<?php
// +----------------------------------------------------------------------
// | ThinkCache
// +----------------------------------------------------------------------
// | Copyright (c) 2006-2012 http://thinkphp.cn All rights reserved.
// +----------------------------------------------------------------------
// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
// +----------------------------------------------------------------------
// | Author: liu21st <liu21st@gmail.com>
// +----------------------------------------------------------------------
namespace Think\Cache\Driver;
/**
 * Memcache缓存驱动
 * @author    liu21st <liu21st@gmail.com>
 */
class Memcache {
    protected $handler  =   null;
    protected $options  =   array(
        'host'        =>  '127.0.0.1',
        'port'        =>  11211,
        'expire'        =>  0,
        'timeout'     =>  false,
        'persistent'  =>  false,
        'length'        =>  0,
    );

    /**
     * 架构函数
     * @param array $options 缓存参数
     * @access public
     */
    public function __construct($options=[]) {
        if ( !extension_loaded('memcache') ) {
            E('_NOT_SUPPERT_:memcache');
        }
        if(!empty($options)) {
            $this->options      =   array_merge($this->options,$options);
        }
        $func               =   $this->options['persistent'] ? 'pconnect' : 'connect';
        $this->handler      =   new \Memcache;
        $options['timeout'] === false ?
            $this->handler->$func($options['host'], $options['port']) :
            $this->handler->$func($options['host'], $options['port'], $options['timeout']);
    }

    /**
     * 读取缓存
     * @access public
     * @param string $name 缓存变量名
     * @return mixed
     */
    public function get($name) {
        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 $expire  有效时间（秒）
     * @return boolen
     */
    public function set($name, $value, $expire = null) {
        if(is_null($expire)) {
            $expire  =  $this->options['expire'];
        }
        $name   =   $this->options['prefix'].$name;
        if($this->handler->set($name, $value, 0, $expire)) {
            if($this->options['length']>0) {
                // 记录缓存队列
                $queue  =   $this->handler->get('__info__');
                if(!$queue) {
                    $queue  =   [];
                }
                if(false===array_search($name, $queue))  array_push($queue,$name);
                if(count($queue) > $this->options['length']) {
                    // 出列
                    $key =  array_shift($queue);
                    // 删除缓存
                    $this->handler->delete($key);
                }
                $this->handler->set('__info__', $queue);
            }
            return true;
        }
        return false;
    }

    /**
     * 删除缓存
     * @access public
     * @param string $name 缓存变量名
     * @return boolen
     */
    public function rm($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 boolen
     */
    public function clear() {
        return $this->handler->flush();
    }
}