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// 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.
#ifndef BASE_TASK_SCHEDULER_TASK_SCHEDULER_IMPL_H_
#define BASE_TASK_SCHEDULER_TASK_SCHEDULER_IMPL_H_
#include <memory>
#include <vector>
#include "base/base_export.h"
#include "base/callback.h"
#include "base/logging.h"
#include "base/macros.h"
#include "base/memory/ptr_util.h"
#include "base/memory/ref_counted.h"
#include "base/strings/string_piece.h"
#include "base/synchronization/atomic_flag.h"
#include "base/task_scheduler/delayed_task_manager.h"
#include "base/task_scheduler/scheduler_single_thread_task_runner_manager.h"
#include "base/task_scheduler/scheduler_worker_pool_impl.h"
#include "base/task_scheduler/single_thread_task_runner_thread_mode.h"
#include "base/task_scheduler/task_scheduler.h"
#include "base/task_scheduler/task_tracker.h"
#include "base/task_scheduler/task_traits.h"
#include "base/threading/thread.h"
#include "build/build_config.h"
#if defined(OS_POSIX) && !defined(OS_NACL_SFI)
#include "base/task_scheduler/task_tracker_posix.h"
#endif
#if defined(OS_WIN)
#include "base/win/com_init_check_hook.h"
#endif
namespace base {
class HistogramBase;
namespace internal {
// Default TaskScheduler implementation. This class is thread-safe.
class BASE_EXPORT TaskSchedulerImpl : public TaskScheduler {
public:
using TaskTrackerImpl =
#if defined(OS_POSIX) && !defined(OS_NACL_SFI)
TaskTrackerPosix;
#else
TaskTracker;
#endif
// |name| is used to label threads and histograms. |task_tracker| can be used
// for tests that need more execution control. By default, the production
// TaskTracker is used.
explicit TaskSchedulerImpl(StringPiece name,
std::unique_ptr<TaskTrackerImpl> task_tracker =
std::make_unique<TaskTrackerImpl>());
~TaskSchedulerImpl() override;
// TaskScheduler:
void Start(const TaskScheduler::InitParams& init_params) override;
void PostDelayedTaskWithTraits(const Location& from_here,
const TaskTraits& traits,
OnceClosure task,
TimeDelta delay) override;
scoped_refptr<TaskRunner> CreateTaskRunnerWithTraits(
const TaskTraits& traits) override;
scoped_refptr<SequencedTaskRunner> CreateSequencedTaskRunnerWithTraits(
const TaskTraits& traits) override;
scoped_refptr<SingleThreadTaskRunner> CreateSingleThreadTaskRunnerWithTraits(
const TaskTraits& traits,
SingleThreadTaskRunnerThreadMode thread_mode) override;
#if defined(OS_WIN)
scoped_refptr<SingleThreadTaskRunner> CreateCOMSTATaskRunnerWithTraits(
const TaskTraits& traits,
SingleThreadTaskRunnerThreadMode thread_mode) override;
#endif // defined(OS_WIN)
std::vector<const HistogramBase*> GetHistograms() const override;
int GetMaxConcurrentNonBlockedTasksWithTraitsDeprecated(
const TaskTraits& traits) const override;
void Shutdown() override;
void FlushForTesting() override;
void JoinForTesting() override;
private:
// Returns the worker pool that runs Tasks with |traits|.
SchedulerWorkerPoolImpl* GetWorkerPoolForTraits(
const TaskTraits& traits) const;
// Returns |traits|, with priority set to TaskPriority::USER_BLOCKING if
// |all_tasks_user_blocking_| is set.
TaskTraits SetUserBlockingPriorityIfNeeded(const TaskTraits& traits) const;
const std::string name_;
Thread service_thread_;
const std::unique_ptr<TaskTrackerImpl> task_tracker_;
DelayedTaskManager delayed_task_manager_;
SchedulerSingleThreadTaskRunnerManager single_thread_task_runner_manager_;
// Indicates that all tasks are handled as if they had been posted with
// TaskPriority::USER_BLOCKING. Since this is set in Start(), it doesn't apply
// to tasks posted before Start() or to tasks posted to TaskRunners created
// before Start().
//
// TODO(fdoray): Remove after experiment. https://crbug.com/757022
AtomicFlag all_tasks_user_blocking_;
// There are 4 SchedulerWorkerPoolImpl in this array to match the 4
// SchedulerWorkerPoolParams in TaskScheduler::InitParams.
std::unique_ptr<SchedulerWorkerPoolImpl> worker_pools_[4];
#if DCHECK_IS_ON()
// Set once JoinForTesting() has returned.
AtomicFlag join_for_testing_returned_;
#endif
#if defined(OS_WIN) && defined(COM_INIT_CHECK_HOOK_ENABLED)
// Provides COM initialization verification for supported builds.
base::win::ComInitCheckHook com_init_check_hook_;
#endif
DISALLOW_COPY_AND_ASSIGN(TaskSchedulerImpl);
};
} // namespace internal
} // namespace base
#endif // BASE_TASK_SCHEDULER_TASK_SCHEDULER_IMPL_H_