Function parseStructTag

proto/reflect.go:532–595

(tag string)

}

func parseStructTag(tag string) (structTag, error) {
	t := structTag{
		version:    2,
		extensions: make(map[string]string),
	}

	for i, f := range splitFields(tag) {
		switch i {
		case 0:
			switch f {
			case "varint":
				t.wireType = Varint
			case "bytes":
				t.wireType = Varlen
			case "fixed32":
				t.wireType = Fixed32
			case "fixed64":
				t.wireType = Fixed64
			case "zigzag32":
				t.wireType = Varint
				t.zigzag = true
			case "zigzag64":
				t.wireType = Varint
				t.zigzag = true
			default:
				return t, fmt.Errorf("unsupported wire type in struct tag %q: %s", tag, f)
			}

		case 1:
			n, err := strconv.Atoi(f)
			if err != nil {
				return t, fmt.Errorf("unsupported field number in struct tag %q: %w", tag, err)
			}
			t.fieldNumber = FieldNumber(n)

		case 2:
			switch f {
			case "opt":
				// not sure what this is for
			case "rep":
				t.repeated = true
			default:
				return t, fmt.Errorf("unsupported field option in struct tag %q: %s", tag, f)
			}

		default:
			name, value := splitNameValue(f)
			switch name {
			case "name":
				t.name = value
			case "enum":
				t.enum = value
			case "json":
				t.json = value
			case "proto3":
				t.version = 3
			default:
				t.extensions[name] = value