protected function _getSortFields()
    {
        $sortFields = [];

        foreach ($this->controller->sortFields as $field => $options) {
            if (isset($options['actions']) &&
                is_array($options['actions']) &&
                in_array($this->action, $options['actions'])
            ) {
                $sortFields[$field] = $options;
            }
        }

        return $sortFields;
    }