--- /dev/null
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\DependencyInjection\Extension;
+
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+use Symfony\Component\Config\Definition\ConfigurationInterface;
+
+/**
+ * ConfigurationExtensionInterface is the interface implemented by container extension classes.
+ *
+ * @author Kevin Bond <kevinbond@gmail.com>
+ */
+interface ConfigurationExtensionInterface
+{
+ /**
+ * Returns extension configuration.
+ *
+ * @param array $config An array of configuration values
+ * @param ContainerBuilder $container A ContainerBuilder instance
+ *
+ * @return ConfigurationInterface|null The configuration or null
+ */
+ public function getConfiguration(array $config, ContainerBuilder $container);
+}