Discard all useless QUIC retransmissions instead of only the most recent

net/quic/quic_unacked_packet_map.cc

 // Copyright 2014 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_unacked_packet_map.h"
 
 #include "base/logging.h"
 #include "base/stl_util.h"
 #include "net/quic/quic_connection_stats.h"
 #include "net/quic/quic_utils_chromium.h"
@@ skipping 42 matching lines @@
           == IS_HANDSHAKE) {
     ++pending_crypto_packet_count_;
   }
 }
 
 void QuicUnackedPacketMap::RemoveObsoletePackets() {
   while (!unacked_packets_.empty()) {
     if (!IsPacketRemovable(least_unacked_, unacked_packets_.front())) {
       break;
     }
-    delete unacked_packets_.front().all_transmissions;
     unacked_packets_.pop_front();
     ++least_unacked_;
   }
 }
 
 void QuicUnackedPacketMap::OnRetransmittedPacket(
     QuicPacketSequenceNumber old_sequence_number,
     QuicPacketSequenceNumber new_sequence_number,
     TransmissionType transmission_type) {
   DCHECK_GE(old_sequence_number, least_unacked_);
@@ skipping 10 matching lines @@
   RetransmittableFrames* frames = transmission_info->retransmittable_frames;
   LOG_IF(DFATAL, frames == NULL) << "Attempt to retransmit packet with no "
                                  << "retransmittable frames: "
                                  << old_sequence_number;
 
   // We keep the old packet in the unacked packet list until it, or one of
   // the retransmissions of it are acked.
   transmission_info->retransmittable_frames = NULL;
   // Only keep one transmission older than largest observed, because only the
   // most recent is expected to possibly be a spurious retransmission.
-  if (transmission_info->all_transmissions != NULL &&
-      *(++transmission_info->all_transmissions->begin()) < largest_observed_) {
+  while (transmission_info->all_transmissions != NULL &&
+         transmission_info->all_transmissions->size() > 1 &&
+         *(++transmission_info->all_transmissions->begin())
+             < largest_observed_) {
     QuicPacketSequenceNumber old_transmission =
         *transmission_info->all_transmissions->begin();
     TransmissionInfo* old_info =
         &unacked_packets_[old_transmission - least_unacked_];
     // Don't remove old packets if they're still in flight.
-    if (!old_info->in_flight) {
-      old_info->all_transmissions->pop_front();
-      // This will cause the packet be removed in RemoveObsoletePackets.
-      old_info->all_transmissions = NULL;
+    if (old_info->in_flight) {
+      break;
     }
+    old_info->all_transmissions->pop_front();
+    // This will cause the packet be removed in RemoveObsoletePackets.
+    old_info->all_transmissions = NULL;
   }
   // Don't link old transmissions to new ones when version or
   // encryption changes.
   if (transmission_type == ALL_INITIAL_RETRANSMISSION ||
       transmission_type == ALL_UNACKED_RETRANSMISSION) {
     RemoveAckability(transmission_info);
   } else {
     if (transmission_info->all_transmissions == NULL) {
       transmission_info->all_transmissions = new SequenceNumberList();
       transmission_info->all_transmissions->push_back(old_sequence_number);
@@ skipping 267 matching lines @@
   TransmissionInfo* info = &unacked_packets_[sequence_number - least_unacked_];
   DCHECK(!info->in_flight);
   DCHECK_NE(0u, info->bytes_sent);
   DCHECK(info->sent_time.IsInitialized());
 
   bytes_in_flight_ += info->bytes_sent;
   info->in_flight = true;
 }
 
 }  // namespace net