| // Copyright 2017 The Prometheus Authors |
| // Licensed 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. |
| |
| // +build !go1.8 |
| |
| package promhttp |
| |
| import ( |
| "io" |
| "net/http" |
| ) |
| |
| func newDelegator(w http.ResponseWriter, observeWriteHeaderFunc func(int)) delegator { |
| d := &responseWriterDelegator{ |
| ResponseWriter: w, |
| observeWriteHeader: observeWriteHeaderFunc, |
| } |
| |
| id := 0 |
| if _, ok := w.(http.CloseNotifier); ok { |
| id += closeNotifier |
| } |
| if _, ok := w.(http.Flusher); ok { |
| id += flusher |
| } |
| if _, ok := w.(http.Hijacker); ok { |
| id += hijacker |
| } |
| if _, ok := w.(io.ReaderFrom); ok { |
| id += readerFrom |
| } |
| |
| return pickDelegator[id](d) |
| } |