src: allow non-Node.js TracingControllers

We do not need a Node.js-provided `v8::TracingController`, generally. Loosen that restriction in order to make it easier for embedders to provide their own subclass of `v8::TracingController`, or none at all. Refs: electron/electron@9c36576 Backport-PR-URL: #35241 PR-URL: #30467 Reviewed-By: James M Snell <[email protected]> Reviewed-By: Gireesh Punathil <[email protected]>

Author: addaleax

src/api/environment.cc

@@ -485,6 +485,14 @@ MultiIsolatePlatform* GetMultiIsolatePlatform(IsolateData* env){
 MultiIsolatePlatform* CreatePlatform(
 int thread_pool_size,
  node::tracing::TracingController* tracing_controller){
+returnCreatePlatform(
+ thread_pool_size,
+static_cast<v8::TracingController*>(tracing_controller));
+}
+
+MultiIsolatePlatform* CreatePlatform(
+int thread_pool_size,
+ v8::TracingController* tracing_controller){
 returnMultiIsolatePlatform::Create(thread_pool_size, tracing_controller)
  .release();
 }
@@ -495,7 +503,7 @@ void FreePlatform(MultiIsolatePlatform* platform){
 
 std::unique_ptr<MultiIsolatePlatform> MultiIsolatePlatform::Create(
 int thread_pool_size,
-node::tracing::TracingController* tracing_controller){
+v8::TracingController* tracing_controller){
 return std::make_unique<NodePlatform>(thread_pool_size, tracing_controller);
 }
 

src/node.h

@@ -311,7 +311,7 @@ class NODE_EXTERN MultiIsolatePlatform : public v8::Platform{
 
 static std::unique_ptr<MultiIsolatePlatform> Create(
 int thread_pool_size,
-node::tracing::TracingController* tracing_controller = nullptr);
+v8::TracingController* tracing_controller = nullptr);
 };
 
 enum IsolateSettingsFlags{
@@ -466,9 +466,13 @@ NODE_EXTERN MultiIsolatePlatform* GetMultiIsolatePlatform(Environment* env);
 NODE_EXTERN MultiIsolatePlatform* GetMultiIsolatePlatform(IsolateData* env);
 
 // Legacy variants of MultiIsolatePlatform::Create().
+// TODO(addaleax): Deprecate in favour of the v8::TracingController variant.
 NODE_EXTERN MultiIsolatePlatform* CreatePlatform(
 int thread_pool_size,
  node::tracing::TracingController* tracing_controller);
+NODE_EXTERN MultiIsolatePlatform* CreatePlatform(
+int thread_pool_size,
+ v8::TracingController* tracing_controller);
 NODE_EXTERN voidFreePlatform(MultiIsolatePlatform* platform);
 
 NODE_EXTERN voidEmitBeforeExit(Environment* env);

src/node_platform.cc

@@ -13,7 +13,6 @@ using v8::Isolate;
 using v8::Object;
 using v8::Platform;
 using v8::Task;
-using node::tracing::TracingController;
 
 namespace{
 
@@ -320,12 +319,16 @@ void PerIsolatePlatformData::DecreaseHandleCount(){
 }
 
 NodePlatform::NodePlatform(int thread_pool_size,
- TracingController* tracing_controller){
-if (tracing_controller){
+v8::TracingController* tracing_controller){
+if (tracing_controller != nullptr){
  tracing_controller_ = tracing_controller;
  } else{
- tracing_controller_ = newTracingController();
+ tracing_controller_ = newv8::TracingController();
  }
+// TODO(addaleax): It's a bit icky that we use global state here, but we can't
+// really do anything about it unless V8 starts exposing a way to access the
+// current v8::Platform instance.
+tracing::TraceEventHelper::SetTracingController(tracing_controller_);
  worker_thread_task_runner_ =
  std::make_shared<WorkerThreadsTaskRunner>(thread_pool_size);
 }
@@ -490,7 +493,7 @@ double NodePlatform::CurrentClockTimeMillis(){
 returnSystemClockTimeMillis();
 }
 
-TracingController* NodePlatform::GetTracingController(){
+v8::TracingController* NodePlatform::GetTracingController(){
 CHECK_NOT_NULL(tracing_controller_);
 return tracing_controller_;
 }

src/node_platform.h

@@ -137,7 +137,7 @@ class WorkerThreadsTaskRunner{
 classNodePlatform : publicMultiIsolatePlatform{
 public:
 NodePlatform(int thread_pool_size,
-node::tracing::TracingController* tracing_controller);
+v8::TracingController* tracing_controller);
 ~NodePlatform() override = default;
 
 voidDrainTasks(v8::Isolate* isolate) override;
@@ -159,7 +159,7 @@ class NodePlatform : public MultiIsolatePlatform{
 boolIdleTasksEnabled(v8::Isolate* isolate) override;
 doubleMonotonicallyIncreasingTime() override;
 doubleCurrentClockTimeMillis() override;
-node::tracing::TracingController* GetTracingController() override;
+v8::TracingController* GetTracingController() override;
 boolFlushForegroundTasks(v8::Isolate* isolate) override;
 
 voidRegisterIsolate(v8::Isolate* isolate, uv_loop_t* loop) override;
@@ -179,7 +179,7 @@ class NodePlatform : public MultiIsolatePlatform{
  std::unordered_map<v8::Isolate*,
  std::shared_ptr<PerIsolatePlatformData>> per_isolate_;
 
-node::tracing::TracingController* tracing_controller_;
+v8::TracingController* tracing_controller_;
  std::shared_ptr<WorkerThreadsTaskRunner> worker_thread_task_runner_;
 };
 

src/tracing/agent.cc

@@ -242,8 +242,9 @@ void TracingController::AddMetadataEvent(
  TRACE_EVENT_FLAG_NONE,
 CurrentTimestampMicroseconds(),
 CurrentCpuTimestampMicroseconds());
-node::tracing::TraceEventHelper::GetAgent()->AddMetadataEvent(
-std::move(trace_event));
+ Agent* node_agent = node::tracing::TraceEventHelper::GetAgent();
+if (node_agent != nullptr)
+ node_agent->AddMetadataEvent(std::move(trace_event));
 }
 
 } // namespace tracing

src/tracing/trace_event.cc

@@ -4,17 +4,23 @@ namespace node{
 namespacetracing{
 
 Agent* g_agent = nullptr;
+v8::TracingController* g_controller = nullptr;
 
 voidTraceEventHelper::SetAgent(Agent* agent){
  g_agent = agent;
+ g_controller = agent->GetTracingController();
 }
 
 Agent* TraceEventHelper::GetAgent(){
 return g_agent;
 }
 
-TracingController* TraceEventHelper::GetTracingController(){
-return g_agent->GetTracingController();
+v8::TracingController* TraceEventHelper::GetTracingController(){
+return g_controller;
+}
+
+voidTraceEventHelper::SetTracingController(v8::TracingController* controller){
+ g_controller = controller;
 }
 
 } // namespace tracing

src/tracing/trace_event.h

@@ -314,7 +314,9 @@ const uint64_t kNoId = 0;
 // Refs: https://github.com/nodejs/node/pull/28724
 classNODE_EXTERN TraceEventHelper{
 public:
-static TracingController* GetTracingController();
+static v8::TracingController* GetTracingController();
+staticvoidSetTracingController(v8::TracingController* controller);
+
 static Agent* GetAgent();
 staticvoidSetAgent(Agent* agent);
 
@@ -514,9 +516,10 @@ static V8_INLINE void AddMetadataEventImpl(
  arg_convertibles[1].reset(reinterpret_cast<v8::ConvertableToTraceFormat*>(
 static_cast<intptr_t>(arg_values[1])));
  }
- node::tracing::TracingController* controller =
-node::tracing::TraceEventHelper::GetTracingController();
-return controller->AddMetadataEvent(
+ node::tracing::Agent* agent =
+node::tracing::TraceEventHelper::GetAgent();
+if (agent == nullptr) return;
+return agent->GetTracingController()->AddMetadataEvent(
  category_group_enabled, name, num_args, arg_names, arg_types, arg_values,
  arg_convertibles, flags);
 }