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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 | |
3 // found in the LICENSE file. | |
4 | |
5 #include "base/task_scheduler/worker_thread.h" | |
6 | |
7 #include <stddef.h> | |
8 | |
9 #include <utility> | |
10 | |
11 #include "base/logging.h" | |
12 #include "base/task_scheduler/task_tracker.h" | |
13 | |
14 namespace base { | |
15 namespace internal { | |
16 | |
17 scoped_ptr<WorkerThread> WorkerThread::CreateWorkerThread( | |
18 ThreadPriority thread_priority, | |
19 const GetWorkCallback& get_work_callback, | |
20 const RanTaskFromSequenceCallback& ran_task_from_sequence_callback, | |
21 TaskTracker* task_tracker) { | |
22 scoped_ptr<WorkerThread> worker_thread( | |
23 new WorkerThread(thread_priority, get_work_callback, | |
24 ran_task_from_sequence_callback, task_tracker)); | |
25 | |
26 if (worker_thread->thread_handle_.is_null()) | |
27 return scoped_ptr<WorkerThread>(); | |
danakj
2016/03/31 00:25:13
return nullptr
fdoray
2016/03/31 03:26:31
Done.
| |
28 return worker_thread; | |
29 } | |
30 | |
31 WorkerThread::~WorkerThread() { | |
32 DCHECK(should_exit_for_testing()); | |
33 } | |
34 | |
35 void WorkerThread::WakeUp() { | |
36 wake_up_event_.Signal(); | |
37 } | |
38 | |
39 void WorkerThread::JoinForTesting() { | |
40 should_exit_for_testing_ = true; | |
41 base::subtle::MemoryBarrier(); | |
42 WakeUp(); | |
43 PlatformThread::Join(thread_handle_); | |
44 } | |
45 | |
46 WorkerThread::WorkerThread( | |
47 ThreadPriority thread_priority, | |
48 const GetWorkCallback& get_work_callback, | |
49 const RanTaskFromSequenceCallback& ran_task_from_sequence_callback, | |
50 TaskTracker* task_tracker) | |
51 : wake_up_event_(false, false), | |
52 get_work_callback_(get_work_callback), | |
53 ran_task_from_sequence_callback_(ran_task_from_sequence_callback), | |
54 task_tracker_(task_tracker) { | |
55 DCHECK(!get_work_callback_.is_null()); | |
56 DCHECK(!ran_task_from_sequence_callback_.is_null()); | |
57 DCHECK(task_tracker_); | |
58 | |
59 static const size_t kDefaultStackSize = 0; | |
60 PlatformThread::CreateWithPriority(kDefaultStackSize, this, &thread_handle_, | |
61 thread_priority); | |
62 } | |
63 | |
64 void WorkerThread::ThreadMain() { | |
65 // A WorkerThread starts out sleeping. | |
66 wake_up_event_.Wait(); | |
67 | |
68 while (!task_tracker_->shutdown_completed() && !should_exit_for_testing()) { | |
69 // Get the sequence containing the next task to execute. | |
70 scoped_refptr<Sequence> sequence = get_work_callback_.Run(this); | |
71 | |
72 if (!sequence) { | |
73 wake_up_event_.Wait(); | |
74 continue; | |
75 } | |
76 | |
77 task_tracker_->RunTask(sequence->PeekTask()); | |
78 ran_task_from_sequence_callback_.Run(this, std::move(sequence)); | |
79 | |
80 // Calling WakeUp() guarantees that this WorkerThread will run Tasks from | |
81 // Sequences returned by |get_work_callback_| until the callback returns | |
82 // nullptr. Resetting |wake_up_event_| here doesn't break this invariant and | |
83 // avoids a useless loop iteration before going to sleep if WakeUp() is | |
84 // called while this WorkerThread is awake. | |
85 wake_up_event_.Reset(); | |
86 } | |
87 } | |
88 | |
89 } // namespace internal | |
90 } // namespace base | |
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