public function rename(PhingFile $f1, PhingFile $f2)
    {
        // get the canonical paths of the file to rename
        $src = $f1->getAbsolutePath();
        $dest = $f2->getAbsolutePath();
        if (false === @rename($src, $dest)) {
            $msg = "Rename FAILED. Cannot rename $src to $dest. $php_errormsg";
            throw new IOException($msg);
        }
    }