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 15 package ochttp 16 17 import ( 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. 24 func 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