chore: remove redundant code in node integration (#33500)

shell/browser/electron_browser_main_parts.cc

@@ -402,8 +402,8 @@ void ElectronBrowserMainParts::ToolkitInitialized() {
 int ElectronBrowserMainParts::PreMainMessageLoopRun() {
   // Run user's main script before most things get initialized, so we can have
   // a chance to setup everything.
-  node_bindings_->PrepareMessageLoop();
-  node_bindings_->RunMessageLoop();
+  node_bindings_->PrepareEmbedThread();
+  node_bindings_->StartPolling();
 
   // url::Add*Scheme are not threadsafe, this helps prevent data races.
   url::LockSchemeRegistries();

shell/common/node_bindings.cc

@@ -584,7 +584,16 @@ void NodeBindings::LoadEnvironment(node::Environment* env) {
   gin_helper::EmitEvent(env->isolate(), env->process_object(), "loaded");
 }
 
-void NodeBindings::PrepareMessageLoop() {
+void NodeBindings::PrepareEmbedThread() {
+  // IOCP does not change for the process until the loop is recreated,
+  // we ensure that there is only a single polling thread satisfying
+  // the concurrency limit set from CreateIoCompletionPort call by
+  // uv_loop_init for the lifetime of this process.
+  // More background can be found at:
+  // https://github.com/microsoft/vscode/issues/142786#issuecomment-1061673400
+  if (initialized_)
+    return;
+
   // Add dummy handle for libuv, otherwise libuv would quit when there is
   // nothing to do.
   uv_async_init(uv_loop_, dummy_uv_handle_.get(), nullptr);
@@ -594,7 +603,15 @@ void NodeBindings::PrepareMessageLoop() {
   uv_thread_create(&embed_thread_, EmbedThreadRunner, this);
 }
 
-void NodeBindings::RunMessageLoop() {
+void NodeBindings::StartPolling() {
+  // Avoid calling UvRunOnce if the loop is already active,
+  // otherwise it can lead to situations were the number of active
+  // threads processing on IOCP is greater than the concurrency limit.
+  if (initialized_)
+    return;
+
+  initialized_ = true;
+
   // The MessageLoop should have been created, remember the one in main thread.
   task_runner_ = base::ThreadTaskRunnerHandle::Get();
 

shell/common/node_bindings.h

@@ -92,11 +92,11 @@ class NodeBindings {
   // Load node.js in the environment.
   void LoadEnvironment(node::Environment* env);
 
-  // Prepare for message loop integration.
-  virtual void PrepareMessageLoop();
+  // Prepare embed thread for message loop integration.
+  void PrepareEmbedThread();
 
-  // Do message loop integration.
-  virtual void RunMessageLoop();
+  // Notify embed thread to start polling after environment is loaded.
+  void StartPolling();
 
   // Gets/sets the per isolate data.
   void set_isolate_data(node::IsolateData* isolate_data) {
@@ -144,6 +144,9 @@ class NodeBindings {
   // Thread to poll uv events.
   static void EmbedThreadRunner(void* arg);
 
+  // Indicates whether polling thread has been created.
+  bool initialized_ = false;
+
   // Whether the libuv loop has ended.
   bool embed_closed_ = false;
 

shell/common/node_bindings_linux.cc

@@ -17,30 +17,6 @@ NodeBindingsLinux::NodeBindingsLinux(BrowserEnvironment browser_env)
   epoll_ctl(epoll_, EPOLL_CTL_ADD, backend_fd, &ev);
 }
 
-NodeBindingsLinux::~NodeBindingsLinux() = default;
-
-void NodeBindingsLinux::PrepareMessageLoop() {
-  int handle = uv_backend_fd(uv_loop_);
-
-  // If the backend fd hasn't changed, don't proceed.
-  if (handle == handle_)
-    return;
-
-  NodeBindings::PrepareMessageLoop();
-}
-
-void NodeBindingsLinux::RunMessageLoop() {
-  int handle = uv_backend_fd(uv_loop_);
-
-  // If the backend fd hasn't changed, don't proceed.
-  if (handle == handle_)
-    return;
-
-  handle_ = handle;
-
-  NodeBindings::RunMessageLoop();
-}
-
 void NodeBindingsLinux::PollEvents() {
   int timeout = uv_backend_timeout(uv_loop_);
 

shell/common/node_bindings_linux.h

@@ -13,19 +13,12 @@ namespace electron {
 class NodeBindingsLinux : public NodeBindings {
  public:
   explicit NodeBindingsLinux(BrowserEnvironment browser_env);
-  ~NodeBindingsLinux() override;
-
-  void PrepareMessageLoop() override;
-  void RunMessageLoop() override;
 
  private:
   void PollEvents() override;
 
   // Epoll to poll for uv's backend fd.
   int epoll_;
-
-  // uv's backend fd.
-  int handle_ = -1;
 };
 
 }  // namespace electron

shell/common/node_bindings_mac.cc

@@ -17,30 +17,6 @@ namespace electron {
 NodeBindingsMac::NodeBindingsMac(BrowserEnvironment browser_env)
     : NodeBindings(browser_env) {}
 
-NodeBindingsMac::~NodeBindingsMac() = default;
-
-void NodeBindingsMac::PrepareMessageLoop() {
-  int handle = uv_backend_fd(uv_loop_);
-
-  // If the backend fd hasn't changed, don't proceed.
-  if (handle == handle_)
-    return;
-
-  NodeBindings::PrepareMessageLoop();
-}
-
-void NodeBindingsMac::RunMessageLoop() {
-  int handle = uv_backend_fd(uv_loop_);
-
-  // If the backend fd hasn't changed, don't proceed.
-  if (handle == handle_)
-    return;
-
-  handle_ = handle;
-
-  NodeBindings::RunMessageLoop();
-}
-
 void NodeBindingsMac::PollEvents() {
   struct timeval tv;
   int timeout = uv_backend_timeout(uv_loop_);

shell/common/node_bindings_mac.h

@@ -13,16 +13,9 @@ namespace electron {
 class NodeBindingsMac : public NodeBindings {
  public:
   explicit NodeBindingsMac(BrowserEnvironment browser_env);
-  ~NodeBindingsMac() override;
-
-  void PrepareMessageLoop() override;
-  void RunMessageLoop() override;
 
  private:
   void PollEvents() override;
-
-  // uv's backend fd.
-  int handle_ = -1;
 };
 
 }  // namespace electron

shell/common/node_bindings_win.cc

@@ -27,31 +27,6 @@ NodeBindingsWin::NodeBindingsWin(BrowserEnvironment browser_env)
   }
 }
 
-NodeBindingsWin::~NodeBindingsWin() = default;
-
-void NodeBindingsWin::PrepareMessageLoop() {
-  // IOCP does not change for the process until the loop is recreated,
-  // we ensure that there is only a single polling thread satisfying
-  // the concurrency limit set from CreateIoCompletionPort call by
-  // uv_loop_init for the lifetime of this process.
-  if (initialized_)
-    return;
-
-  NodeBindings::PrepareMessageLoop();
-}
-
-void NodeBindingsWin::RunMessageLoop() {
-  // Avoid calling UvRunOnce if the loop is already active,
-  // otherwise it can lead to situations were the number of active
-  // threads processing on IOCP is greater than the concurrency limit.
-  if (initialized_)
-    return;
-
-  initialized_ = true;
-
-  NodeBindings::RunMessageLoop();
-}
-
 void NodeBindingsWin::PollEvents() {
   // If there are other kinds of events pending, uv_backend_timeout will
   // instruct us not to wait.

shell/common/node_bindings_win.h

@@ -13,16 +13,9 @@ namespace electron {
 class NodeBindingsWin : public NodeBindings {
  public:
   explicit NodeBindingsWin(BrowserEnvironment browser_env);
-  ~NodeBindingsWin() override;
-
-  void PrepareMessageLoop() override;
-  void RunMessageLoop() override;
 
  private:
   void PollEvents() override;
-
-  // Indicates whether polling thread has been created.
-  bool initialized_ = false;
 };
 
 }  // namespace electron

shell/renderer/electron_renderer_client.cc

@@ -93,9 +93,7 @@ void ElectronRendererClient::DidCreateScriptContext(
   if (!node_integration_initialized_) {
     node_integration_initialized_ = true;
     node_bindings_->Initialize();
-    node_bindings_->PrepareMessageLoop();
-  } else {
-    node_bindings_->PrepareMessageLoop();
+    node_bindings_->PrepareEmbedThread();
   }
 
   // Setup node tracing controller.
@@ -131,7 +129,7 @@ void ElectronRendererClient::DidCreateScriptContext(
     node_bindings_->set_uv_env(env);
 
     // Give the node loop a run to make sure everything is ready.
-    node_bindings_->RunMessageLoop();
+    node_bindings_->StartPolling();
   }
 }
 

shell/renderer/web_worker_observer.cc

@@ -56,7 +56,7 @@ void WebWorkerObserver::WorkerScriptReadyForEvaluation(
       isolate, v8::MicrotasksScope::kDoNotRunMicrotasks);
 
   // Start the embed thread.
-  node_bindings_->PrepareMessageLoop();
+  node_bindings_->PrepareEmbedThread();
 
   // Setup node tracing controller.
   if (!node::tracing::TraceEventHelper::GetAgent())
@@ -78,7 +78,7 @@ void WebWorkerObserver::WorkerScriptReadyForEvaluation(
   node_bindings_->set_uv_env(env);
 
   // Give the node loop a run to make sure everything is ready.
-  node_bindings_->RunMessageLoop();
+  node_bindings_->StartPolling();
 }
 
 void WebWorkerObserver::ContextWillDestroy(v8::Local<v8::Context> context) {