private function isHeaderLine(string $line): bool
    {
        $matches = [];
        if (preg_match('#^diff --git [a|b|c|i|w|o]/(.*) [a|b|c|i|w|o]/(.*)#', $line, $matches)) {
            $this->appendCollectedFileAndChanges();
            $this->currentOperation = File::OP_MODIFIED;
            $this->currentFileName  = $matches[2];
            return true;
        }
        return false;
    }