user-accounts: Add a launcher for parental controls app

malcontent ships malcontent-control[1] which is the user interface
to interact with various parental-control settings. Add a launcher
as per the design mockups[2] to launch malcontent-control.

[1]: https://gitlab.freedesktop.org/pwithnall/malcontent/-/blob/master/README.md
[2]: https://gitlab.gnome.org/Teams/Design/settings-mockups/blob/master/users/users.png

panels/user-accounts/cc-user-panel.c

@@ -39,6 +39,10 @@
 #define GNOME_DESKTOP_USE_UNSTABLE_API
 #include <libgnome-desktop/gnome-languages.h>
 
+#ifdef HAVE_MALCONTENT
+#include <libmalcontent/malcontent.h>
+#endif
+
 #include "cc-add-user-dialog.h"
 #include "cc-avatar-chooser.h"
 #include "cc-carousel.h"
@@ -87,6 +91,11 @@ struct _CcUserPanel {
         GtkBox          *no_users_box;
         GtkRevealer     *notification_revealer;
         GtkLabel        *password_button_label;
+#ifdef HAVE_MALCONTENT
+        GtkLabel        *parental_controls_button_label;
+        GtkImage        *parental_control_go_next;
+        GtkListBoxRow   *parental_controls_row;
+#endif
         GtkListBoxRow   *password_row;
         CcPermissionInfobar *permission_infobar;
         GtkButton       *remove_user_button;
@@ -291,6 +300,7 @@ reload_users (CcUserPanel *self, ActUser *selected_user)
         CcCarouselItem *item = NULL;
         GtkSettings *settings;
         gboolean animations;
+        guint users_count;
 
         settings = gtk_widget_get_settings (GTK_WIDGET (self->carousel));
 
@@ -301,7 +311,8 @@ reload_users (CcUserPanel *self, ActUser *selected_user)
         self->other_accounts = 0;
 
         list = act_user_manager_list_users (self->um);
-        g_debug ("Got %d users\n", g_slist_length (list));
+        users_count = g_slist_length (list);
+        g_debug ("Got %d users\n", users_count);
 
         list = g_slist_sort (list, (GCompareFunc) sort_users);
         for (l = list; l; l = l->next) {
@@ -321,6 +332,10 @@ reload_users (CcUserPanel *self, ActUser *selected_user)
         cc_carousel_select_item (self->carousel, item);
 
         g_object_set (settings, "gtk-enable-animations", animations, NULL);
+#ifdef HAVE_MALCONTENT
+        /* Parental Controls row not to be shown for single user setups. */
+        gtk_widget_set_visible (GTK_WIDGET (self->parental_controls_row), users_count > 1);
+#endif
 }
 
 static gint
@@ -796,6 +811,41 @@ get_autologin_possible (ActUser *user)
 static void on_permission_changed (CcUserPanel *self);
 static void full_name_edit_button_toggled (CcUserPanel *self);
 
+#ifdef HAVE_MALCONTENT
+static gboolean
+is_parental_controls_enabled_for_user (ActUser *user)
+{
+        g_autoptr(MctManager) manager = NULL;
+        g_autoptr(MctAppFilter) app_filter = NULL;
+        g_autoptr(GDBusConnection) system_bus = NULL;
+        g_autoptr(GError) error = NULL;
+
+        /* FIXME: should become asynchronous */
+        system_bus = g_bus_get_sync (G_BUS_TYPE_SYSTEM, NULL, &error);
+        if (system_bus == NULL) {
+	        g_warning ("Error getting system bus while trying to show user details: %s", error->message);
+	        return FALSE;
+        }
+
+        manager = mct_manager_new (system_bus);
+        app_filter = mct_manager_get_app_filter (manager,
+                                                 act_user_get_uid (user),
+                                                 MCT_GET_APP_FILTER_FLAGS_NONE,
+                                                 NULL,
+                                                 &error);
+        if (error) {
+                if (!g_error_matches (error, MCT_MANAGER_ERROR, MCT_MANAGER_ERROR_DISABLED))
+                        g_warning ("Error retrieving app filter for user %s: %s",
+                                   act_user_get_user_name (user),
+                                   error->message);
+
+                return FALSE;
+        }
+
+        return mct_app_filter_is_enabled (app_filter);
+}
+#endif
+
 static void
 show_user (ActUser *user, CcUserPanel *self)
 {
@@ -877,6 +927,24 @@ show_user (ActUser *user, CcUserPanel *self)
         show = act_user_is_local_account (user);
         gtk_widget_set_visible (GTK_WIDGET (self->autologin_row), show);
 
+#ifdef HAVE_MALCONTENT
+        /* Parental Controls: Unavailable if user is admin */
+        if (act_user_get_account_type (user) == ACT_USER_ACCOUNT_TYPE_ADMINISTRATOR) {
+                gtk_widget_hide (GTK_WIDGET (self->parental_control_go_next));
+                /* TRANSLATORS: Status of Parental Controls setup */
+                gtk_label_set_text (self->parental_controls_button_label, _("Unavailable"));
+        } else {
+                if (is_parental_controls_enabled_for_user (user))
+                        /* TRANSLATORS: Status of Parental Controls setup */
+                        gtk_label_set_text (self->parental_controls_button_label, _("Enabled"));
+                else
+                        /* TRANSLATORS: Status of Parental Controls setup */
+                        gtk_label_set_text (self->parental_controls_button_label, _("Disabled"));
+
+                gtk_widget_show (GTK_WIDGET (self->parental_control_go_next));
+        }
+#endif
+
         /* Language: do not show for current user */
         show = act_user_get_uid (user) != getuid();
         gtk_widget_set_visible (GTK_WIDGET (self->language_row), show);
@@ -1134,6 +1202,22 @@ show_history (CcUserPanel *self)
         gtk_widget_destroy (GTK_WIDGET (dialog));
 }
 
+#ifdef HAVE_MALCONTENT
+static void
+spawn_malcontent_control (CcUserPanel *self)
+{
+        ActUser *user;
+
+        user = get_selected_user (self);
+
+        /* no-op if the user is administrator */
+        if (act_user_get_account_type (user) != ACT_USER_ACCOUNT_TYPE_ADMINISTRATOR) {
+                const gchar *argv[] = { "malcontent-control", NULL };
+                g_spawn_async (NULL, (char **)argv, NULL, G_SPAWN_SEARCH_PATH, NULL, NULL, NULL, NULL);
+        }
+}
+#endif
+
 static void
 activate_row (GtkListBox *box, GtkListBoxRow *row, CcUserPanel *self)
 {
@@ -1149,6 +1233,12 @@ activate_row (GtkListBox *box, GtkListBoxRow *row, CcUserPanel *self)
         } else if (row == self->last_login_row) {
                 show_history (self);
         }
+
+#ifdef HAVE_MALCONTENT
+        if (row == self->parental_controls_row) {
+		spawn_malcontent_control (self);
+        }
+#endif
 }
 
 static void
@@ -1343,6 +1433,10 @@ on_permission_changed (CcUserPanel *self)
 
                 gtk_widget_set_sensitive (GTK_WIDGET (self->last_login_row), TRUE);
                 remove_unlock_tooltip (GTK_WIDGET (self->last_login_row));
+#ifdef HAVE_MALCONTENT
+                gtk_widget_set_sensitive (GTK_WIDGET (self->parental_controls_row), TRUE);
+                remove_unlock_tooltip (GTK_WIDGET (self->parental_controls_row));
+#endif
         }
         else {
                 gtk_stack_set_visible_child (self->user_icon_stack, GTK_WIDGET (self->user_icon_image));
@@ -1358,6 +1452,10 @@ on_permission_changed (CcUserPanel *self)
 
                 gtk_widget_set_sensitive (GTK_WIDGET (self->last_login_row), FALSE);
                 add_unlock_tooltip (GTK_WIDGET (self->last_login_row));
+#ifdef HAVE_MALCONTENT
+                gtk_widget_set_sensitive (GTK_WIDGET (self->parental_controls_row), FALSE);
+                add_unlock_tooltip (GTK_WIDGET (self->parental_controls_row));
+#endif
         }
 }
 
@@ -1534,6 +1632,11 @@ cc_user_panel_class_init (CcUserPanelClass *klass)
         gtk_widget_class_bind_template_child (widget_class, CcUserPanel, last_login_row);
         gtk_widget_class_bind_template_child (widget_class, CcUserPanel, no_users_box);
         gtk_widget_class_bind_template_child (widget_class, CcUserPanel, notification_revealer);
+#ifdef HAVE_MALCONTENT
+        gtk_widget_class_bind_template_child (widget_class, CcUserPanel, parental_controls_button_label);
+        gtk_widget_class_bind_template_child (widget_class, CcUserPanel, parental_control_go_next);
+        gtk_widget_class_bind_template_child (widget_class, CcUserPanel, parental_controls_row);
+#endif
         gtk_widget_class_bind_template_child (widget_class, CcUserPanel, password_button_label);
         gtk_widget_class_bind_template_child (widget_class, CcUserPanel, password_row);
         gtk_widget_class_bind_template_child (widget_class, CcUserPanel, permission_infobar);

panels/user-accounts/cc-user-panel.ui

@@ -305,6 +305,51 @@
                                     </child>
                                   </object>
                                 </child>
+
+                                <child>
+                                  <object class="GtkListBoxRow" id="parental_controls_row">
+                                    <property name="visible">False</property>
+                                    <child>
+                                      <object class="GtkBox">
+                                        <property name="visible">True</property>
+                                        <property name="border-width">10</property>
+                                        <property name="spacing">10</property>
+                                        <child>
+                                          <object class="GtkLabel">
+                                            <property name="visible">True</property>
+                                            <property name="label" translatable="yes">_Parental Controls</property>
+                                            <property name="use_underline">True</property>
+                                            <property name="mnemonic_widget">parental_controls_button_label</property>
+                                          </object>
+                                        </child>
+                                        <child>
+                                          <object class="GtkImage" id="parental_control_go_next">
+                                            <property name="visible">True</property>
+                                            <property name="icon-name">go-next-symbolic</property>
+                                            <style>
+                                              <class name="dim-label"/>
+                                            </style>
+                                          </object>
+                                          <packing>
+                                            <property name="pack_type">end</property>
+                                          </packing>
+                                        </child>
+                                        <child>
+                                          <object class="GtkLabel" id="parental_controls_button_label">
+                                            <property name="visible">True</property>
+                                            <style>
+                                              <class name="dim-label"/>
+                                            </style>
+                                          </object>
+                                          <packing>
+                                            <property name="pack_type">end</property>
+                                          </packing>
+                                        </child>
+                                      </object>
+                                    </child>
+                                  </object>
+                                </child>
+
                                 <child>
                                   <object class="GtkListBoxRow" id="language_row">
                                     <property name="visible">True</property>

panels/user-accounts/meson.build

@@ -175,6 +175,10 @@ if enable_cheese
   deps += cheese_deps
 endif
 
+if enable_malcontent
+  deps += malcontent_dep
+endif
+
 cflags += [
   '-DGNOMELOCALEDIR="@0@"'.format(control_center_localedir),
   '-DHAVE_LIBPWQUALITY',