protected function process($xml)
    {
        if ($this->basedir) {
            $cwd = getcwd();
            chdir($this->basedir);
        }

        // Create and setup document.
        $xmlDom = new DomDocument();
        $xmlDom->resolveExternals = $this->resolveExternals;

        $xmlDom->loadXML($xml);

        $xmlDom->xinclude();

        if ($this->basedir) {
            chdir($cwd);
        }

        return $xmlDom->saveXML();
    }