Moved cache drivers outside core to extensions (plugins)

plugins/cache-redis/Predis/Collection/Iterator/ListKey.php

@@ -0,0 +1,176 @@
+<?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\Collection\Iterator;
+
+use Predis\ClientInterface;
+use Predis\NotSupportedException;
+
+/**
+ * Abstracts the iteration of items stored in a list by leveraging the LRANGE
+ * command wrapped in a fully-rewindable PHP iterator.
+ *
+ * This iterator tries to emulate the behaviour of cursor-based iterators based
+ * on the SCAN-family of commands introduced in Redis <= 2.8, meaning that due
+ * to its incremental nature with multiple fetches it can only offer limited
+ * guarantees on the returned elements because the collection can change several
+ * times (trimmed, deleted, overwritten) during the iteration process.
+ *
+ * @author Daniele Alessandri <suppakilla@gmail.com>
+ *
+ * @link http://redis.io/commands/lrange
+ */
+class ListKey implements \Iterator
+{
+    protected $client;
+    protected $count;
+    protected $key;
+
+    protected $valid;
+    protected $fetchmore;
+    protected $elements;
+    protected $position;
+    protected $current;
+
+    /**
+     * @param ClientInterface $client Client connected to Redis.
+     * @param string          $key    Redis list key.
+     * @param int             $count  Number of items retrieved on each fetch operation.
+     *
+     * @throws \InvalidArgumentException
+     */
+    public function __construct(ClientInterface $client, $key, $count = 10)
+    {
+        $this->requiredCommand($client, 'LRANGE');
+
+        if ((false === $count = filter_var($count, FILTER_VALIDATE_INT)) || $count < 0) {
+            throw new \InvalidArgumentException('The $count argument must be a positive integer.');
+        }
+
+        $this->client = $client;
+        $this->key = $key;
+        $this->count = $count;
+
+        $this->reset();
+    }
+
+    /**
+     * Ensures that the client instance supports the specified Redis command
+     * required to fetch elements from the server to perform the iteration.
+     *
+     * @param ClientInterface $client    Client connected to Redis.
+     * @param string          $commandID Command ID.
+     *
+     * @throws NotSupportedException
+     */
+    protected function requiredCommand(ClientInterface $client, $commandID)
+    {
+        if (!$client->getProfile()->supportsCommand($commandID)) {
+            throw new NotSupportedException("The current profile does not support '$commandID'.");
+        }
+    }
+
+    /**
+     * Resets the inner state of the iterator.
+     */
+    protected function reset()
+    {
+        $this->valid = true;
+        $this->fetchmore = true;
+        $this->elements = array();
+        $this->position = -1;
+        $this->current = null;
+    }
+
+    /**
+     * Fetches a new set of elements from the remote collection, effectively
+     * advancing the iteration process.
+     *
+     * @return array
+     */
+    protected function executeCommand()
+    {
+        return $this->client->lrange($this->key, $this->position + 1, $this->position + $this->count);
+    }
+
+    /**
+     * Populates the local buffer of elements fetched from the server during the
+     * iteration.
+     */
+    protected function fetch()
+    {
+        $elements = $this->executeCommand();
+
+        if (count($elements) < $this->count) {
+            $this->fetchmore = false;
+        }
+
+        $this->elements = $elements;
+    }
+
+    /**
+     * Extracts next values for key() and current().
+     */
+    protected function extractNext()
+    {
+        ++$this->position;
+        $this->current = array_shift($this->elements);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function rewind()
+    {
+        $this->reset();
+        $this->next();
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function current()
+    {
+        return $this->current;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function key()
+    {
+        return $this->position;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function next()
+    {
+        if (!$this->elements && $this->fetchmore) {
+            $this->fetch();
+        }
+
+        if ($this->elements) {
+            $this->extractNext();
+        } else {
+            $this->valid = false;
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function valid()
+    {
+        return $this->valid;
+    }
+}