update vendor

Signed-off-by: Jess Frazelle <acidburn@microsoft.com>

vendor/github.com/docker/distribution/registry/handlers/helpers.go

@@ -0,0 +1,66 @@
+package handlers
+
+import (
+	"context"
+	"errors"
+	"io"
+	"net/http"
+
+	dcontext "github.com/docker/distribution/context"
+)
+
+// closeResources closes all the provided resources after running the target
+// handler.
+func closeResources(handler http.Handler, closers ...io.Closer) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		for _, closer := range closers {
+			defer closer.Close()
+		}
+		handler.ServeHTTP(w, r)
+	})
+}
+
+// copyFullPayload copies the payload of an HTTP request to destWriter. If it
+// receives less content than expected, and the client disconnected during the
+// upload, it avoids sending a 400 error to keep the logs cleaner.
+//
+// The copy will be limited to `limit` bytes, if limit is greater than zero.
+func copyFullPayload(ctx context.Context, responseWriter http.ResponseWriter, r *http.Request, destWriter io.Writer, limit int64, action string) error {
+	// Get a channel that tells us if the client disconnects
+	clientClosed := r.Context().Done()
+	var body = r.Body
+	if limit > 0 {
+		body = http.MaxBytesReader(responseWriter, body, limit)
+	}
+
+	// Read in the data, if any.
+	copied, err := io.Copy(destWriter, body)
+	if clientClosed != nil && (err != nil || (r.ContentLength > 0 && copied < r.ContentLength)) {
+		// Didn't receive as much content as expected. Did the client
+		// disconnect during the request? If so, avoid returning a 400
+		// error to keep the logs cleaner.
+		select {
+		case <-clientClosed:
+			// Set the response code to "499 Client Closed Request"
+			// Even though the connection has already been closed,
+			// this causes the logger to pick up a 499 error
+			// instead of showing 0 for the HTTP status.
+			responseWriter.WriteHeader(499)
+
+			dcontext.GetLoggerWithFields(ctx, map[interface{}]interface{}{
+				"error":         err,
+				"copied":        copied,
+				"contentLength": r.ContentLength,
+			}, "error", "copied", "contentLength").Error("client disconnected during " + action)
+			return errors.New("client disconnected")
+		default:
+		}
+	}
+
+	if err != nil {
+		dcontext.GetLogger(ctx).Errorf("unknown error reading request payload: %v", err)
+		return err
+	}
+
+	return nil
+}