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1 // Copyright 2016 The Chromium Authors. All rights reserved. | 1 // Copyright 2016 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #ifndef BASE_TASK_SCHEDULER_TASK_H_ | 5 #ifndef BASE_TASK_SCHEDULER_TASK_H_ |
6 #define BASE_TASK_SCHEDULER_TASK_H_ | 6 #define BASE_TASK_SCHEDULER_TASK_H_ |
7 | 7 |
8 #include "base/base_export.h" | 8 #include "base/base_export.h" |
9 #include "base/callback_forward.h" | 9 #include "base/callback_forward.h" |
10 #include "base/location.h" | 10 #include "base/location.h" |
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22 // A task is a unit of work inside the task scheduler. Support for tracing and | 22 // A task is a unit of work inside the task scheduler. Support for tracing and |
23 // profiling inherited from PendingTask. | 23 // profiling inherited from PendingTask. |
24 struct BASE_EXPORT Task : public PendingTask { | 24 struct BASE_EXPORT Task : public PendingTask { |
25 // |posted_from| is the site the task was posted from. |task| is the closure | 25 // |posted_from| is the site the task was posted from. |task| is the closure |
26 // to run. |traits_in| is metadata about the task. |delay| is a delay that | 26 // to run. |traits_in| is metadata about the task. |delay| is a delay that |
27 // must expire before the Task runs. If |delay| is non-zero and the shutdown | 27 // must expire before the Task runs. If |delay| is non-zero and the shutdown |
28 // behavior in |traits| is BLOCK_SHUTDOWN, the shutdown behavior is | 28 // behavior in |traits| is BLOCK_SHUTDOWN, the shutdown behavior is |
29 // automatically adjusted to SKIP_ON_SHUTDOWN. | 29 // automatically adjusted to SKIP_ON_SHUTDOWN. |
30 Task(const tracked_objects::Location& posted_from, | 30 Task(const tracked_objects::Location& posted_from, |
31 const Closure& task, | 31 const Closure& task, |
32 const TaskTraits& traits_in, | 32 const TaskTraits& traits, |
33 const TimeDelta& delay); | 33 const TimeDelta& delay); |
34 ~Task(); | 34 ~Task(); |
35 | 35 |
36 // The TaskTraits of this task. | 36 // The TaskTraits of this task. |
37 TaskTraits traits; | 37 const TaskTraits traits; |
38 | 38 |
39 // The time at which the task was inserted in its sequence. For an undelayed | 39 // The time at which the task was inserted in its sequence. For an undelayed |
40 // task, this happens at post time. For a delayed task, this happens some | 40 // task, this happens at post time. For a delayed task, this happens some |
41 // time after the task's delay has expired. If the task hasn't been inserted | 41 // time after the task's delay has expired. If the task hasn't been inserted |
42 // in a sequence yet, this defaults to a null TimeTicks. | 42 // in a sequence yet, this defaults to a null TimeTicks. |
43 TimeTicks sequenced_time; | 43 TimeTicks sequenced_time; |
44 | 44 |
45 // A reference to the SequencedTaskRunner or SingleThreadTaskRunner that | 45 // A reference to the SequencedTaskRunner or SingleThreadTaskRunner that |
46 // posted this task, if any. Used to set ThreadTaskRunnerHandle and/or | 46 // posted this task, if any. Used to set ThreadTaskRunnerHandle and/or |
47 // SequencedTaskRunnerHandle while the task is running. | 47 // SequencedTaskRunnerHandle while the task is running. |
48 // Note: this creates an ownership cycle | 48 // Note: this creates an ownership cycle |
49 // Sequence -> Task -> TaskRunner -> Sequence -> ... | 49 // Sequence -> Task -> TaskRunner -> Sequence -> ... |
50 // but that's okay as it's broken when the Task is popped from its Sequence | 50 // but that's okay as it's broken when the Task is popped from its Sequence |
51 // after being executed which means this cycle forces the TaskRunner to stick | 51 // after being executed which means this cycle forces the TaskRunner to stick |
52 // around until all its tasks have been executed which is a requirement to | 52 // around until all its tasks have been executed which is a requirement to |
53 // support TaskRunnerHandles. | 53 // support TaskRunnerHandles. |
54 scoped_refptr<SequencedTaskRunner> sequenced_task_runner_ref; | 54 scoped_refptr<SequencedTaskRunner> sequenced_task_runner_ref; |
55 scoped_refptr<SingleThreadTaskRunner> single_thread_task_runner_ref; | 55 scoped_refptr<SingleThreadTaskRunner> single_thread_task_runner_ref; |
56 | 56 |
57 private: | 57 private: |
58 // Disallow copies to make sure no unnecessary ref-bumps are incurred. Making | 58 // Disallow copies to make sure no unnecessary ref-bumps are incurred. Making |
59 // it move-only would be an option, but isn't necessary for now. | 59 // it move-only would be an option, but isn't necessary for now. |
60 DISALLOW_COPY_AND_ASSIGN(Task); | 60 DISALLOW_COPY_AND_ASSIGN(Task); |
61 }; | 61 }; |
62 | 62 |
63 } // namespace internal | 63 } // namespace internal |
64 } // namespace base | 64 } // namespace base |
65 | 65 |
66 #endif // BASE_TASK_SCHEDULER_TASK_H_ | 66 #endif // BASE_TASK_SCHEDULER_TASK_H_ |
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