Function ParseSumFile

fs/operations/check.go:572–626

ParseSumFile parses a hash SUM file and returns hashes as a map

(ctx context.Context, sumFile fs.Object)

// ParseSumFile parses a hash SUM file and returns hashes as a map
func ParseSumFile(ctx context.Context, sumFile fs.Object) (HashSums, error) {
	rd, err := Open(ctx, sumFile)
	if err != nil {
		return nil, err
	}
	parser := bufio.NewReader(rd)

	const maxWarn = 3
	numWarn := 0

	re := regexp.MustCompile(`^([^ ]+) [ *](.+)$`)
	hashes := HashSums{}
	for lineNo := 0; true; lineNo++ {
		lineBytes, _, err := parser.ReadLine()
		if err == io.EOF {
			break
		}
		if err != nil {
			return nil, err
		}
		line := string(lineBytes)
		if line == "" {
			continue
		}

		fields := re.FindStringSubmatch(ApplyTransforms(ctx, line))
		if fields == nil {
			numWarn++
			if numWarn <= maxWarn {
				fs.Logf(sumFile, "improperly formatted checksum line %d", lineNo)
			}
			continue
		}

		sum, file := fields[1], fields[2]
		if hashes[file] != "" {
			numWarn++
			if numWarn <= maxWarn {
				fs.Logf(sumFile, "duplicate file on checksum line %d", lineNo)
			}
			continue
		}

		// We've standardised on lower case checksums in rclone internals.
		hashes[file] = strings.ToLower(sum)
	}

	if numWarn > maxWarn {
		fs.Logf(sumFile, "%d warning(s) suppressed...", numWarn-maxWarn)
	}
	if err = rd.Close(); err != nil {
		return nil, err
	}
	return hashes, nil
}