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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 "base/base_export.h"
#include "base/logging.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/synchronization/waitable_event.h"
#include "base/task_runner.h"
#include "base/task_scheduler/delayed_task_manager.h"
#include "base/task_scheduler/sequence.h"
#include "base/task_scheduler/task_scheduler.h"
#include "base/task_scheduler/task_tracker.h"
#include "base/task_scheduler/task_traits.h"
namespace base {
namespace internal {
class SchedulerServiceThread;
class SchedulerThreadPoolImpl;
// Default TaskScheduler implementation. This class is thread-safe.
class BASE_EXPORT TaskSchedulerImpl : public TaskScheduler {
public:
// Creates and returns an initialized TaskSchedulerImpl. CHECKs on failure to
// do so (never returns null).
static std::unique_ptr<TaskSchedulerImpl> Create();
// Destroying a TaskSchedulerImpl is not allowed in production; it is always
// leaked. In tests, it can only be destroyed after JoinForTesting() has
// returned.
~TaskSchedulerImpl() override;
// TaskScheduler:
void PostTaskWithTraits(const tracked_objects::Location& from_here,
const TaskTraits& traits,
const Closure& task) override;
scoped_refptr<TaskRunner> CreateTaskRunnerWithTraits(
const TaskTraits& traits,
ExecutionMode execution_mode) override;
void Shutdown() override;
// Joins all threads of this scheduler. Tasks that are already running are
// allowed to complete their execution. This can only be called once.
void JoinForTesting();
private:
TaskSchedulerImpl();
void Initialize();
// Returns the thread pool that runs Tasks with |traits|.
SchedulerThreadPool* GetThreadPoolForTraits(const TaskTraits& traits);
// Callback invoked when a non-single-thread |sequence| isn't empty after a
// worker thread pops a Task from it.
void ReEnqueueSequenceCallback(scoped_refptr<Sequence> sequence);
// Callback invoked when the delayed run time is changed from the
// DelayedTaskManager.
void OnDelayedRunTimeUpdated();
TaskTracker task_tracker_;
DelayedTaskManager delayed_task_manager_;
// Thread pool for BACKGROUND Tasks without file I/O.
std::unique_ptr<SchedulerThreadPoolImpl> background_thread_pool_;
// Thread pool for BACKGROUND Tasks with file I/O.
std::unique_ptr<SchedulerThreadPoolImpl> background_file_io_thread_pool_;
// Thread pool for USER_VISIBLE and USER_BLOCKING Tasks without file I/O.
std::unique_ptr<SchedulerThreadPoolImpl> normal_thread_pool_;
// Thread pool for USER_VISIBLE and USER_BLOCKING Tasks with file I/O.
std::unique_ptr<SchedulerThreadPoolImpl> normal_file_io_thread_pool_;
std::unique_ptr<SchedulerServiceThread> service_thread_;
#if DCHECK_IS_ON()
// Signaled once JoinForTesting() has returned.
WaitableEvent join_for_testing_returned_;
#endif
DISALLOW_COPY_AND_ASSIGN(TaskSchedulerImpl);
};
} // namespace internal
} // namespace base
#endif // BASE_TASK_SCHEDULER_TASK_SCHEDULER_IMPL_H_