protected function getFileFunctions($filePath)
    {
        $source = file_get_contents($filePath);
        $tokens = token_get_all($source);

        $functions = [];
        $nextStringIsFunc = false;
        foreach($tokens as $token) {
            switch($token[0]) {
                case T_FUNCTION:
                    $nextStringIsFunc = true;
                    break;

                case T_STRING:
                    if ($nextStringIsFunc) {
                        $nextStringIsFunc = false;
                        $functions[] = $token[1];
                    }
                    break;
            }
        }

        return $functions;
    }