int NodeMain()

in shell/app/node_main.cc [140:303]

• 110 lines of code
• 11 McCabe index (conditional complexity)

int NodeMain(int argc, char* argv[]) {
  base::CommandLine::Init(argc, argv);

#if defined(OS_WIN)
  v8_crashpad_support::SetUp();
#endif

#if !defined(MAS_BUILD)
  ElectronCrashReporterClient::Create();
#endif

#if defined(OS_WIN) || (defined(OS_MAC) && !defined(MAS_BUILD))
  crash_reporter::InitializeCrashpad(false, "node");
#endif

#if !defined(MAS_BUILD)
  crash_keys::SetCrashKeysFromCommandLine(
      *base::CommandLine::ForCurrentProcess());
  crash_keys::SetPlatformCrashKey();
#endif

  int exit_code = 1;
  {
    // Feed gin::PerIsolateData with a task runner.
    uv_loop_t* loop = uv_default_loop();
    auto uv_task_runner = base::MakeRefCounted<UvTaskRunner>(loop);
    base::ThreadTaskRunnerHandle handle(uv_task_runner);

    // Initialize feature list.
    auto feature_list = std::make_unique<base::FeatureList>();
    feature_list->InitializeFromCommandLine("", "");
    base::FeatureList::SetInstance(std::move(feature_list));

    // Explicitly register electron's builtin modules.
    NodeBindings::RegisterBuiltinModules();

    // Parse and set Node.js cli flags.
    int flags_exit_code = SetNodeCliFlags();
    if (flags_exit_code != 0)
      exit(flags_exit_code);

    node::InitializationSettingsFlags flags = node::kRunPlatformInit;
    node::InitializationResult result =
        node::InitializeOncePerProcess(argc, argv, flags);

    if (result.early_return)
      exit(result.exit_code);

    gin::V8Initializer::LoadV8Snapshot(
        gin::V8SnapshotFileType::kWithAdditionalContext);

    // V8 requires a task scheduler.
    base::ThreadPoolInstance::CreateAndStartWithDefaultParams("Electron");

    // Allow Node.js to track the amount of time the event loop has spent
    // idle in the kernel’s event provider .
    uv_loop_configure(loop, UV_METRICS_IDLE_TIME);

    // Initialize gin::IsolateHolder.
    JavascriptEnvironment gin_env(loop);

    v8::Isolate* isolate = gin_env.isolate();

    v8::Isolate::Scope isolate_scope(isolate);
    v8::Locker locker(isolate);
    node::Environment* env = nullptr;
    node::IsolateData* isolate_data = nullptr;
    {
      v8::HandleScope scope(isolate);

      isolate_data = node::CreateIsolateData(isolate, loop, gin_env.platform());
      CHECK_NE(nullptr, isolate_data);

      uint64_t flags = node::EnvironmentFlags::kDefaultFlags |
                       node::EnvironmentFlags::kHideConsoleWindows;
      env = node::CreateEnvironment(
          isolate_data, gin_env.context(), result.args, result.exec_args,
          static_cast<node::EnvironmentFlags::Flags>(flags));
      CHECK_NE(nullptr, env);

      node::IsolateSettings is;
      node::SetIsolateUpForNode(isolate, is);

      gin_helper::Dictionary process(isolate, env->process_object());
      process.SetMethod("crash", &ElectronBindings::Crash);

      // Setup process.crashReporter in child node processes
      gin_helper::Dictionary reporter = gin::Dictionary::CreateEmpty(isolate);
#if defined(OS_LINUX)
      reporter.SetMethod("start", &CrashReporterStart);
#endif

      reporter.SetMethod("getParameters", &GetParameters);
#if defined(MAS_BUILD)
      reporter.SetMethod("addExtraParameter", &SetCrashKeyStub);
      reporter.SetMethod("removeExtraParameter", &ClearCrashKeyStub);
#else
      reporter.SetMethod("addExtraParameter",
                         &electron::crash_keys::SetCrashKey);
      reporter.SetMethod("removeExtraParameter",
                         &electron::crash_keys::ClearCrashKey);
#endif

      process.Set("crashReporter", reporter);

      gin_helper::Dictionary versions;
      if (process.Get("versions", &versions)) {
        versions.SetReadOnly(ELECTRON_PROJECT_NAME, ELECTRON_VERSION_STRING);
      }
    }

    v8::HandleScope scope(isolate);
    node::LoadEnvironment(env, node::StartExecutionCallback{});

    env->set_trace_sync_io(env->options()->trace_sync_io);

    {
      v8::SealHandleScope seal(isolate);
      bool more;
      env->performance_state()->Mark(
          node::performance::NODE_PERFORMANCE_MILESTONE_LOOP_START);
      do {
        uv_run(env->event_loop(), UV_RUN_DEFAULT);

        gin_env.platform()->DrainTasks(isolate);

        more = uv_loop_alive(env->event_loop());
        if (more && !env->is_stopping())
          continue;

        if (!uv_loop_alive(env->event_loop())) {
          EmitBeforeExit(env);
        }

        // Emit `beforeExit` if the loop became alive either after emitting
        // event, or after running some callbacks.
        more = uv_loop_alive(env->event_loop());
      } while (more && !env->is_stopping());
      env->performance_state()->Mark(
          node::performance::NODE_PERFORMANCE_MILESTONE_LOOP_EXIT);
    }

    env->set_trace_sync_io(false);

    exit_code = node::EmitExit(env);

    node::ResetStdio();

    node::Stop(env);
    node::FreeEnvironment(env);
    node::FreeIsolateData(isolate_data);
  }

  // According to "src/gin/shell/gin_main.cc":
  //
  // gin::IsolateHolder waits for tasks running in ThreadPool in its
  // destructor and thus must be destroyed before ThreadPool starts skipping
  // CONTINUE_ON_SHUTDOWN tasks.
  base::ThreadPoolInstance::Get()->Shutdown();

  v8::V8::Dispose();

  return exit_code;
}