Record the last packet send time before we start sending the packet

net/quic/quic_connection_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_connection.h"
 
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/stl_util.h"
 #include "net/base/net_errors.h"
@@ skipping 242 matching lines @@
 
  private:
   MockClock* clock_;
   MockRandom* random_generator_;
 
   DISALLOW_COPY_AND_ASSIGN(TestConnectionHelper);
 };
 
 class TestPacketWriter : public QuicPacketWriter {
  public:
-  explicit TestPacketWriter(QuicVersion version)
+  TestPacketWriter(QuicVersion version, MockClock *clock)
       : version_(version),
         framer_(SupportedVersions(version_)),
         last_packet_size_(0),
         write_blocked_(false),
         block_on_next_write_(false),
         is_write_blocked_data_buffered_(false),
         final_bytes_of_last_packet_(0),
         final_bytes_of_previous_packet_(0),
         use_tagging_decrypter_(false),
-        packets_write_attempts_(0) {
+        packets_write_attempts_(0),
+        clock_(clock),
+        write_pause_time_delta_(QuicTime::Delta::Zero()) {
   }
 
   // QuicPacketWriter interface
   WriteResult WritePacket(const char* buffer,
                           size_t buf_len,
                           const IPAddressNumber& self_address,
                           const IPEndPoint& peer_address) override {
     QuicEncryptedPacket packet(buffer, buf_len);
     ++packets_write_attempts_;
 
     if (packet.length() >= sizeof(final_bytes_of_last_packet_)) {
       final_bytes_of_previous_packet_ = final_bytes_of_last_packet_;
       memcpy(&final_bytes_of_last_packet_, packet.data() + packet.length() - 4,
              sizeof(final_bytes_of_last_packet_));
     }
 
     if (use_tagging_decrypter_) {
       framer_.framer()->SetDecrypter(new TaggingDecrypter, ENCRYPTION_NONE);
     }
     EXPECT_TRUE(framer_.ProcessPacket(packet));
     if (block_on_next_write_) {
       write_blocked_ = true;
       block_on_next_write_ = false;
     }
     if (IsWriteBlocked()) {
       return WriteResult(WRITE_STATUS_BLOCKED, -1);
     }
     last_packet_size_ = packet.length();
+
+    if (!write_pause_time_delta_.IsZero()) {
+      clock_->AdvanceTime(write_pause_time_delta_);
+    }
     return WriteResult(WRITE_STATUS_OK, last_packet_size_);
   }
 
   bool IsWriteBlockedDataBuffered() const override {
     return is_write_blocked_data_buffered_;
   }
 
   bool IsWriteBlocked() const override { return write_blocked_; }
 
   void SetWritable() override { write_blocked_ = false; }
 
   void BlockOnNextWrite() { block_on_next_write_ = true; }
 
+  // Sets the amount of time that the writer should before the actual write.
+  void SetWritePauseTimeDelta(QuicTime::Delta delta) {
+    write_pause_time_delta_ = delta;
+  }
+
   const QuicPacketHeader& header() { return framer_.header(); }
 
   size_t frame_count() const { return framer_.num_frames(); }
 
   const vector<QuicAckFrame>& ack_frames() const {
     return framer_.ack_frames();
   }
 
   const vector<QuicCongestionFeedbackFrame>& feedback_frames() const {
     return framer_.feedback_frames();
@@ skipping 60 matching lines @@
   QuicVersion version_;
   SimpleQuicFramer framer_;
   size_t last_packet_size_;
   bool write_blocked_;
   bool block_on_next_write_;
   bool is_write_blocked_data_buffered_;
   uint32 final_bytes_of_last_packet_;
   uint32 final_bytes_of_previous_packet_;
   bool use_tagging_decrypter_;
   uint32 packets_write_attempts_;
+  MockClock *clock_;
+  // If non-zero, the clock will pause during WritePacket for this amount of
+  // time.
+  QuicTime::Delta write_pause_time_delta_;
 
   DISALLOW_COPY_AND_ASSIGN(TestPacketWriter);
 };
 
 class TestConnection : public QuicConnection {
  public:
   TestConnection(QuicConnectionId connection_id,
                  IPEndPoint address,
                  TestConnectionHelper* helper,
                  const PacketWriterFactory& factory,
@@ skipping 201 matching lines @@
 
 class QuicConnectionTest : public ::testing::TestWithParam<QuicVersion> {
  protected:
   QuicConnectionTest()
       : connection_id_(42),
         framer_(SupportedVersions(version()), QuicTime::Zero(), false),
         peer_creator_(connection_id_, &framer_, &random_generator_),
         send_algorithm_(new StrictMock<MockSendAlgorithm>),
         loss_algorithm_(new MockLossAlgorithm()),
         helper_(new TestConnectionHelper(&clock_, &random_generator_)),
-        writer_(new TestPacketWriter(version())),
+        writer_(new TestPacketWriter(version(), &clock_)),
         factory_(writer_.get()),
         connection_(connection_id_, IPEndPoint(), helper_.get(),
                     factory_, false, version()),
         frame1_(1, false, 0, MakeIOVector(data1)),
         frame2_(1, false, 3, MakeIOVector(data2)),
         sequence_number_length_(PACKET_6BYTE_SEQUENCE_NUMBER),
         connection_id_length_(PACKET_8BYTE_CONNECTION_ID) {
     connection_.set_visitor(&visitor_);
     connection_.SetSendAlgorithm(send_algorithm_);
     connection_.SetLossAlgorithm(loss_algorithm_);
@@ skipping 342 matching lines @@
     ProcessDataPacket(6000, 0, !kEntropyFlag);
     EXPECT_FALSE(QuicConnectionPeer::GetConnectionClosePacket(&connection_) ==
                  nullptr);
   }
 
   void BlockOnNextWrite() {
     writer_->BlockOnNextWrite();
     EXPECT_CALL(visitor_, OnWriteBlocked()).Times(AtLeast(1));
   }
 
+  void SetWritePauseTimeDelta(QuicTime::Delta delta) {
+    writer_->SetWritePauseTimeDelta(delta);
+  }
+
   void CongestionBlockWrites() {
     EXPECT_CALL(*send_algorithm_,
                 TimeUntilSend(_, _, _)).WillRepeatedly(
                     testing::Return(QuicTime::Delta::FromSeconds(1)));
   }
 
   void CongestionUnblockWrites() {
     EXPECT_CALL(*send_algorithm_,
                 TimeUntilSend(_, _, _)).WillRepeatedly(
                     testing::Return(QuicTime::Delta::Zero()));
@@ skipping 554 matching lines @@
   SendAckPacketToPeer();  // Packet 7
   EXPECT_EQ(7u, least_unacked());
 
   // But if we send more data it should.
   SendStreamDataToPeer(1, "eep", 6, !kFin, &last_packet);  // Packet 8
   EXPECT_EQ(8u, last_packet);
   SendAckPacketToPeer();  // Packet 9
   EXPECT_EQ(7u, least_unacked());
 }
 
+// If FLAGS_quic_record_send_time_before_write is disabled, QuicConnection
+// should record the packet sen-tdime after the packet is sent.
+TEST_P(QuicConnectionTest, RecordSentTimeAfterPacketSent) {
+  ValueRestore<bool> old_flag(&FLAGS_quic_record_send_time_before_write, false);
+  // We're using a MockClock for the tests, so we have complete control over the
+  // time.
+  // Our recorded timestamp for the last packet sent time will be passed in to
+  // the send_algorithm.  Make sure that it is set to the correct value.
+  QuicTime actual_recorded_send_time = QuicTime::Zero();
+  EXPECT_CALL(*send_algorithm_, OnPacketSent(_, _, _, _, _))
+      .WillOnce(DoAll(SaveArg<0>(&actual_recorded_send_time), Return(true)));
+
+  // First send without any pause and check the result.
+  QuicTime expected_recorded_send_time = clock_.Now();
+  connection_.SendStreamDataWithString(1, "foo", 0, !kFin, nullptr);
+  EXPECT_EQ(expected_recorded_send_time, actual_recorded_send_time)
+      << "Expected time = " << expected_recorded_send_time.ToDebuggingValue()
+      << ".  Actual time = " << actual_recorded_send_time.ToDebuggingValue();
+
+  // Now pause during the write, and check the results.
+  actual_recorded_send_time = QuicTime::Zero();
+  const QuicTime::Delta kWritePauseTimeDelta =
+      QuicTime::Delta::FromMilliseconds(5000);
+  SetWritePauseTimeDelta(kWritePauseTimeDelta);
+  expected_recorded_send_time = clock_.Now().Add(kWritePauseTimeDelta);
+
+  EXPECT_CALL(*send_algorithm_, OnPacketSent(_, _, _, _, _))
+      .WillOnce(DoAll(SaveArg<0>(&actual_recorded_send_time), Return(true)));
+  connection_.SendStreamDataWithString(2, "baz", 0, !kFin, nullptr);
+  EXPECT_EQ(expected_recorded_send_time, actual_recorded_send_time)
+      << "Expected time = " << expected_recorded_send_time.ToDebuggingValue()
+      << ".  Actual time = " << actual_recorded_send_time.ToDebuggingValue();
+}
+
+// If FLAGS_quic_record_send_time_before_write is enabled, QuicConnection should
+// record the the packet sent-time prior to sending the packet.
+TEST_P(QuicConnectionTest, RecordSentTimeBeforePacketSent) {
+  ValueRestore<bool> old_flag(&FLAGS_quic_record_send_time_before_write, true);
+  // We're using a MockClock for the tests, so we have complete control over the
+  // time.
+  // Our recorded timestamp for the last packet sent time will be passed in to
+  // the send_algorithm.  Make sure that it is set to the correct value.
+  QuicTime actual_recorded_send_time = QuicTime::Zero();
+  EXPECT_CALL(*send_algorithm_, OnPacketSent(_, _, _, _, _))
+      .WillOnce(DoAll(SaveArg<0>(&actual_recorded_send_time), Return(true)));
+
+  // First send without any pause and check the result.
+  QuicTime expected_recorded_send_time = clock_.Now();
+  connection_.SendStreamDataWithString(1, "foo", 0, !kFin, nullptr);
+  EXPECT_EQ(expected_recorded_send_time, actual_recorded_send_time)
+      << "Expected time = " << expected_recorded_send_time.ToDebuggingValue()
+      << ".  Actual time = " << actual_recorded_send_time.ToDebuggingValue();
+
+  // Now pause during the write, and check the results.
+  actual_recorded_send_time = QuicTime::Zero();
+  const QuicTime::Delta kWritePauseTimeDelta =
+      QuicTime::Delta::FromMilliseconds(5000);
+  SetWritePauseTimeDelta(kWritePauseTimeDelta);
+  expected_recorded_send_time = clock_.Now();
+
+  EXPECT_CALL(*send_algorithm_, OnPacketSent(_, _, _, _, _))
+      .WillOnce(DoAll(SaveArg<0>(&actual_recorded_send_time), Return(true)));
+  connection_.SendStreamDataWithString(2, "baz", 0, !kFin, nullptr);
+  EXPECT_EQ(expected_recorded_send_time, actual_recorded_send_time)
+      << "Expected time = " << expected_recorded_send_time.ToDebuggingValue()
+      << ".  Actual time = " << actual_recorded_send_time.ToDebuggingValue();
+}
+
 TEST_P(QuicConnectionTest, FECSending) {
   // All packets carry version info till version is negotiated.
   QuicPacketCreator* creator =
       QuicConnectionPeer::GetPacketCreator(&connection_);
   size_t payload_length;
   // GetPacketLengthForOneStream() assumes a stream offset of 0 in determining
   // packet length. The size of the offset field in a stream frame is 0 for
   // offset 0, and 2 for non-zero offsets up through 64K. Increase
   // max_packet_length by 2 so that subsequent packets containing subsequent
   // stream frames with non-zero offets will fit within the packet length.
@@ skipping 2535 matching lines @@
   QuicBlockedFrame blocked;
   blocked.stream_id = 3;
   EXPECT_CALL(visitor_, OnBlockedFrames(_));
   ProcessFramePacket(QuicFrame(&blocked));
   EXPECT_TRUE(ack_alarm->IsSet());
 }
 
 }  // namespace
 }  // namespace test
 }  // namespace net