Discard old packets from the QuicSentPacketManager which are only

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 34 matching lines @@
                        serialized_packet.sequence_number_length));
   if (serialized_packet.retransmittable_frames != NULL &&
       serialized_packet.retransmittable_frames->HasCryptoHandshake()
           == IS_HANDSHAKE) {
     ++pending_crypto_packet_count_;
   }
 }
 
 void QuicUnackedPacketMap::RemoveObsoletePackets() {
   while (!unacked_packets_.empty()) {
-    if (!IsPacketUseless(least_unacked_, unacked_packets_.front())) {
+    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,
@@ skipping 134 matching lines @@
 
 bool QuicUnackedPacketMap::IsPacketUseless(
     QuicPacketSequenceNumber sequence_number,
     const TransmissionInfo& info) const {
   return sequence_number <= largest_observed_ &&
       !info.in_flight &&
       info.retransmittable_frames == NULL &&
       info.all_transmissions == NULL;
 }
 
+bool QuicUnackedPacketMap::IsPacketRemovable(
+    QuicPacketSequenceNumber sequence_number,
+    const TransmissionInfo& info) const {
+  return (sequence_number <= largest_observed_ ||
+          unacked_packets_.size() > kMaxTcpCongestionWindow) &&
+      !info.in_flight &&
+      info.retransmittable_frames == NULL &&
+      info.all_transmissions == NULL;
+}
+
 bool QuicUnackedPacketMap::IsUnacked(
     QuicPacketSequenceNumber sequence_number) const {
   if (sequence_number < least_unacked_ ||
       sequence_number >= least_unacked_ + unacked_packets_.size()) {
     return false;
   }
   return !IsPacketUseless(sequence_number,
                           unacked_packets_[sequence_number - least_unacked_]);
 }
 
@@ skipping 119 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