src: avoid Isolate::GetCurrent() for platform implementation

There’s no need to use `Isolate::GetCurrent()`, which is generally
discouraged, as the `Isolate*` pointer can generally be looked up
from the per-Isolate platform data structure.

PR-URL: #32269
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

src/node_platform.cc

@@ -222,7 +222,7 @@ int WorkerThreadsTaskRunner::NumberOfWorkerThreads() const {
 
 PerIsolatePlatformData::PerIsolatePlatformData(
     Isolate* isolate, uv_loop_t* loop)
-  : loop_(loop) {
+  : isolate_(isolate), loop_(loop) {
   flush_tasks_ = new uv_async_t();
   CHECK_EQ(0, uv_async_init(loop, flush_tasks_, FlushTasks));
   flush_tasks_->data = static_cast<void*>(this);
@@ -391,12 +391,11 @@ int NodePlatform::NumberOfWorkerThreads() {
 }
 
 void PerIsolatePlatformData::RunForegroundTask(std::unique_ptr<Task> task) {
-  Isolate* isolate = Isolate::GetCurrent();
-  DebugSealHandleScope scope(isolate);
-  Environment* env = Environment::GetCurrent(isolate);
+  DebugSealHandleScope scope(isolate_);
+  Environment* env = Environment::GetCurrent(isolate_);
   if (env != nullptr) {
-    v8::HandleScope scope(isolate);
-    InternalCallbackScope cb_scope(env, Object::New(isolate), { 0, 0 },
+    v8::HandleScope scope(isolate_);
+    InternalCallbackScope cb_scope(env, Object::New(isolate_), { 0, 0 },
                                    InternalCallbackScope::kNoFlags);
     task->Run();
   } else {
@@ -415,8 +414,8 @@ void PerIsolatePlatformData::DeleteFromScheduledTasks(DelayedTask* task) {
 }
 
 void PerIsolatePlatformData::RunForegroundTask(uv_timer_t* handle) {
-  DelayedTask* delayed = static_cast<DelayedTask*>(handle->data);
-  RunForegroundTask(std::move(delayed->task));
+  DelayedTask* delayed = ContainerOf(&DelayedTask::timer, handle);
+  delayed->platform_data->RunForegroundTask(std::move(delayed->task));
   delayed->platform_data->DeleteFromScheduledTasks(delayed);
 }
 

src/node_platform.h

@@ -88,7 +88,7 @@ class PerIsolatePlatformData :
   void DecreaseHandleCount();
 
   static void FlushTasks(uv_async_t* handle);
-  static void RunForegroundTask(std::unique_ptr<v8::Task> task);
+  void RunForegroundTask(std::unique_ptr<v8::Task> task);
   static void RunForegroundTask(uv_timer_t* timer);
 
   struct ShutdownCallback {
@@ -101,6 +101,7 @@ class PerIsolatePlatformData :
   std::shared_ptr<PerIsolatePlatformData> self_reference_;
   uint32_t uv_handle_count_ = 1;  // 1 = flush_tasks_
 
+  v8::Isolate* const isolate_;
   uv_loop_t* const loop_;
   uv_async_t* flush_tasks_ = nullptr;
   TaskQueue<v8::Task> foreground_tasks_;