Moved cache drivers outside core to extensions (plugins)

plugins/cache-redis/Predis/Cluster/RedisStrategy.php

@@ -0,0 +1,58 @@
+<?php
+
+/*
+ * This file is part of the Predis package.
+ *
+ * (c) Daniele Alessandri <suppakilla@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Predis\Cluster;
+
+use Predis\Cluster\Hash\CRC16;
+use Predis\Cluster\Hash\HashGeneratorInterface;
+use Predis\NotSupportedException;
+
+/**
+ * Default class used by Predis to calculate hashes out of keys of
+ * commands supported by redis-cluster.
+ *
+ * @author Daniele Alessandri <suppakilla@gmail.com>
+ */
+class RedisStrategy extends ClusterStrategy
+{
+    protected $hashGenerator;
+
+    /**
+     * @param HashGeneratorInterface $hashGenerator Hash generator instance.
+     */
+    public function __construct(HashGeneratorInterface $hashGenerator = null)
+    {
+        parent::__construct();
+
+        $this->hashGenerator = $hashGenerator ?: new CRC16();
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getSlotByKey($key)
+    {
+        $key = $this->extractKeyTag($key);
+        $slot = $this->hashGenerator->hash($key) & 0x3FFF;
+
+        return $slot;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getDistributor()
+    {
+        throw new NotSupportedException(
+            'This cluster strategy does not provide an external distributor'
+        );
+    }
+}