session-limits: Add serialize and deserialize methods

See the previous commit; this is the same, but for session limits.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

libmalcontent/manager.c

@@ -738,9 +738,6 @@ mct_manager_get_session_limits (MctManager                *self,
   g_autoptr(GVariant) result_variant = NULL;
   g_autoptr(GVariant) properties = NULL;
   g_autoptr(GError) local_error = NULL;
-  g_autoptr(MctSessionLimits) session_limits = NULL;
-  guint32 limit_type;
-  guint32 daily_start_time, daily_end_time;
 
   g_return_val_if_fail (MCT_IS_MANAGER (self), NULL);
   g_return_val_if_fail (cancellable == NULL || G_IS_CANCELLABLE (cancellable), NULL);
@@ -791,8 +788,7 @@ mct_manager_get_session_limits (MctManager                *self,
   /* Extract the properties we care about. They may be silently omitted from the
    * results if we don’t have permission to access them. */
   properties = g_variant_get_child_value (result_variant, 0);
-  if (!g_variant_lookup (properties, "LimitType", "u",
+  if (!g_variant_lookup (properties, "LimitType", "u", NULL))
-                         &limit_type))
     {
       g_set_error (error, MCT_MANAGER_ERROR,
                    MCT_MANAGER_ERROR_PERMISSION_DENIED,
@@ -801,45 +797,7 @@ mct_manager_get_session_limits (MctManager                *self,
       return NULL;
     }
 
-  /* Check that the limit type is something we support. */
+  return mct_session_limits_deserialize (properties, user_id, error);
-  G_STATIC_ASSERT (sizeof (limit_type) >= sizeof (MctSessionLimitsType));
-
-  if ((guint) limit_type > MCT_SESSION_LIMITS_TYPE_DAILY_SCHEDULE)
-    {
-      g_set_error (error, MCT_MANAGER_ERROR,
-                   MCT_MANAGER_ERROR_INVALID_DATA,
-                   _("Session limit for user %u has an unrecognized type ‘%u’"),
-                   (guint) user_id, limit_type);
-      return NULL;
-    }
-
-  if (!g_variant_lookup (properties, "DailySchedule", "(uu)",
-                         &daily_start_time, &daily_end_time))
-    {
-      /* Default value. */
-      daily_start_time = 0;
-      daily_end_time = 24 * 60 * 60;
-    }
-
-  if (daily_start_time >= daily_end_time ||
-      daily_end_time > 24 * 60 * 60)
-    {
-      g_set_error (error, MCT_MANAGER_ERROR,
-                   MCT_MANAGER_ERROR_INVALID_DATA,
-                   _("Session limit for user %u has invalid daily schedule %u–%u"),
-                   (guint) user_id, daily_start_time, daily_end_time);
-      return NULL;
-    }
-
-  /* Success. Create an #MctSessionLimits object to contain the results. */
-  session_limits = g_new0 (MctSessionLimits, 1);
-  session_limits->ref_count = 1;
-  session_limits->user_id = user_id;
-  session_limits->limit_type = limit_type;
-  session_limits->daily_start_time = daily_start_time;
-  session_limits->daily_end_time = daily_end_time;
-
-  return g_steal_pointer (&session_limits);
 }
 
 static void get_session_limits_thread_cb (GTask        *task,
@@ -973,11 +931,12 @@ mct_manager_set_session_limits (MctManager                *self,
                                 GError                   **error)
 {
   g_autofree gchar *object_path = NULL;
-  g_autoptr(GVariant) limit_variant = NULL;
-  const gchar *limit_property_name = NULL;
   g_autoptr(GVariant) limit_type_variant = NULL;
-  g_autoptr(GVariant) limit_result_variant = NULL;
   g_autoptr(GVariant) limit_type_result_variant = NULL;
+  g_autoptr(GVariant) properties_variant = NULL;
+  g_autoptr(GVariant) properties_value = NULL;
+  const gchar *properties_key = NULL;
+  GVariantIter iter;
   g_autoptr(GError) local_error = NULL;
 
   g_return_val_if_fail (MCT_IS_MANAGER (self), FALSE);
@@ -992,29 +951,22 @@ mct_manager_set_session_limits (MctManager                *self,
   if (object_path == NULL)
     return FALSE;
 
-  switch (session_limits->limit_type)
+  properties_variant = mct_session_limits_serialize (session_limits);
-    {
-    case MCT_SESSION_LIMITS_TYPE_DAILY_SCHEDULE:
-      limit_variant = g_variant_new ("(uu)",
-                                     session_limits->daily_start_time,
-                                     session_limits->daily_end_time);
-      limit_property_name = "DailySchedule";
-      break;
-    case MCT_SESSION_LIMITS_TYPE_NONE:
-      limit_variant = NULL;
-      limit_property_name = NULL;
-      break;
-    default:
-      g_assert_not_reached ();
-    }
 
-  limit_type_variant = g_variant_new_uint32 (session_limits->limit_type);
+  g_variant_iter_init (&iter, properties_variant);
-
+  while (g_variant_iter_loop (&iter, "{&sv}", &properties_key, &properties_value))
-  if (limit_property_name != NULL)
     {
-      /* Change the details of the new limit first, so that all the properties are
+      g_autoptr(GVariant) result_variant = NULL;
-       * correct by the time the limit type is changed over. */
+
-      limit_result_variant =
+      /* Change the limit type last, so all the details of the new limit are
+       * correct by the time it’s changed over. */
+      if (g_str_equal (properties_key, "LimitType"))
+        {
+          limit_type_variant = g_steal_pointer (&properties_value);
+          continue;
+        }
+
+      result_variant =
           g_dbus_connection_call_sync (self->connection,
                                        "org.freedesktop.Accounts",
                                        object_path,
@@ -1022,8 +974,8 @@ mct_manager_set_session_limits (MctManager                *self,
                                        "Set",
                                        g_variant_new ("(ssv)",
                                                       "com.endlessm.ParentalControls.SessionLimits",
-                                                      limit_property_name,
+                                                      properties_key,
-                                                      g_steal_pointer (&limit_variant)),
+                                                      properties_value),
                                        G_VARIANT_TYPE ("()"),
                                        (flags & MCT_MANAGER_SET_VALUE_FLAGS_INTERACTIVE)
                                          ? G_DBUS_CALL_FLAGS_ALLOW_INTERACTIVE_AUTHORIZATION
@@ -1047,7 +999,7 @@ mct_manager_set_session_limits (MctManager                *self,
                                    g_variant_new ("(ssv)",
                                                   "com.endlessm.ParentalControls.SessionLimits",
                                                   "LimitType",
-                                                  g_steal_pointer (&limit_type_variant)),
+                                                  limit_type_variant),
                                    G_VARIANT_TYPE ("()"),
                                    (flags & MCT_MANAGER_SET_VALUE_FLAGS_INTERACTIVE)
                                      ? G_DBUS_CALL_FLAGS_ALLOW_INTERACTIVE_AUTHORIZATION

libmalcontent/session-limits.c

@@ -26,6 +26,7 @@
 #include <glib-object.h>
 #include <glib/gi18n-lib.h>
 #include <gio/gio.h>
+#include <libmalcontent/manager.h>
 #include <libmalcontent/session-limits.h>
 
 #include "libmalcontent/session-limits-private.h"
@@ -85,7 +86,7 @@ mct_session_limits_unref (MctSessionLimits *limits)
  *
  * Get the user ID of the user this #MctSessionLimits is for.
  *
- * Returns: user ID of the relevant user
+ * Returns: user ID of the relevant user, or `(uid_t) -1` if unknown
  * Since: 0.5.0
  */
 uid_t
@@ -190,6 +191,149 @@ out:
   return user_allowed_now;
 }
 
+/**
+ * mct_session_limits_serialize:
+ * @limits: an #MctSessionLimits
+ *
+ * Build a #GVariant which contains the session limits from @limits, in an
+ * opaque variant format. This format may change in future, but
+ * mct_session_limits_deserialize() is guaranteed to always be able to load any
+ * variant produced by the current or any previous version of
+ * mct_session_limits_serialize().
+ *
+ * Returns: (transfer floating): a new, floating #GVariant containing the
+ *    session limits
+ * Since: 0.7.0
+ */
+GVariant *
+mct_session_limits_serialize (MctSessionLimits *limits)
+{
+  g_auto(GVariantBuilder) builder = G_VARIANT_BUILDER_INIT (G_VARIANT_TYPE ("a{sv}"));
+  g_autoptr(GVariant) limit_variant = NULL;
+  const gchar *limit_property_name;
+
+  g_return_val_if_fail (limits != NULL, NULL);
+  g_return_val_if_fail (limits->ref_count >= 1, NULL);
+
+  /* The serialisation format is exactly the
+   * `com.endlessm.ParentalControls.SessionLimits` D-Bus interface. */
+  switch (limits->limit_type)
+    {
+    case MCT_SESSION_LIMITS_TYPE_DAILY_SCHEDULE:
+      limit_variant = g_variant_new ("(uu)",
+                                     limits->daily_start_time,
+                                     limits->daily_end_time);
+      limit_property_name = "DailySchedule";
+      break;
+    case MCT_SESSION_LIMITS_TYPE_NONE:
+      limit_variant = NULL;
+      limit_property_name = NULL;
+      break;
+    default:
+      g_assert_not_reached ();
+    }
+
+  if (limit_property_name != NULL)
+    {
+      g_variant_builder_add (&builder, "{sv}", limit_property_name,
+                             g_steal_pointer (&limit_variant));
+    }
+
+  g_variant_builder_add (&builder, "{sv}", "LimitType",
+                         g_variant_new_uint32 (limits->limit_type));
+
+  return g_variant_builder_end (&builder);
+}
+
+/**
+ * mct_session_limits_deserialize:
+ * @variant: a serialized session limits variant
+ * @user_id: the ID of the user the session limits relate to
+ * @error: return location for a #GError, or %NULL
+ *
+ * Deserialize a set of session limits previously serialized with
+ * mct_session_limits_serialize(). This function guarantees to be able to
+ * deserialize any serialized form from this version or older versions of
+ * libmalcontent.
+ *
+ * If deserialization fails, %MCT_MANAGER_ERROR_INVALID_DATA will be returned.
+ *
+ * Returns: (transfer full): deserialized session limits
+ * Since: 0.7.0
+ */
+MctSessionLimits *
+mct_session_limits_deserialize (GVariant  *variant,
+                                uid_t      user_id,
+                                GError   **error)
+{
+  g_autoptr(MctSessionLimits) session_limits = NULL;
+  guint32 limit_type;
+  guint32 daily_start_time, daily_end_time;
+
+  g_return_val_if_fail (variant != NULL, NULL);
+  g_return_val_if_fail (error == NULL || *error == NULL, NULL);
+
+  /* Check the overall type. */
+  if (!g_variant_is_of_type (variant, G_VARIANT_TYPE ("a{sv}")))
+    {
+      g_set_error (error, MCT_MANAGER_ERROR,
+                   MCT_MANAGER_ERROR_INVALID_DATA,
+                   _("Session limit for user %u was in an unrecognized format"),
+                   (guint) user_id);
+      return NULL;
+    }
+
+  /* Extract the properties we care about. The default values here should be
+   * kept in sync with those in the `com.endlessm.ParentalControls.SessionLimits`
+   * D-Bus interface. */
+  if (!g_variant_lookup (variant, "LimitType", "u",
+                         &limit_type))
+    {
+      /* Default value. */
+      limit_type = MCT_SESSION_LIMITS_TYPE_NONE;
+    }
+
+  /* Check that the limit type is something we support. */
+  G_STATIC_ASSERT (sizeof (limit_type) >= sizeof (MctSessionLimitsType));
+
+  if ((guint) limit_type > MCT_SESSION_LIMITS_TYPE_DAILY_SCHEDULE)
+    {
+      g_set_error (error, MCT_MANAGER_ERROR,
+                   MCT_MANAGER_ERROR_INVALID_DATA,
+                   _("Session limit for user %u has an unrecognized type ‘%u’"),
+                   (guint) user_id, limit_type);
+      return NULL;
+    }
+
+  if (!g_variant_lookup (variant, "DailySchedule", "(uu)",
+                         &daily_start_time, &daily_end_time))
+    {
+      /* Default value. */
+      daily_start_time = 0;
+      daily_end_time = 24 * 60 * 60;
+    }
+
+  if (daily_start_time >= daily_end_time ||
+      daily_end_time > 24 * 60 * 60)
+    {
+      g_set_error (error, MCT_MANAGER_ERROR,
+                   MCT_MANAGER_ERROR_INVALID_DATA,
+                   _("Session limit for user %u has invalid daily schedule %u–%u"),
+                   (guint) user_id, daily_start_time, daily_end_time);
+      return NULL;
+    }
+
+  /* Success. Create an #MctSessionLimits object to contain the results. */
+  session_limits = g_new0 (MctSessionLimits, 1);
+  session_limits->ref_count = 1;
+  session_limits->user_id = user_id;
+  session_limits->limit_type = limit_type;
+  session_limits->daily_start_time = daily_start_time;
+  session_limits->daily_end_time = daily_end_time;
+
+  return g_steal_pointer (&session_limits);
+}
+
 /*
  * Actual implementation of #MctSessionLimitsBuilder.
  *

libmalcontent/session-limits.h

@@ -57,6 +57,11 @@ gboolean mct_session_limits_check_time_remaining (MctSessionLimits *limits,
                                                   guint64          *time_remaining_secs_out,
                                                   gboolean         *time_limit_enabled_out);
 
+GVariant         *mct_session_limits_serialize   (MctSessionLimits  *limits);
+MctSessionLimits *mct_session_limits_deserialize (GVariant          *variant,
+                                                  uid_t              user_id,
+                                                  GError           **error);
+
 /**
  * MctSessionLimitsBuilder:
  *

libmalcontent/tests/session-limits.c

@@ -92,6 +92,84 @@ test_session_limits_check_time_remaining_invalid_time (void)
   g_assert_true (time_limit_enabled);
 }
 
+/* Basic test of mct_session_limits_serialize() on session limits. */
+static void
+test_session_limits_serialize (void)
+{
+  g_auto(MctSessionLimitsBuilder) builder = MCT_SESSION_LIMITS_BUILDER_INIT ();
+  g_autoptr(MctSessionLimits) limits = NULL;
+  g_autoptr(GVariant) serialized = NULL;
+
+  /* Use an empty #MctSessionLimits. */
+  limits = mct_session_limits_builder_end (&builder);
+
+  /* We can’t assert anything about the serialisation format, since it’s opaque. */
+  serialized = mct_session_limits_serialize (limits);
+  g_assert_nonnull (serialized);
+}
+
+/* Basic test of mct_session_limits_deserialize() on various current and historic
+ * serialised app filter variants. */
+static void
+test_session_limits_deserialize (void)
+{
+  /* These are all opaque. Older versions should be kept around to test
+   * backwards compatibility. */
+  const gchar *valid_session_limits[] =
+    {
+      "@a{sv} {}",
+      "{ 'LimitType': <@u 0> }",
+      "{ 'LimitType': <@u 1>, 'DailySchedule': <(@u 0, @u 100)> }",
+      "{ 'DailySchedule': <(@u 0, @u 100)> }",
+    };
+
+  for (gsize i = 0; i < G_N_ELEMENTS (valid_session_limits); i++)
+    {
+      g_autoptr(GVariant) serialized = NULL;
+      g_autoptr(MctSessionLimits) limits = NULL;
+      g_autoptr(GError) local_error = NULL;
+
+      g_test_message ("%" G_GSIZE_FORMAT ": %s", i, valid_session_limits[i]);
+
+      serialized = g_variant_parse (NULL, valid_session_limits[i], NULL, NULL, NULL);
+      g_assert (serialized != NULL);
+
+      limits = mct_session_limits_deserialize (serialized, 1, &local_error);
+      g_assert_no_error (local_error);
+      g_assert_nonnull (limits);
+    }
+}
+
+/* Test of mct_session_limits_deserialize() on various invalid variants. */
+static void
+test_session_limits_deserialize_invalid (void)
+{
+  const gchar *invalid_session_limits[] =
+    {
+      "false",
+      "()",
+      "{ 'LimitType': <@u 100> }",
+      "{ 'DailySchedule': <(@u 100, @u 0)> }",
+      "{ 'DailySchedule': <(@u 0, @u 4294967295)> }",
+    };
+
+  for (gsize i = 0; i < G_N_ELEMENTS (invalid_session_limits); i++)
+    {
+      g_autoptr(GVariant) serialized = NULL;
+      g_autoptr(MctSessionLimits) limits = NULL;
+      g_autoptr(GError) local_error = NULL;
+
+      g_test_message ("%" G_GSIZE_FORMAT ": %s", i, invalid_session_limits[i]);
+
+      serialized = g_variant_parse (NULL, invalid_session_limits[i], NULL, NULL, NULL);
+      g_assert (serialized != NULL);
+
+      limits = mct_session_limits_deserialize (serialized, 1, &local_error);
+      g_assert_error (local_error, MCT_MANAGER_ERROR, MCT_MANAGER_ERROR_INVALID_DATA);
+      g_assert_null (limits);
+    }
+}
+
 /* Fixture for tests which use an #MctSessionLimitsBuilder. The builder can
  * either be heap- or stack-allocated. @builder will always be a valid pointer
  * to it.
@@ -1130,6 +1208,10 @@ main (int    argc,
   g_test_add_func ("/session-limits/check-time-remaining/invalid-time",
                    test_session_limits_check_time_remaining_invalid_time);
 
+  g_test_add_func ("/session-limits/serialize", test_session_limits_serialize);
+  g_test_add_func ("/session-limits/deserialize", test_session_limits_deserialize);
+  g_test_add_func ("/session-limits/deserialize/invalid", test_session_limits_deserialize_invalid);
+
   g_test_add ("/session-limits/builder/stack/non-empty", BuilderFixture, NULL,
               builder_set_up_stack, test_session_limits_builder_non_empty,
               builder_tear_down_stack);