Method unmarshalMessage

encoding/protojson/decode.go:124–248

unmarshalMessage unmarshals a message into the given protoreflect.Message.

(m protoreflect.Message, skipTypeURL bool)

// unmarshalMessage unmarshals a message into the given protoreflect.Message.
func (d decoder) unmarshalMessage(m protoreflect.Message, skipTypeURL bool) error {
	d.opts.RecursionLimit--
	if d.opts.RecursionLimit < 0 {
		return errors.New("exceeded max recursion depth")
	}
	if unmarshal := wellKnownTypeUnmarshaler(m.Descriptor().FullName()); unmarshal != nil {
		return unmarshal(d, m)
	}

	tok, err := d.Read()
	if err != nil {
		return err
	}
	if tok.Kind() != json.ObjectOpen {
		return d.unexpectedTokenError(tok)
	}

	messageDesc := m.Descriptor()
	if !flags.ProtoLegacy && messageset.IsMessageSet(messageDesc) {
		return errors.New("no support for proto1 MessageSets")
	}

	var seenNums set.Ints
	var seenOneofs set.Ints
	fieldDescs := messageDesc.Fields()
	for {
		// Read field name.
		tok, err := d.Read()
		if err != nil {
			return err
		}
		switch tok.Kind() {
		default:
			return d.unexpectedTokenError(tok)
		case json.ObjectClose:
			return nil
		case json.Name:
			// Continue below.
		}

		name := tok.Name()
		// Unmarshaling a non-custom embedded message in Any will contain the
		// JSON field "@type" which should be skipped because it is not a field
		// of the embedded message, but simply an artifact of the Any format.
		if skipTypeURL && name == "@type" {
			d.Read()
			continue
		}

		// Get the FieldDescriptor.
		var fd protoreflect.FieldDescriptor
		if strings.HasPrefix(name, "[") && strings.HasSuffix(name, "]") {
			// Only extension names are in [name] format.
			extName := protoreflect.FullName(name[1 : len(name)-1])
			extType, err := d.opts.Resolver.FindExtensionByName(extName)
			if err != nil && err != protoregistry.NotFound {
				return d.newError(tok.Pos(), "unable to resolve %s: %v", tok.RawString(), err)
			}