Twig update to latest Twig 1.x legacy as per vichan

inc/lib/Twig/BaseNodeVisitor.php

@@ -0,0 +1,54 @@
+<?php
+
+/*
+ * This file is part of Twig.
+ *
+ * (c) Fabien Potencier
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+/**
+ * Twig_BaseNodeVisitor can be used to make node visitors compatible with Twig 1.x and 2.x.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+abstract class Twig_BaseNodeVisitor implements Twig_NodeVisitorInterface
+{
+    final public function enterNode(Twig_NodeInterface $node, Twig_Environment $env)
+    {
+        if (!$node instanceof Twig_Node) {
+            throw new LogicException('Twig_BaseNodeVisitor only supports Twig_Node instances.');
+        }
+
+        return $this->doEnterNode($node, $env);
+    }
+
+    final public function leaveNode(Twig_NodeInterface $node, Twig_Environment $env)
+    {
+        if (!$node instanceof Twig_Node) {
+            throw new LogicException('Twig_BaseNodeVisitor only supports Twig_Node instances.');
+        }
+
+        return $this->doLeaveNode($node, $env);
+    }
+
+    /**
+     * Called before child nodes are visited.
+     *
+     * @return Twig_Node The modified node
+     */
+    abstract protected function doEnterNode(Twig_Node $node, Twig_Environment $env);
+
+    /**
+     * Called after child nodes are visited.
+     *
+     * @return Twig_Node|false The modified node or false if the node must be removed
+     */
+    abstract protected function doLeaveNode(Twig_Node $node, Twig_Environment $env);
+}
+
+class_alias('Twig_BaseNodeVisitor', 'Twig\NodeVisitor\AbstractNodeVisitor', false);
+class_exists('Twig_Environment');
+class_exists('Twig_Node');