blob: e4d9c7f2f8597c1fee0ea9e5d7e4c19b120169e6 [file] [log] [blame]
// 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.
#include "base/base_export.h"
#include "base/callback.h"
#include "base/location.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/pending_task.h"
#include "base/sequenced_task_runner.h"
#include "base/single_thread_task_runner.h"
#include "base/time/time.h"
namespace base {
namespace internal {
// A task is a unit of work inside the task scheduler. Support for tracing and
// profiling inherited from PendingTask.
struct BASE_EXPORT Task : public PendingTask {
// |posted_from| is the site the task was posted from. |task| is the closure
// to run. |delay| is a delay that must expire before the Task runs.
Task(const Location& posted_from,
OnceClosure task,
TimeDelta delay);
// Task is move-only to avoid mistakes that cause reference counts to be
// accidentally bumped.
Task(Task&& other) noexcept;
Task& operator=(Task&& other);
// The delay that must expire before the task runs.
TimeDelta delay;
// The time at which the task was inserted in its sequence. For an undelayed
// task, this happens at post time. For a delayed task, this happens some
// time after the task's delay has expired. If the task hasn't been inserted
// in a sequence yet, this defaults to a null TimeTicks.
TimeTicks sequenced_time;
// A reference to the SequencedTaskRunner or SingleThreadTaskRunner that
// posted this task, if any. Used to set ThreadTaskRunnerHandle and/or
// SequencedTaskRunnerHandle while the task is running.
// Note: this creates an ownership cycle
// Sequence -> Task -> TaskRunner -> Sequence -> ...
// but that's okay as it's broken when the Task is popped from its Sequence
// after being executed which means this cycle forces the TaskRunner to stick
// around until all its tasks have been executed which is a requirement to
// support TaskRunnerHandles.
scoped_refptr<SequencedTaskRunner> sequenced_task_runner_ref;
scoped_refptr<SingleThreadTaskRunner> single_thread_task_runner_ref;
} // namespace internal
} // namespace base