1 files changed, 70 insertions, 0 deletions
diff --git a/vendor/github.com/prometheus/client_golang/prometheus/promhttp/delegator_1_8.go b/vendor/github.com/prometheus/client_golang/prometheus/promhttp/delegator_1_8.go
new file mode 100644
index 000000000..98b565096
--- /dev/null
+++ b/vendor/github.com/prometheus/client_golang/prometheus/promhttp/delegator_1_8.go
@@ -0,0 +1,70 @@
+// 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"
+)
+
+// newDelegator handles the four different methods of upgrading a
+// http.ResponseWriter to delegator.
+func newDelegator(w http.ResponseWriter) delegator {
+	d := &responseWriterDelegator{ResponseWriter: w}
+
+	_, cn := w.(http.CloseNotifier)
+	_, fl := w.(http.Flusher)
+	_, hj := w.(http.Hijacker)
+	_, ps := w.(http.Pusher)
+	_, rf := w.(io.ReaderFrom)
+
+	// Check for the four most common combination of interfaces a
+	// http.ResponseWriter might implement.
+	switch {
+	case cn && fl && hj && rf && ps:
+		// All interfaces.
+		return &fancyPushDelegator{
+			fancyDelegator: &fancyDelegator{d},
+			p:              &pushDelegator{d},
+		}
+	case cn && fl && hj && rf:
+		// All interfaces, except http.Pusher.
+		return &fancyDelegator{d}
+	case ps:
+		// Just http.Pusher.
+		return &pushDelegator{d}
+	}
+
+	return d
+}
+
+type fancyPushDelegator struct {
+	p *pushDelegator
+
+	*fancyDelegator
+}
+
+func (f *fancyPushDelegator) Push(target string, opts *http.PushOptions) error {
+	return f.p.Push(target, opts)
+}
+
+type pushDelegator struct {
+	*responseWriterDelegator
+}
+
+func (f *pushDelegator) Push(target string, opts *http.PushOptions) error {
+	return f.ResponseWriter.(http.Pusher).Push(target, opts)
+}