base/task/delay_policy.h

// Copyright 2021 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_DELAY_POLICY_H_
#define BASE_TASK_DELAY_POLICY_H_

#include "base/time/time.h"

namespace base {
namespace subtle {

// Policies affecting how a delayed task is scheduled when a TimeTicks is
// specified.
enum class DelayPolicy {
  // A delayed task with kFlexibleNoSooner may not run any sooner than the
  // specified time, but might run slightly after. This is the behavior implied
  // by PostDelayedTask.
  kFlexibleNoSooner,
  // A delayed task with kFlexiblePreferEarly means the task should attempt to
  // run near the deadline and preferably a little bit before than after if the
  // scheduler applies slack.
  kFlexiblePreferEarly,
  // A delayed task with kPrecise means it may not run any sooner than the
  // specified time and preferably as close as possible to the specified time,
  // which may affect scheduling policies if the scheduler usually applies
  // slack.
  kPrecise,
};

inline DelayPolicy MaybeOverrideDelayPolicy(DelayPolicy delay_policy,
                                            TimeDelta delay,
                                            TimeDelta max_precise_delay) {
  if (delay >= max_precise_delay && delay_policy == DelayPolicy::kPrecise) {
    return DelayPolicy::kFlexibleNoSooner;
  }
  return delay_policy;
}

}  // namespace subtle
}  // namespace base

#endif  // BASE_TASK_DELAY_POLICY_H_