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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | 1 // Copyright (c) 2012 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 #include "components/sync/engine/model_safe_worker.h" | 5 #include "components/sync/engine/model_safe_worker.h" |
6 | 6 |
| 7 #include <utility> |
| 8 |
| 9 #include "base/bind.h" |
7 #include "base/json/json_writer.h" | 10 #include "base/json/json_writer.h" |
8 #include "base/values.h" | 11 #include "base/values.h" |
9 | 12 |
10 namespace syncer { | 13 namespace syncer { |
11 | 14 |
12 std::unique_ptr<base::DictionaryValue> ModelSafeRoutingInfoToValue( | 15 std::unique_ptr<base::DictionaryValue> ModelSafeRoutingInfoToValue( |
13 const ModelSafeRoutingInfo& routing_info) { | 16 const ModelSafeRoutingInfo& routing_info) { |
14 std::unique_ptr<base::DictionaryValue> dict(new base::DictionaryValue()); | 17 std::unique_ptr<base::DictionaryValue> dict(new base::DictionaryValue()); |
15 for (ModelSafeRoutingInfo::const_iterator it = routing_info.begin(); | 18 for (ModelSafeRoutingInfo::const_iterator it = routing_info.begin(); |
16 it != routing_info.end(); ++it) { | 19 it != routing_info.end(); ++it) { |
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62 case GROUP_PASSWORD: | 65 case GROUP_PASSWORD: |
63 return "GROUP_PASSWORD"; | 66 return "GROUP_PASSWORD"; |
64 case GROUP_NON_BLOCKING: | 67 case GROUP_NON_BLOCKING: |
65 return "GROUP_NON_BLOCKING"; | 68 return "GROUP_NON_BLOCKING"; |
66 default: | 69 default: |
67 NOTREACHED(); | 70 NOTREACHED(); |
68 return "INVALID"; | 71 return "INVALID"; |
69 } | 72 } |
70 } | 73 } |
71 | 74 |
72 ModelSafeWorker::ModelSafeWorker() {} | 75 ModelSafeWorker::ModelSafeWorker() |
| 76 : work_done_or_abandoned_(base::WaitableEvent::ResetPolicy::AUTOMATIC, |
| 77 base::WaitableEvent::InitialState::NOT_SIGNALED) { |
| 78 } |
73 ModelSafeWorker::~ModelSafeWorker() {} | 79 ModelSafeWorker::~ModelSafeWorker() {} |
74 | 80 |
75 void ModelSafeWorker::RequestStop() { | 81 void ModelSafeWorker::RequestStop() { |
76 // Set stop flag. This prevents any *further* tasks from being posted to | 82 base::AutoLock auto_lock(lock_); |
77 // worker threads (see DoWorkAndWaitUntilDone below), but note that one may | 83 |
78 // already be posted. | 84 // Set stop flag to prevent any *further* WorkCallback from starting to run |
79 stopped_.Set(); | 85 // (note that one may alreay be running). |
| 86 stopped_ = true; |
| 87 |
| 88 // If no work is running, unblock DoWorkAndWaitUntilDone(). If work is |
| 89 // running, it is unsafe to return from DoWorkAndWaitUntilDone(). |
| 90 // ScopedSignalWorkDoneOrAbandoned will take care of signaling the event when |
| 91 // the work is done. |
| 92 if (!is_work_running_) |
| 93 work_done_or_abandoned_.Signal(); |
80 } | 94 } |
81 | 95 |
82 SyncerError ModelSafeWorker::DoWorkAndWaitUntilDone(const WorkCallback& work) { | 96 SyncerError ModelSafeWorker::DoWorkAndWaitUntilDone(WorkCallback work) { |
83 if (stopped_.IsSet()) | 97 { |
84 return CANNOT_DO_WORK; | 98 // It is important to check |stopped_| and reset |work_done_or_abandoned_| |
85 return DoWorkAndWaitUntilDoneImpl(work); | 99 // atomically to prevent this race: |
| 100 // |
| 101 // Thread Action |
| 102 // Sync Sees that |stopped_| is false. |
| 103 // UI Calls RequestStop(). Signals |work_done_or_abandoned_|. |
| 104 // Sync Resets |work_done_or_abandoned_|. |
| 105 // Waits on |work_done_or_abandoned_| forever since the task may not |
| 106 // run after RequestStop() is called. |
| 107 base::AutoLock auto_lock(lock_); |
| 108 if (stopped_) |
| 109 return CANNOT_DO_WORK; |
| 110 DCHECK(!is_work_running_); |
| 111 work_done_or_abandoned_.Reset(); |
| 112 } |
| 113 |
| 114 SyncerError error = UNSET; |
| 115 bool did_run = false; |
| 116 ScheduleWork(base::BindOnce( |
| 117 &ModelSafeWorker::DoWork, this, base::Passed(std::move(work)), |
| 118 base::Passed(base::ScopedClosureRunner(base::Bind( |
| 119 [](scoped_refptr<ModelSafeWorker> worker) { |
| 120 worker->work_done_or_abandoned_.Signal(); |
| 121 }, |
| 122 make_scoped_refptr(this)))), |
| 123 base::Unretained(&error), base::Unretained(&did_run))); |
| 124 |
| 125 // Unblocked when the task runs or is deleted or when RequestStop() is called |
| 126 // before the task starts running. |
| 127 work_done_or_abandoned_.Wait(); |
| 128 |
| 129 return did_run ? error : CANNOT_DO_WORK; |
86 } | 130 } |
87 | 131 |
88 bool ModelSafeWorker::IsStopped() { | 132 void ModelSafeWorker::DoWork(WorkCallback work, |
89 return stopped_.IsSet(); | 133 base::ScopedClosureRunner scoped_closure_runner, |
| 134 SyncerError* error, |
| 135 bool* did_run) { |
| 136 { |
| 137 base::AutoLock auto_lock(lock_); |
| 138 if (stopped_) |
| 139 return; |
| 140 |
| 141 // Set |is_work_running_| to make sure that DoWorkAndWaitUntilDone() doesn't |
| 142 // return while |work| is running. |
| 143 DCHECK(!is_work_running_); |
| 144 is_work_running_ = true; |
| 145 } |
| 146 |
| 147 *error = std::move(work).Run(); |
| 148 *did_run = true; |
| 149 |
| 150 { |
| 151 base::AutoLock auto_lock(lock_); |
| 152 DCHECK(is_work_running_); |
| 153 is_work_running_ = false; |
| 154 } |
90 } | 155 } |
91 | 156 |
92 } // namespace syncer | 157 } // namespace syncer |
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