Land Recent QUIC Changes.

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 48 matching lines @@
       TransmissionInfo(frames,
                        new_sequence_number,
                        transmission_info->sequence_number_length,
                        transmission_info->all_transmissions);
 }
 
 void QuicUnackedPacketMap::ClearPreviousRetransmissions(size_t num_to_clear) {
   UnackedPacketMap::iterator it = unacked_packets_.begin();
   while (it != unacked_packets_.end() && num_to_clear > 0) {
     QuicPacketSequenceNumber sequence_number = it->first;
-    // If this is a pending packet, or has retransmittable data, then there is
+    // If this packet is in flight, or has retransmittable data, then there is
     // no point in clearing out any further packets, because they would not
     // affect the high water mark.
-    if (it->second.pending || it->second.retransmittable_frames != NULL) {
+    if (it->second.in_flight || it->second.retransmittable_frames != NULL) {
       break;
     }
 
     it->second.all_transmissions->erase(sequence_number);
     LOG_IF(DFATAL, it->second.all_transmissions->empty())
         << "Previous retransmissions must have a newer transmission.";
     ++it;
     unacked_packets_.erase(sequence_number);
     --num_to_clear;
   }
@@ skipping 16 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->in_flight) {
       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) const {
+  return it->first <= largest_observed_ &&
+      !it->second.in_flight &&
+      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(
+void QuicUnackedPacketMap::RemoveFromInFlight(
     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: "
+    LOG(DFATAL) << "RemoveFromFlight called for packet that is not unacked: "
                 << sequence_number;
     return;
   }
-  if (it->second.pending) {
+  if (it->second.in_flight) {
     LOG_IF(DFATAL, bytes_in_flight_ < it->second.bytes_sent);
     bytes_in_flight_ -= it->second.bytes_sent;
-    it->second.pending = false;
+    it->second.in_flight = 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 {
+bool QuicUnackedPacketMap::HasInFlightPackets() const {
   return bytes_in_flight_ > 0;
 }
 
 const TransmissionInfo& QuicUnackedPacketMap::GetTransmissionInfo(
     QuicPacketSequenceNumber sequence_number) const {
   return unacked_packets_.find(sequence_number)->second;
 }
 
 QuicTime QuicUnackedPacketMap::GetLastPacketSentTime() const {
   UnackedPacketMap::const_reverse_iterator it = unacked_packets_.rbegin();
   while (it != unacked_packets_.rend()) {
-    if (it->second.pending) {
+    if (it->second.in_flight) {
       LOG_IF(DFATAL, it->second.sent_time == QuicTime::Zero())
-          << "Sent time can never be zero for a pending packet.";
+          << "Sent time can never be zero for a packet in flight.";
       return it->second.sent_time;
     }
     ++it;
   }
-  LOG(DFATAL) << "Unable to find sent time.  "
-              << "This method is only intended when there are pending packets.";
+  LOG(DFATAL) << "GetLastPacketSentTime requires in flight packets.";
   return QuicTime::Zero();
 }
 
-QuicTime QuicUnackedPacketMap::GetFirstPendingPacketSentTime() const {
+QuicTime QuicUnackedPacketMap::GetFirstInFlightPacketSentTime() const {
   UnackedPacketMap::const_iterator it = unacked_packets_.begin();
-  while (it != unacked_packets_.end() && !it->second.pending) {
+  while (it != unacked_packets_.end() && !it->second.in_flight) {
     ++it;
   }
   if (it == unacked_packets_.end()) {
-    LOG(DFATAL) << "No pending packets";
+    LOG(DFATAL) << "GetFirstInFlightPacketSentTime requires in flight packets.";
     return QuicTime::Zero();
   }
   return it->second.sent_time;
 }
 
 size_t QuicUnackedPacketMap::GetNumUnackedPackets() const {
   return unacked_packets_.size();
 }
 
-bool QuicUnackedPacketMap::HasMultiplePendingPackets() const {
-  size_t num_pending = 0;
+bool QuicUnackedPacketMap::HasMultipleInFlightPackets() const {
+  size_t num_in_flight = 0;
   for (UnackedPacketMap::const_reverse_iterator it = unacked_packets_.rbegin();
        it != unacked_packets_.rend(); ++it) {
-    if (it->second.pending) {
-      ++num_pending;
+    if (it->second.in_flight) {
+      ++num_in_flight;
     }
-    if (num_pending > 1) {
+    if (num_in_flight > 1) {
       return true;
     }
   }
   return false;
 }
 
 bool QuicUnackedPacketMap::HasPendingCryptoPackets() const {
   return pending_crypto_packet_count_ > 0;
 }
 
 bool QuicUnackedPacketMap::HasUnackedRetransmittableFrames() const {
   for (UnackedPacketMap::const_reverse_iterator it =
            unacked_packets_.rbegin(); it != unacked_packets_.rend(); ++it) {
-    if (it->second.pending && it->second.retransmittable_frames) {
+    if (it->second.in_flight && it->second.retransmittable_frames) {
       return true;
     }
   }
   return false;
 }
 
 QuicPacketSequenceNumber
 QuicUnackedPacketMap::GetLeastUnackedSentPacket() const {
   if (unacked_packets_.empty()) {
     // If there are no unacked packets, return 0.
     return 0;
   }
 
   return unacked_packets_.begin()->first;
 }
 
 void QuicUnackedPacketMap::SetSent(QuicPacketSequenceNumber sequence_number,
                                    QuicTime sent_time,
                                    QuicByteCount bytes_sent,
-                                   bool set_pending) {
+                                   bool set_in_flight) {
   DCHECK_LT(0u, sequence_number);
   UnackedPacketMap::iterator it = unacked_packets_.find(sequence_number);
   if (it == unacked_packets_.end()) {
     LOG(DFATAL) << "OnPacketSent called for packet that is not unacked: "
                 << sequence_number;
     return;
   }
-  DCHECK(!it->second.pending);
+  DCHECK(!it->second.in_flight);
 
   largest_sent_packet_ = max(sequence_number, largest_sent_packet_);
   it->second.sent_time = sent_time;
-  if (set_pending) {
+  if (set_in_flight) {
     bytes_in_flight_ += bytes_sent;
     it->second.bytes_sent = bytes_sent;
-    it->second.pending = true;
+    it->second.in_flight = true;
   }
 }
 
 }  // namespace net