vendor: update buildkit to v0.19.0-rc1

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

vendor/k8s.io/apimachinery/pkg/util/httpstream/wsstream/stream.go

@@ -0,0 +1,177 @@
+/*
+Copyright 2015 The Kubernetes 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.
+*/
+
+package wsstream
+
+import (
+	"encoding/base64"
+	"io"
+	"net/http"
+	"sync"
+	"time"
+
+	"golang.org/x/net/websocket"
+
+	"k8s.io/apimachinery/pkg/util/runtime"
+)
+
+// The WebSocket subprotocol "binary.k8s.io" will only send messages to the
+// client and ignore messages sent to the server. The received messages are
+// the exact bytes written to the stream. Zero byte messages are possible.
+const binaryWebSocketProtocol = "binary.k8s.io"
+
+// The WebSocket subprotocol "base64.binary.k8s.io" will only send messages to the
+// client and ignore messages sent to the server. The received messages are
+// a base64 version of the bytes written to the stream. Zero byte messages are
+// possible.
+const base64BinaryWebSocketProtocol = "base64.binary.k8s.io"
+
+// ReaderProtocolConfig describes a websocket subprotocol with one stream.
+type ReaderProtocolConfig struct {
+	Binary bool
+}
+
+// NewDefaultReaderProtocols returns a stream protocol map with the
+// subprotocols "", "channel.k8s.io", "base64.channel.k8s.io".
+func NewDefaultReaderProtocols() map[string]ReaderProtocolConfig {
+	return map[string]ReaderProtocolConfig{
+		"":                            {Binary: true},
+		binaryWebSocketProtocol:       {Binary: true},
+		base64BinaryWebSocketProtocol: {Binary: false},
+	}
+}
+
+// Reader supports returning an arbitrary byte stream over a websocket channel.
+type Reader struct {
+	err              chan error
+	r                io.Reader
+	ping             bool
+	timeout          time.Duration
+	protocols        map[string]ReaderProtocolConfig
+	selectedProtocol string
+
+	handleCrash func(additionalHandlers ...func(interface{})) // overridable for testing
+}
+
+// NewReader creates a WebSocket pipe that will copy the contents of r to a provided
+// WebSocket connection. If ping is true, a zero length message will be sent to the client
+// before the stream begins reading.
+//
+// The protocols parameter maps subprotocol names to StreamProtocols. The empty string
+// subprotocol name is used if websocket.Config.Protocol is empty.
+func NewReader(r io.Reader, ping bool, protocols map[string]ReaderProtocolConfig) *Reader {
+	return &Reader{
+		r:           r,
+		err:         make(chan error),
+		ping:        ping,
+		protocols:   protocols,
+		handleCrash: runtime.HandleCrash,
+	}
+}
+
+// SetIdleTimeout sets the interval for both reads and writes before timeout. If not specified,
+// there is no timeout on the reader.
+func (r *Reader) SetIdleTimeout(duration time.Duration) {
+	r.timeout = duration
+}
+
+func (r *Reader) handshake(config *websocket.Config, req *http.Request) error {
+	supportedProtocols := make([]string, 0, len(r.protocols))
+	for p := range r.protocols {
+		supportedProtocols = append(supportedProtocols, p)
+	}
+	return handshake(config, req, supportedProtocols)
+}
+
+// Copy the reader to the response. The created WebSocket is closed after this
+// method completes.
+func (r *Reader) Copy(w http.ResponseWriter, req *http.Request) error {
+	go func() {
+		defer r.handleCrash()
+		websocket.Server{Handshake: r.handshake, Handler: r.handle}.ServeHTTP(w, req)
+	}()
+	return <-r.err
+}
+
+// handle implements a WebSocket handler.
+func (r *Reader) handle(ws *websocket.Conn) {
+	// Close the connection when the client requests it, or when we finish streaming, whichever happens first
+	closeConnOnce := &sync.Once{}
+	closeConn := func() {
+		closeConnOnce.Do(func() {
+			ws.Close()
+		})
+	}
+
+	negotiated := ws.Config().Protocol
+	r.selectedProtocol = negotiated[0]
+	defer close(r.err)
+	defer closeConn()
+
+	go func() {
+		defer runtime.HandleCrash()
+		// This blocks until the connection is closed.
+		// Client should not send anything.
+		IgnoreReceives(ws, r.timeout)
+		// Once the client closes, we should also close
+		closeConn()
+	}()
+
+	r.err <- messageCopy(ws, r.r, !r.protocols[r.selectedProtocol].Binary, r.ping, r.timeout)
+}
+
+func resetTimeout(ws *websocket.Conn, timeout time.Duration) {
+	if timeout > 0 {
+		ws.SetDeadline(time.Now().Add(timeout))
+	}
+}
+
+func messageCopy(ws *websocket.Conn, r io.Reader, base64Encode, ping bool, timeout time.Duration) error {
+	buf := make([]byte, 2048)
+	if ping {
+		resetTimeout(ws, timeout)
+		if base64Encode {
+			if err := websocket.Message.Send(ws, ""); err != nil {
+				return err
+			}
+		} else {
+			if err := websocket.Message.Send(ws, []byte{}); err != nil {
+				return err
+			}
+		}
+	}
+	for {
+		resetTimeout(ws, timeout)
+		n, err := r.Read(buf)
+		if err != nil {
+			if err == io.EOF {
+				return nil
+			}
+			return err
+		}
+		if n > 0 {
+			if base64Encode {
+				if err := websocket.Message.Send(ws, base64.StdEncoding.EncodeToString(buf[:n])); err != nil {
+					return err
+				}
+			} else {
+				if err := websocket.Message.Send(ws, buf[:n]); err != nil {
+					return err
+				}
+			}
+		}
+	}
+}