Merge pull request #462 from lucas-clemente/fix-461

fix detection of duplicate stream data in streamFrameSorter

stream_frame_sorter.go

@@ -51,14 +51,13 @@ func (s *streamFrameSorter) Push(frame *frames.StreamFrame) error {
 	start := frame.Offset
 	end := frame.Offset + frame.DataLen()
 
-	// the frame is a duplicate. Ignore it
-	if end <= s.gaps.Front().Value.Start {
-		return errDuplicateStreamData
-	}
-
 	// skip all gaps that are before this stream frame
 	var gap *utils.ByteIntervalElement
 	for gap = s.gaps.Front(); gap != nil; gap = gap.Next() {
+		// the frame is a duplicate. Ignore it
+		if end <= gap.Value.Start {
+			return errDuplicateStreamData
+		}
 		if end > gap.Value.Start && start <= gap.Value.End {
 			break
 		}

stream_frame_sorter_test.go

@@ -512,7 +512,7 @@ var _ = Describe("StreamFrame sorter", func() {
 				}
 
 				BeforeEach(func() {
-					// create gaps: 5-10, 15-20, 25-inf
+					// create gaps: 5-10, 15-inf
 					err := s.Push(&frames.StreamFrame{Offset: 0, Data: []byte("12345")})
 					Expect(err).ToNot(HaveOccurred())
 					err = s.Push(&frames.StreamFrame{Offset: 10, Data: []byte("12345")})
@@ -546,6 +546,22 @@ var _ = Describe("StreamFrame sorter", func() {
 					Expect(s.queuedFrames).ToNot(HaveKey(protocol.ByteCount(1)))
 				})
 
+				It("detects a duplicate frame that is smaller than the original, somewhere in the middle in the last block", func() {
+					// 11 to 14
+					err := s.Push(&frames.StreamFrame{Offset: 11, Data: []byte("123")})
+					Expect(err).To(MatchError(errDuplicateStreamData))
+					Expect(s.queuedFrames[10].Data).To(HaveLen(5))
+					Expect(s.queuedFrames).ToNot(HaveKey(protocol.ByteCount(11)))
+				})
+
+				It("detects a duplicate frame that is smaller than the original, with aligned end in the last block", func() {
+					// 11 to 14
+					err := s.Push(&frames.StreamFrame{Offset: 11, Data: []byte("1234")})
+					Expect(err).To(MatchError(errDuplicateStreamData))
+					Expect(s.queuedFrames[10].Data).To(HaveLen(5))
+					Expect(s.queuedFrames).ToNot(HaveKey(protocol.ByteCount(11)))
+				})
+
 				It("detects a duplicate frame that is smaller than the original, with aligned end", func() {
 					// 3 to 5
 					err := s.Push(&frames.StreamFrame{Offset: 3, Data: []byte("12")})