Adds dynamic setting of FEC group size based on the connection's current

net/quic/quic_packet_generator_test.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/quic/quic_packet_generator.h"
 
 #include <string>
 
 #include "net/quic/crypto/crypto_protocol.h"
 #include "net/quic/crypto/null_encrypter.h"
@@ skipping 545 matching lines @@
   EXPECT_EQ(3u, consumed.bytes_consumed);
   EXPECT_TRUE(consumed.fin_consumed);
   EXPECT_FALSE(generator_.HasQueuedFrames());
 
   PacketContents contents;
   contents.num_stream_frames = 1;
   CheckPacketContains(contents, packet_);
   CheckPacketContains(contents, packet2_);
 }
 
+TEST_F(QuicPacketGeneratorTest, FecGroupSizeOnCongestionWindowChange) {
+  delegate_.SetCanWriteAnything();
+  creator_->set_max_packets_per_fec_group(50);
+  EXPECT_EQ(50u, creator_->max_packets_per_fec_group());
+  EXPECT_FALSE(creator_->IsFecGroupOpen());
+
+  // On reduced cwnd.
+  generator_.OnCongestionWindowChange(7 * kDefaultTCPMSS);
+  EXPECT_EQ(3u, creator_->max_packets_per_fec_group());
+
+  // On increased cwnd.
+  generator_.OnCongestionWindowChange(100 * kDefaultTCPMSS);
+  EXPECT_EQ(50u, creator_->max_packets_per_fec_group());
+
+  // On collapsed cwnd.
+  generator_.OnCongestionWindowChange(1 * kDefaultTCPMSS);
+  EXPECT_EQ(2u, creator_->max_packets_per_fec_group());
+}
+
+TEST_F(QuicPacketGeneratorTest, FecGroupSizeChangeWithOpenGroup) {
+  delegate_.SetCanWriteAnything();
+  // TODO(jri): This starting of batch mode should not be required when
+  // FEC sending is separated from batching operations.
+  generator_.StartBatchOperations();
+  creator_->set_max_packets_per_fec_group(50);
+  EXPECT_EQ(50u, creator_->max_packets_per_fec_group());
+  EXPECT_FALSE(creator_->IsFecGroupOpen());
+
+  // Send enough data to create 4 packets with MUST_FEC_PROTECT flag.
+  // 3 packets are sent, one is queued in the creator.
+  {
+    InSequence dummy;
+    EXPECT_CALL(delegate_, OnSerializedPacket(_)).WillOnce(
+        DoAll(SaveArg<0>(&packet_), Return(true)));
+    EXPECT_CALL(delegate_, OnSerializedPacket(_)).WillOnce(
+        DoAll(SaveArg<0>(&packet2_), Return(true)));
+    EXPECT_CALL(delegate_, OnSerializedPacket(_)).WillOnce(
+        DoAll(SaveArg<0>(&packet3_), Return(true)));
+  }
+  size_t data_len = 3 * kDefaultMaxPacketSize + 1;
+  QuicConsumedData consumed = generator_.ConsumeData(
+      7, CreateData(data_len), 0, true, MUST_FEC_PROTECT, NULL);
+  EXPECT_EQ(data_len, consumed.bytes_consumed);
+  EXPECT_TRUE(creator_->IsFecGroupOpen());
+
+  // Change FEC groupsize.
+  generator_.OnCongestionWindowChange(2 * kDefaultTCPMSS);
+  EXPECT_EQ(2u, creator_->max_packets_per_fec_group());
+
+  // Send enough data to trigger one unprotected data packet,
+  // causing the FEC packet to also be sent.
+  {
+    InSequence dummy;
+    EXPECT_CALL(delegate_, OnSerializedPacket(_)).WillOnce(
+        DoAll(SaveArg<0>(&packet4_), Return(true)));
+    EXPECT_CALL(delegate_, OnSerializedPacket(_)).WillOnce(
+        DoAll(SaveArg<0>(&packet5_), Return(true)));
+  }
+  consumed = generator_.ConsumeData(7, CreateData(kDefaultMaxPacketSize), 0,
+                                    true, MAY_FEC_PROTECT, NULL);
+  EXPECT_EQ(kDefaultMaxPacketSize, consumed.bytes_consumed);
+  // Verify that one FEC packet was sent.
+  CheckPacketIsFec(packet5_, /*fec_group=*/1u);
+  EXPECT_FALSE(creator_->IsFecGroupOpen());
+  EXPECT_FALSE(creator_->IsFecProtected());
+}
+
 TEST_F(QuicPacketGeneratorTest, SwitchFecOnOff) {
   delegate_.SetCanWriteAnything();
-  // Enable FEC.
   creator_->set_max_packets_per_fec_group(2);
   EXPECT_FALSE(creator_->IsFecProtected());
 
   // Send one unprotected data packet.
   EXPECT_CALL(delegate_, OnSerializedPacket(_)).WillOnce(
         DoAll(SaveArg<0>(&packet_), Return(true)));
   QuicConsumedData consumed =
       generator_.ConsumeData(5, CreateData(1u), 0, true, MAY_FEC_PROTECT,
                              NULL);
   EXPECT_EQ(1u, consumed.bytes_consumed);
@@ skipping 318 matching lines @@
 
   // The second should have the remainder of the stream data.
   PacketContents contents2;
   contents2.num_goaway_frames = 1;
   contents2.num_stream_frames = 1;
   CheckPacketContains(contents2, packet2_);
 }
 
 }  // namespace test
 }  // namespace net