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chromium / chromium / src / main / . / base / timer / wall_clock_timer.h
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Avi Drissmane4622aa2022-09-08 20:36:06[diff] [blame]1// Copyright 2018 The Chromium Authors
Roman Aleksandrov9f6594c2019-01-04 12:12:39[diff] [blame]2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
Albert J. Wong276d6ff2021-07-26 17:47:49[diff] [blame]5#ifndef BASE_TIMER_WALL_CLOCK_TIMER_H_
6#define BASE_TIMER_WALL_CLOCK_TIMER_H_
Roman Aleksandrov9f6594c2019-01-04 12:12:39[diff] [blame]7
Albert J. Wong276d6ff2021-07-26 17:47:49[diff] [blame]8#include "base/base_export.h"
Avi Drissman63e1f992023-01-13 18:54:43[diff] [blame]9#include "base/functional/bind.h"
10#include "base/functional/callback.h"
Roman Aleksandrov9f6594c2019-01-04 12:12:39[diff] [blame]11#include "base/location.h"
Keishi Hattori0e45c022021-11-27 09:25:52[diff] [blame]12#include "base/memory/raw_ptr.h"
Roman Aleksandrov9f6594c2019-01-04 12:12:39[diff] [blame]13#include "base/power_monitor/power_observer.h"
Peter Kasting47b4de142025-01-02 20:48:46[diff] [blame]14#include "base/sequence_checker.h"
Roman Aleksandrov9f6594c2019-01-04 12:12:39[diff] [blame]15#include "base/time/time.h"
16#include "base/timer/timer.h"
17
18namespace base {
Peter Kasting99791752025-01-02 20:48:59[diff] [blame]19
Roman Aleksandrov9f6594c2019-01-04 12:12:39[diff] [blame]20class Clock;
21class TickClock;
Owen Min782b8932020-04-06 14:31:06[diff] [blame]22
Peter Kasting99791752025-01-02 20:48:59[diff] [blame]23// `WallClockTimer` is based on `OneShotTimer` and provides a similar API.
24// Where `OneShotTimer` uses `TimeTicks`, however, `WallClockTimer` uses `Time`.
25// On some platforms, `TimeTicks` freezes during suspend; `Time` does not.
26// `WallClockTimer` recomputes the desired delay after resuming from suspend, so
27// on these platforms, suspends will "delay" `OneShotTimer` but not
28// `WallClockTimer`.
Roman Aleksandrov9f6594c2019-01-04 12:12:39[diff] [blame]29//
Peter Kasting99791752025-01-02 20:48:59[diff] [blame]30// This does not attempt to observe and accommodate other `Time` changes, e.g.
31// `Time` moving backwards in response to a DST change. `WallClockTimer` will
32// only notice such changes if the system is subsequently suspended (which will
33// cause a recalculation on resume that will coincidentally take them into
34// account).
Roman Aleksandrov9f6594c2019-01-04 12:12:39[diff] [blame]35//
Peter Kasting47b4de142025-01-02 20:48:46[diff] [blame]36// After construction, the timer will become bound to the first sequence any
37// method is called on. All subsequent calls must happen on that sequence until
38// the task runs or is canceled via `Stop()`, after which the timer may be
39// destroyed or restarted on another sequence.
Albert J. Wong276d6ff2021-07-26 17:47:49[diff] [blame]40class BASE_EXPORT WallClockTimer : public PowerSuspendObserver {
Roman Aleksandrov9f6594c2019-01-04 12:12:39[diff] [blame]41 public:
Owen Min782b8932020-04-06 14:31:06[diff] [blame]42 // Constructs a timer. Start() must be called later to start the timer.
43 // If |clock| is provided, it's used instead of
Albert J. Wong276d6ff2021-07-26 17:47:49[diff] [blame]44 // DefaultClock::GetInstance() to calulate timer's delay. If |tick_clock|
45 // is provided, it's used instead of TimeTicks::Now() to get TimeTicks when
46 // scheduling tasks.
Roman Aleksandrov9f6594c2019-01-04 12:12:39[diff] [blame]47 WallClockTimer();
Albert J. Wong276d6ff2021-07-26 17:47:49[diff] [blame]48 WallClockTimer(const Clock* clock, const TickClock* tick_clock);
Owen Min782b8932020-04-06 14:31:06[diff] [blame]49 WallClockTimer(const WallClockTimer&) = delete;
50 WallClockTimer& operator=(const WallClockTimer&) = delete;
Roman Aleksandrov9f6594c2019-01-04 12:12:39[diff] [blame]51 ~WallClockTimer() override;
52
Owen Min5eda9bf2020-04-09 14:20:27[diff] [blame]53 // Starts the timer to run at the given |desired_run_time|. If the timer is
Roman Aleksandrov9f6594c2019-01-04 12:12:39[diff] [blame]54 // already running, it will be replaced to call the given |user_task|.
Albert J. Wong276d6ff2021-07-26 17:47:49[diff] [blame]55 virtual void Start(const Location& posted_from,
56 Time desired_run_time,
57 OnceClosure user_task);
Roman Aleksandrov9f6594c2019-01-04 12:12:39[diff] [blame]58
Owen Min5eda9bf2020-04-09 14:20:27[diff] [blame]59 // Starts the timer to run at the given |desired_run_time|. If the timer is
Roman Aleksandrov9f6594c2019-01-04 12:12:39[diff] [blame]60 // already running, it will be replaced to call a task formed from
Owen Min5eda9bf2020-04-09 14:20:27[diff] [blame]61 // |receiver|->*|method|.
Roman Aleksandrov9f6594c2019-01-04 12:12:39[diff] [blame]62 template <class Receiver>
Albert J. Wong276d6ff2021-07-26 17:47:49[diff] [blame]63 void Start(const Location& posted_from,
64 Time desired_run_time,
Roman Aleksandrov9f6594c2019-01-04 12:12:39[diff] [blame]65 Receiver* receiver,
66 void (Receiver::*method)()) {
Roman Aleksandrov7ed8e1042019-01-16 12:15:32[diff] [blame]67 Start(posted_from, desired_run_time,
Albert J. Wong276d6ff2021-07-26 17:47:49[diff] [blame]68 BindOnce(method, Unretained(receiver)));
Roman Aleksandrov9f6594c2019-01-04 12:12:39[diff] [blame]69 }
70
Peter Kasting99791752025-01-02 20:48:59[diff] [blame]71 // Stops the timer. No-op if the timer is not running.
Roman Aleksandrov9f6594c2019-01-04 12:12:39[diff] [blame]72 void Stop();
73
Peter Kasting99791752025-01-02 20:48:59[diff] [blame]74 // Returns whether the timer is running.
Owen Min491d0dc2020-01-22 19:42:37[diff] [blame]75 bool IsRunning() const;
Roman Aleksandrov9f6594c2019-01-04 12:12:39[diff] [blame]76
Albert J. Wong276d6ff2021-07-26 17:47:49[diff] [blame]77 // PowerSuspendObserver:
Roman Aleksandrov9f6594c2019-01-04 12:12:39[diff] [blame]78 void OnResume() override;
79
Peter Kasting47b4de142025-01-02 20:48:46[diff] [blame]80 Time desired_run_time() const {
81 DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
82 return desired_run_time_;
83 }
Roman Aleksandrov9f6594c2019-01-04 12:12:39[diff] [blame]84
85 private:
Roman Aleksandrov9f6594c2019-01-04 12:12:39[diff] [blame]86 void RunUserTask();
87
Peter Kasting47b4de142025-01-02 20:48:46[diff] [blame]88 SEQUENCE_CHECKER(sequence_checker_);
89
Roman Aleksandrov9f6594c2019-01-04 12:12:39[diff] [blame]90 // Location in user code.
Peter Kasting47b4de142025-01-02 20:48:46[diff] [blame]91 Location posted_from_ GUARDED_BY_CONTEXT(sequence_checker_);
Roman Aleksandrov9f6594c2019-01-04 12:12:39[diff] [blame]92
Roman Aleksandrov9f6594c2019-01-04 12:12:39[diff] [blame]93 // The desired run time of |user_task_|.
Peter Kasting47b4de142025-01-02 20:48:46[diff] [blame]94 Time desired_run_time_ GUARDED_BY_CONTEXT(sequence_checker_);
Roman Aleksandrov9f6594c2019-01-04 12:12:39[diff] [blame]95
Peter Kasting47b4de142025-01-02 20:48:46[diff] [blame]96 OnceClosure user_task_ GUARDED_BY_CONTEXT(sequence_checker_);
Roman Aleksandrov9f6594c2019-01-04 12:12:39[diff] [blame]97
Albert J. Wong276d6ff2021-07-26 17:47:49[diff] [blame]98 OneShotTimer timer_;
Roman Aleksandrov9f6594c2019-01-04 12:12:39[diff] [blame]99
100 // The clock used to calculate the run time for scheduled tasks.
Peter Kasting47b4de142025-01-02 20:48:46[diff] [blame]101 const raw_ptr<const Clock> clock_;
Roman Aleksandrov9f6594c2019-01-04 12:12:39[diff] [blame]102};
103
Albert J. Wong276d6ff2021-07-26 17:47:49[diff] [blame]104} // namespace base
Owen Min782b8932020-04-06 14:31:06[diff] [blame]105
Albert J. Wong276d6ff2021-07-26 17:47:49[diff] [blame]106#endif // BASE_TIMER_WALL_CLOCK_TIMER_H_