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";   
}