owncloud/core

<?php
/**
 * @author Joas Schilling <coding@schilljs.com>
 * @author Jörn Friedrich Dreyer <jfd@butonic.de>
 * @author Morris Jobke <hey@morrisjobke.de>
 * @author Robin Appelman <icewind@owncloud.com>
 * @author Stefan Weil <sw@weilnetz.de>
 *
 * @copyright Copyright (c) 2018, ownCloud GmbH
 * @license AGPL-3.0
 *
 * This code is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License, version 3,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License, version 3,
 * along with this program.  If not, see <http://www.gnu.org/licenses/>
 *
 */

namespace OC\Memcache;

use OCP\IMemcacheTTL;

class Redis extends Cache implements IMemcacheTTL {
    /** @var \Redis | \RedisCluster $cache */
    private static $cache = null;

    public function __construct($prefix = '') {
        parent::__construct($prefix);
        if (self::$cache === null) {
            self::$cache = \OC::$server->getGetRedisFactory()->getInstance();
        }
    }

    /**
     * entries in redis get namespaced to prevent collisions between ownCloud instances and users
     */
    protected function getNameSpace() {
        return $this->prefix;
    }

    public function get($key) {
        $result = self::$cache->get($this->getNameSpace() . $key);
        if ($result === false && !self::$cache->exists($this->getNameSpace() . $key)) {
            return null;
        } else {
            return \json_decode($result, true);
        }
    }

    public function set($key, $value, $ttl = 0) {
        if ($ttl > 0) {
            return self::$cache->setex($this->getNameSpace() . $key, $ttl, \json_encode($value));
        } else {
            return self::$cache->set($this->getNameSpace() . $key, \json_encode($value));
        }
    }

    public function hasKey($key) {
        return self::$cache->exists($this->getNameSpace() . $key);
    }

    public function remove($key) {
        if (self::$cache->del($this->getNameSpace() . $key)) {
            return true;
        } else {
            return false;
        }
    }

    public function clear($prefix = '') {
        $prefix = $this->getNameSpace() . $prefix . '*';
        $it = null;
        self::$cache->setOption(\Redis::OPT_SCAN, \Redis::SCAN_RETRY);
        while ($keys = self::$cache->scan($it, $prefix)) {
            self::$cache->del($keys);
        }
        return true;
    }

    /**
     * Set a value in the cache if it's not already stored
     *
     * @param string $key
     * @param mixed $value
     * @param int $ttl Time To Live in seconds. Defaults to 60*60*24
     * @return bool
     */
    public function add($key, $value, $ttl = 0) {
        // don't encode ints for inc/dec
        if (!\is_int($value)) {
            $value = \json_encode($value);
        }
        return self::$cache->setnx($this->getPrefix() . $key, $value);
    }

    /**
     * Increase a stored number
     *
     * @param string $key
     * @param int $step
     * @return int | bool
     */
    public function inc($key, $step = 1) {
        return self::$cache->incrBy($this->getNameSpace() . $key, $step);
    }

    /**
     * Decrease a stored number
     *
     * @param string $key
     * @param int $step
     * @return int | bool
     */
    public function dec($key, $step = 1) {
        if (!$this->hasKey($key)) {
            return false;
        }
        return self::$cache->decrBy($this->getNameSpace() . $key, $step);
    }

    /**
     * Compare and set
     *
     * @param string $key
     * @param mixed $old
     * @param mixed $new
     * @return bool
     */
    public function cas($key, $old, $new) {
        if (!\is_int($new)) {
            $new = \json_encode($new);
        }
        self::$cache->watch($this->getNameSpace() . $key);
        if ($this->get($key) === $old) {
            /** @phan-suppress-next-line PhanNonClassMethodCall */
            $result = self::$cache->multi()
                ->set($this->getNameSpace() . $key, $new)
                ->exec();
            return ($result === false) ? false : true;
        }
        self::$cache->unwatch();
        return false;
    }

    /**
     * Compare and delete
     *
     * @param string $key
     * @param mixed $old
     * @return bool
     */
    public function cad($key, $old) {
        self::$cache->watch($this->getNameSpace() . $key);
        if ($this->get($key) === $old) {
            /** @phan-suppress-next-line PhanNonClassMethodCall */
            $result = self::$cache->multi()
                ->del($this->getNameSpace() . $key)
                ->exec();
            return ($result === false) ? false : true;
        }
        self::$cache->unwatch();
        return false;
    }

    public function setTTL($key, $ttl) {
        self::$cache->expire($this->getNameSpace() . $key, $ttl);
    }

    public static function isAvailable() {
        return \OC::$server->getGetRedisFactory()->isAvailable();
    }
}