blob: f901486cab9a542ce1609f6ac9115faed8bf90ac [file] [log] [blame]
// 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 "quic/core/quic_stream_send_buffer.h"
#include <algorithm>
#include "quic/core/quic_data_writer.h"
#include "quic/core/quic_interval.h"
#include "quic/core/quic_utils.h"
#include "quic/platform/api/quic_bug_tracker.h"
#include "quic/platform/api/quic_flag_utils.h"
#include "quic/platform/api/quic_flags.h"
#include "quic/platform/api/quic_logging.h"
#include "common/platform/api/quiche_mem_slice.h"
namespace quic {
namespace {
struct CompareOffset {
bool operator()(const BufferedSlice& slice, QuicStreamOffset offset) const {
return slice.offset + slice.slice.length() < offset;
}
};
} // namespace
BufferedSlice::BufferedSlice(quiche::QuicheMemSlice mem_slice,
QuicStreamOffset offset)
: slice(std::move(mem_slice)), offset(offset) {}
BufferedSlice::BufferedSlice(BufferedSlice&& other) = default;
BufferedSlice& BufferedSlice::operator=(BufferedSlice&& other) = default;
BufferedSlice::~BufferedSlice() {}
QuicInterval<std::size_t> BufferedSlice::interval() const {
const std::size_t length = slice.length();
return QuicInterval<std::size_t>(offset, offset + length);
}
bool StreamPendingRetransmission::operator==(
const StreamPendingRetransmission& other) const {
return offset == other.offset && length == other.length;
}
QuicStreamSendBuffer::QuicStreamSendBuffer(
quiche::QuicheBufferAllocator* allocator)
: current_end_offset_(0),
stream_offset_(0),
allocator_(allocator),
stream_bytes_written_(0),
stream_bytes_outstanding_(0),
write_index_(-1) {}
QuicStreamSendBuffer::~QuicStreamSendBuffer() {}
void QuicStreamSendBuffer::SaveStreamData(absl::string_view data) {
QUICHE_DCHECK(!data.empty());
// Latch the maximum data slice size.
const QuicByteCount max_data_slice_size =
GetQuicFlag(FLAGS_quic_send_buffer_max_data_slice_size);
while (!data.empty()) {
auto slice_len = std::min<absl::string_view::size_type>(
data.length(), max_data_slice_size);
auto buffer =
quiche::QuicheBuffer::Copy(allocator_, data.substr(0, slice_len));
SaveMemSlice(quiche::QuicheMemSlice(std::move(buffer)));
data = data.substr(slice_len);
}
}
void QuicStreamSendBuffer::SaveMemSlice(quiche::QuicheMemSlice slice) {
QUIC_DVLOG(2) << "Save slice offset " << stream_offset_ << " length "
<< slice.length();
if (slice.empty()) {
QUIC_BUG(quic_bug_10853_1) << "Try to save empty MemSlice to send buffer.";
return;
}
size_t length = slice.length();
// Need to start the offsets at the right interval.
if (interval_deque_.Empty()) {
const QuicStreamOffset end = stream_offset_ + length;
current_end_offset_ = std::max(current_end_offset_, end);
}
BufferedSlice bs = BufferedSlice(std::move(slice), stream_offset_);
interval_deque_.PushBack(std::move(bs));
stream_offset_ += length;
}
QuicByteCount QuicStreamSendBuffer::SaveMemSliceSpan(
absl::Span<quiche::QuicheMemSlice> span) {
QuicByteCount total = 0;
for (quiche::QuicheMemSlice& slice : span) {
if (slice.length() == 0) {
// Skip empty slices.
continue;
}
total += slice.length();
SaveMemSlice(std::move(slice));
}
return total;
}
void QuicStreamSendBuffer::OnStreamDataConsumed(size_t bytes_consumed) {
stream_bytes_written_ += bytes_consumed;
stream_bytes_outstanding_ += bytes_consumed;
}
bool QuicStreamSendBuffer::WriteStreamData(QuicStreamOffset offset,
QuicByteCount data_length,
QuicDataWriter* writer) {
QUIC_BUG_IF(quic_bug_12823_1, current_end_offset_ < offset)
<< "Tried to write data out of sequence. last_offset_end:"
<< current_end_offset_ << ", offset:" << offset;
// The iterator returned from |interval_deque_| will automatically advance
// the internal write index for the QuicIntervalDeque. The incrementing is
// done in operator++.
for (auto slice_it = interval_deque_.DataAt(offset);
slice_it != interval_deque_.DataEnd(); ++slice_it) {
if (data_length == 0 || offset < slice_it->offset) {
break;
}
QuicByteCount slice_offset = offset - slice_it->offset;
QuicByteCount available_bytes_in_slice =
slice_it->slice.length() - slice_offset;
QuicByteCount copy_length = std::min(data_length, available_bytes_in_slice);
if (!writer->WriteBytes(slice_it->slice.data() + slice_offset,
copy_length)) {
QUIC_BUG(quic_bug_10853_2) << "Writer fails to write.";
return false;
}
offset += copy_length;
data_length -= copy_length;
const QuicStreamOffset new_end =
slice_it->offset + slice_it->slice.length();
current_end_offset_ = std::max(current_end_offset_, new_end);
}
return data_length == 0;
}
bool QuicStreamSendBuffer::OnStreamDataAcked(
QuicStreamOffset offset,
QuicByteCount data_length,
QuicByteCount* newly_acked_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 QuicStreamSendBuffer::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 QuicStreamSendBuffer::OnStreamDataRetransmitted(
QuicStreamOffset offset,
QuicByteCount data_length) {
if (data_length == 0) {
return;
}
pending_retransmissions_.Difference(offset, offset + data_length);
}
bool QuicStreamSendBuffer::HasPendingRetransmission() const {
return !pending_retransmissions_.Empty();
}
StreamPendingRetransmission QuicStreamSendBuffer::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 QuicStreamSendBuffer::FreeMemSlices(QuicStreamOffset start,
QuicStreamOffset end) {
auto it = interval_deque_.DataBegin();
if (it == interval_deque_.DataEnd() || it->slice.empty()) {
QUIC_BUG(quic_bug_10853_4)
<< "Trying to ack stream data [" << start << ", " << end << "), "
<< (it == interval_deque_.DataEnd()
? "and there is no outstanding data."
: "and the first slice is empty.");
return false;
}
if (!it->interval().Contains(start)) {
// Slow path that not the earliest outstanding data gets acked.
it = std::lower_bound(interval_deque_.DataBegin(),
interval_deque_.DataEnd(), start, CompareOffset());
}
if (it == interval_deque_.DataEnd() || it->slice.empty()) {
QUIC_BUG(quic_bug_10853_5)
<< "Offset " << start << " with iterator offset: " << it->offset
<< (it == interval_deque_.DataEnd() ? " does not exist."
: " has already been acked.");
return false;
}
for (; it != interval_deque_.DataEnd(); ++it) {
if (it->offset >= end) {
break;
}
if (!it->slice.empty() &&
bytes_acked_.Contains(it->offset, it->offset + it->slice.length())) {
it->slice.Reset();
}
}
return true;
}
void QuicStreamSendBuffer::CleanUpBufferedSlices() {
while (!interval_deque_.Empty() &&
interval_deque_.DataBegin()->slice.empty()) {
QUIC_BUG_IF(quic_bug_12823_2,
interval_deque_.DataBegin()->offset > current_end_offset_)
<< "Fail to pop front from interval_deque_. Front element contained "
"a slice whose data has not all be written. Front offset "
<< interval_deque_.DataBegin()->offset << " length "
<< interval_deque_.DataBegin()->slice.length();
interval_deque_.PopFront();
}
}
bool QuicStreamSendBuffer::IsStreamDataOutstanding(
QuicStreamOffset offset,
QuicByteCount data_length) const {
return data_length > 0 &&
!bytes_acked_.Contains(offset, offset + data_length);
}
size_t QuicStreamSendBuffer::size() const {
return interval_deque_.Size();
}
} // namespace quic