Function ParseMetadata

tenant/metadata.go:72–103

ParseMetadata validates and constructs a [Metadata]. See [NewMetadata]. It doesn't allocate.

(source string)

//
// It doesn't allocate.
func ParseMetadata(source string) (Metadata, error) {
	if err := ValidMetadata(source); err != nil || source == "" {
		return Metadata{}, err
	}

	remaining := source
	if remaining[0] != metadataSeparator {
		return Metadata{}, errMalformedMetadata{source: source, reason: fmt.Sprintf("missing '%c' at start", metadataSeparator)}
	}
	prevKey := "" // < than every other string
	for len(remaining) > 0 {
		next := strings.IndexByte(remaining[1:], metadataSeparator)
		if next < 0 {
			next = len(remaining)
		} else {
			next += 1 // Add back the ':'
		}

		kv := remaining[:next]
		remaining = remaining[next:]

		key, _, ok := stringsCut(kv, metadataKVSeparator)
		if !ok {
			return Metadata{}, errMalformedMetadata{source: source, reason: fmt.Sprintf("no key-value separator '%c' in %q", metadataKVSeparator, kv)}
		}
		if prevKey >= key {
			return Metadata{}, errMalformedMetadata{source: source, reason: "keys must be unique and sorted"}
		}
		prevKey = key
	}
	return NewMetadata(source), nil
}

// ValidMetadata returns an error if the metadata is invalid, nil otherwise.
// Metadata must contain only lowercase letters, digits, '-', and '='.