Move retransmittable frame logic to the ackhandler package

ackhandler/retransmittable.go

@@ -0,0 +1,38 @@
+package ackhandler
+
+import (
+	"github.com/lucas-clemente/quic-go/frames"
+)
+
+// Returns a new slice with all non-retransmittable frames deleted.
+func stripNonRetransmittableFrames(fs []frames.Frame) []frames.Frame {
+	res := make([]frames.Frame, 0, len(fs))
+	for _, f := range fs {
+		if IsFrameRetransmittable(f) {
+			res = append(res, f)
+		}
+	}
+	return res
+}
+
+// IsFrameRetransmittable returns true if the frame should be retransmitted.
+func IsFrameRetransmittable(f frames.Frame) bool {
+	switch f.(type) {
+	case *frames.StopWaitingFrame:
+		return false
+	case *frames.AckFrame:
+		return false
+	default:
+		return true
+	}
+}
+
+// HasRetransmittableFrames returns true if at least one frame is retransmittable.
+func HasRetransmittableFrames(fs []frames.Frame) bool {
+	for _, f := range fs {
+		if IsFrameRetransmittable(f) {
+			return true
+		}
+	}
+	return false
+}

ackhandler/retransmittable_test.go

@@ -0,0 +1,44 @@
+package ackhandler
+
+import (
+	"reflect"
+
+	"github.com/lucas-clemente/quic-go/frames"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("retransmittable frames", func() {
+	for fl, el := range map[frames.Frame]bool{
+		&frames.AckFrame{}:             false,
+		&frames.StopWaitingFrame{}:     false,
+		&frames.BlockedFrame{}:         true,
+		&frames.ConnectionCloseFrame{}: true,
+		&frames.GoawayFrame{}:          true,
+		&frames.PingFrame{}:            true,
+		&frames.RstStreamFrame{}:       true,
+		&frames.StreamFrame{}:          true,
+		&frames.WindowUpdateFrame{}:    true,
+	} {
+		f := fl
+		e := el
+		fName := reflect.ValueOf(f).Elem().Type().Name()
+
+		It("works for "+fName, func() {
+			Expect(IsFrameRetransmittable(f)).To(Equal(e))
+		})
+
+		It("stripping non-retransmittable frames works for "+fName, func() {
+			s := []frames.Frame{f}
+			if e {
+				Expect(stripNonRetransmittableFrames(s)).To(Equal([]frames.Frame{f}))
+			} else {
+				Expect(stripNonRetransmittableFrames(s)).To(BeEmpty())
+			}
+		})
+
+		It("HasRetransmittableFrames works for "+fName, func() {
+			Expect(HasRetransmittableFrames([]frames.Frame{f})).To(Equal(e))
+		})
+	}
+})