Update to drupal 8.0.0-rc1. For more information, see https://www.drupal.org/node/2582663

vendor/symfony-cmf/routing/Enhancer/FieldMapEnhancer.php

@@ -0,0 +1,70 @@
+<?php
+
+/*
+ * This file is part of the Symfony CMF package.
+ *
+ * (c) 2011-2014 Symfony CMF
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Cmf\Component\Routing\Enhancer;
+
+use Symfony\Component\HttpFoundation\Request;
+
+/**
+ * This enhancer can fill one field with the result of a hashmap lookup of
+ * another field. If the target field is already set, it does nothing.
+ *
+ * @author David Buchmann
+ */
+class FieldMapEnhancer implements RouteEnhancerInterface
+{
+    /**
+     * @var string field for key in hashmap lookup
+     */
+    protected $source;
+    /**
+     * @var string field to write hashmap lookup result into
+     */
+    protected $target;
+    /**
+     * @var array containing the mapping between the source field value and target field value
+     */
+    protected $hashmap;
+
+    /**
+     * @param string $source  the field to read
+     * @param string $target  the field to write the result of the lookup into
+     * @param array  $hashmap for looking up value from source and get value for target
+     */
+    public function __construct($source, $target, array $hashmap)
+    {
+        $this->source = $source;
+        $this->target = $target;
+        $this->hashmap = $hashmap;
+    }
+
+    /**
+     * If the target field is not set but the source field is, map the field
+     *
+     * {@inheritDoc}
+     */
+    public function enhance(array $defaults, Request $request)
+    {
+        if (isset($defaults[$this->target])) {
+            return $defaults;
+        }
+        if (! isset($defaults[$this->source])) {
+            return $defaults;
+        }
+        if (! isset($this->hashmap[$defaults[$this->source]])) {
+            return $defaults;
+        }
+
+        $defaults[$this->target] = $this->hashmap[$defaults[$this->source]];
+
+        return $defaults;
+    }
+}