electron/shell/app/node_main.cc

// Copyright (c) 2015 GitHub, Inc.
// Use of this source code is governed by the MIT license that can be
// found in the LICENSE file.

#include "shell/app/node_main.h"

#include <memory>
#include <string>
#include <unordered_set>
#include <utility>
#include <vector>

#include "base/command_line.h"
#include "base/feature_list.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "base/task/thread_pool/thread_pool_instance.h"
#include "base/threading/thread_task_runner_handle.h"
#include "electron/electron_version.h"
#include "gin/array_buffer.h"
#include "gin/public/isolate_holder.h"
#include "gin/v8_initializer.h"
#include "shell/app/uv_task_runner.h"
#include "shell/browser/javascript_environment.h"
#include "shell/browser/node_debugger.h"
#include "shell/common/api/electron_bindings.h"
#include "shell/common/crash_reporter/crash_reporter.h"
#include "shell/common/gin_helper/dictionary.h"
#include "shell/common/node_bindings.h"
#include "shell/common/node_includes.h"

#if defined(_WIN64)
#include "shell/common/crash_reporter/crash_reporter_win.h"
#endif

namespace {

// Initialize Node.js cli options to pass to Node.js
// See https://nodejs.org/api/cli.html#cli_options
void SetNodeCliFlags() {
  // Options that are unilaterally disallowed
  const std::unordered_set<base::StringPiece, base::StringPieceHash>
      disallowed = {"--openssl-config", "--use-bundled-ca", "--use-openssl-ca",
                    "--force-fips", "--enable-fips"};

  const auto argv = base::CommandLine::ForCurrentProcess()->argv();
  std::vector<std::string> args;

  // TODO(codebytere): We need to set the first entry in args to the
  // process name owing to src/node_options-inl.h#L286-L290 but this is
  // redundant and so should be refactored upstream.
  args.reserve(argv.size() + 1);
  args.emplace_back("electron");

  for (const auto& arg : argv) {
#if defined(OS_WIN)
    const auto& option = base::UTF16ToUTF8(arg);
#else
    const auto& option = arg;
#endif
    const auto stripped = base::StringPiece(option).substr(0, option.find('='));
    if (disallowed.count(stripped) != 0) {
      LOG(ERROR) << "The Node.js cli flag " << stripped
                 << " is not supported in Electron";
    } else {
      args.push_back(option);
    }
  }

  std::vector<std::string> errors;

  // Node.js itself will output parsing errors to
  // console so we don't need to handle that ourselves
  ProcessGlobalArgs(&args, nullptr, &errors, node::kDisallowedInEnvironment);
}

// TODO(codebytere): expose this from Node.js itself?
void HostCleanupFinalizationGroupCallback(
    v8::Local<v8::Context> context,
    v8::Local<v8::FinalizationGroup> group) {
  node::Environment* env = node::Environment::GetCurrent(context);
  if (env == nullptr) {
    return;
  }
  env->RegisterFinalizationGroupForCleanup(group);
}

bool AllowWasmCodeGenerationCallback(v8::Local<v8::Context> context,
                                     v8::Local<v8::String>) {
  v8::Local<v8::Value> wasm_code_gen = context->GetEmbedderData(
      node::ContextEmbedderIndex::kAllowWasmCodeGeneration);
  return wasm_code_gen->IsUndefined() || wasm_code_gen->IsTrue();
}

}  // namespace

namespace electron {

#if !defined(OS_LINUX)
void AddExtraParameter(const std::string& key, const std::string& value) {
  crash_reporter::CrashReporter::GetInstance()->AddExtraParameter(key, value);
}

void RemoveExtraParameter(const std::string& key) {
  crash_reporter::CrashReporter::GetInstance()->RemoveExtraParameter(key);
}
#endif

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

  int exit_code = 1;
  {
    // Feed gin::PerIsolateData with a task runner.
    argv = uv_setup_args(argc, argv);
    uv_loop_t* loop = uv_default_loop();
    scoped_refptr<UvTaskRunner> uv_task_runner(new 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));

#if defined(_WIN64)
    crash_reporter::CrashReporterWin::SetUnhandledExceptionFilter();
#endif

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

    // Parse and set Node.js cli flags.
    SetNodeCliFlags();

    int exec_argc;
    const char** exec_argv;
    node::Init(&argc, const_cast<const char**>(argv), &exec_argc, &exec_argv);

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

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

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

    v8::Isolate* isolate = gin_env.isolate();
    // TODO(ckerr) and/or TODO(codebytere) use node::SetIsolateMiscHandlers()
    node::IsolateSettings is;
    isolate->SetMicrotasksPolicy(is.policy);

    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);

      env = node::CreateEnvironment(isolate_data, gin_env.context(), argc, argv,
                                    exec_argc, exec_argv);
      CHECK_NE(nullptr, env);

      // This needs to be called before the inspector is initialized.
      env->InitializeDiagnostics();

      // This is needed in order to enable v8 host weakref hooks.
      // TODO(codebytere): we shouldn't have to call this - upstream?
      isolate->SetHostCleanupFinalizationGroupCallback(
          HostCleanupFinalizationGroupCallback);

      isolate->SetAllowWasmCodeGenerationCallback(
          AllowWasmCodeGenerationCallback);

      gin_helper::Dictionary process(isolate, env->process_object());
#if defined(OS_WIN)
      process.SetMethod("log", &ElectronBindings::Log);
#endif
      process.SetMethod("crash", &ElectronBindings::Crash);

      // Setup process.crashReporter.start in child node processes
      gin_helper::Dictionary reporter = gin::Dictionary::CreateEmpty(isolate);
      reporter.SetMethod("start",
                         &crash_reporter::CrashReporter::StartInstance);

#if !defined(OS_LINUX)
      reporter.SetMethod("addExtraParameter", &AddExtraParameter);
      reporter.SetMethod("removeExtraParameter", &RemoveExtraParameter);
#endif

      process.Set("crashReporter", reporter);

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

    // Enable support for v8 inspector.
    NodeDebugger node_debugger(env);
    node_debugger.Start();

    // TODO(codebytere): we should try to handle this upstream.
    {
      v8::HandleScope scope(isolate);
      node::InternalCallbackScope callback_scope(
          env, v8::Local<v8::Object>(), {1, 0},
          node::InternalCallbackScope::kAllowEmptyResource |
              node::InternalCallbackScope::kSkipAsyncHooks);
      node::LoadEnvironment(env);
    }

    {
      v8::SealHandleScope seal(isolate);
      bool more;
      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());
    }

    node_debugger.Stop();
    exit_code = node::EmitExit(env);

    node::ResetStdio();

    env->set_can_call_into_js(false);
    env->stop_sub_worker_contexts();
    env->RunCleanup();

    node::RunAtExit(env);
    node::FreeEnvironment(env);
    node::FreeIsolateData(isolate_data);

    gin_env.platform()->DrainTasks(isolate);
    gin_env.platform()->CancelPendingDelayedTasks(isolate);
    gin_env.platform()->UnregisterIsolate(isolate);
  }

  // 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;
}

}  // namespace electron