}
		}
		return t, s
	}
	checkType := func(c ChecksumType) {
		if got := h.Get(c.Key()); got != "" {
			// If already set, invalid
			if t != ChecksumNone {
				t = ChecksumInvalid
				s = ""
			} else {
				t = c
				s = got
			}
			return
		}
	}
	checkType(ChecksumCRC32)
	checkType(ChecksumCRC32C)
	checkType(ChecksumSHA1)
	checkType(ChecksumSHA256)
	return t, s