3 files changed, 91 insertions, 66 deletions
diff --git a/vendor/golang.org/x/net/http2/hpack/huffman.go b/vendor/golang.org/x/net/http2/hpack/huffman.go
index fe0b84cc..20d083a7 100644
--- a/vendor/golang.org/x/net/http2/hpack/huffman.go
+++ b/vendor/golang.org/x/net/http2/hpack/huffman.go
@@ -169,25 +169,50 @@ func buildRootHuffmanNode() {
 // AppendHuffmanString appends s, as encoded in Huffman codes, to dst
 // and returns the extended buffer.
 func AppendHuffmanString(dst []byte, s string) []byte {
-	rembits := uint8(8)
-
+	// This relies on the maximum huffman code length being 30 (See tables.go huffmanCodeLen array)
+	// So if a uint64 buffer has less than 32 valid bits can always accommodate another huffmanCode.
+	var (
+		x uint64 // buffer
+		n uint   // number valid of bits present in x
+	)
 	for i := 0; i < len(s); i++ {
-		if rembits == 8 {
-			dst = append(dst, 0)
+		c := s[i]
+		n += uint(huffmanCodeLen[c])
+		x <<= huffmanCodeLen[c] % 64
+		x |= uint64(huffmanCodes[c])
+		if n >= 32 {
+			n %= 32             // Normally would be -= 32 but %= 32 informs compiler 0 <= n <= 31 for upcoming shift
+			y := uint32(x >> n) // Compiler doesn't combine memory writes if y isn't uint32
+			dst = append(dst, byte(y>>24), byte(y>>16), byte(y>>8), byte(y))
 		}
-		dst, rembits = appendByteToHuffmanCode(dst, rembits, s[i])
 	}
-
-	if rembits < 8 {
-		// special EOS symbol
-		code := uint32(0x3fffffff)
-		nbits := uint8(30)
-
-		t := uint8(code >> (nbits - rembits))
-		dst[len(dst)-1] |= t
+	// Add padding bits if necessary
+	if over := n % 8; over > 0 {
+		const (
+			eosCode    = 0x3fffffff
+			eosNBits   = 30
+			eosPadByte = eosCode >> (eosNBits - 8)
+		)
+		pad := 8 - over
+		x = (x << pad) | (eosPadByte >> over)
+		n += pad // 8 now divides into n exactly
 	}
-
-	return dst
+	// n in (0, 8, 16, 24, 32)
+	switch n / 8 {
+	case 0:
+		return dst
+	case 1:
+		return append(dst, byte(x))
+	case 2:
+		y := uint16(x)
+		return append(dst, byte(y>>8), byte(y))
+	case 3:
+		y := uint16(x >> 8)
+		return append(dst, byte(y>>8), byte(y), byte(x))
+	}
+	//	case 4:
+	y := uint32(x)
+	return append(dst, byte(y>>24), byte(y>>16), byte(y>>8), byte(y))
 }
 
 // HuffmanEncodeLength returns the number of bytes required to encode
@@ -199,35 +224,3 @@ func HuffmanEncodeLength(s string) uint64 {
 	}
 	return (n + 7) / 8
 }
-
-// appendByteToHuffmanCode appends Huffman code for c to dst and
-// returns the extended buffer and the remaining bits in the last
-// element. The appending is not byte aligned and the remaining bits
-// in the last element of dst is given in rembits.
-func appendByteToHuffmanCode(dst []byte, rembits uint8, c byte) ([]byte, uint8) {
-	code := huffmanCodes[c]
-	nbits := huffmanCodeLen[c]
-
-	for {
-		if rembits > nbits {
-			t := uint8(code << (rembits - nbits))
-			dst[len(dst)-1] |= t
-			rembits -= nbits
-			break
-		}
-
-		t := uint8(code >> (nbits - rembits))
-		dst[len(dst)-1] |= t
-
-		nbits -= rembits
-		rembits = 8
-
-		if nbits == 0 {
-			break
-		}
-
-		dst = append(dst, 0)
-	}
-
-	return dst, rembits
-}
diff --git a/vendor/golang.org/x/net/http2/server.go b/vendor/golang.org/x/net/http2/server.go
index 33765d3a..2d859af8 100644
--- a/vendor/golang.org/x/net/http2/server.go
+++ b/vendor/golang.org/x/net/http2/server.go
@@ -400,7 +400,7 @@ func (s *Server) ServeConn(c net.Conn, opts *ServeConnOpts) {
 	if s.NewWriteScheduler != nil {
 		sc.writeSched = s.NewWriteScheduler()
 	} else {
-		sc.writeSched = NewRandomWriteScheduler()
+		sc.writeSched = NewPriorityWriteScheduler(nil)
 	}
 
 	// These start at the RFC-specified defaults. If there is a higher
@@ -2316,17 +2316,18 @@ type requestBody struct {
 	_             incomparable
 	stream        *stream
 	conn          *serverConn
-	closed        bool  // for use by Close only
-	sawEOF        bool  // for use by Read only
-	pipe          *pipe // non-nil if we have a HTTP entity message body
-	needsContinue bool  // need to send a 100-continue
+	closeOnce     sync.Once // for use by Close only
+	sawEOF        bool      // for use by Read only
+	pipe          *pipe     // non-nil if we have a HTTP entity message body
+	needsContinue bool      // need to send a 100-continue
 }
 
 func (b *requestBody) Close() error {
-	if b.pipe != nil && !b.closed {
-		b.pipe.BreakWithError(errClosedBody)
-	}
-	b.closed = true
+	b.closeOnce.Do(func() {
+		if b.pipe != nil {
+			b.pipe.BreakWithError(errClosedBody)
+		}
+	})
 	return nil
 }
 
@@ -2644,8 +2645,7 @@ func checkWriteHeaderCode(code int) {
 	// Issue 22880: require valid WriteHeader status codes.
 	// For now we only enforce that it's three digits.
 	// In the future we might block things over 599 (600 and above aren't defined
-	// at http://httpwg.org/specs/rfc7231.html#status.codes)
-	// and we might block under 200 (once we have more mature 1xx support).
+	// at http://httpwg.org/specs/rfc7231.html#status.codes).
 	// But for now any three digits.
 	//
 	// We used to send "HTTP/1.1 000 0" on the wire in responses but there's
@@ -2666,13 +2666,41 @@ func (w *responseWriter) WriteHeader(code int) {
 }
 
 func (rws *responseWriterState) writeHeader(code int) {
-	if !rws.wroteHeader {
-		checkWriteHeaderCode(code)
-		rws.wroteHeader = true
-		rws.status = code
-		if len(rws.handlerHeader) > 0 {
-			rws.snapHeader = cloneHeader(rws.handlerHeader)
+	if rws.wroteHeader {
+		return
+	}
+
+	checkWriteHeaderCode(code)
+
+	// Handle informational headers
+	if code >= 100 && code <= 199 {
+		// Per RFC 8297 we must not clear the current header map
+		h := rws.handlerHeader
+
+		_, cl := h["Content-Length"]
+		_, te := h["Transfer-Encoding"]
+		if cl || te {
+			h = h.Clone()
+			h.Del("Content-Length")
+			h.Del("Transfer-Encoding")
+		}
+
+		if rws.conn.writeHeaders(rws.stream, &writeResHeaders{
+			streamID:    rws.stream.id,
+			httpResCode: code,
+			h:           h,
+			endStream:   rws.handlerDone && !rws.hasTrailers(),
+		}) != nil {
+			rws.dirty = true
 		}
+
+		return
+	}
+
+	rws.wroteHeader = true
+	rws.status = code
+	if len(rws.handlerHeader) > 0 {
+		rws.snapHeader = cloneHeader(rws.handlerHeader)
 	}
 }
 
diff --git a/vendor/golang.org/x/net/http2/transport.go b/vendor/golang.org/x/net/http2/transport.go
index 9180ba3d..4ded4dfd 100644
--- a/vendor/golang.org/x/net/http2/transport.go
+++ b/vendor/golang.org/x/net/http2/transport.go
@@ -16,7 +16,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"log"
 	"math"
 	mathrand "math/rand"
@@ -2904,7 +2903,12 @@ func (t *Transport) logf(format string, args ...interface{}) {
 	log.Printf(format, args...)
 }
 
-var noBody io.ReadCloser = ioutil.NopCloser(bytes.NewReader(nil))
+var noBody io.ReadCloser = noBodyReader{}
+
+type noBodyReader struct{}
+
+func (noBodyReader) Close() error             { return nil }
+func (noBodyReader) Read([]byte) (int, error) { return 0, io.EOF }
 
 type missingBody struct{}