text: <?php
  // +----------------------------------------------------------------------
  // | ThinkPHP [ WE CAN DO IT JUST THINK ]
  // +----------------------------------------------------------------------
  // | Copyright (c) 2006~2016 http://thinkphp.cn All rights reserved.
  // +----------------------------------------------------------------------
  // | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
  // +----------------------------------------------------------------------
  // | Author: liu21st <liu21st@gmail.com>
  // +----------------------------------------------------------------------
  
  namespace think\cache\driver;
  
  use think\cache\Driver;
  
  class Memcached extends Driver
  {
      protected $handler;
      protected $options = [
          'host'     => '127.0.0.1',
          'port'     => 11211,
          'expire'   => 0,
          'timeout'  => 0, // 超时时间（单位：毫秒）
          'prefix'   => '',
          'username' => '', //账号
          'password' => '', //密码
          'option'   => [],
      ];
  
      /**
       * 架构函数
       * @param array $options 缓存参数
       * @access public
       */
      public function __construct($options = [])
      {
          if (!extension_loaded('memcached')) {
              throw new \BadFunctionCallException('not support: memcached');
          }
          if (!empty($options)) {
              $this->options = array_merge($this->options, $options);
          }
          $this->handler = new \Memcached;
          if (!empty($this->options['option'])) {
              $this->handler->setOptions($this->options['option']);
          }
          // 设置连接超时时间（单位：毫秒）
          if ($this->options['timeout'] > 0) {
              $this->handler->setOption(\Memcached::OPT_CONNECT_TIMEOUT, $this->options['timeout']);
          }
          // 支持集群
          $hosts = explode(',', $this->options['host']);
          $ports = explode(',', $this->options['port']);
          if (empty($ports[0])) {
              $ports[0] = 11211;
          }
          // 建立连接
          $servers = [];
          foreach ((array) $hosts as $i => $host) {
              $servers[] = [$host, (isset($ports[$i]) ? $ports[$i] : $ports[0]), 1];
          }
          $this->handler->addServers($servers);
          if ('' != $this->options['username']) {
              $this->handler->setOption(\Memcached::OPT_BINARY_PROTOCOL, true);
              $this->handler->setSaslAuthData($this->options['username'], $this->options['password']);
          }
      }
  
      /**
       * 判断缓存
       * @access public
       * @param string $name 缓存变量名
       * @return bool
       */
      public function has($name)
      {
          $key = $this->getCacheKey($name);
          return $this->handler->get($key) ? true : false;
      }
  
      /**
       * 读取缓存
       * @access public
       * @param string $name 缓存变量名
       * @param mixed  $default 默认值
       * @return mixed
       */
      public function get($name, $default = false)
      {
          $result = $this->handler->get($this->getCacheKey($name));
          return false !== $result ? $result : $default;
      }
  
      /**
       * 写入缓存
       * @access public
       * @param string    $name 缓存变量名
       * @param mixed     $value  存储数据
       * @param integer   $expire  有效时间（秒）
       * @return bool
       */
      public function set($name, $value, $expire = null)
      {
          if (is_null($expire)) {
              $expire = $this->options['expire'];
          }
          if ($this->tag && !$this->has($name)) {
              $first = true;
          }
          $key    = $this->getCacheKey($name);
          $expire = 0 == $expire ? 0 : $_SERVER['REQUEST_TIME'] + $expire;
          if ($this->handler->set($key, $value, $expire)) {
              isset($first) && $this->setTagItem($key);
              return true;
          }
          return false;
      }
  
      /**
       * 自增缓存（针对数值缓存）
       * @access public
       * @param string    $name 缓存变量名
       * @param int       $step 步长
       * @return false|int
       */
      public function inc($name, $step = 1)
      {
          $key = $this->getCacheKey($name);
          return $this->handler->increment($key, $step);
      }
  
      /**
       * 自减缓存（针对数值缓存）
       * @access public
       * @param string    $name 缓存变量名
       * @param int       $step 步长
       * @return false|int
       */
      public function dec($name, $step = 1)
      {
          $key   = $this->getCacheKey($name);
          $value = $this->handler->get($key) - $step;
          $res   = $this->handler->set($key, $value);
          if (!$res) {
              return false;
          } else {
              return $value;
          }
      }
  
      /**
       * 删除缓存
       * @param    string  $name 缓存变量名
       * @param bool|false $ttl
       * @return bool
       */
      public function rm($name, $ttl = false)
      {
          $key = $this->getCacheKey($name);
          return false === $ttl ?
          $this->handler->delete($key) :
          $this->handler->delete($key, $ttl);
      }
  
      /**
       * 清除缓存
       * @access public
       * @param string $tag 标签名
       * @return bool
       */
      public function clear($tag = null)
      {
          if ($tag) {
              // 指定标签清除
              $keys = $this->getTagItem($tag);
              $this->handler->deleteMulti($keys);
              $this->rm('tag_' . md5($tag));
              return true;
          }
          return $this->handler->flush();
      }
  }
  