1// Copyright 2019, OpenCensus Authors
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15package ochttp
16
17import (
18	"io"
19)
20
21// wrappedBody returns a wrapped version of the original
22// Body and only implements the same combination of additional
23// interfaces as the original.
24func wrappedBody(wrapper io.ReadCloser, body io.ReadCloser) io.ReadCloser {
25	var (
26		wr, i0 = body.(io.Writer)
27	)
28	switch {
29	case !i0:
30		return struct {
31			io.ReadCloser
32		}{wrapper}
33
34	case i0:
35		return struct {
36			io.ReadCloser
37			io.Writer
38		}{wrapper, wr}
39	default:
40		return struct {
41			io.ReadCloser
42		}{wrapper}
43	}
44}
45