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/*
* Copyright (c) 2016 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/video_coding/nack_requester.h"
#include <algorithm>
#include <cstdint>
#include <cstring>
#include <memory>
#include "system_wrappers/include/clock.h"
#include "test/gtest.h"
#include "test/run_loop.h"
#include "test/scoped_key_value_config.h"
namespace webrtc {
// TODO(bugs.webrtc.org/11594): Use the use the GlobalSimulatedTimeController
// instead of RunLoop. At the moment we mix use of the Clock and the underlying
// implementation of RunLoop, which is realtime.
class TestNackRequester : public ::testing::Test,
public NackSender,
public KeyFrameRequestSender {
protected:
TestNackRequester()
: clock_(new SimulatedClock(0)), keyframes_requested_(0) {}
void SetUp() override {}
void SendNack(const std::vector<uint16_t>& sequence_numbers,
bool buffering_allowed) override {
sent_nacks_.insert(sent_nacks_.end(), sequence_numbers.begin(),
sequence_numbers.end());
if (waiting_for_send_nack_) {
waiting_for_send_nack_ = false;
loop_.Quit();
}
}
void RequestKeyFrame() override { ++keyframes_requested_; }
void Flush() {
// nack_module.Process();
loop_.Flush();
}
bool WaitForSendNack() {
if (timed_out_) {
RTC_DCHECK_NOTREACHED();
return false;
}
RTC_DCHECK(!waiting_for_send_nack_);
waiting_for_send_nack_ = true;
loop_.task_queue()->PostDelayedTask(
[this]() {
timed_out_ = true;
loop_.Quit();
},
TimeDelta::Seconds(1));
loop_.Run();
if (timed_out_)
return false;
RTC_DCHECK(!waiting_for_send_nack_);
return true;
}
NackRequester& CreateNackModule(
TimeDelta interval = NackPeriodicProcessor::kUpdateInterval) {
RTC_DCHECK(!nack_module_.get());
nack_periodic_processor_ =
std::make_unique<NackPeriodicProcessor>(interval);
test::ScopedKeyValueConfig empty_field_trials_;
nack_module_ = std::make_unique<NackRequester>(
TaskQueueBase::Current(), nack_periodic_processor_.get(), clock_.get(),
this, this, empty_field_trials_);
nack_module_->UpdateRtt(kDefaultRttMs);
return *nack_module_.get();
}
static constexpr int64_t kDefaultRttMs = 20;
rtc::AutoThread main_thread_;
test::RunLoop loop_;
std::unique_ptr<SimulatedClock> clock_;
std::unique_ptr<NackPeriodicProcessor> nack_periodic_processor_;
std::unique_ptr<NackRequester> nack_module_;
std::vector<uint16_t> sent_nacks_;
int keyframes_requested_;
bool waiting_for_send_nack_ = false;
bool timed_out_ = false;
};
TEST_F(TestNackRequester, NackOnePacket) {
NackRequester& nack_module = CreateNackModule();
nack_module.OnReceivedPacket(1);
nack_module.OnReceivedPacket(3);
ASSERT_EQ(1u, sent_nacks_.size());
EXPECT_EQ(2, sent_nacks_[0]);
}
TEST_F(TestNackRequester, WrappingSeqNum) {
NackRequester& nack_module = CreateNackModule();
nack_module.OnReceivedPacket(0xfffe);
nack_module.OnReceivedPacket(1);
ASSERT_EQ(2u, sent_nacks_.size());
EXPECT_EQ(0xffff, sent_nacks_[0]);
EXPECT_EQ(0, sent_nacks_[1]);
}
TEST_F(TestNackRequester, ResendNack) {
NackRequester& nack_module = CreateNackModule(TimeDelta::Millis(1));
nack_module.OnReceivedPacket(1);
nack_module.OnReceivedPacket(3);
size_t expected_nacks_sent = 1;
ASSERT_EQ(expected_nacks_sent, sent_nacks_.size());
EXPECT_EQ(2, sent_nacks_[0]);
nack_module.UpdateRtt(1);
clock_->AdvanceTimeMilliseconds(1);
WaitForSendNack(); // Fast retransmit allowed.
EXPECT_EQ(++expected_nacks_sent, sent_nacks_.size());
// Each try has to wait rtt by default.
for (int i = 2; i < 10; ++i) {
// Change RTT, above the 40ms max for exponential backoff.
TimeDelta rtt = TimeDelta::Millis(160); // + (i * 10 - 40)
nack_module.UpdateRtt(rtt.ms());
// RTT gets capped at 160ms in backoff calculations.
TimeDelta expected_backoff_delay =
(i - 1) * std::min(rtt, TimeDelta::Millis(160));
// Move to one millisecond before next allowed NACK.
clock_->AdvanceTimeMilliseconds(expected_backoff_delay.ms() - 1);
Flush();
EXPECT_EQ(expected_nacks_sent, sent_nacks_.size());
// Move to one millisecond after next allowed NACK.
// After rather than on to avoid rounding errors.
clock_->AdvanceTimeMilliseconds(2);
WaitForSendNack(); // Now allowed.
EXPECT_EQ(++expected_nacks_sent, sent_nacks_.size());
}
// Giving up after 10 tries.
clock_->AdvanceTimeMilliseconds(3000);
Flush();
EXPECT_EQ(expected_nacks_sent, sent_nacks_.size());
}
TEST_F(TestNackRequester, ResendPacketMaxRetries) {
NackRequester& nack_module = CreateNackModule(TimeDelta::Millis(1));
nack_module.OnReceivedPacket(1);
nack_module.OnReceivedPacket(3);
ASSERT_EQ(1u, sent_nacks_.size());
EXPECT_EQ(2, sent_nacks_[0]);
int backoff_factor = 1;
for (size_t retries = 1; retries < 10; ++retries) {
// Exponential backoff, so that we don't reject NACK because of time.
clock_->AdvanceTimeMilliseconds(backoff_factor * kDefaultRttMs);
backoff_factor *= 2;
WaitForSendNack();
EXPECT_EQ(retries + 1, sent_nacks_.size());
}
clock_->AdvanceTimeMilliseconds(backoff_factor * kDefaultRttMs);
Flush();
EXPECT_EQ(10u, sent_nacks_.size());
}
TEST_F(TestNackRequester, TooLargeNackList) {
NackRequester& nack_module = CreateNackModule();
nack_module.OnReceivedPacket(0);
nack_module.OnReceivedPacket(1001);
EXPECT_EQ(1000u, sent_nacks_.size());
EXPECT_EQ(0, keyframes_requested_);
nack_module.OnReceivedPacket(1003);
EXPECT_EQ(1000u, sent_nacks_.size());
EXPECT_EQ(1, keyframes_requested_);
nack_module.OnReceivedPacket(1004);
EXPECT_EQ(1000u, sent_nacks_.size());
EXPECT_EQ(1, keyframes_requested_);
}
TEST_F(TestNackRequester, ClearUpTo) {
NackRequester& nack_module = CreateNackModule(TimeDelta::Millis(1));
nack_module.OnReceivedPacket(0);
nack_module.OnReceivedPacket(100);
EXPECT_EQ(99u, sent_nacks_.size());
sent_nacks_.clear();
clock_->AdvanceTimeMilliseconds(100);
nack_module.ClearUpTo(50);
WaitForSendNack();
ASSERT_EQ(50u, sent_nacks_.size());
EXPECT_EQ(50, sent_nacks_[0]);
}
TEST_F(TestNackRequester, ClearUpToWrap) {
NackRequester& nack_module = CreateNackModule();
nack_module.OnReceivedPacket(0xfff0);
nack_module.OnReceivedPacket(0xf);
EXPECT_EQ(30u, sent_nacks_.size());
sent_nacks_.clear();
clock_->AdvanceTimeMilliseconds(100);
nack_module.ClearUpTo(0);
WaitForSendNack();
ASSERT_EQ(15u, sent_nacks_.size());
EXPECT_EQ(0, sent_nacks_[0]);
}
TEST_F(TestNackRequester, PacketNackCount) {
NackRequester& nack_module = CreateNackModule(TimeDelta::Millis(1));
EXPECT_EQ(0, nack_module.OnReceivedPacket(0));
EXPECT_EQ(0, nack_module.OnReceivedPacket(2));
EXPECT_EQ(1, nack_module.OnReceivedPacket(1));
sent_nacks_.clear();
nack_module.UpdateRtt(100);
EXPECT_EQ(0, nack_module.OnReceivedPacket(5));
clock_->AdvanceTimeMilliseconds(100);
WaitForSendNack();
EXPECT_EQ(4u, sent_nacks_.size());
clock_->AdvanceTimeMilliseconds(125);
WaitForSendNack();
EXPECT_EQ(6u, sent_nacks_.size());
EXPECT_EQ(3, nack_module.OnReceivedPacket(3));
EXPECT_EQ(3, nack_module.OnReceivedPacket(4));
EXPECT_EQ(0, nack_module.OnReceivedPacket(4));
}
TEST_F(TestNackRequester, HandleFecRecoveredPacket) {
NackRequester& nack_module = CreateNackModule();
nack_module.OnReceivedPacket(1);
nack_module.OnReceivedPacket(4, /*is_recovered=*/true);
EXPECT_EQ(0u, sent_nacks_.size());
nack_module.OnReceivedPacket(5);
EXPECT_EQ(2u, sent_nacks_.size());
}
TEST_F(TestNackRequester, SendNackWithoutDelay) {
NackRequester& nack_module = CreateNackModule();
nack_module.OnReceivedPacket(0);
nack_module.OnReceivedPacket(100);
EXPECT_EQ(99u, sent_nacks_.size());
}
class TestNackRequesterWithFieldTrial : public ::testing::Test,
public NackSender,
public KeyFrameRequestSender {
protected:
TestNackRequesterWithFieldTrial()
: nack_delay_field_trial_("WebRTC-SendNackDelayMs/10/"),
clock_(new SimulatedClock(0)),
nack_module_(TaskQueueBase::Current(),
&nack_periodic_processor_,
clock_.get(),
this,
this,
nack_delay_field_trial_),
keyframes_requested_(0) {}
void SendNack(const std::vector<uint16_t>& sequence_numbers,
bool buffering_allowed) override {
sent_nacks_.insert(sent_nacks_.end(), sequence_numbers.begin(),
sequence_numbers.end());
}
void RequestKeyFrame() override { ++keyframes_requested_; }
test::ScopedKeyValueConfig nack_delay_field_trial_;
rtc::AutoThread main_thread_;
std::unique_ptr<SimulatedClock> clock_;
NackPeriodicProcessor nack_periodic_processor_;
NackRequester nack_module_;
std::vector<uint16_t> sent_nacks_;
int keyframes_requested_;
};
TEST_F(TestNackRequesterWithFieldTrial, SendNackWithDelay) {
nack_module_.OnReceivedPacket(0);
nack_module_.OnReceivedPacket(100);
EXPECT_EQ(0u, sent_nacks_.size());
clock_->AdvanceTimeMilliseconds(10);
nack_module_.OnReceivedPacket(106);
EXPECT_EQ(99u, sent_nacks_.size());
clock_->AdvanceTimeMilliseconds(10);
nack_module_.OnReceivedPacket(109);
EXPECT_EQ(104u, sent_nacks_.size());
}
} // namespace webrtc