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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 // An object which signals the |work_done_or_abandoned_| event of a |
76 // ModelSafeWorker when it is deleted. | |
77 class ModelSafeWorker::ScopedSignalWorkDoneOrAbandoned { | |
skym
2017/04/06 00:34:54
This feels like a generic problem that is being so
fdoray
2017/04/06 18:10:55
Done.
| |
78 public: | |
79 explicit ScopedSignalWorkDoneOrAbandoned(scoped_refptr<ModelSafeWorker> outer) | |
80 : outer_(std::move(outer)) {} | |
81 | |
82 ScopedSignalWorkDoneOrAbandoned(ScopedSignalWorkDoneOrAbandoned&& other) = | |
83 default; | |
84 ScopedSignalWorkDoneOrAbandoned& operator=( | |
85 ScopedSignalWorkDoneOrAbandoned&& other) = default; | |
86 | |
87 ~ScopedSignalWorkDoneOrAbandoned() { | |
88 if (outer_) | |
skym
2017/04/06 00:34:54
Why's this if check needed?
fdoray
2017/04/06 18:10:55
n/a
| |
89 outer_->work_done_or_abandoned_.Signal(); | |
90 } | |
91 | |
92 private: | |
93 scoped_refptr<ModelSafeWorker> outer_; | |
94 | |
95 DISALLOW_COPY_AND_ASSIGN(ScopedSignalWorkDoneOrAbandoned); | |
96 }; | |
97 | |
98 ModelSafeWorker::ModelSafeWorker() | |
99 : work_done_or_abandoned_(base::WaitableEvent::ResetPolicy::AUTOMATIC, | |
100 base::WaitableEvent::InitialState::NOT_SIGNALED) { | |
101 } | |
73 ModelSafeWorker::~ModelSafeWorker() {} | 102 ModelSafeWorker::~ModelSafeWorker() {} |
74 | 103 |
75 void ModelSafeWorker::RequestStop() { | 104 void ModelSafeWorker::RequestStop() { |
76 // Set stop flag. This prevents any *further* tasks from being posted to | 105 base::AutoLock auto_lock(lock_); |
77 // worker threads (see DoWorkAndWaitUntilDone below), but note that one may | 106 |
78 // already be posted. | 107 // Set stop flag to prevent any *further* WorkCallback from starting to run |
79 stopped_.Set(); | 108 // (note that one may alreay be running). |
109 stopped_ = true; | |
110 | |
111 // If no work is running, unblock DoWorkAndWaitUntilDone(). If work is | |
112 // running, it is unsafe to return from DoWorkAndWaitUntilDone(). | |
113 // ScopedSignalWorkDoneOrAbandoned will take care of signaling the event when | |
114 // the work is done. | |
115 if (!is_work_running_) | |
116 work_done_or_abandoned_.Signal(); | |
80 } | 117 } |
81 | 118 |
82 SyncerError ModelSafeWorker::DoWorkAndWaitUntilDone(const WorkCallback& work) { | 119 SyncerError ModelSafeWorker::DoWorkAndWaitUntilDone(const WorkCallback& work) { |
83 if (stopped_.IsSet()) | 120 { |
84 return CANNOT_DO_WORK; | 121 // It is important to check |stopped_| and reset |work_done_or_abandoned_| |
85 return DoWorkAndWaitUntilDoneImpl(work); | 122 // atomically to prevent this race: |
123 // | |
124 // Thread Action | |
125 // Sync Sees that |stopped_| is false. | |
126 // UI Calls RequestStop(). Signals |work_done_or_abandoned_|. | |
127 // Sync Resets |work_done_or_abandoned_|. | |
128 // Waits on |work_done_or_abandoned_| forever since the task may not | |
129 // run after RequestStop() is called. | |
130 base::AutoLock auto_lock(lock_); | |
131 if (stopped_) | |
132 return CANNOT_DO_WORK; | |
133 DCHECK(!is_work_running_); | |
134 work_done_or_abandoned_.Reset(); | |
135 } | |
136 | |
137 SyncerError error = UNSET; | |
138 bool did_run = false; | |
139 ScheduleWork(base::Bind(&ModelSafeWorker::DoWork, this, work, | |
140 base::Passed(ScopedSignalWorkDoneOrAbandoned(this)), | |
141 base::Unretained(&error), | |
142 base::Unretained(&did_run))); | |
143 | |
144 // Unblocked when the task runs or is deleted or when RequestStop() is called | |
145 // before the task starts running. | |
146 work_done_or_abandoned_.Wait(); | |
147 | |
148 return did_run ? error : CANNOT_DO_WORK; | |
86 } | 149 } |
87 | 150 |
88 bool ModelSafeWorker::IsStopped() { | 151 void ModelSafeWorker::DoWork( |
89 return stopped_.IsSet(); | 152 const WorkCallback& work, |
153 ScopedSignalWorkDoneOrAbandoned scoped_signal_work_done_or_abandoned, | |
154 SyncerError* error, | |
155 bool* did_run) { | |
156 { | |
157 base::AutoLock auto_lock(lock_); | |
158 if (stopped_) | |
159 return; | |
160 | |
161 // Set |is_work_running_| to make sure that DoWorkAndWaitUntilDone() doesn't | |
162 // return while the work is running. | |
163 DCHECK(!is_work_running_); | |
164 is_work_running_ = true; | |
165 } | |
166 | |
167 *error = work.Run(); | |
168 *did_run = true; | |
169 | |
170 { | |
171 base::AutoLock auto_lock(lock_); | |
172 DCHECK(is_work_running_); | |
173 is_work_running_ = false; | |
174 } | |
90 } | 175 } |
91 | 176 |
92 } // namespace syncer | 177 } // namespace syncer |
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