object-manager: add _get_n_objects() method

lib/wp/object-manager.c

@@ -280,6 +280,19 @@ wp_object_manager_add_interest (WpObjectManager *self,
   i->constraints = constraints ? g_variant_ref_sink (constraints) : NULL;
 }
 
+/**
+ * wp_object_manager_get_n_objects:
+ * @self: the object manager
+ *
+ * Returns: the number of objects managed by this #WpObjectManager
+ */
+guint
+wp_object_manager_get_n_objects (WpObjectManager * self)
+{
+  g_return_val_if_fail (WP_IS_OBJECT_MANAGER (self), 0);
+  return self->objects->len;
+}
+
 /**
  * wp_object_manager_get_objects:
  * @self: the object manager

lib/wp/object-manager.h

@@ -47,6 +47,9 @@ WP_API
 void wp_object_manager_add_interest (WpObjectManager *self,
     GType gtype, GVariant * constraints, WpProxyFeatures wanted_features);
 
+WP_API
+guint wp_object_manager_get_n_objects (WpObjectManager * self);
+
 WP_API
 GPtrArray * wp_object_manager_get_objects (WpObjectManager *self,
     GType type_filter);