diff -r 000000000000 -r 7f95f8617b0b vendor/symfony/src/Symfony/Component/Config/Definition/Builder/TreeBuilder.php
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/vendor/symfony/src/Symfony/Component/Config/Definition/Builder/TreeBuilder.php	Sat Sep 24 15:40:41 2011 +0200
@@ -0,0 +1,62 @@
+<?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\Config\Definition\Builder;
+
+/**
+ * This is the entry class for building a config tree.
+ *
+ * @author Johannes M. Schmitt <schmittjoh@gmail.com>
+ */
+class TreeBuilder implements NodeParentInterface
+{
+    protected $tree;
+    protected $root;
+    protected $builder;
+
+    /**
+     * Creates the root node.
+     *
+     * @param string      $name     The name of the root node
+     * @param string      $type     The type of the root node
+     * @param NodeBuilder $builder  A custom node builder instance
+     *
+     * @return ArrayNodeDefinition|NodeDefinition The root node (as an ArrayNodeDefinition when the type is 'array')
+     *
+     * @throws \RuntimeException When the node type is not supported
+     */
+    public function root($name, $type = 'array', NodeBuilder $builder = null)
+    {
+        $builder = null === $builder ? new NodeBuilder() : $builder;
+
+        $this->root = $builder->node($name, $type);
+        $this->root->setParent($this);
+
+        return $this->root;
+    }
+
+    /**
+     * Builds the tree.
+     *
+     * @return NodeInterface
+     */
+    public function buildTree()
+    {
+        if (null === $this->root) {
+            throw new \RuntimeException('The configuration tree has no root node.');
+        }
+        if (null !== $this->tree) {
+            return $this->tree;
+        }
+
+        return $this->tree = $this->root->getNode(true);
+    }
+}