php-openid中创建多级目录的方法

 

在看php-openid的源码的时候，发现它实现的创建多级目录的方法的思想很巧妙，特将起代码记录下来：

 

/**
    * Create dir_name as a directory if it does not exist. If it
    * exists, make sure that it is, in fact, a directory.  Returns
    * true if the operation succeeded; false if not.
    *
    * @access private
    */
   static  function  ensureDir( $dir_name )
   {
       if  ( is_dir ( $dir_name ) || @ mkdir ( $dir_name )) {
           return  true;
       }  else  {
           $parent_dir  = dirname( $dir_name );

           // Terminal case; there is no parent directory to create.
           if  ( $parent_dir  ==  $dir_name ) {
               return  true;
           }

           return  (Auth_OpenID::ensureDir( $parent_dir ) && @ mkdir ( $dir_name ));
       }
   }