus-in',
+                           Lang.bind(this,
+                                     function() {
+                                         this.scrollToItem(item);
+                                     }));
+
+        this._moveFocusToItems();
+
+        this.emit('item-added', item);
+    },
+
+    removeItem: function(key) {
+        let item = this._items[key];
+
+        if (!item)
+            return;
+
+        item.actor.destroy();
+        delete this._items[key];
+    },
+
+    numItems: function() {
+        return Object.keys(this._items).length;
+    },
+
+    clear: function() {
+        this._box.destroy_all_children();
+        this._items = {};
+    }
+});
+Signals.addSignalMethods(AuthList.prototype);

js/js-resources.gresource.xml

@@ -1,6 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <gresources>
   <gresource prefix="/org/gnome/shell">
+    <file>gdm/authList.js</file>
     <file>gdm/authPrompt.js</file>
     <file>gdm/batch.js</file>
     <file>gdm/fingerprint.js</file>