1 files changed, 24 insertions, 2 deletions
diff --git a/libgo/go/net/http/httputil/reverseproxy.go b/libgo/go/net/http/httputil/reverseproxy.go
index c8e113221c4..4dba352a4fa 100644
--- a/libgo/go/net/http/httputil/reverseproxy.go
+++ b/libgo/go/net/http/httputil/reverseproxy.go
@@ -46,6 +46,18 @@ type ReverseProxy struct {
 	// If nil, logging goes to os.Stderr via the log package's
 	// standard logger.
 	ErrorLog *log.Logger
+
+	// BufferPool optionally specifies a buffer pool to
+	// get byte slices for use by io.CopyBuffer when
+	// copying HTTP response bodies.
+	BufferPool BufferPool
+}
+
+// A BufferPool is an interface for getting and returning temporary
+// byte slices for use by io.CopyBuffer.
+type BufferPool interface {
+	Get() []byte
+	Put([]byte)
 }
 
 func singleJoiningSlash(a, b string) string {
@@ -60,10 +72,13 @@ func singleJoiningSlash(a, b string) string {
 	return a + b
 }
 
-// NewSingleHostReverseProxy returns a new ReverseProxy that rewrites
+// NewSingleHostReverseProxy returns a new ReverseProxy that routes
 // URLs to the scheme, host, and base path provided in target. If the
 // target's path is "/base" and the incoming request was for "/dir",
 // the target request will be for /base/dir.
+// NewSingleHostReverseProxy does not rewrite the Host header.
+// To rewrite Host headers, use ReverseProxy directly with a custom
+// Director policy.
 func NewSingleHostReverseProxy(target *url.URL) *ReverseProxy {
 	targetQuery := target.RawQuery
 	director := func(req *http.Request) {
@@ -242,7 +257,14 @@ func (p *ReverseProxy) copyResponse(dst io.Writer, src io.Reader) {
 		}
 	}
 
-	io.Copy(dst, src)
+	var buf []byte
+	if p.BufferPool != nil {
+		buf = p.BufferPool.Get()
+	}
+	io.CopyBuffer(dst, src, buf)
+	if p.BufferPool != nil {
+		p.BufferPool.Put(buf)
+	}
 }
 
 func (p *ReverseProxy) logf(format string, args ...interface{}) {