quiche/quic/core/quic_stream_send_buffer_base.cc

// Copyright (c) 2017 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 "quiche/quic/core/quic_stream_send_buffer_base.h"

#include <cstddef>

#include "quiche/quic/core/quic_interval.h"
#include "quiche/quic/core/quic_interval_set.h"
#include "quiche/quic/core/quic_types.h"
#include "quiche/quic/platform/api/quic_bug_tracker.h"
#include "quiche/quic/platform/api/quic_logging.h"
#include "quiche/common/platform/api/quiche_logging.h"
#include "quiche/common/quiche_buffer_allocator.h"
#include "quiche/common/quiche_mem_slice.h"

namespace quic {

bool StreamPendingRetransmission::operator==(
    const StreamPendingRetransmission& other) const {
  return offset == other.offset && length == other.length;
}

void QuicStreamSendBufferBase::OnStreamDataConsumed(size_t bytes_consumed) {
  stream_bytes_written_ += bytes_consumed;
  stream_bytes_outstanding_ += bytes_consumed;
}

bool QuicStreamSendBufferBase::OnStreamDataAcked(
    QuicStreamOffset offset, QuicByteCount data_length,
    QuicByteCount* newly_acked_length) {
  QUIC_DVLOG(2) << "Marking data acked at offset " << offset << " length "
                << data_length;
  *newly_acked_length = 0;
  if (data_length == 0) {
    return true;
  }
  if (bytes_acked_.Empty() || offset >= bytes_acked_.rbegin()->max() ||
      bytes_acked_.IsDisjoint(
          QuicInterval<QuicStreamOffset>(offset, offset + data_length))) {
    // Optimization for the typical case, when all data is newly acked.
    if (stream_bytes_outstanding_ < data_length) {
      return false;
    }
    bytes_acked_.AddOptimizedForAppend(offset, offset + data_length);
    *newly_acked_length = data_length;
    stream_bytes_outstanding_ -= data_length;
    pending_retransmissions_.Difference(offset, offset + data_length);
    if (!FreeMemSlices(offset, offset + data_length)) {
      return false;
    }
    CleanUpBufferedSlices();
    return true;
  }
  // Exit if no new data gets acked.
  if (bytes_acked_.Contains(offset, offset + data_length)) {
    return true;
  }
  // Execute the slow path if newly acked data fill in existing holes.
  QuicIntervalSet<QuicStreamOffset> newly_acked(offset, offset + data_length);
  newly_acked.Difference(bytes_acked_);
  for (const auto& interval : newly_acked) {
    *newly_acked_length += (interval.max() - interval.min());
  }
  if (stream_bytes_outstanding_ < *newly_acked_length) {
    return false;
  }
  stream_bytes_outstanding_ -= *newly_acked_length;
  bytes_acked_.Add(offset, offset + data_length);
  pending_retransmissions_.Difference(offset, offset + data_length);
  if (newly_acked.Empty()) {
    return true;
  }
  if (!FreeMemSlices(newly_acked.begin()->min(), newly_acked.rbegin()->max())) {
    return false;
  }
  CleanUpBufferedSlices();
  return true;
}

void QuicStreamSendBufferBase::OnStreamDataLost(QuicStreamOffset offset,
                                                QuicByteCount data_length) {
  if (data_length == 0) {
    return;
  }
  QuicIntervalSet<QuicStreamOffset> bytes_lost(offset, offset + data_length);
  bytes_lost.Difference(bytes_acked_);
  if (bytes_lost.Empty()) {
    return;
  }
  for (const auto& lost : bytes_lost) {
    pending_retransmissions_.Add(lost.min(), lost.max());
  }
}

void QuicStreamSendBufferBase::OnStreamDataRetransmitted(
    QuicStreamOffset offset, QuicByteCount data_length) {
  if (data_length == 0) {
    return;
  }
  pending_retransmissions_.Difference(offset, offset + data_length);
}

bool QuicStreamSendBufferBase::HasPendingRetransmission() const {
  return !pending_retransmissions_.Empty();
}

StreamPendingRetransmission
QuicStreamSendBufferBase::NextPendingRetransmission() const {
  if (HasPendingRetransmission()) {
    const auto pending = pending_retransmissions_.begin();
    return {pending->min(), pending->max() - pending->min()};
  }
  QUIC_BUG(quic_bug_10853_3)
      << "NextPendingRetransmission is called unexpected with no "
         "pending retransmissions.";
  return {0, 0};
}

bool QuicStreamSendBufferBase::IsStreamDataOutstanding(
    QuicStreamOffset offset, QuicByteCount data_length) const {
  return data_length > 0 &&
         !bytes_acked_.Contains(offset, offset + data_length);
}

void QuicStreamSendBufferBase::SetStreamOffsetForTest(
    QuicStreamOffset new_offset) {
  stream_bytes_written_ = new_offset;
  stream_bytes_outstanding_ = new_offset;
}

}  // namespace quic