// estimateUnknownSize returns the expected bytes consumed by a given runtime.Unknown
// object with a nil RawJSON struct and the expected size of the provided buffer. The
// returned size will not be correct if RawJSOn is set on unk.
func estimateUnknownSize(unk *runtime.Unknown, byteSize uint64) uint64 {
size := uint64(unk.Size())
// protobuf uses 1 byte for the tag, a varint for the length of the array (at most 8 bytes - uint64 - here),
// and the size of the array.
size += 1 + 8 + byteSize
return size
}
// Encode serializes the provided object to the given writer.
func (s *Serializer) Encode(obj runtime.Object, w io.Writer) error {
prefixSize := uint64(len(s.prefix))
var unk runtime.Unknown
switch t := obj.(type) {
case *runtime.Unknown:
estimatedSize := prefixSize + uint64(t.Size())
data := make([]byte, estimatedSize)
i, err := t.MarshalTo(data[prefixSize:])
if err != nil {
return err
}
copy(data, s.prefix)
_, err = w.Write(data[:prefixSize+uint64(i)])
return err
default:
kind := obj.GetObjectKind().GroupVersionKind()
unk = runtime.Unknown{
TypeMeta: runtime.TypeMeta{
Kind: kind.Kind,
APIVersion: kind.GroupVersion().String(),
},
}
}
switch t := obj.(type) {
case bufferedMarshaller:
// this path performs a single allocation during write but requires the caller to implement
// the more efficient Size and MarshalTo methods
encodedSize := uint64(t.Size())
estimatedSize := prefixSize + estimateUnknownSize(&unk, encodedSize)
data := make([]byte, estimatedSize)
i, err := unk.NestedMarshalTo(data[prefixSize:], t, encodedSize)
if err != nil {
return err
}
copy(data, s.prefix)
_, err = w.Write(data[:prefixSize+uint64(i)])
return err
case proto.Marshaler:
// this path performs extra allocations
data, err := t.Marshal()
if err != nil {
return err
}
unk.Raw = data
estimatedSize := prefixSize + uint64(unk.Size())
data = make([]byte, estimatedSize)
i, err := unk.MarshalTo(data[prefixSize:])
if err != nil {
return err
}
copy(data, s.prefix)
_, err = w.Write(data[:prefixSize+uint64(i)])
return err
default:
// TODO: marshal with a different content type and serializer (JSON for third party objects)
return errNotMarshalable{reflect.TypeOf(obj)}
}
}