class File
{

    public static function read($path, $default = NULL)
    {
        $fp = @fopen($path, 'r');
        if( ! $fp)
            return $default;

        flock($fp, LOCK_SH);
        $data = fread($fp, filesize($path));
        flock($fp, LOCK_UN);
        fclose($fp);

        return $data;
    }


    public static function write($path, $data)
    {
        self::check(dirname($path));

        $fp = fopen($path, 'c');
        flock($fp, LOCK_EX);
        ftruncate($fp, 0);
        fwrite($fp, $data);
        fflush($fp);
        flock($fp, LOCK_UN);
        fclose($fp);

        return $data;
    }



    public static function check($dir)
    {
        if( ! is_dir($dir))
        {
            // https://en.wikipedia.org/wiki/Chmod#System_call
            @mkdir($dir, 06740, true);
            @chmod($dir, 06740);
        }
        return $dir;
    }
}