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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_SEQUENCE_H_ | 5 #ifndef BASE_TASK_SCHEDULER_SEQUENCE_H_ |
6 #define BASE_TASK_SCHEDULER_SEQUENCE_H_ | 6 #define BASE_TASK_SCHEDULER_SEQUENCE_H_ |
7 | 7 |
8 #include <stddef.h> | 8 #include <stddef.h> |
9 | 9 |
10 #include <memory> | 10 #include <memory> |
11 #include <queue> | 11 #include <queue> |
12 | 12 |
13 #include "base/base_export.h" | 13 #include "base/base_export.h" |
14 #include "base/macros.h" | 14 #include "base/macros.h" |
15 #include "base/memory/ref_counted.h" | 15 #include "base/memory/ref_counted.h" |
16 #include "base/task_scheduler/scheduler_lock.h" | 16 #include "base/task_scheduler/scheduler_lock.h" |
17 #include "base/task_scheduler/sequence_sort_key.h" | 17 #include "base/task_scheduler/sequence_sort_key.h" |
18 #include "base/task_scheduler/task.h" | 18 #include "base/task_scheduler/task.h" |
19 #include "base/task_scheduler/task_traits.h" | 19 #include "base/task_scheduler/task_traits.h" |
20 | 20 |
21 namespace base { | 21 namespace base { |
22 namespace internal { | 22 namespace internal { |
23 | 23 |
24 // A sequence holds tasks that must be executed in posting order. | 24 // A sequence holds tasks that must be executed in posting order. |
25 // | 25 // |
26 // Note: there is a known refcounted-ownership cycle in the Scheduler | 26 // Note: there is a known refcounted-ownership cycle in the Scheduler |
27 // architecture: Sequence -> Task -> TaskRunner -> Sequence -> ... | 27 // architecture: Sequence -> Task -> TaskRunner -> Sequence -> ... |
28 // This is okay so long as the other owners of Sequence (PriorityQueue and | 28 // This is okay so long as the other owners of Sequence (PriorityQueue and |
29 // SchedulerWorkerThread in alternance and | 29 // SchedulerWorkerThread in alternance and |
30 // SchedulerThreadPoolImpl::SchedulerWorkerThreadDelegateImpl::GetWork() | 30 // SchedulerWorkerPoolImpl::SchedulerWorkerThreadDelegateImpl::GetWork() |
31 // temporarily) keep running it (and taking Tasks from it as a result). A | 31 // temporarily) keep running it (and taking Tasks from it as a result). A |
32 // dangling reference cycle would only occur should they release their reference | 32 // dangling reference cycle would only occur should they release their reference |
33 // to it while it's not empty. In other words, it is only correct for them to | 33 // to it while it's not empty. In other words, it is only correct for them to |
34 // release it after PopTask() returns false to indicate it was made empty by | 34 // release it after PopTask() returns false to indicate it was made empty by |
35 // that call (in which case the next PushTask() will return true to indicate to | 35 // that call (in which case the next PushTask() will return true to indicate to |
36 // the caller that the Sequence should be re-enqueued for execution). | 36 // the caller that the Sequence should be re-enqueued for execution). |
37 // | 37 // |
38 // This class is thread-safe. | 38 // This class is thread-safe. |
39 class BASE_EXPORT Sequence : public RefCountedThreadSafe<Sequence> { | 39 class BASE_EXPORT Sequence : public RefCountedThreadSafe<Sequence> { |
40 public: | 40 public: |
(...skipping 29 matching lines...) Expand all Loading... |
70 size_t num_tasks_per_priority_[static_cast<int>(TaskPriority::HIGHEST) + 1] = | 70 size_t num_tasks_per_priority_[static_cast<int>(TaskPriority::HIGHEST) + 1] = |
71 {}; | 71 {}; |
72 | 72 |
73 DISALLOW_COPY_AND_ASSIGN(Sequence); | 73 DISALLOW_COPY_AND_ASSIGN(Sequence); |
74 }; | 74 }; |
75 | 75 |
76 } // namespace internal | 76 } // namespace internal |
77 } // namespace base | 77 } // namespace base |
78 | 78 |
79 #endif // BASE_TASK_SCHEDULER_SEQUENCE_H_ | 79 #endif // BASE_TASK_SCHEDULER_SEQUENCE_H_ |
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