// Copyright 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 "third_party/blink/renderer/core/inspector/inspector_performance_agent.h"

#include <utility>

#include "base/time/time_override.h"
#include "third_party/blink/public/platform/platform.h"
#include "third_party/blink/renderer/core/frame/local_frame.h"
#include "third_party/blink/renderer/core/inspector/inspected_frames.h"
#include "third_party/blink/renderer/core/loader/document_loader.h"
#include "third_party/blink/renderer/core/paint/paint_timing.h"
#include "third_party/blink/renderer/core/probe/core_probes.h"
#include "third_party/blink/renderer/platform/bindings/v8_per_isolate_data.h"
#include "third_party/blink/renderer/platform/instance_counters.h"
#include "third_party/blink/renderer/platform/wtf/dtoa/utils.h"

namespace blink {

using protocol::Response;

namespace {
constexpr bool isPlural(const char* str, int len) {
  return len > 1 && str[len - 2] == 's';
}

static constexpr const char* kInstanceCounterNames[] = {
#define INSTANCE_COUNTER_NAME(name) \
  (isPlural(#name, sizeof(#name)) ? #name : #name "s"),
    INSTANCE_COUNTERS_LIST(INSTANCE_COUNTER_NAME)
#undef INSTANCE_COUNTER_NAME
};

}  // namespace

InspectorPerformanceAgent::InspectorPerformanceAgent(
    InspectedFrames* inspected_frames)
    : inspected_frames_(inspected_frames),
      enabled_(&agent_state_, /*default_value=*/false) {}

InspectorPerformanceAgent::~InspectorPerformanceAgent() = default;

void InspectorPerformanceAgent::Restore() {
  if (enabled_.Get())
    InnerEnable();
}

void InspectorPerformanceAgent::InnerEnable() {
  instrumenting_agents_->addInspectorPerformanceAgent(this);
  Thread::Current()->AddTaskTimeObserver(this);
  layout_start_ticks_ = TimeTicks();
  recalc_style_start_ticks_ = TimeTicks();
  task_start_ticks_ = TimeTicks();
  script_start_ticks_ = TimeTicks();
  v8compile_start_ticks_ = TimeTicks();
}

protocol::Response InspectorPerformanceAgent::enable() {
  if (enabled_.Get())
    return Response::OK();
  enabled_.Set(true);
  InnerEnable();
  return Response::OK();
}

protocol::Response InspectorPerformanceAgent::disable() {
  if (!enabled_.Get())
    return Response::OK();
  enabled_.Clear();
  instrumenting_agents_->removeInspectorPerformanceAgent(this);
  Thread::Current()->RemoveTaskTimeObserver(this);
  return Response::OK();
}

namespace {
void AppendMetric(protocol::Array<protocol::Performance::Metric>* container,
                  const String& name,
                  double value) {
  container->addItem(protocol::Performance::Metric::create()
                         .setName(name)
                         .setValue(value)
                         .build());
}
}  // namespace

Response InspectorPerformanceAgent::setTimeDomain(const String& time_domain) {
  if (enabled_.Get()) {
    return Response::Error(
        "Cannot set time domain while performance metrics collection"
        " is enabled.");
  }

  using namespace protocol::Performance::SetTimeDomain;

  if (time_domain == TimeDomainEnum::TimeTicks) {
    use_thread_ticks_ = false;
  } else if (time_domain == TimeDomainEnum::ThreadTicks) {
    if (!base::ThreadTicks::IsSupported()) {
      return Response::Error("Thread time is not supported on this platform.");
    }
    base::ThreadTicks::WaitUntilInitialized();
    use_thread_ticks_ = true;
  } else {
    return Response::Error("Invalid time domain specification.");
  }

  return Response::OK();
}

TimeTicks InspectorPerformanceAgent::GetTimeTicksNow() {
  return use_thread_ticks_
             ? base::TimeTicks() +
                   base::TimeDelta::FromMicroseconds(
                       base::ThreadTicks::Now().since_origin().InMicroseconds())
             : base::subtle::TimeTicksNowIgnoringOverride();
}

Response InspectorPerformanceAgent::getMetrics(
    std::unique_ptr<protocol::Array<protocol::Performance::Metric>>*
        out_result) {
  if (!enabled_.Get()) {
    *out_result = protocol::Array<protocol::Performance::Metric>::create();
    return Response::OK();
  }

  std::unique_ptr<protocol::Array<protocol::Performance::Metric>> result =
      protocol::Array<protocol::Performance::Metric>::create();

  AppendMetric(result.get(), "Timestamp",
               TimeTicksInSeconds(CurrentTimeTicks()));

  // Renderer instance counters.
  for (size_t i = 0; i < ARRAY_SIZE(kInstanceCounterNames); ++i) {
    AppendMetric(result.get(), kInstanceCounterNames[i],
                 InstanceCounters::CounterValue(
                     static_cast<InstanceCounters::CounterType>(i)));
  }

  // Page performance metrics.
  TimeTicks now = GetTimeTicksNow();
  AppendMetric(result.get(), "LayoutCount", static_cast<double>(layout_count_));
  AppendMetric(result.get(), "RecalcStyleCount",
               static_cast<double>(recalc_style_count_));
  AppendMetric(result.get(), "LayoutDuration", layout_duration_.InSecondsF());
  AppendMetric(result.get(), "RecalcStyleDuration",
               recalc_style_duration_.InSecondsF());

  TimeDelta script_duration = script_duration_;
  if (!script_start_ticks_.is_null())
    script_duration += now - script_start_ticks_;
  AppendMetric(result.get(), "ScriptDuration", script_duration.InSecondsF());

  TimeDelta v8compile_duration = v8compile_duration_;
  if (!v8compile_start_ticks_.is_null())
    v8compile_duration += now - v8compile_start_ticks_;
  AppendMetric(result.get(), "V8CompileDuration",
               v8compile_duration.InSecondsF());

  TimeDelta task_duration = task_duration_;
  if (!task_start_ticks_.is_null())
    task_duration += now - task_start_ticks_;
  AppendMetric(result.get(), "TaskDuration", task_duration.InSecondsF());

  // Compute task time not accounted for by other metrics.
  TimeDelta other_tasks_duration =
      task_duration -
      (script_duration + recalc_style_duration_ + layout_duration_);
  AppendMetric(result.get(), "TaskOtherDuration",
               other_tasks_duration.InSecondsF());

  v8::HeapStatistics heap_statistics;
  V8PerIsolateData::MainThreadIsolate()->GetHeapStatistics(&heap_statistics);
  AppendMetric(result.get(), "JSHeapUsedSize",
               heap_statistics.used_heap_size());
  AppendMetric(result.get(), "JSHeapTotalSize",
               heap_statistics.total_heap_size());

  // Performance timings.
  Document* document = inspected_frames_->Root()->GetDocument();
  if (document) {
    AppendMetric(result.get(), "FirstMeaningfulPaint",
                 TimeTicksInSeconds(
                     PaintTiming::From(*document).FirstMeaningfulPaint()));
    AppendMetric(
        result.get(), "DomContentLoaded",
        TimeTicksInSeconds(document->GetTiming().DomContentLoadedEventStart()));
    AppendMetric(
        result.get(), "NavigationStart",
        TimeTicksInSeconds(document->Loader()->GetTiming().NavigationStart()));
  }

  *out_result = std::move(result);
  return Response::OK();
}

void InspectorPerformanceAgent::ConsoleTimeStamp(const String& title) {
  if (!enabled_.Get())
    return;
  std::unique_ptr<protocol::Array<protocol::Performance::Metric>> metrics;
  getMetrics(&metrics);
  GetFrontend()->metrics(std::move(metrics), title);
}

void InspectorPerformanceAgent::ScriptStarts() {
  if (!script_call_depth_++)
    script_start_ticks_ = GetTimeTicksNow();
}

void InspectorPerformanceAgent::ScriptEnds() {
  if (--script_call_depth_)
    return;
  script_duration_ += GetTimeTicksNow() - script_start_ticks_;
  script_start_ticks_ = TimeTicks();
}

void InspectorPerformanceAgent::Will(const probe::CallFunction& probe) {
  ScriptStarts();
}

void InspectorPerformanceAgent::Did(const probe::CallFunction& probe) {
  ScriptEnds();
}

void InspectorPerformanceAgent::Will(const probe::ExecuteScript& probe) {
  ScriptStarts();
}

void InspectorPerformanceAgent::Did(const probe::ExecuteScript& probe) {
  ScriptEnds();
}

void InspectorPerformanceAgent::Will(const probe::RecalculateStyle& probe) {
  recalc_style_start_ticks_ = GetTimeTicksNow();
}

void InspectorPerformanceAgent::Did(const probe::RecalculateStyle& probe) {
  TimeDelta delta = GetTimeTicksNow() - recalc_style_start_ticks_;
  recalc_style_duration_ += delta;
  recalc_style_count_++;
  recalc_style_start_ticks_ = TimeTicks();

  // Exclude nested style re-calculations from script and layout duration.
  if (!script_start_ticks_.is_null())
    script_start_ticks_ += delta;
  if (!layout_start_ticks_.is_null())
    layout_start_ticks_ += delta;
}

void InspectorPerformanceAgent::Will(const probe::UpdateLayout& probe) {
  if (!layout_depth_++)
    layout_start_ticks_ = GetTimeTicksNow();
}

void InspectorPerformanceAgent::Did(const probe::UpdateLayout& probe) {
  if (--layout_depth_)
    return;
  TimeDelta delta = GetTimeTicksNow() - layout_start_ticks_;
  layout_duration_ += delta;
  layout_count_++;
  layout_start_ticks_ = TimeTicks();

  // Exclude nested layout update from script and style re-calculations
  // duration.
  if (!script_start_ticks_.is_null())
    script_start_ticks_ += delta;
  if (!recalc_style_start_ticks_.is_null())
    recalc_style_start_ticks_ += delta;
}

void InspectorPerformanceAgent::Will(const probe::V8Compile& probe) {
  DCHECK(v8compile_start_ticks_.is_null());
  v8compile_start_ticks_ = GetTimeTicksNow();
}

void InspectorPerformanceAgent::Did(const probe::V8Compile& probe) {
  v8compile_duration_ += GetTimeTicksNow() - v8compile_start_ticks_;
  v8compile_start_ticks_ = TimeTicks();
}

// Will/DidProcessTask() ignore caller provided times to ensure time domain
// consistency with other metrics collected in this module.
void InspectorPerformanceAgent::WillProcessTask(base::TimeTicks start_time) {
  task_start_ticks_ = GetTimeTicksNow();
}

void InspectorPerformanceAgent::DidProcessTask(base::TimeTicks start_time,
                                               base::TimeTicks end_time) {
  if (!task_start_ticks_.is_null())
    task_duration_ += GetTimeTicksNow() - task_start_ticks_;
  task_start_ticks_ = TimeTicks();
}

void InspectorPerformanceAgent::Trace(blink::Visitor* visitor) {
  visitor->Trace(inspected_frames_);
  InspectorBaseAgent<protocol::Performance::Metainfo>::Trace(visitor);
}

}  // namespace blink