<?php
// +----------------------------------------------------------------------
// | ThinkPHP [ WE CAN DO IT JUST THINK IT ]
// +----------------------------------------------------------------------
// | Copyright (c) 2006-2013 http://thinkphp.cn All rights reserved.
// +----------------------------------------------------------------------
// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
// +----------------------------------------------------------------------
// | Author: 何辉 <runphp@qq.com>
// +----------------------------------------------------------------------
namespace Think\Cache\Driver;

use Memcached as MemcachedResource;
use Think\Cache;

/**
 * Memcached缓存驱动
 */
class Memcached extends Cache
{

    /**
     *
     * @param array $options            
     */
    public function __construct($options = array())
    {
        if (! extension_loaded('memcached')) {
            E(L('_NOT_SUPPORT_') . ':memcached');
        }
        $options = array_merge(array(
            'servers' => C('MEMCACHED_SERVER') ?  : null,
            'lib_options' => C('MEMCACHED_LIB') ?  : null
        ), $options);
        $this->options = $options;
        $this->options['expire'] = isset($options['expire']) ? $options['expire'] : C('DATA_CACHE_TIME');
        $this->options['prefix'] = isset($options['prefix']) ? $options['prefix'] : C('DATA_CACHE_PREFIX');
        $this->options['length'] = isset($options['length']) ? $options['length'] : 0;
        $this->handler = new MemcachedResource();
        $options['servers'] && $this->handler->addServers($options['servers']);
        $options['lib_options'] && $this->handler->setOptions($options['lib_options']);
    }

    /**
     * 读取缓存
     * 
     * @access public
     * @param string $name
     *            缓存变量名
     * @return mixed
     */
    public function get($name)
    {
        N('cache_read', 1);
        
        return $this->handler->get($this->options['prefix'] . $name);
    }

    /**
     * 写入缓存
     * 
     * @access public
     * @param string $name
     *            缓存变量名
     * @param mixed $value
     *            存储数据
     * @param integer $expire
     *            有效时间（秒）
     * @return boolean
     */
    public function set($name, $value, $expire = null)
    {
        N('cache_write', 1);
        if (is_null($expire)) {
            $expire = $this->options['expire'];
        }
        $name = $this->options['prefix'] . $name;
        if ($this->handler->set($name, $value, time() + $expire)) {
            if ($this->options['length'] > 0) {
                // 记录缓存队列
                $this->queue($name);
            }
            
            return true;
        }
        
        return false;
    }

    /**
     * 删除缓存
     * 
     * @access public
     * @param string $name
     *            缓存变量名
     * @return boolean
     */
    public function rm($name, $ttl = false)
    {
        $name = $this->options['prefix'] . $name;
        
        return $ttl === false ? $this->handler->delete($name) : $this->handler->delete($name, $ttl);
    }

    /**
     * 清除缓存
     * 
     * @access public
     * @return boolean
     */
    public function clear()
    {
        return $this->handler->flush();
    }
}