src: implement v8::Platform::CallDelayedOnWorkerThread

This method is crucial for Runtime.evaluate protocol command with
timeout flag. At least Chrome DevTools frontend uses this method for
every execution in console.

PR-URL: https://github.com/nodejs/node/pull/22383
Fixes: https://github.com/nodejs/node/issues/22157
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>

1 files changed, 123 insertions, 1 deletions

diff --git a/src/node_platform.cc b/src/node_platform.cc
index 6a3ae2e5dc..92e9b371c5 100644
--- a/src/node_platform.cc
+++ b/src/node_platform.cc
@@ -2,6 +2,7 @@
 #include "node_internals.h"
 
 #include "env-inl.h"
+#include "debug_utils.h"
 #include "util.h"
 #include <algorithm>
 
@@ -29,7 +30,127 @@ static void PlatformWorkerThread(void* data) {
 
 }  // namespace
 
+class WorkerThreadsTaskRunner::DelayedTaskScheduler {
+ public:
+  explicit DelayedTaskScheduler(TaskQueue<Task>* tasks)
+    : pending_worker_tasks_(tasks) {}
+
+  std::unique_ptr<uv_thread_t> Start() {
+    auto start_thread = [](void* data) {
+      static_cast<DelayedTaskScheduler*>(data)->Run();
+    };
+    std::unique_ptr<uv_thread_t> t { new uv_thread_t() };
+    uv_sem_init(&ready_, 0);
+    CHECK_EQ(0, uv_thread_create(t.get(), start_thread, this));
+    uv_sem_wait(&ready_);
+    uv_sem_destroy(&ready_);
+    return t;
+  }
+
+  void PostDelayedTask(std::unique_ptr<Task> task, double delay_in_seconds) {
+    tasks_.Push(std::unique_ptr<Task>(new ScheduleTask(this, std::move(task),
+                                                       delay_in_seconds)));
+    uv_async_send(&flush_tasks_);
+  }
+
+  void Stop() {
+    tasks_.Push(std::unique_ptr<Task>(new StopTask(this)));
+    uv_async_send(&flush_tasks_);
+  }
+
+ private:
+  void Run() {
+    TRACE_EVENT_METADATA1("__metadata", "thread_name", "name",
+                          "WorkerThreadsTaskRunner::DelayedTaskScheduler");
+    loop_.data = this;
+    CHECK_EQ(0, uv_loop_init(&loop_));
+    flush_tasks_.data = this;
+    CHECK_EQ(0, uv_async_init(&loop_, &flush_tasks_, FlushTasks));
+    uv_sem_post(&ready_);
+
+    uv_run(&loop_, UV_RUN_DEFAULT);
+    CheckedUvLoopClose(&loop_);
+  }
+
+  static void FlushTasks(uv_async_t* flush_tasks) {
+    DelayedTaskScheduler* scheduler =
+        ContainerOf(&DelayedTaskScheduler::loop_, flush_tasks->loop);
+    while (std::unique_ptr<Task> task = scheduler->tasks_.Pop())
+      task->Run();
+  }
+
+  class StopTask : public Task {
+   public:
+    explicit StopTask(DelayedTaskScheduler* scheduler): scheduler_(scheduler) {}
+
+    void Run() override {
+      std::vector<uv_timer_t*> timers;
+      for (uv_timer_t* timer : scheduler_->timers_)
+        timers.push_back(timer);
+      for (uv_timer_t* timer : timers)
+        scheduler_->TakeTimerTask(timer);
+      uv_close(reinterpret_cast<uv_handle_t*>(&scheduler_->flush_tasks_),
+               [](uv_handle_t* handle) {});
+    }
+
+   private:
+     DelayedTaskScheduler* scheduler_;
+  };
+
+  class ScheduleTask : public Task {
+   public:
+    ScheduleTask(DelayedTaskScheduler* scheduler,
+                 std::unique_ptr<Task> task,
+                 double delay_in_seconds)
+      : scheduler_(scheduler),
+        task_(std::move(task)),
+        delay_in_seconds_(delay_in_seconds) {}
+
+    void Run() override {
+      uint64_t delay_millis =
+          static_cast<uint64_t>(delay_in_seconds_ + 0.5) * 1000;
+      std::unique_ptr<uv_timer_t> timer(new uv_timer_t());
+      CHECK_EQ(0, uv_timer_init(&scheduler_->loop_, timer.get()));
+      timer->data = task_.release();
+      CHECK_EQ(0, uv_timer_start(timer.get(), RunTask, delay_millis, 0));
+      scheduler_->timers_.insert(timer.release());
+    }
+
+   private:
+    DelayedTaskScheduler* scheduler_;
+    std::unique_ptr<Task> task_;
+    double delay_in_seconds_;
+  };
+
+  static void RunTask(uv_timer_t* timer) {
+    DelayedTaskScheduler* scheduler =
+        ContainerOf(&DelayedTaskScheduler::loop_, timer->loop);
+    scheduler->pending_worker_tasks_->Push(scheduler->TakeTimerTask(timer));
+  }
+
+  std::unique_ptr<Task> TakeTimerTask(uv_timer_t* timer) {
+    std::unique_ptr<Task> task(static_cast<Task*>(timer->data));
+    uv_timer_stop(timer);
+    uv_close(reinterpret_cast<uv_handle_t*>(timer), [](uv_handle_t* handle) {
+      delete reinterpret_cast<uv_timer_t*>(handle);
+    });
+    timers_.erase(timer);
+    return task;
+  }
+
+  uv_sem_t ready_;
+  TaskQueue<v8::Task>* pending_worker_tasks_;
+
+  TaskQueue<v8::Task> tasks_;
+  uv_loop_t loop_;
+  uv_async_t flush_tasks_;
+  std::unordered_set<uv_timer_t*> timers_;
+};
+
 WorkerThreadsTaskRunner::WorkerThreadsTaskRunner(int thread_pool_size) {
+  delayed_task_scheduler_.reset(
+      new DelayedTaskScheduler(&pending_worker_tasks_));
+  threads_.push_back(delayed_task_scheduler_->Start());
   for (int i = 0; i < thread_pool_size; i++) {
     std::unique_ptr<uv_thread_t> t { new uv_thread_t() };
     if (uv_thread_create(t.get(), PlatformWorkerThread,
@@ -46,7 +167,7 @@ void WorkerThreadsTaskRunner::PostTask(std::unique_ptr<Task> task) {
 
 void WorkerThreadsTaskRunner::PostDelayedTask(std::unique_ptr<v8::Task> task,
                                               double delay_in_seconds) {
-  UNREACHABLE();
+  delayed_task_scheduler_->PostDelayedTask(std::move(task), delay_in_seconds);
 }
 
 void WorkerThreadsTaskRunner::BlockingDrain() {
@@ -55,6 +176,7 @@ void WorkerThreadsTaskRunner::BlockingDrain() {
 
 void WorkerThreadsTaskRunner::Shutdown() {
   pending_worker_tasks_.Stop();
+  delayed_task_scheduler_->Stop();
   for (size_t i = 0; i < threads_.size(); i++) {
     CHECK_EQ(0, uv_thread_join(threads_[i].get()));
   }