protected function cacheFile($path, $cachefsPath)
    {
        if (array_key_exists($path, $this->cachedFiles)) {
            return;
        }

        if (file_exists($path)) {
            $contents = file_get_contents($path);
            file_put_contents($cachefsPath, $contents);

            $this->cachedFiles[$path] = $cachefsPath;
        }
    }