func()

in oss/checkpoint.go [121:196]

• 58 lines of code
• 20 McCabe index (conditional complexity)

func (cp *downloadCheckpoint) valid() bool {
	// Compare the CP's Magic and the MD5
	contents, err := os.ReadFile(cp.CpFilePath)
	if err != nil {
		return false
	}

	dcp := downloadCheckpoint{}

	if err = json.Unmarshal(contents, &dcp.Info); err != nil {
		return false
	}

	js, _ := json.Marshal(dcp.Info.Data)
	sum := md5.Sum(js)
	md5sum := hex.EncodeToString(sum[:])

	if CheckpointMagic != dcp.Info.Magic ||
		md5sum != dcp.Info.MD5 {
		return false
	}

	// compare
	if !reflect.DeepEqual(cp.Info.Data.ObjectInfo, dcp.Info.Data.ObjectInfo) ||
		!reflect.DeepEqual(cp.Info.Data.ObjectMeta, dcp.Info.Data.ObjectMeta) ||
		cp.Info.Data.FilePath != dcp.Info.Data.FilePath ||
		cp.Info.Data.PartSize != dcp.Info.Data.PartSize {
		return false
	}

	// download info
	if dcp.Info.Data.DownloadInfo.Offset < 0 {
		return false
	}

	if dcp.Info.Data.DownloadInfo.Offset == 0 &&
		dcp.Info.Data.DownloadInfo.CRC64 != 0 {
		return false
	}

	rOffset := int64(0)
	if len(cp.Info.Data.ObjectInfo.Range) > 0 {
		if r, err := ParseRange(cp.Info.Data.ObjectInfo.Range); err != nil {
			return false
		} else {
			rOffset = r.Offset
		}
	}

	if dcp.Info.Data.DownloadInfo.Offset < rOffset {
		return false
	}

	remains := (dcp.Info.Data.DownloadInfo.Offset - rOffset) % dcp.Info.Data.PartSize
	if remains != 0 {
		return false
	}

	//valid data
	if cp.VerifyData && dcp.Info.Data.DownloadInfo.CRC64 != 0 {
		if file, err := os.Open(cp.Info.Data.FilePath); err == nil {
			hash := NewCRC64(0)
			limitN := dcp.Info.Data.DownloadInfo.Offset - rOffset
			io.Copy(hash, io.LimitReader(file, limitN))
			file.Close()
			if hash.Sum64() != dcp.Info.Data.DownloadInfo.CRC64 {
				return false
			}
		}
	}

	// update
	cp.Info.Data.DownloadInfo = dcp.Info.Data.DownloadInfo

	return true
}