chromium/base/task/sequence_manager/sequence_manager.h

// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef BASE_TASK_SEQUENCE_MANAGER_SEQUENCE_MANAGER_H_
#define BASE_TASK_SEQUENCE_MANAGER_SEQUENCE_MANAGER_H_

#include <memory>
#include <string>
#include <type_traits>
#include <utility>
#include <vector>

#include "base/base_export.h"
#include "base/dcheck_is_on.h"
#include "base/memory/raw_ptr.h"
#include "base/message_loop/message_pump_type.h"
#include "base/task/sequence_manager/task_queue_impl.h"
#include "base/task/sequence_manager/task_time_observer.h"
#include "base/task/sequenced_task_runner.h"
#include "base/task/single_thread_task_runner.h"
#include "base/time/default_tick_clock.h"

namespace base {

class MessagePump;
class TaskObserver;

namespace sequence_manager {
class TimeDomain;

// SequenceManager manages TaskQueues which have different properties
// (e.g. priority, common task type) multiplexing all posted tasks into
// a single backing sequence (currently bound to a single thread, which is
// refererred as *main thread* in the comments below). SequenceManager
// implementation can be used in a various ways to apply scheduling logic.
class BASE_EXPORT SequenceManager { … };

class BASE_EXPORT SequenceManager::Settings::Builder { … };

// Create SequenceManager using MessageLoop on the current thread.
// Implementation is located in sequence_manager_impl.cc.
// TODO(scheduler-dev): Remove after every thread has a SequenceManager.
BASE_EXPORT std::unique_ptr<SequenceManager>
CreateSequenceManagerOnCurrentThread(SequenceManager::Settings settings);

// Create a SequenceManager using the given MessagePump on the current thread.
// MessagePump instances can be created with
// MessagePump::CreateMessagePumpForType().
BASE_EXPORT std::unique_ptr<SequenceManager>
CreateSequenceManagerOnCurrentThreadWithPump(
    std::unique_ptr<MessagePump> message_pump,
    SequenceManager::Settings settings = SequenceManager::Settings());

// Create an unbound SequenceManager (typically for a future thread or because
// additional setup is required before binding). The SequenceManager can be
// initialized on the current thread and then needs to be bound and initialized
// on the target thread by calling one of the Bind*() methods.
BASE_EXPORT std::unique_ptr<SequenceManager> CreateUnboundSequenceManager(
    SequenceManager::Settings settings = SequenceManager::Settings());

}  // namespace sequence_manager
}  // namespace base

#endif  // BASE_TASK_SEQUENCE_MANAGER_SEQUENCE_MANAGER_H_