public function isRoot()
 {
     // FIXME (CSH) Implement for windows ...
     if (Io::systemIsWindows()) {
         return false;
     }
     return '/' === $this->m_path;
 }
 private function accessFlagsForMask($mask_)
 {
     if (null !== $this->m_accessFlags) {
         return $this->m_accessFlags;
     }
     $flag = Io::systemIsWindows() ? 'b' : '';
     if (0 < ($mask_ & self::TRUNCATE)) {
         return $this->m_accessFlags = "{$flag}w+";
     }
     if (0 < ($mask_ & self::APPEND)) {
         return $this->m_accessFlags = "{$flag}a+";
     }
     if (0 < ($mask_ & self::CREATE)) {
         return $this->m_accessFlags = "{$flag}c+";
     }
     if (0 < ($mask_ & self::WRITE)) {
         return $this->m_accessFlags = "{$flag}r+";
     }
     return $this->m_accessFlags = "{$flag}r";
 }