/
nil.go
53 lines (49 loc) · 1.72 KB
/
nil.go
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// Licensed to the Apache Software Foundation (ASF) under one or more
// contributor license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright ownership.
// The ASF licenses this file to You under the Apache License, Version 2.0
// (the "License"); you may not use this file except in compliance with
// the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package coder
import (
"io"
"reflect"
)
// NullableDecoder handles when a value is nillable.
// Nillable types have an extra byte prefixing them indicating nil status.
func NullableDecoder(decodeToElem func(reflect.Value, io.Reader) error) func(reflect.Value, io.Reader) error {
return func(ret reflect.Value, r io.Reader) error {
hasValue, err := DecodeBool(r)
if err != nil {
return err
}
if !hasValue {
return nil
}
if err := decodeToElem(ret, r); err != nil {
return err
}
return nil
}
}
// NullableEncoder handles when a value is nillable.
// Nillable types have an extra byte prefixing them indicating nil status.
func NullableEncoder(encodeElem func(reflect.Value, io.Writer) error) func(reflect.Value, io.Writer) error {
return func(rv reflect.Value, w io.Writer) error {
if rv.IsNil() {
return EncodeBool(false, w)
}
if err := EncodeBool(true, w); err != nil {
return err
}
return encodeElem(rv, w)
}
}