diff: reduce (ethereum#258)

rlp/typecache.go

@@ -51,10 +51,6 @@ type tags struct {
 
 	// rlp:"-" ignores fields.
 	ignored bool
-
-	// rlp:"?" means that this field is not present in the RLP-encoded object if it is nil.
-	// Note: fields like this must be at the end of the struct.
-	omittedIfNil bool
 }
 
 // typekey is the key of a type in typeCache. It includes the struct tags because
@@ -178,8 +174,6 @@ func parseStructTag(typ reflect.Type, fi, lastPublic int) (tags, error) {
 			if f.Type.Kind() != reflect.Slice {
 				return ts, structTagError{typ, f.Name, t, "field type is not slice"}
 			}
-		case "?":
-			ts.omittedIfNil = true
 		default:
 			return ts, fmt.Errorf("rlp: unknown struct tag %q on %v.%s", t, typ, f.Name)
 		}
@@ -199,40 +193,7 @@ func lastPublicField(typ reflect.Type) int {
 
 func (i *typeinfo) generate(typ reflect.Type, tags tags) {
 	i.decoder, i.decoderErr = makeDecoder(typ, tags)
-	omitIfEmpty := tags.omittedIfNil && typ.Kind() == reflect.Ptr
-	if i.decoderErr == nil && omitIfEmpty {
-		i.decoder, i.decoderErr = wrapDecoderToAccountForOmitted(typ, i.decoder)
-	}
-
 	i.writer, i.writerErr = makeWriter(typ, tags)
-	if i.writerErr == nil && omitIfEmpty {
-		i.writer, i.writerErr = wrapWriterToAccountForOmitted(i.writer)
-	}
-}
-
-// wrapDecoderToAccountForOmitted handles decoding nullable types that are omitted when empty.
-// If omitted, this decoder will set the value to nil.
-func wrapDecoderToAccountForOmitted(typ reflect.Type, decoder decoder) (decoder, error) {
-	nilPtr := reflect.Zero(typ)
-	return func(s *Stream, val reflect.Value) (err error) {
-		if err = decoder(s, val); err != nil && err == EOL {
-			val.Set(nilPtr)
-			return nil
-		}
-		return err
-	}, nil
-}
-
-// wrapWriterToAccountForOmitted handles writing nullable types that are omitted when empty.
-// If omitted, this writer omit it from the encoded buffer.
-func wrapWriterToAccountForOmitted(writer writer) (writer, error) {
-	return func(val reflect.Value, w *encbuf) (err error) {
-		if val.IsNil() {
-			// Omit if nil
-			return nil
-		}
-		return writer(val, w)
-	}, nil
 }
 
 // defaultNilKind determines whether a nil pointer to typ encodes/decodes