TaskScheduler: Remove base/task_scheduler/utils.h/.cc

base/task_scheduler/scheduler_thread_pool_impl.cc

 // Copyright 2016 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.
 
-#include "base/task_scheduler/scheduler_thread_pool.h"
+#include "base/task_scheduler/scheduler_thread_pool_impl.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "base/sequenced_task_runner.h"
-#include "base/task_scheduler/utils.h"
+#include "base/task_scheduler/delayed_task_manager.h"
+#include "base/task_scheduler/task_tracker.h"
 #include "base/threading/thread_local.h"
 
 namespace base {
 namespace internal {
 
 namespace {
 
 // SchedulerThreadPool that owns the current thread, if any.
-LazyInstance<ThreadLocalPointer<const SchedulerTaskExecutor>>::Leaky
+LazyInstance<ThreadLocalPointer<const SchedulerThreadPool>>::Leaky
     tls_current_thread_pool = LAZY_INSTANCE_INITIALIZER;
 
 // A task runner that runs tasks with the PARALLEL ExecutionMode.
 class SchedulerParallelTaskRunner : public TaskRunner {
  public:
   // Constructs a SchedulerParallelTaskRunner which can be used to post tasks so
-  // long as |executor| is alive.
-  // TODO(robliao): Find a concrete way to manage |executor|'s memory.
+  // long as |thread_pool| is alive.
+  // TODO(robliao): Find a concrete way to manage |thread_pool|'s memory.
   SchedulerParallelTaskRunner(const TaskTraits& traits,
-                              SchedulerTaskExecutor* executor,
-                              TaskTracker* task_tracker,
-                              DelayedTaskManager* delayed_task_manager)
-      : traits_(traits),
-        executor_(executor),
-        task_tracker_(task_tracker),
-        delayed_task_manager_(delayed_task_manager) {}
+                              SchedulerThreadPool* thread_pool)
+      : traits_(traits), thread_pool_(thread_pool) {}
 
   // TaskRunner:
   bool PostDelayedTask(const tracked_objects::Location& from_here,
                        const Closure& closure,
                        TimeDelta delay) override {
     // Post the task as part of a one-off single-task Sequence.
-    return PostTaskToExecutor(
+    return thread_pool_->PostTaskWithSequence(
         WrapUnique(
             new Task(from_here, closure, traits_,
                      delay.is_zero() ? TimeTicks() : TimeTicks::Now() + delay)),
-        make_scoped_refptr(new Sequence), executor_, task_tracker_,
-        delayed_task_manager_);
+        make_scoped_refptr(new Sequence));
   }
 
   bool RunsTasksOnCurrentThread() const override {
-    return tls_current_thread_pool.Get().Get() == executor_;
+    return tls_current_thread_pool.Get().Get() == thread_pool_;
   }
 
  private:
   ~SchedulerParallelTaskRunner() override = default;
 
   const TaskTraits traits_;
-  SchedulerTaskExecutor* const executor_;
-  TaskTracker* const task_tracker_;
-  DelayedTaskManager* const delayed_task_manager_;
+  SchedulerThreadPool* const thread_pool_;
 
   DISALLOW_COPY_AND_ASSIGN(SchedulerParallelTaskRunner);
 };
 
 // A task runner that runs tasks with the SEQUENCED ExecutionMode.
 class SchedulerSequencedTaskRunner : public SequencedTaskRunner {
  public:
-  // Constructs a SchedulerParallelTaskRunner which can be used to post tasks so
-  // long as |executor| is alive.
-  // TODO(robliao): Find a concrete way to manage |executor|'s memory.
+  // Constructs a SchedulerSequencedTaskRunner which can be used to post tasks
+  // so long as |thread_pool| is alive.
+  // TODO(robliao): Find a concrete way to manage |thread_pool|'s memory.
   SchedulerSequencedTaskRunner(const TaskTraits& traits,
-                               SchedulerTaskExecutor* executor,
-                               TaskTracker* task_tracker,
-                               DelayedTaskManager* delayed_task_manager)
-      : traits_(traits),
-        executor_(executor),
-        task_tracker_(task_tracker),
-        delayed_task_manager_(delayed_task_manager) {}
+                               SchedulerThreadPool* thread_pool)
+      : traits_(traits), thread_pool_(thread_pool) {}
 
   // SequencedTaskRunner:
   bool PostDelayedTask(const tracked_objects::Location& from_here,
                        const Closure& closure,
                        TimeDelta delay) override {
     // Post the task as part of |sequence|.
-    return PostTaskToExecutor(
+    return thread_pool_->PostTaskWithSequence(
         WrapUnique(
             new Task(from_here, closure, traits_,
                      delay.is_zero() ? TimeTicks() : TimeTicks::Now() + delay)),
-        sequence_, executor_, task_tracker_, delayed_task_manager_);
+        sequence_);
   }
 
   bool PostNonNestableDelayedTask(const tracked_objects::Location& from_here,
                                   const Closure& closure,
                                   base::TimeDelta delay) override {
     // Tasks are never nested within the task scheduler.
     return PostDelayedTask(from_here, closure, delay);
   }
 
   bool RunsTasksOnCurrentThread() const override {
-    return tls_current_thread_pool.Get().Get() == executor_;
+    return tls_current_thread_pool.Get().Get() == thread_pool_;
   }
 
  private:
   ~SchedulerSequencedTaskRunner() override = default;
 
   // Sequence for all Tasks posted through this TaskRunner.
   const scoped_refptr<Sequence> sequence_ = new Sequence;
 
   const TaskTraits traits_;
-  SchedulerTaskExecutor* const executor_;
-  TaskTracker* const task_tracker_;
-  DelayedTaskManager* const delayed_task_manager_;
+  SchedulerThreadPool* const thread_pool_;
 
   DISALLOW_COPY_AND_ASSIGN(SchedulerSequencedTaskRunner);
 };
 
 }  // namespace
 
-class SchedulerThreadPool::SchedulerWorkerThreadDelegateImpl
+class SchedulerThreadPoolImpl::SchedulerWorkerThreadDelegateImpl
     : public SchedulerWorkerThread::Delegate {
  public:
   SchedulerWorkerThreadDelegateImpl(
-      SchedulerThreadPool* outer,
-      const EnqueueSequenceCallback& enqueue_sequence_callback);
+      SchedulerThreadPoolImpl* outer,
+      const ReEnqueueSequenceCallback& re_enqueue_sequence_callback);
   ~SchedulerWorkerThreadDelegateImpl() override;
 
   // SchedulerWorkerThread::Delegate:
   void OnMainEntry() override;
   scoped_refptr<Sequence> GetWork(
       SchedulerWorkerThread* worker_thread) override;
-  void EnqueueSequence(scoped_refptr<Sequence> sequence) override;
+  void ReEnqueueSequence(scoped_refptr<Sequence> sequence) override;
 
  private:
-  SchedulerThreadPool* outer_;
-  const EnqueueSequenceCallback enqueue_sequence_callback_;
+  SchedulerThreadPoolImpl* outer_;
+  const ReEnqueueSequenceCallback re_enqueue_sequence_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(SchedulerWorkerThreadDelegateImpl);
 };
 
-SchedulerThreadPool::~SchedulerThreadPool() {
+SchedulerThreadPoolImpl::~SchedulerThreadPoolImpl() {
   // SchedulerThreadPool should never be deleted in production unless its
   // initialization failed.
   DCHECK(join_for_testing_returned_.IsSignaled() || worker_threads_.empty());
 }
 
-std::unique_ptr<SchedulerThreadPool> SchedulerThreadPool::CreateThreadPool(
+std::unique_ptr<SchedulerThreadPoolImpl>
+SchedulerThreadPoolImpl::CreateThreadPool(
     ThreadPriority thread_priority,
     size_t max_threads,
-    const EnqueueSequenceCallback& enqueue_sequence_callback,
+    const ReEnqueueSequenceCallback& re_enqueue_sequence_callback,
     TaskTracker* task_tracker,
     DelayedTaskManager* delayed_task_manager) {
-  std::unique_ptr<SchedulerThreadPool> thread_pool(new SchedulerThreadPool(
-      enqueue_sequence_callback, task_tracker, delayed_task_manager));
+  std::unique_ptr<SchedulerThreadPoolImpl> thread_pool(
+      new SchedulerThreadPoolImpl(re_enqueue_sequence_callback, task_tracker,
+                                  delayed_task_manager));
   if (thread_pool->Initialize(thread_priority, max_threads))
     return thread_pool;
   return nullptr;
 }
 
-scoped_refptr<TaskRunner> SchedulerThreadPool::CreateTaskRunnerWithTraits(
+void SchedulerThreadPoolImpl::WaitForAllWorkerThreadsIdleForTesting() {
+  AutoSchedulerLock auto_lock(idle_worker_threads_stack_lock_);
+  while (idle_worker_threads_stack_.Size() < worker_threads_.size())
+    idle_worker_threads_stack_cv_for_testing_->Wait();
+}
+
+void SchedulerThreadPoolImpl::JoinForTesting() {
+  for (const auto& worker_thread : worker_threads_)
+    worker_thread->JoinForTesting();
+
+  DCHECK(!join_for_testing_returned_.IsSignaled());
+  join_for_testing_returned_.Signal();
+}
+
+scoped_refptr<TaskRunner> SchedulerThreadPoolImpl::CreateTaskRunnerWithTraits(
     const TaskTraits& traits,
     ExecutionMode execution_mode) {
   switch (execution_mode) {
     case ExecutionMode::PARALLEL:
-      return make_scoped_refptr(new SchedulerParallelTaskRunner(
-          traits, this, task_tracker_, delayed_task_manager_));
+      return make_scoped_refptr(new SchedulerParallelTaskRunner(traits, this));
 
     case ExecutionMode::SEQUENCED:
-      return make_scoped_refptr(new SchedulerSequencedTaskRunner(
-          traits, this, task_tracker_, delayed_task_manager_));
+      return make_scoped_refptr(new SchedulerSequencedTaskRunner(traits, this));
 
     case ExecutionMode::SINGLE_THREADED:
       // TODO(fdoray): Support SINGLE_THREADED TaskRunners.
       NOTREACHED();
       return nullptr;
   }
 
   NOTREACHED();
   return nullptr;
 }
 
-void SchedulerThreadPool::EnqueueSequence(
+void SchedulerThreadPoolImpl::ReEnqueueSequence(
     scoped_refptr<Sequence> sequence,
     const SequenceSortKey& sequence_sort_key) {
   shared_priority_queue_.BeginTransaction()->Push(
       WrapUnique(new PriorityQueue::SequenceAndSortKey(std::move(sequence),
                                                        sequence_sort_key)));
 
   // The thread calling this method just ran a Task from |sequence| and will
   // soon try to get another Sequence from which to run a Task. If the thread
   // belongs to this pool, it will get that Sequence from
   // |shared_priority_queue_|. When that's the case, there is no need to wake up
   // another thread after |sequence| is inserted in |shared_priority_queue_|. If
   // we did wake up another thread, we would waste resources by having more
   // threads trying to get a Sequence from |shared_priority_queue_| than the
   // number of Sequences in it.
   if (tls_current_thread_pool.Get().Get() != this)
     WakeUpOneThread();
 }
 
-void SchedulerThreadPool::WaitForAllWorkerThreadsIdleForTesting() {
-  AutoSchedulerLock auto_lock(idle_worker_threads_stack_lock_);
-  while (idle_worker_threads_stack_.Size() < worker_threads_.size())
-    idle_worker_threads_stack_cv_for_testing_->Wait();
-}
-
-void SchedulerThreadPool::JoinForTesting() {
-  for (const auto& worker_thread : worker_threads_)
-    worker_thread->JoinForTesting();
-
-  DCHECK(!join_for_testing_returned_.IsSignaled());
-  join_for_testing_returned_.Signal();
-}
-
-void SchedulerThreadPool::PostTaskWithSequence(
+bool SchedulerThreadPoolImpl::PostTaskWithSequence(
     std::unique_ptr<Task> task,
     scoped_refptr<Sequence> sequence) {
   DCHECK(task);
   DCHECK(sequence);
 
-  const bool sequence_was_empty = AddTaskToSequenceAndPriorityQueue(
-      std::move(task), std::move(sequence), &shared_priority_queue_);
+  if (!task_tracker_->WillPostTask(task.get()))
+    return false;
 
-  // No thread has already been woken up to run Tasks from |sequence| if it was
-  // empty before |task| was inserted into it.
-  if (sequence_was_empty)
-    WakeUpOneThread();
+  if (task->delayed_run_time.is_null()) {
+    PostTaskWithSequenceNow(std::move(task), std::move(sequence));
+  } else {
+    delayed_task_manager_->AddDelayedTask(std::move(task), std::move(sequence),
+                                          this);
+  }
+
+  return true;
 }
 
-SchedulerThreadPool::SchedulerWorkerThreadDelegateImpl::
+void SchedulerThreadPoolImpl::PostTaskWithSequenceNow(
+    std::unique_ptr<Task> task,
+    scoped_refptr<Sequence> sequence) {
+  DCHECK(task);
+  DCHECK(sequence);
+
+  // Confirm that |task| is ready to run (its delayed run time is either null or
+  // in the past).
+  DCHECK_LE(task->delayed_run_time, delayed_task_manager_->Now());
+
+  const bool sequence_was_empty = sequence->PushTask(std::move(task));
+  if (sequence_was_empty) {
+    // Insert |sequence| in |shared_priority_queue_| if it was empty before
+    // |task| was inserted into it. Otherwise, one of these must be true:
+    // - |sequence| is already in a PriorityQueue (not necessarily
+    //   |shared_priority_queue_|), or,
+    // - A worker thread is running a Task from |sequence|. It will insert
+    //   |sequence| in a PriorityQueue once it's done running the Task.
+    const auto sequence_sort_key = sequence->GetSortKey();
+    shared_priority_queue_.BeginTransaction()->Push(
+        WrapUnique(new PriorityQueue::SequenceAndSortKey(std::move(sequence),
+                                                         sequence_sort_key)));
+
+    // Wake up a worker thread to process |sequence|.
+    WakeUpOneThread();
+  }
+}
+
+SchedulerThreadPoolImpl::SchedulerWorkerThreadDelegateImpl::
     SchedulerWorkerThreadDelegateImpl(
-        SchedulerThreadPool* outer,
-        const EnqueueSequenceCallback& enqueue_sequence_callback)
-    : outer_(outer), enqueue_sequence_callback_(enqueue_sequence_callback) {}
+        SchedulerThreadPoolImpl* outer,
+        const ReEnqueueSequenceCallback& re_enqueue_sequence_callback)
+    : outer_(outer),
+      re_enqueue_sequence_callback_(re_enqueue_sequence_callback) {}
 
-SchedulerThreadPool::SchedulerWorkerThreadDelegateImpl::
+SchedulerThreadPoolImpl::SchedulerWorkerThreadDelegateImpl::
     ~SchedulerWorkerThreadDelegateImpl() = default;
 
-void SchedulerThreadPool::SchedulerWorkerThreadDelegateImpl::OnMainEntry() {
+void SchedulerThreadPoolImpl::SchedulerWorkerThreadDelegateImpl::OnMainEntry() {
   DCHECK(!tls_current_thread_pool.Get().Get());
   tls_current_thread_pool.Get().Set(outer_);
 }
 
 scoped_refptr<Sequence>
-SchedulerThreadPool::SchedulerWorkerThreadDelegateImpl::GetWork(
+SchedulerThreadPoolImpl::SchedulerWorkerThreadDelegateImpl::GetWork(
     SchedulerWorkerThread* worker_thread) {
   std::unique_ptr<PriorityQueue::Transaction> transaction(
       outer_->shared_priority_queue_.BeginTransaction());
   const auto& sequence_and_sort_key = transaction->Peek();
 
   if (sequence_and_sort_key.is_null()) {
     // |transaction| is kept alive while |worker_thread| is added to
     // |idle_worker_threads_stack_| to avoid this race:
     // 1. This thread creates a Transaction, finds |shared_priority_queue_|
     //    empty and ends the Transaction.
     // 2. Other thread creates a Transaction, inserts a Sequence into
     //    |shared_priority_queue_| and ends the Transaction. This can't happen
     //    if the Transaction of step 1 is still active because because there can
     //    only be one active Transaction per PriorityQueue at a time.
     // 3. Other thread calls WakeUpOneThread(). No thread is woken up because
     //    |idle_worker_threads_stack_| is empty.
     // 4. This thread adds itself to |idle_worker_threads_stack_| and goes to
     //    sleep. No thread runs the Sequence inserted in step 2.
     outer_->AddToIdleWorkerThreadsStack(worker_thread);
     return nullptr;
   }
 
   scoped_refptr<Sequence> sequence = sequence_and_sort_key.sequence;
   transaction->Pop();
   return sequence;
 }
 
-void SchedulerThreadPool::SchedulerWorkerThreadDelegateImpl::EnqueueSequence(
-    scoped_refptr<Sequence> sequence) {
-  enqueue_sequence_callback_.Run(std::move(sequence));
+void SchedulerThreadPoolImpl::SchedulerWorkerThreadDelegateImpl::
+    ReEnqueueSequence(scoped_refptr<Sequence> sequence) {
+  re_enqueue_sequence_callback_.Run(std::move(sequence));
 }
 
-SchedulerThreadPool::SchedulerThreadPool(
-    const EnqueueSequenceCallback& enqueue_sequence_callback,
+SchedulerThreadPoolImpl::SchedulerThreadPoolImpl(
+    const ReEnqueueSequenceCallback& re_enqueue_sequence_callback,
     TaskTracker* task_tracker,
     DelayedTaskManager* delayed_task_manager)
     : idle_worker_threads_stack_lock_(shared_priority_queue_.container_lock()),
       idle_worker_threads_stack_cv_for_testing_(
           idle_worker_threads_stack_lock_.CreateConditionVariable()),
       join_for_testing_returned_(true, false),
       worker_thread_delegate_(
           new SchedulerWorkerThreadDelegateImpl(this,
-                                                enqueue_sequence_callback)),
+                                                re_enqueue_sequence_callback)),
       task_tracker_(task_tracker),
       delayed_task_manager_(delayed_task_manager) {
   DCHECK(task_tracker_);
   DCHECK(delayed_task_manager_);
 }
 
-bool SchedulerThreadPool::Initialize(ThreadPriority thread_priority,
-                                     size_t max_threads) {
+bool SchedulerThreadPoolImpl::Initialize(ThreadPriority thread_priority,
+                                         size_t max_threads) {
   AutoSchedulerLock auto_lock(idle_worker_threads_stack_lock_);
 
   DCHECK(worker_threads_.empty());
 
   for (size_t i = 0; i < max_threads; ++i) {
     std::unique_ptr<SchedulerWorkerThread> worker_thread =
         SchedulerWorkerThread::CreateSchedulerWorkerThread(
             thread_priority, worker_thread_delegate_.get(), task_tracker_);
     if (!worker_thread)
       break;
     idle_worker_threads_stack_.Push(worker_thread.get());
     worker_threads_.push_back(std::move(worker_thread));
   }
 
   return !worker_threads_.empty();
 }
 
-void SchedulerThreadPool::WakeUpOneThread() {
+void SchedulerThreadPoolImpl::WakeUpOneThread() {
   SchedulerWorkerThread* worker_thread;
   {
     AutoSchedulerLock auto_lock(idle_worker_threads_stack_lock_);
     worker_thread = idle_worker_threads_stack_.Pop();
   }
   if (worker_thread)
     worker_thread->WakeUp();
 }
 
-void SchedulerThreadPool::AddToIdleWorkerThreadsStack(
+void SchedulerThreadPoolImpl::AddToIdleWorkerThreadsStack(
     SchedulerWorkerThread* worker_thread) {
   AutoSchedulerLock auto_lock(idle_worker_threads_stack_lock_);
   idle_worker_threads_stack_.Push(worker_thread);
   DCHECK_LE(idle_worker_threads_stack_.Size(), worker_threads_.size());
 
   if (idle_worker_threads_stack_.Size() == worker_threads_.size())
     idle_worker_threads_stack_cv_for_testing_->Broadcast();
 }
 
 }  // namespace internal
 }  // namespace base