// marshalObject writes a struct to the Writer.
func (m *Marshaler) marshalObject(out *errWriter, v proto.Message, indent string) error {
// Prefer specialized marshalers if available
if mlr, ok := v.(json.Marshaler); ok {
bs, err := mlr.MarshalJSON()
if err != nil {
return err
}
if out.err != nil {
return out.err
}
_, out.err = out.writer.Write(bs)
return out.err
}
out.write("{")
if m.Indent != "" {
out.write("\n")
}
s := reflect.ValueOf(v).Elem()
writeBeforeField := ""
for i := 0; i < s.NumField(); i++ {
value := s.Field(i)
valueField := s.Type().Field(i)
if strings.HasPrefix(valueField.Name, "XXX_") {
continue
}
fieldName := jsonFieldName(valueField)
// TODO: proto3 objects should have default values omitted.
// 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
}
}
// 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)
var p proto.Properties
p.Parse(sv.Type().Field(0).Tag.Get("protobuf"))
fieldName = p.OrigName
}
out.write(writeBeforeField)
if m.Indent != "" {
out.write(indent)
out.write(m.Indent)
}
out.write(`"`)
out.write(fieldName)
out.write(`":`)
if m.Indent != "" {
out.write(" ")
}
if err := m.marshalValue(out, value, valueField, indent); err != nil {
return err
}
if m.Indent != "" {
writeBeforeField = ",\n"
} else {
writeBeforeField = ","
}
}
if m.Indent != "" {
out.write("\n")
out.write(indent)
}
out.write("}")
return out.err
}
// jsonFieldName returns the field name to use.
func jsonFieldName(f reflect.StructField) string {
var prop proto.Properties
prop.Init(f.Type, f.Name, f.Tag.Get("protobuf"), &f)
return prop.OrigName
}