applications: Integrate with malcontent's restrictions

malcontent[1] is  parental(or admin) controlled interface which
can restrict a application's visibility and interactivity for a
standard user. Hence, if the current uid has any restrictions
on its installed applications, filter them out from the applications
panel.

Make the malcontent support enable or disable by setting it up as
a build-time meson option.

[1]: https://gitlab.freedesktop.org/pwithnall/malcontent/

meson.build

@@ -207,6 +207,14 @@ endif
 config_h.set('HAVE_SNAP', enable_snap,
              description: 'Define to 1 if Snap support is enabled')
 
+# malcontent support
+enable_malcontent = get_option('malcontent')
+if enable_malcontent
+  malcontent_dep = dependency('malcontent-0', version: '>= 0.7.0')
+endif
+config_h.set('HAVE_MALCONTENT', enable_malcontent,
+             description: 'Define to 1 if malcontent support is enabled')
+
 if host_is_linux
   # network manager
   network_manager_deps = [
@@ -299,5 +307,6 @@ output += '     IBus (Region panel IBus support) ........... ' + enable_ibus.to_
 output += '     NetworkManager (Network panel) ............. ' + host_is_linux.to_string() + '\n'
 output += '     Wacom (Wacom tablet panel) ................. ' + host_is_linux_not_s390.to_string() + '\n'
 output += '     Snap support ............................... ' + enable_snap.to_string() + '\n'
+output += '     Malcontent support ......................... ' + enable_malcontent.to_string() + '\n'
 
 message(output)

meson_options.txt

@@ -7,3 +7,4 @@ option('tests', type: 'boolean', value: true, description: 'build tests')
 option('tracing', type: 'boolean', value: false, description: 'add extra debugging information')
 option('wayland', type: 'boolean', value: true, description: 'build with Wayland support')
 option('profile', type: 'combo', choices: ['default','development'], value: 'default')
+option('malcontent', type: 'boolean', value: false, description: 'build with malcontent support')

panels/applications/cc-applications-panel.c

@@ -26,6 +26,9 @@
 #ifdef HAVE_SNAP
 #include <snapd-glib/snapd-glib.h>
 #endif
+#ifdef HAVE_MALCONTENT
+#include <libmalcontent/malcontent.h>
+#endif
 
 #include <gio/gdesktopappinfo.h>
 
@@ -61,6 +64,13 @@ struct _CcApplicationsPanel
   GtkLabel        *title_label;
   GAppInfoMonitor *monitor;
   gulong           monitor_id;
+#ifdef HAVE_MALCONTENT
+  GCancellable    *cancellable;
+
+  MctAppFilter    *app_filter;
+  MctManager      *manager;
+  guint            app_filter_id;
+#endif
 
   gchar           *current_app_id;
   gchar           *current_portal_app_id;
@@ -1613,6 +1623,9 @@ populate_applications (CcApplicationsPanel *self)
   GList *l;
 
   container_remove_all (GTK_CONTAINER (self->sidebar_listbox));
+#ifdef HAVE_MALCONTENT
+  g_signal_handler_block (self->manager, self->app_filter_id);
+#endif
 
   infos = g_app_info_get_all ();
 
@@ -1625,6 +1638,11 @@ populate_applications (CcApplicationsPanel *self)
       if (!g_app_info_should_show (info))
         continue;
 
+#ifdef HAVE_MALCONTENT
+      if (!mct_app_filter_is_appinfo_allowed (self->app_filter, info))
+        continue;
+#endif
+
       row = GTK_WIDGET (cc_applications_row_new (info));
       gtk_list_box_insert (self->sidebar_listbox, row, -1);
 
@@ -1632,6 +1650,9 @@ populate_applications (CcApplicationsPanel *self)
       if (g_strcmp0 (id, self->current_app_id) == 0)
         gtk_list_box_select_row (self->sidebar_listbox, GTK_LIST_BOX_ROW (row));
     }
+#ifdef HAVE_MALCONTENT
+  g_signal_handler_unblock (self->manager, self->app_filter_id);
+#endif
 }
 
 static gint
@@ -1665,6 +1686,16 @@ filter_sidebar_rows (GtkListBoxRow *row,
   return g_strstr_len (app_name, -1, search_text) != NULL;
 }
 
+#ifdef HAVE_MALCONTENT
+static void
+app_filter_changed_cb (MctAppFilter        *app_filter,
+                       uid_t               uid,
+                       CcApplicationsPanel *self)
+{
+  populate_applications (self);
+}
+#endif
+
 static void
 apps_changed (CcApplicationsPanel *self)
 {
@@ -1768,7 +1799,16 @@ static void
 cc_applications_panel_finalize (GObject *object)
 {
   CcApplicationsPanel *self = CC_APPLICATIONS_PANEL (object);
+#ifdef HAVE_MALCONTENT
+  if (self->app_filter != NULL && self->app_filter_id != 0)
+    {
+      g_signal_handler_disconnect (self->manager, self->app_filter_id);
+      self->app_filter_id = 0;
+    }
+  g_clear_pointer (&self->app_filter, mct_app_filter_unref);
 
+  g_clear_object (&self->manager);
+#endif
   g_clear_object (&self->notification_settings);
   g_clear_object (&self->location_settings);
   g_clear_object (&self->privacy_settings);
@@ -1932,6 +1972,10 @@ cc_applications_panel_init (CcApplicationsPanel *self)
 {
   g_autoptr(GtkStyleProvider) provider = NULL;
   GtkListBoxRow *row;
+#ifdef HAVE_MALCONTENT
+  g_autoptr(GDBusConnection) system_bus = NULL;
+  g_autoptr(GError) error = NULL;
+#endif
 
   g_resources_register (cc_applications_get_resource ());
 
@@ -1985,7 +2029,31 @@ cc_applications_panel_init (CcApplicationsPanel *self)
   self->location_settings = g_settings_new ("org.gnome.system.location");
   self->privacy_settings = g_settings_new ("org.gnome.desktop.privacy");
   self->search_settings = g_settings_new ("org.gnome.desktop.search-providers");
+#ifdef HAVE_MALCONTENT
+   /* FIXME: should become asynchronous */
+  system_bus = g_bus_get_sync (G_BUS_TYPE_SYSTEM, self->cancellable, &error);
+  if (system_bus == NULL)
+    {
+      g_warning ("Error getting system bus while setting up app permissions: %s", error->message);
+      return;
+    }
 
+  /* Load the user’s parental controls settings too, so we can filter the list. */
+  self->manager = mct_manager_new (system_bus);
+  self->app_filter = mct_manager_get_app_filter (self->manager,
+                                                 getuid (),
+                                                 MCT_GET_APP_FILTER_FLAGS_NONE,
+                                                 self->cancellable,
+                                                 &error);
+  if (error)
+    {
+      g_warning ("Error retrieving app filter: %s", error->message);
+      return;
+    }
+
+  self->app_filter_id = g_signal_connect (self->manager, "app-filter-changed",
+                                          G_CALLBACK (app_filter_changed_cb), self);
+#endif
   populate_applications (self);
 
   self->monitor = g_app_info_monitor_get ();

panels/applications/meson.build

@@ -45,6 +45,10 @@ if enable_snap
   sources += files('cc-snap-row.c')
 endif
 
+if enable_malcontent
+  deps += malcontent_dep
+endif
+
 panels_libs += static_library(
            cappletname,
               sources : sources,