net/quic/quic_socket_data_provider.cc - chromium/src - Git at Google

 // Copyright 2024 The Chromium Authors
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 #include "net/quic/quic_socket_data_provider.h"

 #include <algorithm>
 #include <map>
 #include <memory>
 #include <optional>
 #include <set>
 #include <sstream>
 #include <string>

 #include "base/functional/callback.h"
 #include "base/run_loop.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/task/sequenced_task_runner.h"
 #include "net/base/hex_utils.h"
 #include "net/socket/socket_test_util.h"
 #include "net/third_party/quiche/src/quiche/quic/core/crypto/null_encrypter.h"
 #include "net/third_party/quiche/src/quiche/quic/core/crypto/quic_crypto_server_config.h"
 #include "net/third_party/quiche/src/quiche/quic/core/http/quic_spdy_session.h"
 #include "net/third_party/quiche/src/quiche/quic/core/quic_packets.h"
 #include "net/third_party/quiche/src/quiche/quic/core/quic_time.h"
 #include "net/third_party/quiche/src/quiche/quic/core/quic_versions.h"
 #include "net/third_party/quiche/src/quiche/quic/test_tools/crypto_test_utils.h"
 #include "net/third_party/quiche/src/quiche/quic/test_tools/quic_test_utils.h"
 #include "net/third_party/quiche/src/quiche/quic/tools/quic_simple_server_session.h"

 namespace quic {

 namespace {

 class HttpStreamPrinter : public Http3DebugVisitor {
  public:
   explicit HttpStreamPrinter(std::ostream* output) : output_(output) {}

   void OnControlStreamCreated(QuicStreamId stream_id) override {
     if (output_) {
       *output_ << "OnControlStreamCreated: " << stream_id << "\n";
     }
   }

   void OnQpackEncoderStreamCreated(QuicStreamId stream_id) override {
     if (output_) {
       *output_ << "OnQpackEncoderStreamCreated: " << stream_id << "\n";
     }
   }

   void OnQpackDecoderStreamCreated(QuicStreamId stream_id) override {
     if (output_) {
       *output_ << "OnQpackDecoderStreamCreated: " << stream_id << "\n";
     }
   }

   void OnPeerControlStreamCreated(QuicStreamId stream_id) override {
     if (output_) {
       *output_ << "OnPeerControlStreamCreated: " << stream_id << "\n";
     }
   }

   void OnPeerQpackEncoderStreamCreated(QuicStreamId stream_id) override {
     if (output_) {
       *output_ << "OnPeerQpackEncoderStreamCreated: " << stream_id << "\n";
     }
   }

   void OnPeerQpackDecoderStreamCreated(QuicStreamId stream_id) override {
     if (output_) {
       *output_ << "OnPeerQpackDecoderStreamCreated: " << stream_id << "\n";
     }
   }

   void OnSettingsFrameReceived(const SettingsFrame& frame) override {
     if (output_) {
       *output_ << "OnSettingsFrameReceived: " << frame << "\n";
     }
   }

   void OnGoAwayFrameReceived(const GoAwayFrame& frame) override {
     if (output_) {
       *output_ << "OnGoAwayFrameReceived" << "\n";
     }
   }

   void OnPriorityUpdateFrameReceived(
       const PriorityUpdateFrame& frame) override {
     if (output_) {
       *output_ << "OnPriorityUpdateFrameReceived: " << frame << "\n";
     }
   }

   void OnDataFrameReceived(QuicStreamId stream_id,
                            QuicByteCount payload_length) override {
     if (output_) {
       *output_ << "OnDataFrameReceived: " << stream_id << ", "
                << "received: " << payload_length << " bytes" << "\n";
     }
   }

   void OnHeadersFrameReceived(
       QuicStreamId stream_id,
       QuicByteCount compressed_headers_length) override {
     if (output_) {
       *output_ << "OnHeadersFrameReceived: " << stream_id << ", "
                << "received: " << compressed_headers_length << " bytes" << "\n";
     }
   }

   void OnHeadersDecoded(QuicStreamId stream_id,
                         QuicHeaderList headers) override {
     if (output_) {
       *output_ << "OnHeadersDecoded: " << stream_id << ", "
                << "received: " << headers.DebugString() << "\n";
     }
   }

   void OnUnknownFrameReceived(QuicStreamId stream_id,
                               uint64_t frame_type,
                               QuicByteCount payload_length) override {
     if (output_) {
       *output_ << "OnUnknownFrameReceived: " << stream_id << ", "
                << "frame_type: " << frame_type << ","
                << "received: " << payload_length << "bytes " << "\n ";
     }
   }

   void OnSettingsFrameSent(const SettingsFrame& frame) override {
     if (output_) {
       *output_ << "OnSettingsFrameSent: " << frame << "\n";
     }
   }

   void OnSettingsFrameResumed(const SettingsFrame& frame) override {
     if (output_) {
       *output_ << "OnSettingsFrameResumed: " << frame << "\n";
     }
   }

   void OnGoAwayFrameSent(QuicStreamId stream_id) override {
     if (output_) {
       *output_ << "OnGoAwayFrameSent: " << stream_id << "\n";
     }
   }

   void OnPriorityUpdateFrameSent(const PriorityUpdateFrame& frame) override {
     if (output_) {
       *output_ << "OnPriorityUpdateFrameSent: " << frame << "\n";
     }
   }

   void OnDataFrameSent(QuicStreamId stream_id,
                        QuicByteCount payload_length) override {
     if (output_) {
       *output_ << "OnDataFrameSent: " << stream_id << ", "
                << "sent: " << payload_length << " bytes" << "\n";
     }
   }

   void OnHeadersFrameSent(
       QuicStreamId stream_id,
       const quiche::HttpHeaderBlock& header_block) override {
     if (output_) {
       *output_ << "OnHeadersFrameSent: " << stream_id << ", "
                << "sent: " << header_block.DebugString() << "\n";
     }
   }

  private:
   mutable raw_ptr<std::ostream> output_ = nullptr;
 };
 }  // namespace

 }  // namespace quic

 namespace net::test {

 QuicSimpleServerSessionForTest::~QuicSimpleServerSessionForTest() = default;

 // Always return true if CryptoStream is created, so that the pending stream can
 // handle initial setting frames for tests.
 bool QuicSimpleServerSessionForTest::IsEncryptionEstablished() const {
   return GetCryptoStream() != nullptr;
 }

 QuicSocketDataProvider::Expectation::Expectation(
     std::string name,
     Type type,
     int rv,
     std::unique_ptr<quic::QuicEncryptedPacket> packet)
     : name_(std::move(name)),
       type_(type),
       rv_(rv),
       packet_(std::move(packet)) {}

 QuicSocketDataProvider::Expectation::Expectation(
     QuicSocketDataProvider::Expectation&&) = default;

 QuicSocketDataProvider::Expectation::~Expectation() = default;

 QuicSocketDataProvider::Expectation& QuicSocketDataProvider::Expectation::After(
     std::string name) {
   after_.insert(std::move(name));
   return *this;
 }

 std::string QuicSocketDataProvider::Expectation::TypeToString(
     QuicSocketDataProvider::Expectation::Type type) {
   switch (type) {
     case Expectation::Type::READ:
       return "READ";
     case Expectation::Type::WRITE:
       return "WRITE";
     case Expectation::Type::PAUSE:
       return "PAUSE";
   }
   NOTREACHED();
 }

 void QuicSocketDataProvider::Expectation::Consume() {
   CHECK(!consumed_);
   VLOG(1) << "Consuming " << TypeToString(type_) << " expectation " << name_;
   consumed_ = true;
 }

 QuicSocketDataProvider::QuicSocketDataProvider(quic::ParsedQuicVersion version)
     : printer_(version),
       crypto_config_(quic::QuicCryptoServerConfig::TESTING,
                      quic::QuicRandom::GetInstance(),
                      quic::test::crypto_test_utils::ProofSourceForTesting(),
                      quic::KeyExchangeSource::Default()),
       compressed_certs_cache_(
           quic::QuicCompressedCertsCache::kQuicCompressedCertsCacheSize) {
   session_for_actual_ = GenSimpleServerSession();
   session_for_expected_ = GenSimpleServerSession();
 }

 QuicSocketDataProvider::~QuicSocketDataProvider() = default;

 std::unique_ptr<quic::QuicSimpleServerSession>
 QuicSocketDataProvider::GenSimpleServerSession() {
   quic::test::MockQuicConnection* connection =
       new quic::test::MockQuicConnection(  // IN-TEST
           &helper_, &alarm_factory_, quic::Perspective::IS_SERVER);
   connection->AdvanceTime(quic::QuicTime::Delta::FromSeconds(1));
   connection->SetEncrypter(
       quic::ENCRYPTION_FORWARD_SECURE,
       std::make_unique<quic::NullEncrypter>(connection->perspective()));

   std::unique_ptr<QuicSimpleServerSessionForTest> session =
       std::make_unique<QuicSimpleServerSessionForTest>(
           config_, quic::CurrentSupportedVersions(), connection, &owner_,
           &stream_helper_, &crypto_config_, &compressed_certs_cache_,
           &memory_cache_backend_);
   session->Initialize();
   return session;
 }

 std::string QuicSocketDataProvider::PrintWithQuicSession(
     quic::QuicSimpleServerSession* session,
     std::string data) {
   std::ostringstream output;
   quic::HttpStreamPrinter printer(&output);
   session->set_debug_visitor(&printer);
   std::string res = printer_.PrintWithQuicSession(data, output, session);
   session->set_debug_visitor(nullptr);
   return res;
 }

 QuicSocketDataProvider::Expectation& QuicSocketDataProvider::AddRead(
     std::string name,
     std::unique_ptr<quic::QuicEncryptedPacket> packet) {
   expectations_.push_back(Expectation(std::move(name), Expectation::Type::READ,
                                       OK, std::move(packet)));
   return expectations_.back();
 }

 QuicSocketDataProvider::Expectation& QuicSocketDataProvider::AddRead(
     std::string name,
     std::unique_ptr<quic::QuicReceivedPacket> packet) {
   uint8_t tos_byte = static_cast<uint8_t>(packet->ecn_codepoint());
   return AddRead(std::move(name),
                  static_cast<std::unique_ptr<quic::QuicEncryptedPacket>>(
                      std::move(packet)))
       .TosByte(tos_byte);
 }

 QuicSocketDataProvider::Expectation& QuicSocketDataProvider::AddReadError(
     std::string name,
     int rv) {
   CHECK_NE(rv, OK);
   CHECK_NE(rv, ERR_IO_PENDING);
   expectations_.push_back(
       Expectation(std::move(name), Expectation::Type::READ, rv, nullptr));
   return expectations_.back();
 }

 QuicSocketDataProvider::Expectation& QuicSocketDataProvider::AddWrite(
     std::string name,
     std::unique_ptr<quic::QuicEncryptedPacket> packet,
     int rv) {
   expectations_.push_back(Expectation(std::move(name), Expectation::Type::WRITE,
                                       rv, std::move(packet)));
   return expectations_.back();
 }

 QuicSocketDataProvider::Expectation& QuicSocketDataProvider::AddWriteError(
     std::string name,
     int rv) {
   CHECK_NE(rv, OK);
   CHECK_NE(rv, ERR_IO_PENDING);
   expectations_.push_back(
       Expectation(std::move(name), Expectation::Type::WRITE, rv, nullptr));
   return expectations_.back();
 }

 QuicSocketDataProvider::PausePoint QuicSocketDataProvider::AddPause(
     std::string name) {
   expectations_.push_back(
       Expectation(std::move(name), Expectation::Type::PAUSE, OK, nullptr));
   return expectations_.size() - 1;
 }

 bool QuicSocketDataProvider::AllDataConsumed() const {
   return std::all_of(
       expectations_.begin(), expectations_.end(),
       [](const Expectation& expectation) { return expectation.consumed(); });
 }

 void QuicSocketDataProvider::RunUntilPause(
     QuicSocketDataProvider::PausePoint pause_point) {
   if (!paused_at_.has_value()) {
     run_until_run_loop_ = std::make_unique<base::RunLoop>();
     run_until_run_loop_->Run();
     run_until_run_loop_.reset();
   }
   CHECK(paused_at_.has_value() && *paused_at_ == pause_point)
       << "Did not pause at '" << expectations_[pause_point].name() << "'.";
 }

 void QuicSocketDataProvider::Resume() {
   CHECK(paused_at_.has_value());
   VLOG(1) << "Resuming from pause point " << expectations_[*paused_at_].name();
   expectations_[*paused_at_].Consume();
   paused_at_ = std::nullopt;
   ExpectationConsumed();
 }

 void QuicSocketDataProvider::RunUntilAllConsumed() {
   if (!AllDataConsumed()) {
     run_until_run_loop_ = std::make_unique<base::RunLoop>();
     run_until_run_loop_->Run();
     run_until_run_loop_.reset();
   }

   // If that run timed out, then there will still be un-consumed data.
   if (!AllDataConsumed()) {
     std::vector<size_t> unconsumed;
     for (size_t i = 0; i < expectations_.size(); i++) {
       if (!expectations_[i].consumed()) {
         unconsumed.push_back(i);
       }
     }
     FAIL() << "All expectations were not consumed; remaining: "
            << ExpectationList(unconsumed);
   }
 }

 MockRead QuicSocketDataProvider::OnRead() {
   CHECK(!read_pending_);
   read_pending_ = true;
   std::optional<MockRead> next_read = ConsumeNextRead();
   if (!next_read.has_value()) {
     return MockRead(ASYNC, ERR_IO_PENDING);
   }

   read_pending_ = false;
   return *next_read;
 }

 MockWriteResult QuicSocketDataProvider::OnWrite(const std::string& data) {
   CHECK(!write_pending_.has_value());
   write_pending_ = data;
   std::optional<MockWriteResult> next_write = ConsumeNextWrite();
   if (!next_write.has_value()) {
     // If Write() was called when no corresponding expectation exists, that's
     // an error unless execution is currently paused, in which case it's just
     // pending. This rarely occurs because the only other type of expectation
     // that might be blocking a WRITE is a READ, and QUIC implementations
     // typically eagerly consume READs.
     if (paused_at_.has_value()) {
       return MockWriteResult(ASYNC, ERR_IO_PENDING);
     } else {
       ADD_FAILURE() << "Write call when none is expected:\n"
                     << printer_.PrintWrite(data);
       return MockWriteResult(SYNCHRONOUS, ERR_UNEXPECTED);
     }
   }

   write_pending_ = std::nullopt;
   return *next_write;
 }

 bool QuicSocketDataProvider::AllReadDataConsumed() const {
   return AllDataConsumed();
 }

 bool QuicSocketDataProvider::AllWriteDataConsumed() const {
   return AllDataConsumed();
 }

 void QuicSocketDataProvider::CancelPendingRead() {
   read_pending_ = false;
 }

 void QuicSocketDataProvider::Reset() {
   // Note that `Reset` is a parent-class method with a confusing name. It is
   // used to initialize the socket data provider before it is used.

   // Map names to index, and incidentally check for duplicate names.
   std::map<std::string, size_t> names;
   for (size_t i = 0; i < expectations_.size(); i++) {
     Expectation& expectation = expectations_[i];
     auto [_, inserted] = names.insert({expectation.name(), i});
     CHECK(inserted) << "Another expectation named " << expectation.name()
                     << " exists.";
   }

   // Calculate `dependencies_` mapping indices in `expectations_` to indices
   // of the expectations they depend on.
   dependencies_.clear();
   for (size_t i = 0; i < expectations_.size(); i++) {
     Expectation& expectation = expectations_[i];
     if (expectation.after().empty()) {
       // If no other dependencies are given, make the expectation depend on
       // the previous expectation.
       if (i > 0) {
         dependencies_[i].insert(i - 1);
       }
     } else {
       for (auto& after : expectation.after()) {
         const auto dep = names.find(after);
         CHECK(dep != names.end()) << "No expectation named " << after;
         dependencies_[i].insert(dep->second);
       }
     }
   }

   pending_maybe_consume_expectations_ = false;
   read_pending_ = false;
   write_pending_ = std::nullopt;
   MaybeConsumeExpectations();
 }

 std::optional<size_t> QuicSocketDataProvider::FindReadyExpectations(
     Expectation::Type type) {
   std::vector<size_t> matches;
   for (size_t i = 0; i < expectations_.size(); i++) {
     const Expectation& expectation = expectations_[i];
     if (expectation.consumed() || expectation.type() != type) {
       continue;
     }
     bool found_unconsumed = false;
     for (auto dep : dependencies_[i]) {
       if (!expectations_[dep].consumed_) {
         found_unconsumed = true;
         break;
       }
     }
     if (!found_unconsumed) {
       matches.push_back(i);
     }
   }

   if (matches.size() > 1) {
     std::string exp_type = Expectation::TypeToString(type);
     std::string names = ExpectationList(matches);
     CHECK(matches.size() <= 1)
         << "Multiple expectations of type " << exp_type
         << " are ready: " << names << ". Use .After() to disambiguate.";
   }

   return matches.empty() ? std::nullopt : std::make_optional(matches[0]);
 }

 std::optional<MockRead> QuicSocketDataProvider::ConsumeNextRead() {
   CHECK(read_pending_);
   std::optional<size_t> ready = FindReadyExpectations(Expectation::Type::READ);
   if (!ready.has_value()) {
     return std::nullopt;
   }

   // If there's exactly one matching expectation, return it.
   Expectation& ready_expectation = expectations_[*ready];
   MockRead read(ready_expectation.mode(), ready_expectation.rv());
   if (ready_expectation.packet()) {
     read.data = ready_expectation.packet()->AsStringPiece();
   }
   read.tos = ready_expectation.tos_byte();
   ready_expectation.Consume();
   ExpectationConsumed();
   return read;
 }

 std::optional<MockWriteResult> QuicSocketDataProvider::ConsumeNextWrite() {
   CHECK(write_pending_.has_value());
   std::optional<size_t> ready = FindReadyExpectations(Expectation::Type::WRITE);
   if (!ready.has_value()) {
     return std::nullopt;
   }

   // If there's exactly one matching expectation, check if it matches the
   // write and return it.
   Expectation& ready_expectation = expectations_[*ready];
   if (ready_expectation.packet()) {
     if (!VerifyWriteData(ready_expectation)) {
       return MockWriteResult(SYNCHRONOUS, ERR_UNEXPECTED);
     }
   }
   MockWriteResult write(ready_expectation.mode(),
                         ready_expectation.packet()
                             ? ready_expectation.packet()->length()
                             : ready_expectation.rv());
   ready_expectation.Consume();
   ExpectationConsumed();
   return write;
 }

 void QuicSocketDataProvider::MaybeConsumeExpectations() {
   pending_maybe_consume_expectations_ = false;
   if (read_pending_) {
     std::optional<MockRead> next_read = ConsumeNextRead();
     if (next_read.has_value()) {
       read_pending_ = false;
       if (socket()) {
         socket()->OnReadComplete(*next_read);
       }
     }
   }

   if (write_pending_.has_value()) {
     std::optional<MockWriteResult> next_write = ConsumeNextWrite();
     if (next_write.has_value()) {
       write_pending_ = std::nullopt;
       if (socket()) {
         socket()->OnWriteComplete(next_write->result);
       }
     }
   }

   if (!paused_at_) {
     std::optional<size_t> ready =
         FindReadyExpectations(Expectation::Type::PAUSE);
     if (ready.has_value()) {
       VLOG(1) << "Pausing at " << expectations_[*ready].name();
       paused_at_ = *ready;
       if (run_until_run_loop_) {
         run_until_run_loop_->Quit();
       }
     }
   }

   if (run_until_run_loop_ && AllDataConsumed()) {
     run_until_run_loop_->Quit();
   }
 }

 void QuicSocketDataProvider::ExpectationConsumed() {
   if (pending_maybe_consume_expectations_) {
     return;
   }
   pending_maybe_consume_expectations_ = true;

   // Call `MaybeConsumeExpectations` in a task. That method may trigger
   // consumption of other expectations, and that consumption must happen
   // _after_ the current call to `Read` or `Write` has finished.
   base::SequencedTaskRunner::GetCurrentDefault()->PostTask(
       FROM_HERE,
       base::BindOnce(&QuicSocketDataProvider::MaybeConsumeExpectations,
                      weak_factory_.GetWeakPtr()));
 }

 bool QuicSocketDataProvider::VerifyWriteData(
     QuicSocketDataProvider::Expectation& expectation) {
   std::string expected_data(expectation.packet()->data(),
                             expectation.packet()->length());
   std::string& actual_data = *write_pending_;
   actual_log_.append(
       PrintWithQuicSession(session_for_actual_.get(), actual_data));
   expected_log_.append(
       PrintWithQuicSession(session_for_expected_.get(), expected_data));

   bool write_matches = actual_data == expected_data;
   EXPECT_TRUE(write_matches)
       << "Expectation '" << expectation.name()
       << "' not met. Actual formatted write data:\n"
       << actual_log_ << "But expectation '" << expectation.name()
       << "' expected formatted write data:\n"
       << expected_log_ << "Actual raw write data:\n"
       << HexDump(actual_data) << "Expected raw write data:\n"
       << HexDump(expected_data);
   return write_matches;
 }

 std::string QuicSocketDataProvider::ExpectationList(
     const std::vector<size_t>& indices) {
   std::ostringstream names;
   bool first = true;
   for (auto i : indices) {
     names << (first ? "" : ", ") << expectations_[i].name();
     first = false;
   }
   return names.str();
 }

 }  // namespace net::test
	// Copyright 2024 The Chromium Authors
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	#include "net/quic/quic_socket_data_provider.h"

	#include <algorithm>
	#include <map>
	#include <memory>
	#include <optional>
	#include <set>
	#include <sstream>
	#include <string>

	#include "base/functional/callback.h"
	#include "base/run_loop.h"
	#include "base/strings/string_number_conversions.h"
	#include "base/task/sequenced_task_runner.h"
	#include "net/base/hex_utils.h"
	#include "net/socket/socket_test_util.h"
	#include "net/third_party/quiche/src/quiche/quic/core/crypto/null_encrypter.h"
	#include "net/third_party/quiche/src/quiche/quic/core/crypto/quic_crypto_server_config.h"
	#include "net/third_party/quiche/src/quiche/quic/core/http/quic_spdy_session.h"
	#include "net/third_party/quiche/src/quiche/quic/core/quic_packets.h"
	#include "net/third_party/quiche/src/quiche/quic/core/quic_time.h"
	#include "net/third_party/quiche/src/quiche/quic/core/quic_versions.h"
	#include "net/third_party/quiche/src/quiche/quic/test_tools/crypto_test_utils.h"
	#include "net/third_party/quiche/src/quiche/quic/test_tools/quic_test_utils.h"
	#include "net/third_party/quiche/src/quiche/quic/tools/quic_simple_server_session.h"

	namespace quic {

	namespace {

	class HttpStreamPrinter : public Http3DebugVisitor {
	public:
	explicit HttpStreamPrinter(std::ostream* output) : output_(output) {}

	void OnControlStreamCreated(QuicStreamId stream_id) override {
	if (output_) {
	*output_ << "OnControlStreamCreated: " << stream_id << "\n";
	}
	}

	void OnQpackEncoderStreamCreated(QuicStreamId stream_id) override {
	if (output_) {
	*output_ << "OnQpackEncoderStreamCreated: " << stream_id << "\n";
	}
	}

	void OnQpackDecoderStreamCreated(QuicStreamId stream_id) override {
	if (output_) {
	*output_ << "OnQpackDecoderStreamCreated: " << stream_id << "\n";
	}
	}

	void OnPeerControlStreamCreated(QuicStreamId stream_id) override {
	if (output_) {
	*output_ << "OnPeerControlStreamCreated: " << stream_id << "\n";
	}
	}

	void OnPeerQpackEncoderStreamCreated(QuicStreamId stream_id) override {
	if (output_) {
	*output_ << "OnPeerQpackEncoderStreamCreated: " << stream_id << "\n";
	}
	}

	void OnPeerQpackDecoderStreamCreated(QuicStreamId stream_id) override {
	if (output_) {
	*output_ << "OnPeerQpackDecoderStreamCreated: " << stream_id << "\n";
	}
	}

	void OnSettingsFrameReceived(const SettingsFrame& frame) override {
	if (output_) {
	*output_ << "OnSettingsFrameReceived: " << frame << "\n";
	}
	}

	void OnGoAwayFrameReceived(const GoAwayFrame& frame) override {
	if (output_) {
	*output_ << "OnGoAwayFrameReceived" << "\n";
	}
	}

	void OnPriorityUpdateFrameReceived(
	const PriorityUpdateFrame& frame) override {
	if (output_) {
	*output_ << "OnPriorityUpdateFrameReceived: " << frame << "\n";
	}
	}

	void OnDataFrameReceived(QuicStreamId stream_id,
	QuicByteCount payload_length) override {
	if (output_) {
	*output_ << "OnDataFrameReceived: " << stream_id << ", "
	<< "received: " << payload_length << " bytes" << "\n";
	}
	}

	void OnHeadersFrameReceived(
	QuicStreamId stream_id,
	QuicByteCount compressed_headers_length) override {
	if (output_) {
	*output_ << "OnHeadersFrameReceived: " << stream_id << ", "
	<< "received: " << compressed_headers_length << " bytes" << "\n";
	}
	}

	void OnHeadersDecoded(QuicStreamId stream_id,
	QuicHeaderList headers) override {
	if (output_) {
	*output_ << "OnHeadersDecoded: " << stream_id << ", "
	<< "received: " << headers.DebugString() << "\n";
	}
	}

	void OnUnknownFrameReceived(QuicStreamId stream_id,
	uint64_t frame_type,
	QuicByteCount payload_length) override {
	if (output_) {
	*output_ << "OnUnknownFrameReceived: " << stream_id << ", "
	<< "frame_type: " << frame_type << ","
	<< "received: " << payload_length << "bytes " << "\n ";
	}
	}

	void OnSettingsFrameSent(const SettingsFrame& frame) override {
	if (output_) {
	*output_ << "OnSettingsFrameSent: " << frame << "\n";
	}
	}

	void OnSettingsFrameResumed(const SettingsFrame& frame) override {
	if (output_) {
	*output_ << "OnSettingsFrameResumed: " << frame << "\n";
	}
	}

	void OnGoAwayFrameSent(QuicStreamId stream_id) override {
	if (output_) {
	*output_ << "OnGoAwayFrameSent: " << stream_id << "\n";
	}
	}

	void OnPriorityUpdateFrameSent(const PriorityUpdateFrame& frame) override {
	if (output_) {
	*output_ << "OnPriorityUpdateFrameSent: " << frame << "\n";
	}
	}

	void OnDataFrameSent(QuicStreamId stream_id,
	QuicByteCount payload_length) override {
	if (output_) {
	*output_ << "OnDataFrameSent: " << stream_id << ", "
	<< "sent: " << payload_length << " bytes" << "\n";
	}
	}

	void OnHeadersFrameSent(
	QuicStreamId stream_id,
	const quiche::HttpHeaderBlock& header_block) override {
	if (output_) {
	*output_ << "OnHeadersFrameSent: " << stream_id << ", "
	<< "sent: " << header_block.DebugString() << "\n";
	}
	}

	private:
	mutable raw_ptr<std::ostream> output_ = nullptr;
	};
	} // namespace

	} // namespace quic

	namespace net::test {

	QuicSimpleServerSessionForTest::~QuicSimpleServerSessionForTest() = default;

	// Always return true if CryptoStream is created, so that the pending stream can
	// handle initial setting frames for tests.
	bool QuicSimpleServerSessionForTest::IsEncryptionEstablished() const {
	return GetCryptoStream() != nullptr;
	}

	QuicSocketDataProvider::Expectation::Expectation(
	std::string name,
	Type type,
	int rv,
	std::unique_ptr<quic::QuicEncryptedPacket> packet)
	: name_(std::move(name)),
	type_(type),
	rv_(rv),
	packet_(std::move(packet)) {}

	QuicSocketDataProvider::Expectation::Expectation(
	QuicSocketDataProvider::Expectation&&) = default;

	QuicSocketDataProvider::Expectation::~Expectation() = default;

	QuicSocketDataProvider::Expectation& QuicSocketDataProvider::Expectation::After(
	std::string name) {
	after_.insert(std::move(name));
	return *this;
	}

	std::string QuicSocketDataProvider::Expectation::TypeToString(
	QuicSocketDataProvider::Expectation::Type type) {
	switch (type) {
	case Expectation::Type::READ:
	return "READ";
	case Expectation::Type::WRITE:
	return "WRITE";
	case Expectation::Type::PAUSE:
	return "PAUSE";
	}
	NOTREACHED();
	}

	void QuicSocketDataProvider::Expectation::Consume() {
	CHECK(!consumed_);
	VLOG(1) << "Consuming " << TypeToString(type_) << " expectation " << name_;
	consumed_ = true;
	}

	QuicSocketDataProvider::QuicSocketDataProvider(quic::ParsedQuicVersion version)
	: printer_(version),
	crypto_config_(quic::QuicCryptoServerConfig::TESTING,
	quic::QuicRandom::GetInstance(),
	quic::test::crypto_test_utils::ProofSourceForTesting(),
	quic::KeyExchangeSource::Default()),
	compressed_certs_cache_(
	quic::QuicCompressedCertsCache::kQuicCompressedCertsCacheSize) {
	session_for_actual_ = GenSimpleServerSession();
	session_for_expected_ = GenSimpleServerSession();
	}

	QuicSocketDataProvider::~QuicSocketDataProvider() = default;

	std::unique_ptr<quic::QuicSimpleServerSession>
	QuicSocketDataProvider::GenSimpleServerSession() {
	quic::test::MockQuicConnection* connection =
	new quic::test::MockQuicConnection( // IN-TEST
	&helper_, &alarm_factory_, quic::Perspective::IS_SERVER);
	connection->AdvanceTime(quic::QuicTime::Delta::FromSeconds(1));
	connection->SetEncrypter(
	quic::ENCRYPTION_FORWARD_SECURE,
	std::make_unique<quic::NullEncrypter>(connection->perspective()));

	std::unique_ptr<QuicSimpleServerSessionForTest> session =
	std::make_unique<QuicSimpleServerSessionForTest>(
	config_, quic::CurrentSupportedVersions(), connection, &owner_,
	&stream_helper_, &crypto_config_, &compressed_certs_cache_,
	&memory_cache_backend_);
	session->Initialize();
	return session;
	}

	std::string QuicSocketDataProvider::PrintWithQuicSession(
	quic::QuicSimpleServerSession* session,
	std::string data) {
	std::ostringstream output;
	quic::HttpStreamPrinter printer(&output);
	session->set_debug_visitor(&printer);
	std::string res = printer_.PrintWithQuicSession(data, output, session);
	session->set_debug_visitor(nullptr);
	return res;
	}

	QuicSocketDataProvider::Expectation& QuicSocketDataProvider::AddRead(
	std::string name,
	std::unique_ptr<quic::QuicEncryptedPacket> packet) {
	expectations_.push_back(Expectation(std::move(name), Expectation::Type::READ,
	OK, std::move(packet)));
	return expectations_.back();
	}

	QuicSocketDataProvider::Expectation& QuicSocketDataProvider::AddRead(
	std::string name,
	std::unique_ptr<quic::QuicReceivedPacket> packet) {
	uint8_t tos_byte = static_cast<uint8_t>(packet->ecn_codepoint());
	return AddRead(std::move(name),
	static_cast<std::unique_ptr<quic::QuicEncryptedPacket>>(
	std::move(packet)))
	.TosByte(tos_byte);
	}

	QuicSocketDataProvider::Expectation& QuicSocketDataProvider::AddReadError(
	std::string name,
	int rv) {
	CHECK_NE(rv, OK);
	CHECK_NE(rv, ERR_IO_PENDING);
	expectations_.push_back(
	Expectation(std::move(name), Expectation::Type::READ, rv, nullptr));
	return expectations_.back();
	}

	QuicSocketDataProvider::Expectation& QuicSocketDataProvider::AddWrite(
	std::string name,
	std::unique_ptr<quic::QuicEncryptedPacket> packet,
	int rv) {
	expectations_.push_back(Expectation(std::move(name), Expectation::Type::WRITE,
	rv, std::move(packet)));
	return expectations_.back();
	}

	QuicSocketDataProvider::Expectation& QuicSocketDataProvider::AddWriteError(
	std::string name,
	int rv) {
	CHECK_NE(rv, OK);
	CHECK_NE(rv, ERR_IO_PENDING);
	expectations_.push_back(
	Expectation(std::move(name), Expectation::Type::WRITE, rv, nullptr));
	return expectations_.back();
	}

	QuicSocketDataProvider::PausePoint QuicSocketDataProvider::AddPause(
	std::string name) {
	expectations_.push_back(
	Expectation(std::move(name), Expectation::Type::PAUSE, OK, nullptr));
	return expectations_.size() - 1;
	}

	bool QuicSocketDataProvider::AllDataConsumed() const {
	return std::all_of(
	expectations_.begin(), expectations_.end(),
	[](const Expectation& expectation) { return expectation.consumed(); });
	}

	void QuicSocketDataProvider::RunUntilPause(
	QuicSocketDataProvider::PausePoint pause_point) {
	if (!paused_at_.has_value()) {
	run_until_run_loop_ = std::make_unique<base::RunLoop>();
	run_until_run_loop_->Run();
	run_until_run_loop_.reset();
	}
	CHECK(paused_at_.has_value() && *paused_at_ == pause_point)
	<< "Did not pause at '" << expectations_[pause_point].name() << "'.";
	}

	void QuicSocketDataProvider::Resume() {
	CHECK(paused_at_.has_value());
	VLOG(1) << "Resuming from pause point " << expectations_[*paused_at_].name();
	expectations_[*paused_at_].Consume();
	paused_at_ = std::nullopt;
	ExpectationConsumed();
	}

	void QuicSocketDataProvider::RunUntilAllConsumed() {
	if (!AllDataConsumed()) {
	run_until_run_loop_ = std::make_unique<base::RunLoop>();
	run_until_run_loop_->Run();
	run_until_run_loop_.reset();
	}

	// If that run timed out, then there will still be un-consumed data.
	if (!AllDataConsumed()) {
	std::vector<size_t> unconsumed;
	for (size_t i = 0; i < expectations_.size(); i++) {
	if (!expectations_[i].consumed()) {
	unconsumed.push_back(i);
	}
	}
	FAIL() << "All expectations were not consumed; remaining: "
	<< ExpectationList(unconsumed);
	}
	}

	MockRead QuicSocketDataProvider::OnRead() {
	CHECK(!read_pending_);
	read_pending_ = true;
	std::optional<MockRead> next_read = ConsumeNextRead();
	if (!next_read.has_value()) {
	return MockRead(ASYNC, ERR_IO_PENDING);
	}

	read_pending_ = false;
	return *next_read;
	}

	MockWriteResult QuicSocketDataProvider::OnWrite(const std::string& data) {
	CHECK(!write_pending_.has_value());
	write_pending_ = data;
	std::optional<MockWriteResult> next_write = ConsumeNextWrite();
	if (!next_write.has_value()) {
	// If Write() was called when no corresponding expectation exists, that's
	// an error unless execution is currently paused, in which case it's just
	// pending. This rarely occurs because the only other type of expectation
	// that might be blocking a WRITE is a READ, and QUIC implementations
	// typically eagerly consume READs.
	if (paused_at_.has_value()) {
	return MockWriteResult(ASYNC, ERR_IO_PENDING);
	} else {
	ADD_FAILURE() << "Write call when none is expected:\n"
	<< printer_.PrintWrite(data);
	return MockWriteResult(SYNCHRONOUS, ERR_UNEXPECTED);
	}
	}

	write_pending_ = std::nullopt;
	return *next_write;
	}

	bool QuicSocketDataProvider::AllReadDataConsumed() const {
	return AllDataConsumed();
	}

	bool QuicSocketDataProvider::AllWriteDataConsumed() const {
	return AllDataConsumed();
	}

	void QuicSocketDataProvider::CancelPendingRead() {
	read_pending_ = false;
	}

	void QuicSocketDataProvider::Reset() {
	// Note that `Reset` is a parent-class method with a confusing name. It is
	// used to initialize the socket data provider before it is used.

	// Map names to index, and incidentally check for duplicate names.
	std::map<std::string, size_t> names;
	for (size_t i = 0; i < expectations_.size(); i++) {
	Expectation& expectation = expectations_[i];
	auto [_, inserted] = names.insert({expectation.name(), i});
	CHECK(inserted) << "Another expectation named " << expectation.name()
	<< " exists.";
	}

	// Calculate `dependencies_` mapping indices in `expectations_` to indices
	// of the expectations they depend on.
	dependencies_.clear();
	for (size_t i = 0; i < expectations_.size(); i++) {
	Expectation& expectation = expectations_[i];
	if (expectation.after().empty()) {
	// If no other dependencies are given, make the expectation depend on
	// the previous expectation.
	if (i > 0) {
	dependencies_[i].insert(i - 1);
	}
	} else {
	for (auto& after : expectation.after()) {
	const auto dep = names.find(after);
	CHECK(dep != names.end()) << "No expectation named " << after;
	dependencies_[i].insert(dep->second);
	}
	}
	}

	pending_maybe_consume_expectations_ = false;
	read_pending_ = false;
	write_pending_ = std::nullopt;
	MaybeConsumeExpectations();
	}

	std::optional<size_t> QuicSocketDataProvider::FindReadyExpectations(
	Expectation::Type type) {
	std::vector<size_t> matches;
	for (size_t i = 0; i < expectations_.size(); i++) {
	const Expectation& expectation = expectations_[i];
	if (expectation.consumed() \|\| expectation.type() != type) {
	continue;
	}
	bool found_unconsumed = false;
	for (auto dep : dependencies_[i]) {
	if (!expectations_[dep].consumed_) {
	found_unconsumed = true;
	break;
	}
	}
	if (!found_unconsumed) {
	matches.push_back(i);
	}
	}

	if (matches.size() > 1) {
	std::string exp_type = Expectation::TypeToString(type);
	std::string names = ExpectationList(matches);
	CHECK(matches.size() <= 1)
	<< "Multiple expectations of type " << exp_type
	<< " are ready: " << names << ". Use .After() to disambiguate.";
	}

	return matches.empty() ? std::nullopt : std::make_optional(matches[0]);
	}

	std::optional<MockRead> QuicSocketDataProvider::ConsumeNextRead() {
	CHECK(read_pending_);
	std::optional<size_t> ready = FindReadyExpectations(Expectation::Type::READ);
	if (!ready.has_value()) {
	return std::nullopt;
	}

	// If there's exactly one matching expectation, return it.
	Expectation& ready_expectation = expectations_[*ready];
	MockRead read(ready_expectation.mode(), ready_expectation.rv());
	if (ready_expectation.packet()) {
	read.data = ready_expectation.packet()->AsStringPiece();
	}
	read.tos = ready_expectation.tos_byte();
	ready_expectation.Consume();
	ExpectationConsumed();
	return read;
	}

	std::optional<MockWriteResult> QuicSocketDataProvider::ConsumeNextWrite() {
	CHECK(write_pending_.has_value());
	std::optional<size_t> ready = FindReadyExpectations(Expectation::Type::WRITE);
	if (!ready.has_value()) {
	return std::nullopt;
	}

	// If there's exactly one matching expectation, check if it matches the
	// write and return it.
	Expectation& ready_expectation = expectations_[*ready];
	if (ready_expectation.packet()) {
	if (!VerifyWriteData(ready_expectation)) {
	return MockWriteResult(SYNCHRONOUS, ERR_UNEXPECTED);
	}
	}
	MockWriteResult write(ready_expectation.mode(),
	ready_expectation.packet()
	? ready_expectation.packet()->length()
	: ready_expectation.rv());
	ready_expectation.Consume();
	ExpectationConsumed();
	return write;
	}

	void QuicSocketDataProvider::MaybeConsumeExpectations() {
	pending_maybe_consume_expectations_ = false;
	if (read_pending_) {
	std::optional<MockRead> next_read = ConsumeNextRead();
	if (next_read.has_value()) {
	read_pending_ = false;
	if (socket()) {
	socket()->OnReadComplete(*next_read);
	}
	}
	}

	if (write_pending_.has_value()) {
	std::optional<MockWriteResult> next_write = ConsumeNextWrite();
	if (next_write.has_value()) {
	write_pending_ = std::nullopt;
	if (socket()) {
	socket()->OnWriteComplete(next_write->result);
	}
	}
	}

	if (!paused_at_) {
	std::optional<size_t> ready =
	FindReadyExpectations(Expectation::Type::PAUSE);
	if (ready.has_value()) {
	VLOG(1) << "Pausing at " << expectations_[*ready].name();
	paused_at_ = *ready;
	if (run_until_run_loop_) {
	run_until_run_loop_->Quit();
	}
	}
	}

	if (run_until_run_loop_ && AllDataConsumed()) {
	run_until_run_loop_->Quit();
	}
	}

	void QuicSocketDataProvider::ExpectationConsumed() {
	if (pending_maybe_consume_expectations_) {
	return;
	}
	pending_maybe_consume_expectations_ = true;

	// Call `MaybeConsumeExpectations` in a task. That method may trigger
	// consumption of other expectations, and that consumption must happen
	// _after_ the current call to `Read` or `Write` has finished.
	base::SequencedTaskRunner::GetCurrentDefault()->PostTask(
	FROM_HERE,
	base::BindOnce(&QuicSocketDataProvider::MaybeConsumeExpectations,
	weak_factory_.GetWeakPtr()));
	}

	bool QuicSocketDataProvider::VerifyWriteData(
	QuicSocketDataProvider::Expectation& expectation) {
	std::string expected_data(expectation.packet()->data(),
	expectation.packet()->length());
	std::string& actual_data = *write_pending_;
	actual_log_.append(
	PrintWithQuicSession(session_for_actual_.get(), actual_data));
	expected_log_.append(
	PrintWithQuicSession(session_for_expected_.get(), expected_data));

	bool write_matches = actual_data == expected_data;
	EXPECT_TRUE(write_matches)
	<< "Expectation '" << expectation.name()
	<< "' not met. Actual formatted write data:\n"
	<< actual_log_ << "But expectation '" << expectation.name()
	<< "' expected formatted write data:\n"
	<< expected_log_ << "Actual raw write data:\n"
	<< HexDump(actual_data) << "Expected raw write data:\n"
	<< HexDump(expected_data);
	return write_matches;
	}

	std::string QuicSocketDataProvider::ExpectationList(
	const std::vector<size_t>& indices) {
	std::ostringstream names;
	bool first = true;
	for (auto i : indices) {
	names << (first ? "" : ", ") << expectations_[i].name();
	first = false;
	}
	return names.str();
	}

	} // namespace net::test