func()

in protoc-gen-go/generator/generator.go [1447:1559]

• 98 lines of code
• 39 McCabe index (conditional complexity)

func (g *Generator) goTag(message *Descriptor, field *descriptor.FieldDescriptorProto, wiretype string) string {
	optrepreq := ""
	switch {
	case isOptional(field):
		optrepreq = "opt"
	case isRequired(field):
		optrepreq = "req"
	case isRepeated(field):
		optrepreq = "rep"
	}
	var defaultValue string
	if dv := field.DefaultValue; dv != nil { // set means an explicit default
		defaultValue = *dv
		// Some types need tweaking.
		switch *field.Type {
		case descriptor.FieldDescriptorProto_TYPE_BOOL:
			if defaultValue == "true" {
				defaultValue = "1"
			} else {
				defaultValue = "0"
			}
		case descriptor.FieldDescriptorProto_TYPE_STRING,
			descriptor.FieldDescriptorProto_TYPE_BYTES:
			// Nothing to do. Quoting is done for the whole tag.
		case descriptor.FieldDescriptorProto_TYPE_ENUM:
			// For enums we need to provide the integer constant.
			obj := g.ObjectNamed(field.GetTypeName())
			if id, ok := obj.(*ImportedDescriptor); ok {
				// It is an enum that was publicly imported.
				// We need the underlying type.
				obj = id.o
			}
			enum, ok := obj.(*EnumDescriptor)
			if !ok {
				log.Printf("obj is a %T", obj)
				if id, ok := obj.(*ImportedDescriptor); ok {
					log.Printf("id.o is a %T", id.o)
				}
				g.Fail("unknown enum type", CamelCaseSlice(obj.TypeName()))
			}
			defaultValue = enum.integerValueAsString(defaultValue)
		case descriptor.FieldDescriptorProto_TYPE_FLOAT:
			if def := defaultValue; def != "inf" && def != "-inf" && def != "nan" {
				if f, err := strconv.ParseFloat(defaultValue, 32); err == nil {
					defaultValue = fmt.Sprint(float32(f))
				}
			}
		case descriptor.FieldDescriptorProto_TYPE_DOUBLE:
			if def := defaultValue; def != "inf" && def != "-inf" && def != "nan" {
				if f, err := strconv.ParseFloat(defaultValue, 64); err == nil {
					defaultValue = fmt.Sprint(f)
				}
			}
		}
		defaultValue = ",def=" + defaultValue
	}
	enum := ""
	if *field.Type == descriptor.FieldDescriptorProto_TYPE_ENUM {
		// We avoid using obj.GoPackageName(), because we want to use the
		// original (proto-world) package name.
		obj := g.ObjectNamed(field.GetTypeName())
		if id, ok := obj.(*ImportedDescriptor); ok {
			obj = id.o
		}
		enum = ",enum="
		if pkg := obj.File().GetPackage(); pkg != "" {
			enum += pkg + "."
		}
		enum += CamelCaseSlice(obj.TypeName())
	}
	packed := ""
	if (field.Options != nil && field.Options.GetPacked()) ||
		// Per https://developers.google.com/protocol-buffers/docs/proto3#simple:
		// "In proto3, repeated fields of scalar numeric types use packed encoding by default."
		(message.proto3() && (field.Options == nil || field.Options.Packed == nil) &&
			isRepeated(field) && isScalar(field)) {
		packed = ",packed"
	}
	fieldName := field.GetName()
	name := fieldName
	if *field.Type == descriptor.FieldDescriptorProto_TYPE_GROUP {
		// We must use the type name for groups instead of
		// the field name to preserve capitalization.
		// type_name in FieldDescriptorProto is fully-qualified,
		// but we only want the local part.
		name = *field.TypeName
		if i := strings.LastIndex(name, "."); i >= 0 {
			name = name[i+1:]
		}
	}
	if json := field.GetJsonName(); field.Extendee == nil && json != "" && json != name {
		// TODO: escaping might be needed, in which case
		// perhaps this should be in its own "json" tag.
		name += ",json=" + json
	}
	name = ",name=" + name
	if message.proto3() {
		name += ",proto3"
	}
	oneof := ""
	if field.OneofIndex != nil {
		oneof = ",oneof"
	}
	return strconv.Quote(fmt.Sprintf("%s,%d,%s%s%s%s%s%s",
		wiretype,
		field.GetNumber(),
		optrepreq,
		packed,
		name,
		enum,
		oneof,
		defaultValue))
}