content/browser/devtools/protocol/tracing_handler.cc

// Copyright 2014 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 "content/browser/devtools/protocol/tracing_handler.h"

#include <algorithm>
#include <cmath>
#include <memory>
#include <set>
#include <string>
#include <utility>
#include <vector>

#include "base/bind.h"
#include "base/format_macros.h"
#include "base/json/json_writer.h"
#include "base/memory/ref_counted_memory.h"
#include "base/strings/string_split.h"
#include "base/strings/stringprintf.h"
#include "base/time/time.h"
#include "base/timer/timer.h"
#include "base/trace_event/memory_dump_manager.h"
#include "base/trace_event/trace_event_impl.h"
#include "base/trace_event/tracing_agent.h"
#include "components/tracing/common/trace_config_file.h"
#include "components/viz/common/features.h"
#include "content/browser/devtools/devtools_frame_trace_recorder_for_viz.h"
#include "content/browser/devtools/devtools_io_context.h"
#include "content/browser/devtools/devtools_session.h"
#include "content/browser/frame_host/render_frame_host_impl.h"
#include "content/browser/renderer_host/render_widget_host_impl.h"
#include "content/browser/tracing/tracing_controller_impl.h"
#include "content/public/browser/browser_thread.h"
#include "services/resource_coordinator/public/cpp/memory_instrumentation/memory_instrumentation.h"
#include "services/tracing/public/mojom/constants.mojom.h"

namespace content {
namespace protocol {

namespace {

const double kMinimumReportingInterval = 250.0;

const char kRecordModeParam[] = "record_mode";

// Convert from camel case to separator + lowercase.
std::string ConvertFromCamelCase(const std::string& in_str, char separator) {
  std::string out_str;
  out_str.reserve(in_str.size());
  for (const char& c : in_str) {
    if (isupper(c)) {
      out_str.push_back(separator);
      out_str.push_back(tolower(c));
    } else {
      out_str.push_back(c);
    }
  }
  return out_str;
}

std::unique_ptr<base::Value> ConvertDictKeyStyle(const base::Value& value) {
  const base::DictionaryValue* dict = nullptr;
  if (value.GetAsDictionary(&dict)) {
    std::unique_ptr<base::DictionaryValue> out_dict(
        new base::DictionaryValue());
    for (base::DictionaryValue::Iterator it(*dict); !it.IsAtEnd();
         it.Advance()) {
      out_dict->Set(ConvertFromCamelCase(it.key(), '_'),
                    ConvertDictKeyStyle(it.value()));
    }
    return std::move(out_dict);
  }

  const base::ListValue* list = nullptr;
  if (value.GetAsList(&list)) {
    std::unique_ptr<base::ListValue> out_list(new base::ListValue());
    for (const auto& key : *list)
      out_list->Append(ConvertDictKeyStyle(key));
    return std::move(out_list);
  }

  return value.CreateDeepCopy();
}

class DevToolsTraceEndpointProxy : public TracingController::TraceDataEndpoint {
 public:
  explicit DevToolsTraceEndpointProxy(base::WeakPtr<TracingHandler> handler)
      : tracing_handler_(handler) {}

  void ReceiveTraceChunk(std::unique_ptr<std::string> chunk) override {
    if (TracingHandler* h = tracing_handler_.get())
      h->OnTraceDataCollected(std::move(chunk));
  }
  void ReceiveTraceFinalContents(
      std::unique_ptr<const base::DictionaryValue> metadata) override {
    if (TracingHandler* h = tracing_handler_.get())
      h->OnTraceComplete();
  }

 private:
  ~DevToolsTraceEndpointProxy() override {}

  base::WeakPtr<TracingHandler> tracing_handler_;
};

class DevToolsStreamEndpoint : public TracingController::TraceDataEndpoint {
 public:
  explicit DevToolsStreamEndpoint(
      base::WeakPtr<TracingHandler> handler,
      const scoped_refptr<DevToolsIOContext::RWStream>& stream)
      : stream_(stream), tracing_handler_(handler) {}

  void ReceiveTraceChunk(std::unique_ptr<std::string> chunk) override {
    if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
      BrowserThread::PostTask(
          BrowserThread::UI, FROM_HERE,
          base::BindOnce(&DevToolsStreamEndpoint::ReceiveTraceChunk, this,
                         std::move(chunk)));
      return;
    }

    stream_->Append(std::move(chunk));
  }

  void ReceiveTraceFinalContents(
      std::unique_ptr<const base::DictionaryValue> metadata) override {
    if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
      BrowserThread::PostTask(
          BrowserThread::UI, FROM_HERE,
          base::BindOnce(&DevToolsStreamEndpoint::ReceiveTraceFinalContents,
                         this, std::move(metadata)));
      return;
    }
    if (TracingHandler* h = tracing_handler_.get())
      h->OnTraceToStreamComplete(stream_->handle());
  }

 private:
  ~DevToolsStreamEndpoint() override {}

  scoped_refptr<DevToolsIOContext::RWStream> stream_;
  base::WeakPtr<TracingHandler> tracing_handler_;
};

}  // namespace

TracingHandler::TracingHandler(TracingHandler::Target target,
                               int frame_tree_node_id,
                               DevToolsIOContext* io_context)
    : DevToolsDomainHandler(Tracing::Metainfo::domainName),
      target_(target),
      io_context_(io_context),
      frame_tree_node_id_(frame_tree_node_id),
      did_initiate_recording_(false),
      return_as_stream_(false),
      gzip_compression_(false),
      weak_factory_(this) {
  if (base::FeatureList::IsEnabled(features::kVizDisplayCompositor)) {
    frame_trace_recorder_ =
        std::make_unique<DevToolsFrameTraceRecorderForViz>();
  }
}

TracingHandler::~TracingHandler() {
}

// static
std::vector<TracingHandler*> TracingHandler::ForAgentHost(
    DevToolsAgentHostImpl* host) {
  return DevToolsSession::HandlersForAgentHost<TracingHandler>(
      host, Tracing::Metainfo::domainName);
}

void TracingHandler::SetRenderer(int process_host_id,
                                 RenderFrameHostImpl* frame_host) {
  if (!frame_trace_recorder_ || !frame_host)
    return;
  frame_trace_recorder_->SetFrameSinkId(
      frame_host->GetRenderWidgetHost()->GetFrameSinkId());
}

void TracingHandler::Wire(UberDispatcher* dispatcher) {
  frontend_.reset(new Tracing::Frontend(dispatcher->channel()));
  Tracing::Dispatcher::wire(dispatcher, this);
}

Response TracingHandler::Disable() {
  if (did_initiate_recording_)
    StopTracing(nullptr, "");
  return Response::OK();
}

void TracingHandler::OnTraceDataCollected(
    std::unique_ptr<std::string> trace_fragment) {
  const std::string valid_trace_fragment =
      UpdateTraceDataBuffer(*trace_fragment);
  if (valid_trace_fragment.empty())
    return;

  // Hand-craft protocol notification message so we can substitute JSON
  // that we already got as string as a bare object, not a quoted string.
  std::string message(
      "{ \"method\": \"Tracing.dataCollected\", \"params\": { \"value\": [");
  const size_t messageSuffixSize = 10;
  message.reserve(message.size() + valid_trace_fragment.size() +
                  messageSuffixSize - trace_data_buffer_state_.offset);
  message.append(valid_trace_fragment.c_str() +
                 trace_data_buffer_state_.offset);
  message += "] } }";
  frontend_->sendRawNotification(message);
}

void TracingHandler::OnTraceComplete() {
  if (!trace_data_buffer_state_.data.empty())
    OnTraceDataCollected(std::make_unique<std::string>(""));

  DCHECK(trace_data_buffer_state_.data.empty());
  DCHECK_EQ(0u, trace_data_buffer_state_.pos);
  DCHECK_EQ(0, trace_data_buffer_state_.open_braces);
  DCHECK(!trace_data_buffer_state_.in_string);
  DCHECK(!trace_data_buffer_state_.slashed);

  frontend_->TracingComplete();
}

std::string TracingHandler::UpdateTraceDataBuffer(
    const std::string& trace_fragment) {
  size_t end = 0;
  size_t last_open = 0;
  TraceDataBufferState& state = trace_data_buffer_state_;
  state.offset = 0;
  bool update_offset = state.open_braces == 0;
  for (; state.pos < trace_fragment.size(); ++state.pos) {
    char c = trace_fragment[state.pos];
    switch (c) {
      case '{':
        if (!state.in_string && !state.slashed) {
          state.open_braces++;
          if (state.open_braces == 1) {
            last_open = state.data.size() + state.pos;
            if (update_offset) {
              state.offset = last_open;
              update_offset = false;
            }
          }
        }
        break;
      case '}':
        if (!state.in_string && !state.slashed) {
          DCHECK_GT(state.open_braces, 0);
          state.open_braces--;
          if (state.open_braces == 0)
            end = state.data.size() + state.pos + 1;
        }
        break;
      case '"':
        if (!state.slashed)
          state.in_string = !state.in_string;
        break;
      case 'u':
        if (state.slashed)
          state.pos += 4;
        break;
    }

    if (state.in_string && c == '\\') {
      state.slashed = !state.slashed;
    } else {
      state.slashed = false;
    }
  }

  // Next starting position is usually 0 except when we are in the middle of
  // processing a unicode character, i.e. \uxxxx.
  state.pos -= trace_fragment.size();

  std::string complete_str = state.data + trace_fragment;
  state.data = complete_str.substr(std::max(end, last_open));

  complete_str.resize(end);
  return complete_str;
}

void TracingHandler::OnTraceToStreamComplete(const std::string& stream_handle) {
  std::string stream_compression =
      (gzip_compression_ ? Tracing::StreamCompressionEnum::Gzip
                         : Tracing::StreamCompressionEnum::None);
  frontend_->TracingComplete(stream_handle, stream_compression);
}

void TracingHandler::Start(Maybe<std::string> categories,
                           Maybe<std::string> options,
                           Maybe<double> buffer_usage_reporting_interval,
                           Maybe<std::string> transfer_mode,
                           Maybe<std::string> transfer_compression,
                           Maybe<Tracing::TraceConfig> config,
                           std::unique_ptr<StartCallback> callback) {
  bool return_as_stream = transfer_mode.fromMaybe("") ==
      Tracing::Start::TransferModeEnum::ReturnAsStream;
  bool gzip_compression = transfer_compression.fromMaybe("") ==
                          Tracing::StreamCompressionEnum::Gzip;
  if (IsTracing()) {
    if (!did_initiate_recording_ && IsStartupTracingActive()) {
      // If tracing is already running because it was initiated by startup
      // tracing, honor the transfer mode update, as that's the only way
      // for the client to communicate it.
      return_as_stream_ = return_as_stream;
      gzip_compression_ = gzip_compression;
    }
    callback->sendFailure(Response::Error("Tracing is already started"));
    return;
  }

  if (config.isJust() && (categories.isJust() || options.isJust())) {
    callback->sendFailure(Response::InvalidParams(
        "Either trace config (preferred), or categories+options should be "
        "specified, but not both."));
    return;
  }

  did_initiate_recording_ = true;
  return_as_stream_ = return_as_stream;
  gzip_compression_ = gzip_compression;
  if (buffer_usage_reporting_interval.isJust())
    SetupTimer(buffer_usage_reporting_interval.fromJust());

  base::trace_event::TraceConfig trace_config;
  if (config.isJust()) {
    std::unique_ptr<base::Value> value =
        protocol::toBaseValue(config.fromJust()->toValue().get(), 1000);
    if (value && value->is_dict()) {
      trace_config = GetTraceConfigFromDevToolsConfig(
          *static_cast<base::DictionaryValue*>(value.get()));
    }
  } else if (categories.isJust() || options.isJust()) {
    trace_config = base::trace_event::TraceConfig(
        categories.fromMaybe(""), options.fromMaybe(""));
  }

  // If inspected target is a render process Tracing.start will be handled by
  // tracing agent in the renderer.
  if (target_ == Renderer)
    callback->fallThrough();

  TracingController::GetInstance()->StartTracing(
      trace_config,
      base::Bind(&TracingHandler::OnRecordingEnabled,
                 weak_factory_.GetWeakPtr(),
                 base::Passed(std::move(callback))));
}

void TracingHandler::End(std::unique_ptr<EndCallback> callback) {
  // Startup tracing triggered by --trace-config-file is a special case, where
  // tracing is started automatically upon browser startup and can be stopped
  // via DevTools.
  if (!did_initiate_recording_ && !IsStartupTracingActive()) {
    callback->sendFailure(Response::Error("Tracing is not started"));
    return;
  }

  scoped_refptr<TracingController::TraceDataEndpoint> endpoint;
  if (return_as_stream_) {
    endpoint = new DevToolsStreamEndpoint(
        weak_factory_.GetWeakPtr(), io_context_->CreateTempFileBackedStream(
                                        gzip_compression_ /* binary */));
    if (gzip_compression_) {
      endpoint = TracingControllerImpl::CreateCompressedStringEndpoint(
          endpoint, true /* compress_with_background_priority */);
    }
    StopTracing(endpoint, "");
  } else {
    // Reset the trace data buffer state.
    trace_data_buffer_state_ = TracingHandler::TraceDataBufferState();
    endpoint = new DevToolsTraceEndpointProxy(weak_factory_.GetWeakPtr());
    StopTracing(endpoint, tracing::mojom::kChromeTraceEventLabel);
  }
  // If inspected target is a render process Tracing.end will be handled by
  // tracing agent in the renderer.
  if (target_ == Renderer)
    callback->fallThrough();
  else
    callback->sendSuccess();
}

void TracingHandler::GetCategories(
    std::unique_ptr<GetCategoriesCallback> callback) {
  TracingController::GetInstance()->GetCategories(
      base::Bind(&TracingHandler::OnCategoriesReceived,
                 weak_factory_.GetWeakPtr(),
                 base::Passed(std::move(callback))));
}

void TracingHandler::OnRecordingEnabled(
    std::unique_ptr<StartCallback> callback) {
  TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline"),
                       "TracingStartedInBrowser", TRACE_EVENT_SCOPE_THREAD,
                       "frameTreeNodeId", frame_tree_node_id_);
  if (target_ != Renderer)
    callback->sendSuccess();

  bool screenshot_enabled;
  TRACE_EVENT_CATEGORY_GROUP_ENABLED(
      TRACE_DISABLED_BY_DEFAULT("devtools.screenshot"), &screenshot_enabled);
  if (frame_trace_recorder_ && screenshot_enabled)
    frame_trace_recorder_->StartCapture();
}

void TracingHandler::OnBufferUsage(float percent_full,
                                   size_t approximate_event_count) {
  // TODO(crbug426117): remove set_value once all clients have switched to
  // the new interface of the event.
  frontend_->BufferUsage(percent_full, approximate_event_count, percent_full);
}

void TracingHandler::OnCategoriesReceived(
    std::unique_ptr<GetCategoriesCallback> callback,
    const std::set<std::string>& category_set) {
  std::unique_ptr<protocol::Array<std::string>> categories =
      protocol::Array<std::string>::create();
  for (const std::string& category : category_set)
    categories->addItem(category);
  callback->sendSuccess(std::move(categories));
}

void TracingHandler::RequestMemoryDump(
    std::unique_ptr<RequestMemoryDumpCallback> callback) {
  if (!IsTracing()) {
    callback->sendFailure(Response::Error("Tracing is not started"));
    return;
  }

  auto on_memory_dump_finished =
      base::Bind(&TracingHandler::OnMemoryDumpFinished,
                 weak_factory_.GetWeakPtr(), base::Passed(std::move(callback)));
  memory_instrumentation::MemoryInstrumentation::GetInstance()
      ->RequestGlobalDumpAndAppendToTrace(
          base::trace_event::MemoryDumpType::EXPLICITLY_TRIGGERED,
          base::trace_event::MemoryDumpLevelOfDetail::DETAILED,
          on_memory_dump_finished);
}

void TracingHandler::OnMemoryDumpFinished(
    std::unique_ptr<RequestMemoryDumpCallback> callback,
    bool success,
    uint64_t dump_id) {
  callback->sendSuccess(base::StringPrintf("0x%" PRIx64, dump_id), success);
}

Response TracingHandler::RecordClockSyncMarker(const std::string& sync_id) {
  if (!IsTracing())
    return Response::Error("Tracing is not started");
  TRACE_EVENT_CLOCK_SYNC_RECEIVER(sync_id);
  return Response::OK();
}

void TracingHandler::SetupTimer(double usage_reporting_interval) {
  if (usage_reporting_interval == 0) return;

  if (usage_reporting_interval < kMinimumReportingInterval)
      usage_reporting_interval = kMinimumReportingInterval;

  base::TimeDelta interval = base::TimeDelta::FromMilliseconds(
      std::ceil(usage_reporting_interval));
  buffer_usage_poll_timer_.reset(new base::Timer(
      FROM_HERE, interval,
      base::Bind(base::IgnoreResult(&TracingController::GetTraceBufferUsage),
                 base::Unretained(TracingController::GetInstance()),
                 base::Bind(&TracingHandler::OnBufferUsage,
                            weak_factory_.GetWeakPtr())),
      true));
  buffer_usage_poll_timer_->Reset();
}

void TracingHandler::StopTracing(
    const scoped_refptr<TracingController::TraceDataEndpoint>& endpoint,
    const std::string& agent_label) {
  buffer_usage_poll_timer_.reset();
  TracingController::GetInstance()->StopTracing(endpoint, agent_label);
  did_initiate_recording_ = false;
  if (frame_trace_recorder_)
    frame_trace_recorder_->StopCapture();
}

bool TracingHandler::IsTracing() const {
  return TracingController::GetInstance()->IsTracing();
}

bool TracingHandler::IsStartupTracingActive() {
  return ::tracing::TraceConfigFile::GetInstance()->IsEnabled() &&
      TracingController::GetInstance()->IsTracing();
}

// static
base::trace_event::TraceConfig TracingHandler::GetTraceConfigFromDevToolsConfig(
    const base::DictionaryValue& devtools_config) {
  std::unique_ptr<base::Value> value = ConvertDictKeyStyle(devtools_config);
  DCHECK(value && value->is_dict());
  std::unique_ptr<base::DictionaryValue> tracing_dict(
      static_cast<base::DictionaryValue*>(value.release()));

  std::string mode;
  if (tracing_dict->GetString(kRecordModeParam, &mode))
    tracing_dict->SetString(kRecordModeParam, ConvertFromCamelCase(mode, '-'));

  return base::trace_event::TraceConfig(*tracing_dict);
}

}  // namespace tracing
}  // namespace protocol