C:/xampp/htdocs/moodle/lib/memcached.class.php

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<?php

// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

defined('MOODLE_INTERNAL') || die();

class memcached {

    function memcached() {
        global $CFG;

        if (!function_exists('memcache_connect')) {
            debugging("Memcached is set to true but the memcached extension is not installed");
            return false;
        }
        $this->_cache = new Memcache;

        $hosts = explode(',', $CFG->memcachedhosts);
        if (count($hosts) === 1 && !empty($CFG->memcachedpconn)) {
            // the faster pconnect is only available
            // for single-server setups
            // NOTE: PHP-PECL client is buggy and pconnect()
            // will segfault if the server is unavailable
            $this->_cache->pconnect($hosts[0]);
        } else {
            // multi-host setup will share key space
            foreach ($hosts as $host) {
                $host = trim($host);
                $this->_cache->addServer($host);
            }
        }

        $this->prefix = $CFG->dbname .'|' . $CFG->prefix . '|';
    }

    function status() {
        if (is_object($this->_cache)) {
            return true;
        }
        return false;
    }

    function set($key, $value, $ttl=0) {

        // we may have acquired a lock via getforfill
        // release if it exists
        @$this->_cache->delete($this->prefix . $key . '_forfill');

        return $this->_cache->set($this->prefix . $key, $value, false);
    }

    function get($key) {
        $rec = $this->_cache->get($this->prefix . $key);
        return $rec;
    }

    function delete($key) {
        return $this->_cache->delete($this->prefix . $key);
    }

    function getforfill ($key) {

        $rec = $this->_cache->get($this->prefix . $key);
        if ($rec) {
            return $rec;
        }
        if ($this->_cache->add($this->prefix . $key . '_forfill', 'true', false, 1)) {
            // we obtained the _forfill lock
            // our caller will compute and set the value
            return false;
        }
        // someone else has the lock
        // "block" till we can get the value
        // actually, loop .05s waiting for it
        for ($n=0;$n<5;$n++) {
            usleep(10000);
            $rec = $this->_cache->get($this->prefix . $key);
            if ($rec) {
                return $rec;
            }
        }
        return false;
    }

    function releaseforfill ($key) {
        return $this->_cache->delete($this->prefix . $key . '_forfill');
    }
}