// marshalObject writes a struct to the Writer.
func (m *Marshaler) marshalObject(out *errWriter, v proto.Message, indent string) error {
out.write("{")
if m.Indent != "" {
out.write("\n")
}
s := reflect.ValueOf(v).Elem()
firstField := true
for i := 0; i < s.NumField(); i++ {
value := s.Field(i)
valueField := s.Type().Field(i)
if strings.HasPrefix(valueField.Name, "XXX_") {
continue
}
// IsNil will panic on most value kinds.
switch value.Kind() {
case reflect.Chan, reflect.Func, reflect.Interface, reflect.Map, reflect.Ptr, reflect.Slice:
if value.IsNil() {
continue
}
}
if !m.EmitDefaults {
switch value.Kind() {
case reflect.Bool:
if !value.Bool() {
continue
}
case reflect.Int32, reflect.Int64:
if value.Int() == 0 {
continue
}
case reflect.Uint32, reflect.Uint64:
if value.Uint() == 0 {
continue
}
case reflect.Float32, reflect.Float64:
if value.Float() == 0 {
continue
}
case reflect.String:
if value.Len() == 0 {
continue
}
}
}
// Oneof fields need special handling.
if valueField.Tag.Get("protobuf_oneof") != "" {
// value is an interface containing &T{real_value}.
sv := value.Elem().Elem() // interface -> *T -> T
value = sv.Field(0)
valueField = sv.Type().Field(0)
}
prop := jsonProperties(valueField)
if !firstField {
m.writeSep(out)
}
// If the map value is a cast type, it may not implement proto.Message, therefore
// allow the struct tag to declare the underlying message type. Instead of changing
// the signatures of the child types (and because prop.mvalue is not public), use
// CustomType as a passer.
if value.Kind() == reflect.Map {
if tag := valueField.Tag.Get("protobuf"); tag != "" {
for _, v := range strings.Split(tag, ",") {
if !strings.HasPrefix(v, "castvaluetype=") {
continue
}
v = strings.TrimPrefix(v, "castvaluetype=")
prop.CustomType = v
break
}
}
}
if err := m.marshalField(out, prop, value, indent); err != nil {
return err
}
firstField = false
}
// Handle proto2 extensions.
if ep, ok := v.(extendableProto); ok {
extensions := proto.RegisteredExtensions(v)
extensionMap := ep.ExtensionMap()
// Sort extensions for stable output.
ids := make([]int32, 0, len(extensionMap))
for id := range extensionMap {
ids = append(ids, id)
}
sort.Sort(int32Slice(ids))
for _, id := range ids {
desc := extensions[id]
if desc == nil {
// unknown extension
continue
}
ext, extErr := proto.GetExtension(ep, desc)
if extErr != nil {
return extErr
}
value := reflect.ValueOf(ext)
var prop proto.Properties
prop.Parse(desc.Tag)
prop.OrigName = fmt.Sprintf("[%s]", desc.Name)
if !firstField {
m.writeSep(out)
}
if err := m.marshalField(out, &prop, value, indent); err != nil {
return err
}
firstField = false
}
}
if m.Indent != "" {
out.write("\n")
out.write(indent)
}
out.write("}")
return out.err
}
// jsonProperties returns parsed proto.Properties for the field.
func jsonProperties(f reflect.StructField) *proto.Properties {
var prop proto.Properties
prop.Init(f.Type, f.Name, f.Tag.Get("protobuf"), &f)
return &prop
}