From 6e0d99a3860b0e5184a9b8b9f7a8f66035340f59 Mon Sep 17 00:00:00 2001
From: Marten Seemann <martenseemann@gmail.com>
Date: Sun, 29 May 2022 19:51:08 +0200
Subject: [PATCH] remove the http3.DataStreamer

---
 http3/response_writer.go | 28 +++-------------------------
 http3/server.go          | 10 +---------
 http3/server_test.go     | 39 ---------------------------------------
 3 files changed, 4 insertions(+), 73 deletions(-)

diff --git a/http3/response_writer.go b/http3/response_writer.go
index 9f232e0f2bb..c0de2d4ec2a 100644
--- a/http3/response_writer.go
+++ b/http3/response_writer.go
@@ -12,25 +12,14 @@ import (
 	"github.com/marten-seemann/qpack"
 )
 
-// DataStreamer lets the caller take over the stream. After a call to DataStream
-// the HTTP server library will not do anything else with the connection.
-//
-// It becomes the caller's responsibility to manage and close the stream.
-//
-// After a call to DataStream, the original Request.Body must not be used.
-type DataStreamer interface {
-	DataStream() quic.Stream
-}
-
 type responseWriter struct {
 	conn           quic.Connection
 	stream         quic.Stream // needed for DataStream()
 	bufferedStream *bufio.Writer
 
-	header         http.Header
-	status         int // status code passed to WriteHeader
-	headerWritten  bool
-	dataStreamUsed bool // set when DataSteam() is called
+	header        http.Header
+	status        int // status code passed to WriteHeader
+	headerWritten bool
 
 	logger utils.Logger
 }
@@ -38,7 +27,6 @@ type responseWriter struct {
 var (
 	_ http.ResponseWriter = &responseWriter{}
 	_ http.Flusher        = &responseWriter{}
-	_ DataStreamer        = &responseWriter{}
 	_ Hijacker            = &responseWriter{}
 )
 
@@ -112,16 +100,6 @@ func (w *responseWriter) Flush() {
 	}
 }
 
-func (w *responseWriter) usedDataStream() bool {
-	return w.dataStreamUsed
-}
-
-func (w *responseWriter) DataStream() quic.Stream {
-	w.dataStreamUsed = true
-	w.Flush()
-	return w.stream
-}
-
 func (w *responseWriter) StreamID() quic.StreamID {
 	return w.stream.StreamID()
 }
diff --git a/http3/server.go b/http3/server.go
index b52e546d182..45ca3f4c81b 100644
--- a/http3/server.go
+++ b/http3/server.go
@@ -562,11 +562,7 @@ func (s *Server) handleRequest(conn quic.Connection, str quic.Stream, decoder *q
 	ctx = context.WithValue(ctx, http.LocalAddrContextKey, conn.LocalAddr())
 	req = req.WithContext(ctx)
 	r := newResponseWriter(str, conn, s.logger)
-	defer func() {
-		if !r.usedDataStream() {
-			r.Flush()
-		}
-	}()
+	defer r.Flush()
 	handler := s.Handler
 	if handler == nil {
 		handler = http.DefaultServeMux
@@ -587,10 +583,6 @@ func (s *Server) handleRequest(conn quic.Connection, str quic.Stream, decoder *q
 		handler.ServeHTTP(r, req)
 	}()
 
-	if r.usedDataStream() {
-		return requestError{err: errHijacked}
-	}
-
 	if panicked {
 		r.WriteHeader(500)
 	} else {
diff --git a/http3/server_test.go b/http3/server_test.go
index e652072a9eb..064380c3d88 100644
--- a/http3/server_test.go
+++ b/http3/server_test.go
@@ -222,45 +222,6 @@ var _ = Describe("Server", func() {
 			Expect(hfs).To(HaveKeyWithValue(":status", []string{"500"}))
 		})
 
-		It("doesn't close the stream if the handler called DataStream()", func() {
-			s.Handler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-				str := w.(DataStreamer).DataStream()
-				str.Write([]byte("foobar"))
-			})
-
-			rspWritten := make(chan struct{})
-			setRequest(encodeRequest(exampleGetRequest))
-			str.EXPECT().Context().Return(reqContext)
-			str.EXPECT().Write([]byte("foobar")).Do(func(b []byte) (int, error) {
-				close(rspWritten)
-				return len(b), nil
-			})
-			// don't EXPECT CancelRead()
-
-			ctrlStr := mockquic.NewMockStream(mockCtrl)
-			ctrlStr.EXPECT().Write(gomock.Any()).AnyTimes()
-			conn.EXPECT().OpenUniStream().Return(ctrlStr, nil)
-			conn.EXPECT().AcceptUniStream(gomock.Any()).DoAndReturn(func(context.Context) (quic.ReceiveStream, error) {
-				<-rspWritten
-				return nil, errors.New("done")
-			})
-			conn.EXPECT().AcceptStream(gomock.Any()).Return(str, nil)
-			conn.EXPECT().AcceptStream(gomock.Any()).DoAndReturn(func(context.Context) (quic.Stream, error) {
-				<-rspWritten
-				return nil, errors.New("done")
-			})
-
-			done := make(chan struct{})
-			go func() {
-				defer GinkgoRecover()
-				defer close(done)
-				s.handleConn(conn)
-			}()
-			Eventually(rspWritten).Should(BeClosed())
-			time.Sleep(50 * time.Millisecond) // make sure that after str.Write there are no further calls to stream methods
-			Eventually(done).Should(BeClosed())
-		})
-
 		Context("hijacking bidirectional streams", func() {
 			var conn *mockquic.MockEarlyConnection
 			testDone := make(chan struct{})