Landing Recent QUIC changes until 2016-07-02 02:45 UTC

net/quic/congestion_control/general_loss_algorithm.cc

 // Copyright 2015 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/congestion_control/general_loss_algorithm.h"
 
 #include "net/quic/congestion_control/rtt_stats.h"
 #include "net/quic/quic_bug_tracker.h"
 #include "net/quic/quic_flags.h"
 #include "net/quic/quic_protocol.h"
@@ skipping 49 matching lines @@
     SendAlgorithmInterface::CongestionVector* packets_lost) {
   QuicPacketNumber largest_observed = unacked_packets.largest_observed();
   if (FLAGS_quic_loss_recovery_use_largest_acked) {
     largest_observed = largest_newly_acked;
   }
   loss_detection_timeout_ = QuicTime::Zero();
   QuicTime::Delta max_rtt =
       QuicTime::Delta::Max(rtt_stats.previous_srtt(), rtt_stats.latest_rtt());
   QuicTime::Delta loss_delay =
       QuicTime::Delta::Max(QuicTime::Delta::FromMilliseconds(kMinLossDelayMs),
-                           max_rtt.Add(max_rtt >> reordering_shift_));
+                           max_rtt + (max_rtt >> reordering_shift_));
   QuicPacketNumber packet_number = unacked_packets.GetLeastUnacked();
   for (QuicUnackedPacketMap::const_iterator it = unacked_packets.begin();
        it != unacked_packets.end() && packet_number <= largest_observed;
        ++it, ++packet_number) {
     if (!it->in_flight) {
       continue;
     }
 
     if (loss_type_ == kNack) {
       // FACK based loss detection.
       if (largest_observed - packet_number >=
           kNumberOfNacksBeforeRetransmission) {
         packets_lost->push_back(std::make_pair(packet_number, it->bytes_sent));
         continue;
       }
     }
 
     // Only early retransmit(RFC5827) when the last packet gets acked and
     // there are retransmittable packets in flight.
     // This also implements a timer-protected variant of FACK.
     if ((!it->retransmittable_frames.empty() &&
          unacked_packets.largest_sent_packet() == largest_observed) ||
         (loss_type_ == kTime || loss_type_ == kAdaptiveTime)) {
-      QuicTime when_lost = it->sent_time.Add(loss_delay);
+      QuicTime when_lost = it->sent_time + loss_delay;
       if (time < when_lost) {
         loss_detection_timeout_ = when_lost;
         break;
       }
       packets_lost->push_back(std::make_pair(packet_number, it->bytes_sent));
       continue;
     }
 
     // NACK-based loss detection allows for a max reordering window of 1 RTT.
-    if (it->sent_time.Add(rtt_stats.smoothed_rtt()) <
+    if (it->sent_time + rtt_stats.smoothed_rtt() <
         unacked_packets.GetTransmissionInfo(largest_observed).sent_time) {
       packets_lost->push_back(std::make_pair(packet_number, it->bytes_sent));
       continue;
     }
   }
 }
 
 QuicTime GeneralLossAlgorithm::GetLossTimeout() const {
   return loss_detection_timeout_;
 }
 
 void GeneralLossAlgorithm::SpuriousRetransmitDetected(
     const QuicUnackedPacketMap& unacked_packets,
     QuicTime time,
     const RttStats& rtt_stats,
     QuicPacketNumber spurious_retransmission) {
   if (loss_type_ != kAdaptiveTime || reordering_shift_ == 0) {
     return;
   }
   if (spurious_retransmission <= largest_sent_on_spurious_retransmit_) {
     return;
   }
   largest_sent_on_spurious_retransmit_ = unacked_packets.largest_sent_packet();
   // Calculate the extra time needed so this wouldn't have been declared lost.
   // Extra time needed is based on how long it's been since the spurious
   // retransmission was sent, because the SRTT and latest RTT may have changed.
-  QuicTime::Delta extra_time_needed = time.Subtract(
-      unacked_packets.GetTransmissionInfo(spurious_retransmission).sent_time);
+  QuicTime::Delta extra_time_needed =
+      time -
+      unacked_packets.GetTransmissionInfo(spurious_retransmission).sent_time;
   // Increase the reordering fraction until enough time would be allowed.
   QuicTime::Delta max_rtt =
       QuicTime::Delta::Max(rtt_stats.previous_srtt(), rtt_stats.latest_rtt());
   QuicTime::Delta proposed_extra_time(QuicTime::Delta::Zero());
   do {
     proposed_extra_time = max_rtt >> reordering_shift_;
     --reordering_shift_;
   } while (proposed_extra_time < extra_time_needed && reordering_shift_ > 0);
 }
 
 }  // namespace net