Move shared files in net/quic/ into net/quic/core/

net/quic/congestion_control/send_algorithm_simulator.cc

Index: net/quic/congestion_control/send_algorithm_simulator.cc
diff --git a/net/quic/congestion_control/send_algorithm_simulator.cc b/net/quic/congestion_control/send_algorithm_simulator.cc
deleted file mode 100644
index d1eac0c2a3f6b188ccab68a09d72c370c40ec4eb..0000000000000000000000000000000000000000
--- a/net/quic/congestion_control/send_algorithm_simulator.cc
+++ /dev/null
@@ -1,393 +0,0 @@
-// 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/congestion_control/send_algorithm_simulator.h"
-
-#include <stdint.h>
-
-#include <limits>
-
-#include "base/logging.h"
-#include "base/rand_util.h"
-#include "net/quic/crypto/quic_random.h"
-
-using std::list;
-using std::max;
-using std::min;
-using std::string;
-using std::vector;
-
-namespace net {
-
-namespace {
-
-const QuicByteCount kPacketSize = 1200;
-
-}  // namespace
-
-SendAlgorithmSimulator::Sender::Sender(SendAlgorithmInterface* send_algorithm,
-                                       RttStats* rtt_stats)
-    : Sender(send_algorithm, rtt_stats, QuicTime::Delta::Zero()) {}
-
-SendAlgorithmSimulator::Sender::Sender(SendAlgorithmInterface* send_algorithm,
-                                       RttStats* rtt_stats,
-                                       QuicTime::Delta additional_rtt)
-    : send_algorithm(send_algorithm),
-      rtt_stats(rtt_stats),
-      additional_rtt(additional_rtt),
-      last_sent(0),
-      last_acked(0),
-      next_acked(1),
-      max_cwnd(0),
-      min_cwnd(100000),
-      max_cwnd_drop(0),
-      last_cwnd(0),
-      last_transfer_bandwidth(QuicBandwidth::Zero()),
-      last_transfer_loss_rate(0) {}
-
-SendAlgorithmSimulator::Transfer::Transfer(Sender* sender,
-                                           QuicByteCount num_bytes,
-                                           QuicTime start_time,
-                                           string name)
-    : sender(sender),
-      num_bytes(num_bytes),
-      bytes_acked(0),
-      bytes_lost(0),
-      bytes_in_flight(0),
-      start_time(start_time),
-      name(name) {}
-
-SendAlgorithmSimulator::SendAlgorithmSimulator(MockClock* clock,
-                                               QuicBandwidth bandwidth,
-                                               QuicTime::Delta rtt)
-    : clock_(clock),
-      lose_next_ack_(false),
-      forward_loss_rate_(0),
-      reverse_loss_rate_(0),
-      loss_correlation_(0),
-      bandwidth_(bandwidth),
-      rtt_(rtt),
-      buffer_size_(1000000),
-      delayed_ack_timer_(QuicTime::Delta::FromMilliseconds(100)) {
-  uint32_t seed = base::RandInt(0, std::numeric_limits<int32_t>::max());
-  DVLOG(1) << "Seeding SendAlgorithmSimulator with " << seed;
-  simple_random_.set_seed(seed);
-}
-
-SendAlgorithmSimulator::~SendAlgorithmSimulator() {}
-
-void SendAlgorithmSimulator::AddTransfer(Sender* sender, size_t num_bytes) {
-  AddTransfer(sender, num_bytes, clock_->Now(),
-              StringPrintf("#%zu", pending_transfers_.size()));
-}
-
-void SendAlgorithmSimulator::AddTransfer(Sender* sender,
-                                         size_t num_bytes,
-                                         QuicTime start_time,
-                                         string name) {
-  pending_transfers_.push_back(Transfer(sender, num_bytes, start_time, name));
-  // Record initial stats from when the transfer begins.
-  pending_transfers_.back().sender->RecordStats();
-}
-
-void SendAlgorithmSimulator::TransferBytes() {
-  TransferBytes(std::numeric_limits<uint64_t>::max(),
-                QuicTime::Delta::Infinite());
-}
-
-void SendAlgorithmSimulator::TransferBytes(QuicByteCount max_bytes,
-                                           QuicTime::Delta max_time) {
-  const QuicTime end_time = max_time.IsInfinite()
-                                ? QuicTime::Zero() + QuicTime::Delta::Infinite()
-                                : clock_->Now() + max_time;
-  QuicByteCount bytes_sent = 0;
-  while (!pending_transfers_.empty() && clock_->Now() < end_time &&
-         bytes_sent < max_bytes) {
-    // Determine the times of next send and of the next ack arrival.
-    PacketEvent send_event = NextSendEvent();
-    PacketEvent ack_event = NextAckEvent();
-    // If both times are infinite, fire a TLP.
-    if (ack_event.time_delta.IsInfinite() &&
-        send_event.time_delta.IsInfinite()) {
-      DVLOG(1) << "Both times are infinite, simulating a TLP.";
-      // TODO(ianswett): Use a more sophisticated TLP timer or never lose
-      // the last ack?
-      clock_->AdvanceTime(QuicTime::Delta::FromMilliseconds(100));
-      SendDataNow(&pending_transfers_.front());
-    } else if (ack_event.time_delta < send_event.time_delta) {
-      DVLOG(1) << "Handling ack of largest observed:"
-               << ack_event.transfer->sender->next_acked
-               << ", advancing time:" << ack_event.time_delta.ToMicroseconds()
-               << "us";
-      // Ack data all the data up to ack time and lose any missing packet
-      // numbers.
-      clock_->AdvanceTime(ack_event.time_delta);
-      HandlePendingAck(ack_event.transfer);
-    } else {
-      DVLOG(1) << "Sending transfer '" << send_event.transfer->name
-               << "', advancing time:" << send_event.time_delta.ToMicroseconds()
-               << "us";
-      clock_->AdvanceTime(send_event.time_delta);
-      SendDataNow(send_event.transfer);
-      bytes_sent += kPacketSize;
-    }
-  }
-}
-
-SendAlgorithmSimulator::PacketEvent SendAlgorithmSimulator::NextSendEvent() {
-  QuicTime::Delta next_send_time = QuicTime::Delta::Infinite();
-  Transfer* transfer = nullptr;
-  for (vector<Transfer>::iterator it = pending_transfers_.begin();
-       it != pending_transfers_.end(); ++it) {
-    // If we've already sent enough bytes, wait for them to be acked.
-    if (it->bytes_acked + it->bytes_in_flight >= it->num_bytes) {
-      continue;
-    }
-    // If the flow hasn't started, use the start time.
-    QuicTime::Delta transfer_send_time = it->start_time - clock_->Now();
-    if (clock_->Now() >= it->start_time) {
-      transfer_send_time = it->sender->send_algorithm->TimeUntilSend(
-          clock_->Now(), it->bytes_in_flight);
-    }
-    if (transfer_send_time < next_send_time) {
-      next_send_time = transfer_send_time;
-      transfer = &(*it);
-    }
-  }
-  DVLOG(1) << "NextSendTime returning delta(ms):"
-           << next_send_time.ToMilliseconds() << ", transfer '"
-           << transfer->name;
-  return PacketEvent(next_send_time, transfer);
-}
-
-// NextAck takes into account packet loss in both forward and reverse
-// direction, as well as correlated losses.  And it assumes the receiver acks
-// every other packet when there is no loss.
-SendAlgorithmSimulator::PacketEvent SendAlgorithmSimulator::NextAckEvent() {
-  if (sent_packets_.empty()) {
-    DVLOG(1) << "No outstanding packets to ack for any transfer.";
-    return PacketEvent(QuicTime::Delta::Infinite(), nullptr);
-  }
-
-  // For each connection, find the next acked packet.
-  QuicTime::Delta ack_time = QuicTime::Delta::Infinite();
-  Transfer* transfer = nullptr;
-  for (vector<Transfer>::iterator it = pending_transfers_.begin();
-       it != pending_transfers_.end(); ++it) {
-    QuicTime::Delta transfer_ack_time = FindNextAcked(&(*it));
-    if (transfer_ack_time < ack_time) {
-      ack_time = transfer_ack_time;
-      transfer = &(*it);
-    }
-  }
-
-  return PacketEvent(ack_time, transfer);
-}
-
-QuicTime::Delta SendAlgorithmSimulator::FindNextAcked(Transfer* transfer) {
-  Sender* sender = transfer->sender;
-  if (sender->next_acked == sender->last_acked) {
-    // Determine if the next ack is lost only once, to ensure determinism.
-    lose_next_ack_ = reverse_loss_rate_ * std::numeric_limits<uint64_t>::max() >
-                     simple_random_.RandUint64();
-  }
-
-  QuicPacketNumber next_acked = sender->last_acked;
-  QuicTime::Delta next_ack_delay =
-      FindNextAck(transfer, sender->last_acked, &next_acked);
-  if (lose_next_ack_) {
-    next_ack_delay = FindNextAck(transfer, next_acked, &next_acked);
-  }
-  sender->next_acked = next_acked;
-  return next_ack_delay;
-}
-
-QuicTime::Delta SendAlgorithmSimulator::FindNextAck(
-    const Transfer* transfer,
-    QuicPacketNumber last_acked,
-    QuicPacketNumber* next_acked) const {
-  *next_acked = last_acked;
-  QuicTime::Delta ack_delay = QuicTime::Delta::Infinite();
-  // Remove any packets that are simulated as lost.
-  for (list<SentPacket>::const_iterator it = sent_packets_.begin();
-       it != sent_packets_.end(); ++it) {
-    if (transfer != it->transfer) {
-      continue;
-    }
-    // Skip over any packets less than or equal to last_acked.
-    if (it->packet_number <= last_acked) {
-      continue;
-    }
-    // Lost packets don't trigger an ack.
-    if (it->lost) {
-      continue;
-    }
-    DCHECK_LT(*next_acked, it->packet_number);
-    // Consider a delayed ack for the current next_acked.
-    if (ack_delay < it->ack_time - clock_->Now()) {
-      break;
-    }
-    *next_acked = it->packet_number;
-    ack_delay = it->ack_time - clock_->Now();
-    if (HasRecentLostPackets(transfer, *next_acked) ||
-        (*next_acked - last_acked) >= 2) {
-      break;
-    }
-    ack_delay = ack_delay + delayed_ack_timer_;
-  }
-
-  DVLOG(1) << "FindNextAck found next_acked_:" << transfer->sender->next_acked
-           << " last_acked:" << transfer->sender->last_acked
-           << " ack_time(ms):" << ack_delay.ToMilliseconds();
-  return ack_delay;
-}
-
-bool SendAlgorithmSimulator::HasRecentLostPackets(
-    const Transfer* transfer,
-    QuicPacketNumber next_acked) const {
-  QuicPacketNumber last_packet = transfer->sender->last_acked;
-  for (list<SentPacket>::const_iterator it = sent_packets_.begin();
-       it != sent_packets_.end() && it->packet_number < next_acked; ++it) {
-    if (transfer != it->transfer) {
-      continue;
-    }
-    // Lost packets don't trigger an ack.
-    if (it->lost) {
-      return true;
-    }
-    // Buffer dropped packets are skipped automatically, but still end up
-    // being lost and cause acks to be sent immediately.
-    if (it->packet_number > last_packet + 1) {
-      return true;
-    }
-    last_packet = it->packet_number;
-  }
-  return false;
-}
-
-void SendAlgorithmSimulator::HandlePendingAck(Transfer* transfer) {
-  Sender* sender = transfer->sender;
-  DCHECK_LT(sender->last_acked, sender->next_acked);
-  SendAlgorithmInterface::CongestionVector acked_packets;
-  SendAlgorithmInterface::CongestionVector lost_packets;
-  DVLOG(1) << "Acking packets from:" << sender->last_acked << " to "
-           << sender->next_acked
-           << " bytes_in_flight:" << transfer->bytes_in_flight
-           << " Now():" << (clock_->Now().ToDebuggingValue() / 1000) << "ms";
-  // Some entries may be missing from the sent_packets_ array, if they were
-  // dropped due to buffer overruns.
-  SentPacket largest_observed;
-  list<SentPacket>::iterator it = sent_packets_.begin();
-  while (sender->last_acked < sender->next_acked) {
-    ++sender->last_acked;
-    // Find the next SentPacket for this transfer.
-    while (it->transfer != transfer) {
-      DCHECK(it != sent_packets_.end());
-      ++it;
-    }
-    // If it's missing from the array, it's a loss.
-    if (it->packet_number > sender->last_acked) {
-      DVLOG(1) << "Lost packet:" << sender->last_acked
-               << " dropped by buffer overflow.";
-      lost_packets.push_back(std::make_pair(sender->last_acked, kPacketSize));
-      continue;
-    }
-    if (it->lost) {
-      lost_packets.push_back(std::make_pair(sender->last_acked, kPacketSize));
-    } else {
-      acked_packets.push_back(std::make_pair(sender->last_acked, kPacketSize));
-    }
-    // This packet has been acked or lost, remove it from sent_packets_.
-    largest_observed = *it;
-    sent_packets_.erase(it++);
-  }
-
-  DCHECK(!largest_observed.lost);
-  DVLOG(1) << "Updating RTT from send_time:"
-           << largest_observed.send_time.ToDebuggingValue()
-           << " to ack_time:" << largest_observed.ack_time.ToDebuggingValue();
-  QuicTime::Delta measured_rtt =
-      largest_observed.ack_time - largest_observed.send_time;
-  DCHECK_GE(measured_rtt.ToMicroseconds(), rtt_.ToMicroseconds());
-  sender->rtt_stats->UpdateRtt(measured_rtt, QuicTime::Delta::Zero(),
-                               clock_->Now());
-  sender->send_algorithm->OnCongestionEvent(true, transfer->bytes_in_flight,
-                                            acked_packets, lost_packets);
-  DCHECK_LE(kPacketSize * (acked_packets.size() + lost_packets.size()),
-            transfer->bytes_in_flight);
-  transfer->bytes_in_flight -=
-      kPacketSize * (acked_packets.size() + lost_packets.size());
-
-  sender->RecordStats();
-  transfer->bytes_acked += acked_packets.size() * kPacketSize;
-  transfer->bytes_lost += lost_packets.size() * kPacketSize;
-  if (transfer->bytes_acked >= transfer->num_bytes) {
-    // Remove completed transfers and record transfer bandwidth.
-    QuicTime::Delta transfer_time = clock_->Now() - transfer->start_time;
-    sender->last_transfer_loss_rate =
-        static_cast<float>(transfer->bytes_lost) /
-        (transfer->bytes_lost + transfer->bytes_acked);
-    sender->last_transfer_bandwidth = QuicBandwidth::FromBytesAndTimeDelta(
-        transfer->num_bytes, transfer_time);
-    DCHECK_GE(bandwidth_.ToBitsPerSecond(),
-              sender->last_transfer_bandwidth.ToBitsPerSecond());
-    for (vector<Transfer>::iterator it = pending_transfers_.begin();
-         it != pending_transfers_.end(); ++it) {
-      if (transfer == &(*it)) {
-        pending_transfers_.erase(it);
-        break;
-      }
-    }
-  }
-}
-
-void SendAlgorithmSimulator::SendDataNow(Transfer* transfer) {
-  Sender* sender = transfer->sender;
-  ++sender->last_sent;
-  DVLOG(1) << "Sending packet:" << sender->last_sent
-           << " name:" << transfer->name
-           << " bytes_in_flight:" << transfer->bytes_in_flight
-           << " cwnd:" << sender->send_algorithm->GetCongestionWindow()
-           << " Now():" << (clock_->Now().ToDebuggingValue() / 1000) << "ms";
-  sender->send_algorithm->OnPacketSent(clock_->Now(), transfer->bytes_in_flight,
-                                       sender->last_sent, kPacketSize,
-                                       HAS_RETRANSMITTABLE_DATA);
-  // Lose the packet immediately if the buffer is full.
-  if (sent_packets_.size() * kPacketSize < buffer_size_) {
-    // TODO(ianswett): This buffer simulation is an approximation.
-    // An ack time of zero means loss.
-    bool packet_lost =
-        forward_loss_rate_ * std::numeric_limits<uint64_t>::max() >
-        simple_random_.RandUint64();
-    // Handle correlated loss.
-    if (!sent_packets_.empty() && sent_packets_.back().lost &&
-        loss_correlation_ * std::numeric_limits<uint64_t>::max() >
-            simple_random_.RandUint64()) {
-      packet_lost = true;
-    }
-    DVLOG(1) << "losing packet:" << sender->last_sent
-             << " name:" << transfer->name << " due to random loss.";
-
-    // If the number of bytes in flight are less than the bdp, there's
-    // no buffering delay.  Bytes lost from the buffer are not counted.
-    QuicByteCount bdp = bandwidth_.ToBytesPerPeriod(rtt_);
-    QuicTime ack_time = clock_->Now() + rtt_ + sender->additional_rtt;
-    if (kPacketSize > bdp) {
-      ack_time = ack_time + bandwidth_.TransferTime(kPacketSize - bdp);
-    }
-    QuicTime queue_ack_time = sent_packets_.empty()
-                                  ? QuicTime::Zero()
-                                  : sent_packets_.back().ack_time +
-                                        bandwidth_.TransferTime(kPacketSize);
-    ack_time = std::max(ack_time, queue_ack_time);
-    sent_packets_.push_back(SentPacket(sender->last_sent, clock_->Now(),
-                                       ack_time, packet_lost, transfer));
-  } else {
-    DVLOG(1) << "losing packet:" << sender->last_sent
-             << " name:" << transfer->name << " because the buffer was full.";
-  }
-  transfer->bytes_in_flight += kPacketSize;
-}
-
-}  // namespace net