PHP-权限控制类(转)

<?php
/**
* 权限控制类
*/  

class include_purview
{
    /**
      * 类的唯一实例
      */
    private static $instance;   

    /**
      * 权限常量
      */
    const SELECT = 0x1; //查询
    const CREATE = 0x2; //添加
    const EDIT    = 0x4; //修改
    const DELETE = 0x8; //删除   

    /**
      * 角色
      */
    private $annoy = ''; //匿名用户
    private $user   = ''; //注册用户
    private $admin = ''; //管理用户
    private $usertype = 'annoy';
    private $hashtable = array(1=>'查询',2=>'添加',4=>'修改',8=>'删除');   

    /**
      *
      */
    public function __set($name,$value)
     {
        if ($name == 'usertype')
         {
            if ($value != '')
             {
                $this->usertype = $value;
             }
         }
     }   

    /**
      * 构造函数 给角色赋予权限
      */
    private function __construct()
     {
        $this->annoy = self::SELECT;
        $this->user = self::SELECT | self::CREATE;
        $this->admin = self::SELECT | self::CREATE | self::EDIT | self::DELETE;
     }   

    /**
      * 获取类的唯一实例
      */
    public static function getInstance()
     {
        if (self::$instance === null){
             self::$instance = new include_purview();
         }
        return self::$instance;
     }   

    /**
      * 检查权限
      *
      * @param $usertype 角色
      * @param $purview 权限
      */
    public function check($purview)
     {
        if ($this->{$this->usertype} & $purview)
         {
            return true;
         }
        return false;
     }   

    /**
      * 给角色加权限
      */
    public function addPur($purview)
     {
        $this->{$this->usertype} |= $purview;
     }   

    /**
      * 给角色减权限
      */
    public function delPur($purview)
     {
        $this->{$this->usertype} ^= $purview;
     }   

    /**
      * 返回角色拥有的权限
      */
    public function getPur()
     {
        $arr = array();
        foreach ($this->hashtable as $k => $v)
         {
            if ($k & $this->{$this->usertype})
             {
                $arr[] = $v;
             }
         }
        return $arr;
     }
}
调用示例
PHP代码
/**
* 示例
*/
//在session中读用户组
@session_start();
$_SESSION['role'] = 'user';   

//获取权限类的实例
$pruview = include_purview::getInstance();
//设置角色
$pruview->usertype = $_SESSION['role'];
//获取该角色拥有的权限
$arr = $pruview->getpur();
echo '该用户的权限有:'.join(',',$arr)."\n";
//判断执行的操作是否有权限
if (true === $pruview->check(include_purview::CREATE ))
{
     create(); //要执行的操作
}
else
{
    exit('您没有权限!');
}
//去掉用户的添加权限
$pruview->delPur(include_purview::CREATE );
$arr = $pruview->getpur();
echo '该用户的权限有:'.join(',',$arr)."\n";
//执行添加操作
if (true === $pruview->check(include_purview::CREATE ))
{
     create(); //要执行的操作
}
else
{
    echo '您没有权限!'."\n";
}
//加上用户的添加权限
$pruview->addPur(include_purview::CREATE );
$arr = $pruview->getpur();
echo '该用户的权限有:'.join(',',$arr)."\n";
//执行添加操作
if (true === $pruview->check(include_purview::CREATE ))
{
     create(); //要执行的操作
}
else
{
    exit('您没有权限!');
}   

//具体的操作
function create()
{
    echo '执行了添加操作'."\n";
}