Ensure the UnackedPacketMap only keeps one previous transmission less

net/quic/quic_unacked_packet_map_test.cc

Index: net/quic/quic_unacked_packet_map_test.cc
diff --git a/net/quic/quic_unacked_packet_map_test.cc b/net/quic/quic_unacked_packet_map_test.cc
index c5264fd16e906db066c02a598f6411dde8b5b1ce..87c6ca818fbb0afe77a54935deb6b4ed124e553e 100644
--- a/net/quic/quic_unacked_packet_map_test.cc
+++ b/net/quic/quic_unacked_packet_map_test.cc
@@ -33,8 +33,8 @@ class QuicUnackedPacketMapTest : public ::testing::Test {
         sequence_number, PACKET_1BYTE_SEQUENCE_NUMBER, NULL, 0, NULL);
   }
 
-  void VerifyPendingPackets(QuicPacketSequenceNumber* packets,
-                            size_t num_packets) {
+  void VerifyInFlightPackets(QuicPacketSequenceNumber* packets,
+                             size_t num_packets) {
     if (num_packets == 0) {
       EXPECT_FALSE(unacked_packets_.HasInFlightPackets());
       EXPECT_FALSE(unacked_packets_.HasMultipleInFlightPackets());
@@ -43,11 +43,21 @@ class QuicUnackedPacketMapTest : public ::testing::Test {
     if (num_packets == 1) {
       EXPECT_TRUE(unacked_packets_.HasInFlightPackets());
       EXPECT_FALSE(unacked_packets_.HasMultipleInFlightPackets());
+      ASSERT_TRUE(unacked_packets_.IsUnacked(packets[0]));
+      EXPECT_TRUE(unacked_packets_.GetTransmissionInfo(packets[0]).in_flight);
     }
     for (size_t i = 0; i < num_packets; ++i) {
       ASSERT_TRUE(unacked_packets_.IsUnacked(packets[i]));
       EXPECT_TRUE(unacked_packets_.GetTransmissionInfo(packets[i]).in_flight);
     }
+    size_t in_flight_count = 0;
+    for (QuicUnackedPacketMap::const_iterator it = unacked_packets_.begin();
+         it != unacked_packets_.end(); ++it) {
+      if (it->second.in_flight) {
+        ++in_flight_count;
+      }
+    }
+    EXPECT_EQ(num_packets, in_flight_count);
   }
 
   void VerifyUnackedPackets(QuicPacketSequenceNumber* packets,
@@ -61,6 +71,12 @@ class QuicUnackedPacketMapTest : public ::testing::Test {
     for (size_t i = 0; i < num_packets; ++i) {
       EXPECT_TRUE(unacked_packets_.IsUnacked(packets[i])) << packets[i];
     }
+    size_t unacked_count = 0;
+    for (QuicUnackedPacketMap::const_iterator it = unacked_packets_.begin();
+         it != unacked_packets_.end(); ++it) {
+      ++unacked_count;
+    }
+    EXPECT_EQ(num_packets, unacked_count);
   }
 
   void VerifyRetransmittablePackets(QuicPacketSequenceNumber* packets,
@@ -90,12 +106,12 @@ TEST_F(QuicUnackedPacketMapTest, RttOnly) {
 
   QuicPacketSequenceNumber unacked[] = { 1 };
   VerifyUnackedPackets(unacked, arraysize(unacked));
-  VerifyPendingPackets(NULL, 0);
+  VerifyInFlightPackets(NULL, 0);
   VerifyRetransmittablePackets(NULL, 0);
 
   unacked_packets_.IncreaseLargestObserved(1);
   VerifyUnackedPackets(NULL, 0);
-  VerifyPendingPackets(NULL, 0);
+  VerifyInFlightPackets(NULL, 0);
   VerifyRetransmittablePackets(NULL, 0);
 }
 
@@ -106,22 +122,22 @@ TEST_F(QuicUnackedPacketMapTest, RetransmittableInflightAndRtt) {
 
   QuicPacketSequenceNumber unacked[] = { 1 };
   VerifyUnackedPackets(unacked, arraysize(unacked));
-  VerifyPendingPackets(unacked, arraysize(unacked));
+  VerifyInFlightPackets(unacked, arraysize(unacked));
   VerifyRetransmittablePackets(unacked, arraysize(unacked));
 
   unacked_packets_.RemoveRetransmittability(1);
   VerifyUnackedPackets(unacked, arraysize(unacked));
-  VerifyPendingPackets(unacked, arraysize(unacked));
+  VerifyInFlightPackets(unacked, arraysize(unacked));
   VerifyRetransmittablePackets(NULL, 0);
 
   unacked_packets_.IncreaseLargestObserved(1);
   VerifyUnackedPackets(unacked, arraysize(unacked));
-  VerifyPendingPackets(unacked, arraysize(unacked));
+  VerifyInFlightPackets(unacked, arraysize(unacked));
   VerifyRetransmittablePackets(NULL, 0);
 
   unacked_packets_.RemoveFromInFlight(1);
   VerifyUnackedPackets(NULL, 0);
-  VerifyPendingPackets(NULL, 0);
+  VerifyInFlightPackets(NULL, 0);
   VerifyRetransmittablePackets(NULL, 0);
 }
 
@@ -135,32 +151,78 @@ TEST_F(QuicUnackedPacketMapTest, RetransmittedPacket) {
 
   QuicPacketSequenceNumber unacked[] = { 1, 2 };
   VerifyUnackedPackets(unacked, arraysize(unacked));
-  VerifyPendingPackets(unacked, arraysize(unacked));
+  VerifyInFlightPackets(unacked, arraysize(unacked));
   QuicPacketSequenceNumber retransmittable[] = { 2 };
   VerifyRetransmittablePackets(retransmittable, arraysize(retransmittable));
 
   unacked_packets_.RemoveRetransmittability(1);
   VerifyUnackedPackets(unacked, arraysize(unacked));
-  VerifyPendingPackets(unacked, arraysize(unacked));
+  VerifyInFlightPackets(unacked, arraysize(unacked));
   VerifyRetransmittablePackets(NULL, 0);
 
   unacked_packets_.IncreaseLargestObserved(2);
   VerifyUnackedPackets(unacked, arraysize(unacked));
-  VerifyPendingPackets(unacked, arraysize(unacked));
+  VerifyInFlightPackets(unacked, arraysize(unacked));
   VerifyRetransmittablePackets(NULL, 0);
 
   unacked_packets_.RemoveFromInFlight(2);
   QuicPacketSequenceNumber unacked2[] = { 1 };
   VerifyUnackedPackets(unacked, arraysize(unacked2));
-  VerifyPendingPackets(unacked, arraysize(unacked2));
+  VerifyInFlightPackets(unacked, arraysize(unacked2));
   VerifyRetransmittablePackets(NULL, 0);
 
   unacked_packets_.RemoveFromInFlight(1);
   VerifyUnackedPackets(NULL, 0);
-  VerifyPendingPackets(NULL, 0);
+  VerifyInFlightPackets(NULL, 0);
   VerifyRetransmittablePackets(NULL, 0);
 }
 
+TEST_F(QuicUnackedPacketMapTest, RetransmitTwice) {
+  // Simulate a retransmittable packet being sent and retransmitted twice.
+  unacked_packets_.AddPacket(CreateRetransmittablePacket(1));
+  unacked_packets_.SetSent(1, now_, kDefaultLength, true);
+  unacked_packets_.AddPacket(CreateRetransmittablePacket(2));
+  unacked_packets_.SetSent(2, now_, kDefaultLength, true);
+
+  QuicPacketSequenceNumber unacked[] = { 1, 2 };
+  VerifyUnackedPackets(unacked, arraysize(unacked));
+  VerifyInFlightPackets(unacked, arraysize(unacked));
+  QuicPacketSequenceNumber retransmittable[] = { 1, 2 };
+  VerifyRetransmittablePackets(retransmittable, arraysize(retransmittable));
+
+  // Early retransmit 1 as 3 and send new data as 4.
+  unacked_packets_.IncreaseLargestObserved(2);
+  unacked_packets_.RemoveFromInFlight(2);
+  unacked_packets_.RemoveRetransmittability(2);
+  unacked_packets_.RemoveFromInFlight(1);
+  unacked_packets_.OnRetransmittedPacket(1, 3, LOSS_RETRANSMISSION);
+  unacked_packets_.SetSent(3, now_, kDefaultLength, true);
+  unacked_packets_.AddPacket(CreateRetransmittablePacket(4));
+  unacked_packets_.SetSent(4, now_, kDefaultLength, true);
+
+  QuicPacketSequenceNumber unacked2[] = { 1, 3, 4 };
+  VerifyUnackedPackets(unacked2, arraysize(unacked2));
+  QuicPacketSequenceNumber pending2[] = { 3, 4, };
+  VerifyInFlightPackets(pending2, arraysize(pending2));
+  QuicPacketSequenceNumber retransmittable2[] = { 3, 4 };
+  VerifyRetransmittablePackets(retransmittable2, arraysize(retransmittable2));
+
+  // Early retransmit 3 (formerly 1) as 5, and remove 1 from unacked.
+  unacked_packets_.IncreaseLargestObserved(4);
+  unacked_packets_.RemoveFromInFlight(4);
+  unacked_packets_.RemoveRetransmittability(4);
+  unacked_packets_.RemoveFromInFlight(3);
+  unacked_packets_.OnRetransmittedPacket(3, 5, LOSS_RETRANSMISSION);
+  unacked_packets_.SetSent(5, now_, kDefaultLength, true);
+
+  QuicPacketSequenceNumber unacked3[] = { 3, 5 };
+  VerifyUnackedPackets(unacked3, arraysize(unacked3));
+  QuicPacketSequenceNumber pending3[] = { 5 };
+  VerifyInFlightPackets(pending3, arraysize(pending3));
+  QuicPacketSequenceNumber retransmittable3[] = { 5 };
+  VerifyRetransmittablePackets(retransmittable3, arraysize(retransmittable3));
+}
+
 }  // namespace
 }  // namespace test
 }  // namespace net