protected function retrieveAllFiles(array $paths)
    {
        $files = [];

        foreach ($paths as $path) {
            $newFiles = [];

            try {
                $newFiles = $this->retrieveFiles($path);
            } catch (FileSystemException $e) {
                continue;
            } finally {
                $files = array_merge($files, $newFiles);
            }
        }

        return $files;
    }