Add an IncreaseLargestObserved to QuicUnackedPacketMap to remove the rtt

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"
 
 using std::max;
 
 namespace net {
 
 QuicUnackedPacketMap::QuicUnackedPacketMap()
     : largest_sent_packet_(0),
+      largest_observed_(0),
       bytes_in_flight_(0),
       pending_crypto_packet_count_(0) {
 }
 
 QuicUnackedPacketMap::~QuicUnackedPacketMap() {
   for (UnackedPacketMap::iterator it = unacked_packets_.begin();
        it != unacked_packets_.end(); ++it) {
     delete it->second.retransmittable_frames;
     // Only delete all_transmissions once, for the newest packet.
     if (it->first == *it->second.all_transmissions->rbegin()) {
@@ skipping 88 matching lines @@
   if (it == unacked_packets_.end()) {
     LOG(DFATAL) << "NackPacket called for packet that is not unacked: "
                 << sequence_number;
     return;
   }
 
   it->second.nack_count = max(min_nacks, it->second.nack_count);
 }
 
 void QuicUnackedPacketMap::RemoveRetransmittability(
-    QuicPacketSequenceNumber sequence_number,
-    QuicPacketSequenceNumber largest_observed) {
+    QuicPacketSequenceNumber sequence_number) {
   UnackedPacketMap::iterator it = unacked_packets_.find(sequence_number);
   if (it == unacked_packets_.end()) {
-    LOG(DFATAL) << "packet is not unacked: " << sequence_number;
+    DVLOG(1) << "packet is not in unacked_packets: " << sequence_number;
     return;
   }
   SequenceNumberSet* all_transmissions = it->second.all_transmissions;
   // TODO(ianswett): Consider optimizing this for lone packets.
-  // TODO(ianswett): Consider adding a check to ensure there are retranmittable
+  // TODO(ianswett): Consider adding a check to ensure there are retransmittable
   // frames associated with this packet.
   for (SequenceNumberSet::reverse_iterator it = all_transmissions->rbegin();
        it != all_transmissions->rend(); ++it) {
     TransmissionInfo* transmission_info = FindOrNull(unacked_packets_, *it);
     if (transmission_info == NULL) {
       LOG(DFATAL) << "All transmissions in all_transmissions must be present "
                   << "in the unacked packet map.";
       continue;
     }
     MaybeRemoveRetransmittableFrames(transmission_info);
-    if (sequence_number <= largest_observed && !transmission_info->pending) {
+    if (*it <= largest_observed_ && !transmission_info->pending) {
       unacked_packets_.erase(*it);
     } else {
       transmission_info->all_transmissions = new SequenceNumberSet();
       transmission_info->all_transmissions->insert(*it);
     }
   }
 
   delete all_transmissions;
 }
 
 void QuicUnackedPacketMap::MaybeRemoveRetransmittableFrames(
     TransmissionInfo* transmission_info) {
   if (transmission_info->retransmittable_frames != NULL) {
     if (transmission_info->retransmittable_frames->HasCryptoHandshake()
             == IS_HANDSHAKE) {
       --pending_crypto_packet_count_;
     }
     delete transmission_info->retransmittable_frames;
     transmission_info->retransmittable_frames = NULL;
   }
 }
 
-void QuicUnackedPacketMap::RemoveRttOnlyPacket(
-    QuicPacketSequenceNumber sequence_number) {
-  UnackedPacketMap::iterator it = unacked_packets_.find(sequence_number);
-  if (it == unacked_packets_.end()) {
-    LOG(DFATAL) << "packet is not unacked: " << sequence_number;
-    return;
+void QuicUnackedPacketMap::IncreaseLargestObserved(
+    QuicPacketSequenceNumber largest_observed) {
+  DCHECK_LT(largest_observed_, largest_observed);
+  largest_observed_ = largest_observed;
+  UnackedPacketMap::iterator it = unacked_packets_.begin();
+  while (it != unacked_packets_.end() && it->first <= largest_observed_) {
+    if (!IsPacketUseless(it)) {
+      ++it;
+      continue;
+    }
+    delete it->second.all_transmissions;
+    QuicPacketSequenceNumber sequence_number = it->first;
+    ++it;
+    unacked_packets_.erase(sequence_number);
   }
-  TransmissionInfo* transmission_info = &it->second;
-  DCHECK(!transmission_info->pending);
-  DCHECK(transmission_info->retransmittable_frames == NULL);
-  DCHECK_EQ(1u, transmission_info->all_transmissions->size());
-  delete transmission_info->all_transmissions;
-  unacked_packets_.erase(it);
 }
 
-// static
-bool QuicUnackedPacketMap::IsForRttOnly(
-    const TransmissionInfo& transmission_info) {
-  return !transmission_info.pending &&
-      transmission_info.retransmittable_frames == NULL &&
-      transmission_info.all_transmissions->size() == 1;
+bool QuicUnackedPacketMap::IsPacketUseless(
+    UnackedPacketMap::const_iterator it) {
+  return it->first <= largest_observed_ &&
+      !it->second.pending &&
+      it->second.retransmittable_frames == NULL &&
+      it->second.all_transmissions->size() == 1;
 }
 
 bool QuicUnackedPacketMap::IsUnacked(
     QuicPacketSequenceNumber sequence_number) const {
   return ContainsKey(unacked_packets_, sequence_number);
 }
 
 void QuicUnackedPacketMap::SetNotPending(
     QuicPacketSequenceNumber sequence_number) {
   UnackedPacketMap::iterator it = unacked_packets_.find(sequence_number);
   if (it == unacked_packets_.end()) {
     LOG(DFATAL) << "SetNotPending called for packet that is not unacked: "
                 << sequence_number;
     return;
   }
   if (it->second.pending) {
     LOG_IF(DFATAL, bytes_in_flight_ < it->second.bytes_sent);
     bytes_in_flight_ -= it->second.bytes_sent;
     it->second.pending = false;
   }
+  if (IsPacketUseless(it)) {
+    delete it->second.all_transmissions;
+    unacked_packets_.erase(it);
+  }
 }
 
 bool QuicUnackedPacketMap::HasUnackedPackets() const {
   return !unacked_packets_.empty();
 }
 
 bool QuicUnackedPacketMap::HasPendingPackets() const {
   return bytes_in_flight_ > 0;
 }
 
@@ skipping 87 matching lines @@
   largest_sent_packet_ = max(sequence_number, largest_sent_packet_);
   it->second.sent_time = sent_time;
   if (set_pending) {
     bytes_in_flight_ += bytes_sent;
     it->second.bytes_sent = bytes_sent;
     it->second.pending = true;
   }
 }
 
 }  // namespace net