net/http: update bundled http2 copy

Updates golang.org/x/net/http2 to git rev 438097d76

Fixes #13444

Change-Id: I699ac02d23b56db3e8a27d3f599ae56cd0a5b4b2
Reviewed-on: https://go-review.googlesource.com/17570Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>

src/net/http/h2_bundle.go

@@ -3858,6 +3858,7 @@ type http2clientStream struct {
 	inflow      http2flow // guarded by cc.mu
 	bytesRemain int64     // -1 means unknown; owned by transportResponseBody.Read
 	readErr     error     // sticky read error; owned by transportResponseBody.Read
+	stopReqBody bool      // stop writing req body; guarded by cc.mu
 
 	peerReset chan struct{} // closed on peer reset
 	resetErr  error         // populated before peerReset is closed
@@ -3874,6 +3875,14 @@ func (cs *http2clientStream) checkReset() error {
 	}
 }
 
+func (cs *http2clientStream) abortRequestBodyWrite() {
+	cc := cs.cc
+	cc.mu.Lock()
+	cs.stopReqBody = true
+	cc.cond.Broadcast()
+	cc.mu.Unlock()
+}
+
 type http2stickyErrWriter struct {
 	w   io.Writer
 	err *error
@@ -4202,26 +4211,25 @@ func (cc *http2ClientConn) RoundTrip(req *Request) (*Response, error) {
 		return nil, werr
 	}
 
-	var bodyCopyErrc chan error
-	var gotResHeaders chan struct{} // closed on resheaders
+	var bodyCopyErrc chan error // result of body copy
 	if hasBody {
 		bodyCopyErrc = make(chan error, 1)
-		gotResHeaders = make(chan struct{})
 		go func() {
-			bodyCopyErrc <- cs.writeRequestBody(req.Body, gotResHeaders)
+			bodyCopyErrc <- cs.writeRequestBody(req.Body)
 		}()
 	}
 
 	for {
 		select {
 		case re := <-cs.resc:
-			if gotResHeaders != nil {
-				close(gotResHeaders)
+			res := re.res
+			if re.err != nil || res.StatusCode > 299 {
+
+				cs.abortRequestBodyWrite()
 			}
 			if re.err != nil {
 				return nil, re.err
 			}
-			res := re.res
 			res.Request = req
 			res.TLS = cc.tlsState
 			return res, nil
@@ -4233,45 +4241,49 @@ func (cc *http2ClientConn) RoundTrip(req *Request) (*Response, error) {
 	}
 }
 
-var http2errServerResponseBeforeRequestBody = errors.New("http2: server sent response while still writing request body")
+// errAbortReqBodyWrite is an internal error value.
+// It doesn't escape to callers.
+var http2errAbortReqBodyWrite = errors.New("http2: aborting request body write")
 
-func (cs *http2clientStream) writeRequestBody(body io.Reader, gotResHeaders <-chan struct{}) error {
+func (cs *http2clientStream) writeRequestBody(body io.ReadCloser) (err error) {
 	cc := cs.cc
 	sentEnd := false
 	buf := cc.frameScratchBuffer()
 	defer cc.putFrameScratchBuffer(buf)
 
-	for !sentEnd {
-		var sawEOF bool
-		n, err := io.ReadFull(body, buf)
-		if err == io.ErrUnexpectedEOF {
+	defer func() {
+
+		cerr := body.Close()
+		if err == nil {
+			err = cerr
+		}
+	}()
+
+	var sawEOF bool
+	for !sawEOF {
+		n, err := body.Read(buf)
+		if err == io.EOF {
 			sawEOF = true
 			err = nil
-		} else if err == io.EOF {
-			break
 		} else if err != nil {
 			return err
 		}
 
-		toWrite := buf[:n]
-		for len(toWrite) > 0 && err == nil {
+		remain := buf[:n]
+		for len(remain) > 0 && err == nil {
 			var allowed int32
-			allowed, err = cs.awaitFlowControl(int32(len(toWrite)))
+			allowed, err = cs.awaitFlowControl(len(remain))
 			if err != nil {
 				return err
 			}
-
 			cc.wmu.Lock()
-			select {
-			case <-gotResHeaders:
-				err = http2errServerResponseBeforeRequestBody
-			case <-cs.peerReset:
-				err = cs.resetErr
-			default:
-				data := toWrite[:allowed]
-				toWrite = toWrite[allowed:]
-				sentEnd = sawEOF && len(toWrite) == 0
-				err = cc.fr.WriteData(cs.ID, sentEnd, data)
+			data := remain[:allowed]
+			remain = remain[allowed:]
+			sentEnd = sawEOF && len(remain) == 0
+			err = cc.fr.WriteData(cs.ID, sentEnd, data)
+			if err == nil {
+
+				err = cc.bw.Flush()
 			}
 			cc.wmu.Unlock()
 		}
@@ -4280,8 +4292,6 @@ func (cs *http2clientStream) writeRequestBody(body io.Reader, gotResHeaders <-ch
 		}
 	}
 
-	var err error
-
 	cc.wmu.Lock()
 	if !sentEnd {
 		err = cc.fr.WriteData(cs.ID, true, nil)
@@ -4298,7 +4308,7 @@ func (cs *http2clientStream) writeRequestBody(body io.Reader, gotResHeaders <-ch
 // control tokens from the server.
 // It returns either the non-zero number of tokens taken or an error
 // if the stream is dead.
-func (cs *http2clientStream) awaitFlowControl(maxBytes int32) (taken int32, err error) {
+func (cs *http2clientStream) awaitFlowControl(maxBytes int) (taken int32, err error) {
 	cc := cs.cc
 	cc.mu.Lock()
 	defer cc.mu.Unlock()
@@ -4306,13 +4316,17 @@ func (cs *http2clientStream) awaitFlowControl(maxBytes int32) (taken int32, err
 		if cc.closed {
 			return 0, http2errClientConnClosed
 		}
+		if cs.stopReqBody {
+			return 0, http2errAbortReqBodyWrite
+		}
 		if err := cs.checkReset(); err != nil {
 			return 0, err
 		}
 		if a := cs.flow.available(); a > 0 {
 			take := a
-			if take > maxBytes {
-				take = maxBytes
+			if int(take) > maxBytes {
+
+				take = int32(maxBytes)
 			}
 			if take > int32(cc.maxFrameSize) {
 				take = int32(cc.maxFrameSize)
@@ -4751,6 +4765,7 @@ func (rl *http2clientConnReadLoop) processResetStream(f *http2RSTStreamFrame) er
 		cs.resetErr = err
 		close(cs.peerReset)
 		cs.bufPipe.CloseWithError(err)
+		cs.cc.cond.Broadcast()
 	}
 	delete(rl.activeRes, cs.ID)
 	return nil