请求高手进来解答，在线等

PHP code

class Smarty_Internal_Write_File {
    /**
     * Writes file in a save way to disk
     * 
     * @param string $_filepath complete filepath
     * @param string $_contents file content
     * @return boolean true
     */
    public static function writeFile($_filepath, $_contents, $smarty)
    {
        $old_umask = umask(0);
        $_dirpath = dirname($_filepath); 
        // if subdirs, create dir structure
        if ($_dirpath !== '.' && !file_exists($_dirpath)) {
            mkdir($_dirpath, $smarty->_dir_perms, true);
        } 
        // write to tmp file, then move to overt file lock race condition
        $_tmp_file = tempnam($_dirpath, 'wrt');

        if (!($fd = @fopen($_tmp_file, 'wb'))) {
            $_tmp_file = $_dirpath . DS . uniqid('wrt');
            if (!($fd = @fopen($_tmp_file, 'wb'))) {
            throw new SmartyException("unable to write file {$_tmp_file}");
            return false;
            }
            }

        fwrite($fd, $_contents);
        fclose($fd);

        // remove original file
        if (file_exists($_filepath))
            @unlink($_filepath); 
        // rename tmp file
        rename($_tmp_file, $_filepath); 
        // set file permissions
        chmod($_filepath, $smarty->_file_perms);
        umask($old_umask);
        return true;
    } 
} 

详细点翻译下这段代码是什么意思，紧急用，在线等

------解决方案--------------------
class Smarty_Internal_Write_File {
/**
* Writes file in a save way to disk
* 
* @param string $_filepath complete filepath
* @param string $_contents file content
* @return boolean true
*/
public static function writeFile($_filepath, $_contents, $smarty)
{
$old_umask = umask(0);
$_dirpath = dirname($_filepath); //$_filepath的路径
// if subdirs, create dir structure
if ($_dirpath !== '.' && !file_exists($_dirpath)) {//路径（文件夹）不存在
mkdir($_dirpath, $smarty->_dir_perms, true);//创建
} 
// write to tmp file, then move to overt file lock race condition
$_tmp_file = tempnam($_dirpath, 'wrt');//tempnam应该是转换路径到配置的模板转换保存目录，就是smarty模板文件转换成php代码文件的文件存放的位置

if (!($fd = @fopen($_tmp_file, 'wb'))) {//检查目录是否可以操作
$_tmp_file = $_dirpath . DS . uniqid('wrt');//转换文件名
if (!($fd = @fopen($_tmp_file, 'wb'))) {
throw new SmartyException("unable to write file {$_tmp_file}");
return false;
}
}

fwrite($fd, $_contents);//写转换后的内容，就是把smarty代码转换成php代码，
fclose($fd);

// remove original file
if (file_exists($_filepath))
@unlink($_filepath); 
// rename tmp file
rename($_tmp_file, $_filepath); 
// set file permissions
chmod($_filepath, $smarty->_file_perms);
umask($old_umask);
return true;
} 
}