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/*
* Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "modules/pacing/packet_queue2.h"
#include <algorithm>
#include "rtc_base/checks.h"
#include "system_wrappers/include/clock.h"
namespace webrtc {
PacketQueue2::Stream::Stream() : bytes(0) {}
PacketQueue2::Stream::~Stream() {}
PacketQueue2::PacketQueue2(const Clock* clock)
: PacketQueue(clock),
clock_(clock),
time_last_updated_(clock_->TimeInMilliseconds()) {}
PacketQueue2::~PacketQueue2() {}
void PacketQueue2::Push(const Packet& packet_to_insert) {
Packet packet(packet_to_insert);
auto stream_info_it = streams_.find(packet.ssrc);
if (stream_info_it == streams_.end()) {
stream_info_it = streams_.emplace(packet.ssrc, Stream()).first;
stream_info_it->second.priority_it = stream_priorities_.end();
stream_info_it->second.ssrc = packet.ssrc;
}
Stream* streams_ = &stream_info_it->second;
if (streams_->priority_it == stream_priorities_.end()) {
// If the SSRC is not currently scheduled, add it to |stream_priorities_|.
RTC_CHECK(!IsSsrcScheduled(streams_->ssrc));
streams_->priority_it = stream_priorities_.emplace(
StreamPrioKey(packet.priority, streams_->bytes), packet.ssrc);
} else if (packet.priority < streams_->priority_it->first.priority) {
// If the priority of this SSRC increased, remove the outdated StreamPrioKey
// and insert a new one with the new priority. Note that
// RtpPacketSender::Priority uses lower ordinal for higher priority.
stream_priorities_.erase(streams_->priority_it);
streams_->priority_it = stream_priorities_.emplace(
StreamPrioKey(packet.priority, streams_->bytes), packet.ssrc);
}
RTC_CHECK(streams_->priority_it != stream_priorities_.end());
packet.enqueue_time_it = enqueue_times_.insert(packet.enqueue_time_ms);
// In order to figure out how much time a packet has spent in the queue while
// not in a paused state, we subtract the total amount of time the queue has
// been paused so far, and when the packet is poped we subtract the total
// amount of time the queue has been paused at that moment. This way we
// subtract the total amount of time the packet has spent in the queue while
// in a paused state.
UpdateQueueTime(packet.enqueue_time_ms);
packet.enqueue_time_ms -= pause_time_sum_ms_;
streams_->packet_queue.push(packet);
size_packets_ += 1;
size_bytes_ += packet.bytes;
}
const PacketQueue2::Packet& PacketQueue2::BeginPop() {
RTC_CHECK(!pop_packet_ && !pop_stream_);
Stream* stream = GetHighestPriorityStream();
pop_stream_.emplace(stream);
pop_packet_.emplace(stream->packet_queue.top());
stream->packet_queue.pop();
return *pop_packet_;
}
void PacketQueue2::CancelPop(const Packet& packet) {
RTC_CHECK(pop_packet_ && pop_stream_);
(*pop_stream_)->packet_queue.push(*pop_packet_);
pop_packet_.reset();
pop_stream_.reset();
}
void PacketQueue2::FinalizePop(const Packet& packet) {
RTC_CHECK(!paused_);
if (!Empty()) {
RTC_CHECK(pop_packet_ && pop_stream_);
Stream* stream = *pop_stream_;
stream_priorities_.erase(stream->priority_it);
const Packet& packet = *pop_packet_;
// Calculate the total amount of time spent by this packet in the queue
// while in a non-paused state. Note that the |pause_time_sum_ms_| was
// subtracted from |packet.enqueue_time_ms| when the packet was pushed, and
// by subtracting it now we effectively remove the time spent in in the
// queue while in a paused state.
int64_t time_in_non_paused_state_ms =
time_last_updated_ - packet.enqueue_time_ms - pause_time_sum_ms_;
queue_time_sum_ms_ -= time_in_non_paused_state_ms;
RTC_CHECK(packet.enqueue_time_it != enqueue_times_.end());
enqueue_times_.erase(packet.enqueue_time_it);
// Update |bytes| of this stream. The general idea is that the stream that
// has sent the least amount of bytes should have the highest priority.
// The problem with that is if streams send with different rates, in which
// case a "budget" will be built up for the stream sending at the lower
// rate. To avoid building a too large budget we limit |bytes| to be within
// kMaxLeading bytes of the stream that has sent the most amount of bytes.
stream->bytes =
std::max(stream->bytes + packet.bytes, max_bytes_ - kMaxLeadingBytes);
max_bytes_ = std::max(max_bytes_, stream->bytes);
size_bytes_ -= packet.bytes;
size_packets_ -= 1;
RTC_CHECK(size_packets_ > 0 || queue_time_sum_ms_ == 0);
// If there are packets left to be sent, schedule the stream again.
RTC_CHECK(!IsSsrcScheduled(stream->ssrc));
if (stream->packet_queue.empty()) {
stream->priority_it = stream_priorities_.end();
} else {
RtpPacketSender::Priority priority = stream->packet_queue.top().priority;
stream->priority_it = stream_priorities_.emplace(
StreamPrioKey(priority, stream->bytes), stream->ssrc);
}
pop_packet_.reset();
pop_stream_.reset();
}
}
bool PacketQueue2::Empty() const {
RTC_CHECK((!stream_priorities_.empty() && size_packets_ > 0) ||
(stream_priorities_.empty() && size_packets_ == 0));
return stream_priorities_.empty();
}
size_t PacketQueue2::SizeInPackets() const {
return size_packets_;
}
uint64_t PacketQueue2::SizeInBytes() const {
return size_bytes_;
}
int64_t PacketQueue2::OldestEnqueueTimeMs() const {
if (Empty())
return 0;
RTC_CHECK(!enqueue_times_.empty());
return *enqueue_times_.begin();
}
void PacketQueue2::UpdateQueueTime(int64_t timestamp_ms) {
RTC_CHECK_GE(timestamp_ms, time_last_updated_);
if (timestamp_ms == time_last_updated_)
return;
int64_t delta_ms = timestamp_ms - time_last_updated_;
if (paused_) {
pause_time_sum_ms_ += delta_ms;
} else {
queue_time_sum_ms_ += delta_ms * size_packets_;
}
time_last_updated_ = timestamp_ms;
}
void PacketQueue2::SetPauseState(bool paused, int64_t timestamp_ms) {
if (paused_ == paused)
return;
UpdateQueueTime(timestamp_ms);
paused_ = paused;
}
int64_t PacketQueue2::AverageQueueTimeMs() const {
if (Empty())
return 0;
return queue_time_sum_ms_ / size_packets_;
}
PacketQueue2::Stream* PacketQueue2::GetHighestPriorityStream() {
RTC_CHECK(!stream_priorities_.empty());
uint32_t ssrc = stream_priorities_.begin()->second;
auto stream_info_it = streams_.find(ssrc);
RTC_CHECK(stream_info_it != streams_.end());
RTC_CHECK(stream_info_it->second.priority_it == stream_priorities_.begin());
RTC_CHECK(!stream_info_it->second.packet_queue.empty());
return &stream_info_it->second;
}
bool PacketQueue2::IsSsrcScheduled(uint32_t ssrc) const {
for (const auto& scheduled_stream : stream_priorities_) {
if (scheduled_stream.second == ssrc)
return true;
}
return false;
}
} // namespace webrtc
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