DESIGN DISCUSSION ONLY Task Scheduler Single Thread Task Runner Manager for Dedicated Threads per S…

base/task_scheduler/scheduler_single_thread_task_runner_manager.h

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BASE_TASK_SCHEDULER_SCHEDULER_SINGLE_THREAD_TASK_RUNNER_MANAGER_H_
+#define BASE_TASK_SCHEDULER_SCHEDULER_SINGLE_THREAD_TASK_RUNNER_MANAGER_H_
+
+#include <memory>
+#include <vector>
+
+#include "base/atomicops.h"
+#include "base/base_export.h"
+#include "base/callback.h"
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/synchronization/condition_variable.h"
+#include "base/task_scheduler/scheduler_lock.h"
+#include "base/task_scheduler/scheduler_worker_pool_params.h"
+#include "base/task_scheduler/task_scheduler.h"
+
+namespace base {
+
+class TaskTraits;
+class SingleThreadTaskRunner;
+
+namespace internal {
+
+class DelayedTaskManager;
+class SchedulerLock;

[fdoray, 2017/02/08 17:59:01]

No forward declaration of SchedulerLock. base/task_scheduler/scheduler_lock.h is
included above.

[robliao, 2017/02/10 00:04:04]

Indeed. I didn't go too carefully through this so we can talk about the
structure first. Removed in the meantime.

+class SchedulerWorker;
+class TaskTracker;
+
+class BASE_EXPORT SchedulerSingleThreadTaskRunnerManager final {
+ public:
+  SchedulerSingleThreadTaskRunnerManager(
+      const std::vector<SchedulerWorkerPoolParams>& worker_pool_params_vector,
+      const TaskScheduler::WorkerPoolIndexForTraitsCallback&
+          worker_pool_index_for_traits_callback,
+      TaskTracker* task_tracker,
+      DelayedTaskManager* delayed_task_manager);
+  ~SchedulerSingleThreadTaskRunnerManager();
+
+  scoped_refptr<SingleThreadTaskRunner> CreateSingleThreadTaskRunnerWithTraits(
+      const TaskTraits& traits);
+
+  void JoinForTesting();
+  void WaitForAllWorkersIdleForTesting();
+
+ private:
+  class SchedulerSingleThreadTaskRunner;
+  class SchedulerWorkerDelegate;
+
+  SchedulerWorker* CreateAndRegisterSchedulerWorker(
+      const SchedulerWorkerPoolParams& params);
+
+  void IncrementIdleWorkerCount();
+  void DecrementIdleWorkerCount();
+
+  void UnregisterSchedulerWorker(SchedulerWorker* worker);
+
+  const std::vector<SchedulerWorkerPoolParams> worker_pool_params_vector_;
+  const TaskScheduler::WorkerPoolIndexForTraitsCallback
+      worker_pool_index_for_traits_callback_;
+  TaskTracker* const task_tracker_;
+  DelayedTaskManager* const delayed_task_manager_;
+
+  SchedulerLock lock_;
+  std::vector<std::unique_ptr<SchedulerWorker>> workers_;
+
+  std::unique_ptr<ConditionVariable> idle_workers_cv_for_testing_;
+  subtle::Atomic32 idle_workers_ = 0;
+
+  DISALLOW_COPY_AND_ASSIGN(SchedulerSingleThreadTaskRunnerManager);
+};
+
+}  // namespace internal
+
+}  // namespace base
+
+#endif  // BASE_TASK_SCHEDULER_SCHEDULER_SINGLE_THREAD_TASK_RUNNER_MANAGER_H_