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