implement a StreamFrame Queue to handle high priority StreamFrames for retransmission

fixes #21

stream_frame_queue_test.go

@@ -0,0 +1,114 @@
+package quic
+
+import (
+	"github.com/lucas-clemente/quic-go/frames"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("StreamFrameQueue", func() {
+	var prioFrame1, prioFrame2 *frames.StreamFrame
+	var frame1, frame2 *frames.StreamFrame
+	var queue StreamFrameQueue
+
+	BeforeEach(func() {
+		queue = StreamFrameQueue{}
+		prioFrame1 = &frames.StreamFrame{
+			StreamID: 5,
+			Data:     []byte{0x13, 0x37},
+		}
+		prioFrame2 = &frames.StreamFrame{
+			StreamID: 6,
+			Data:     []byte{0xDE, 0xCA, 0xFB, 0xAD},
+		}
+		frame1 = &frames.StreamFrame{
+			StreamID: 10,
+			Data:     []byte{0xCA, 0xFE},
+		}
+		frame2 = &frames.StreamFrame{
+			StreamID: 11,
+			Data:     []byte{0xDE, 0xAD, 0xBE, 0xEF},
+		}
+	})
+
+	Context("Queue Length", func() {
+		It("returns the correct length for an empty queue", func() {
+			Expect(queue.Len()).To(BeZero())
+		})
+
+		It("returns the correct lengths for a queue", func() {
+			queue.Push(prioFrame1, true)
+			Expect(queue.Len()).To(Equal(1))
+			queue.Push(frame1, false)
+			queue.Push(frame2, false)
+			Expect(queue.Len()).To(Equal(3))
+		})
+
+		It("returns the correct length when popping", func() {
+			queue.Push(prioFrame1, true)
+			queue.Push(prioFrame2, true)
+			queue.Push(frame1, false)
+			queue.Push(frame2, false)
+			Expect(queue.Len()).To(Equal(4))
+			queue.Pop()
+			Expect(queue.Len()).To(Equal(3))
+			queue.Pop()
+			queue.Pop()
+			queue.Pop()
+			Expect(queue.Len()).To(Equal(0))
+		})
+	})
+
+	Context("Popping", func() {
+		It("returns nil when popping an empty queue", func() {
+			Expect(queue.Pop()).To(BeNil())
+		})
+
+		It("deletes elements once they are popped", func() {
+			queue.Push(frame1, false)
+			Expect(queue.Pop()).To(Equal(frame1))
+			Expect(queue.Pop()).To(BeNil())
+		})
+
+		It("returns normal frames if no prio frames are available", func() {
+			queue.Push(frame1, false)
+			queue.Push(frame2, false)
+			Expect(queue.Pop()).To(Equal(frame1))
+			Expect(queue.Pop()).To(Equal(frame2))
+		})
+
+		It("returns prio frames first", func() {
+			queue.Push(prioFrame1, true)
+			queue.Push(frame1, false)
+			queue.Push(frame2, false)
+			queue.Push(prioFrame2, true)
+			Expect(queue.Pop()).To(Equal(prioFrame1))
+			Expect(queue.Pop()).To(Equal(prioFrame2))
+			Expect(queue.Pop()).To(Equal(frame1))
+		})
+	})
+
+	Context("Front", func() {
+		It("returns nil for an empty queue", func() {
+			Expect(queue.Front()).To(BeNil())
+		})
+
+		It("returns normal frames if no prio frames are available", func() {
+			queue.Push(frame1, false)
+			queue.Push(frame2, false)
+			Expect(queue.Front()).To(Equal(frame1))
+			Expect(queue.Len()).To(Equal(2))
+			Expect(queue.Front()).To(Equal(frame1))
+			Expect(queue.Len()).To(Equal(2))
+		})
+
+		It("returns prio frames first", func() {
+			queue.Push(prioFrame1, true)
+			queue.Push(frame1, false)
+			queue.Push(frame2, false)
+			queue.Push(prioFrame2, true)
+			Expect(queue.Front()).To(Equal(prioFrame1))
+			Expect(queue.Len()).To(Equal(4))
+		})
+	})
+})