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1 // Copyright (c) 2010 The Chromium Authors. All rights reserved. | 1 // Copyright (c) 2010 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_OBSERVER_LIST_THREADSAFE_H_ | 5 #ifndef BASE_OBSERVER_LIST_THREADSAFE_H_ |
6 #define BASE_OBSERVER_LIST_THREADSAFE_H_ | 6 #define BASE_OBSERVER_LIST_THREADSAFE_H_ |
7 #pragma once | 7 #pragma once |
8 | 8 |
9 #include <algorithm> | 9 #include <algorithm> |
10 #include <map> | 10 #include <map> |
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86 // Add an observer to the list. | 86 // Add an observer to the list. |
87 void AddObserver(ObserverType* obs) { | 87 void AddObserver(ObserverType* obs) { |
88 ObserverList<ObserverType>* list = NULL; | 88 ObserverList<ObserverType>* list = NULL; |
89 MessageLoop* loop = MessageLoop::current(); | 89 MessageLoop* loop = MessageLoop::current(); |
90 // TODO(mbelshe): Get rid of this check. Its needed right now because | 90 // TODO(mbelshe): Get rid of this check. Its needed right now because |
91 // Time currently triggers usage of the ObserverList. | 91 // Time currently triggers usage of the ObserverList. |
92 // And unittests use time without a MessageLoop. | 92 // And unittests use time without a MessageLoop. |
93 if (!loop) | 93 if (!loop) |
94 return; // Some unittests may access this without a message loop. | 94 return; // Some unittests may access this without a message loop. |
95 { | 95 { |
96 AutoLock lock(list_lock_); | 96 base::AutoLock lock(list_lock_); |
97 if (observer_lists_.find(loop) == observer_lists_.end()) | 97 if (observer_lists_.find(loop) == observer_lists_.end()) |
98 observer_lists_[loop] = new ObserverList<ObserverType>(type_); | 98 observer_lists_[loop] = new ObserverList<ObserverType>(type_); |
99 list = observer_lists_[loop]; | 99 list = observer_lists_[loop]; |
100 } | 100 } |
101 list->AddObserver(obs); | 101 list->AddObserver(obs); |
102 } | 102 } |
103 | 103 |
104 // Remove an observer from the list. | 104 // Remove an observer from the list. |
105 // If there are pending notifications in-transit to the observer, they will | 105 // If there are pending notifications in-transit to the observer, they will |
106 // be aborted. | 106 // be aborted. |
107 // RemoveObserver MUST be called from the same thread which called | 107 // RemoveObserver MUST be called from the same thread which called |
108 // AddObserver. | 108 // AddObserver. |
109 void RemoveObserver(ObserverType* obs) { | 109 void RemoveObserver(ObserverType* obs) { |
110 ObserverList<ObserverType>* list = NULL; | 110 ObserverList<ObserverType>* list = NULL; |
111 MessageLoop* loop = MessageLoop::current(); | 111 MessageLoop* loop = MessageLoop::current(); |
112 if (!loop) | 112 if (!loop) |
113 return; // On shutdown, it is possible that current() is already null. | 113 return; // On shutdown, it is possible that current() is already null. |
114 { | 114 { |
115 AutoLock lock(list_lock_); | 115 base::AutoLock lock(list_lock_); |
116 list = observer_lists_[loop]; | 116 list = observer_lists_[loop]; |
117 if (!list) { | 117 if (!list) { |
118 NOTREACHED() << "RemoveObserver called on for unknown thread"; | 118 NOTREACHED() << "RemoveObserver called on for unknown thread"; |
119 return; | 119 return; |
120 } | 120 } |
121 | 121 |
122 // If we're about to remove the last observer from the list, | 122 // If we're about to remove the last observer from the list, |
123 // then we can remove this observer_list entirely. | 123 // then we can remove this observer_list entirely. |
124 if (list->size() == 1) | 124 if (list->size() == 1) |
125 observer_lists_.erase(loop); | 125 observer_lists_.erase(loop); |
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158 | 158 |
159 ~ObserverListThreadSafe() { | 159 ~ObserverListThreadSafe() { |
160 typename ObserversListMap::const_iterator it; | 160 typename ObserversListMap::const_iterator it; |
161 for (it = observer_lists_.begin(); it != observer_lists_.end(); ++it) | 161 for (it = observer_lists_.begin(); it != observer_lists_.end(); ++it) |
162 delete (*it).second; | 162 delete (*it).second; |
163 observer_lists_.clear(); | 163 observer_lists_.clear(); |
164 } | 164 } |
165 | 165 |
166 template <class Method, class Params> | 166 template <class Method, class Params> |
167 void Notify(const UnboundMethod<ObserverType, Method, Params>& method) { | 167 void Notify(const UnboundMethod<ObserverType, Method, Params>& method) { |
168 AutoLock lock(list_lock_); | 168 base::AutoLock lock(list_lock_); |
169 typename ObserversListMap::iterator it; | 169 typename ObserversListMap::iterator it; |
170 for (it = observer_lists_.begin(); it != observer_lists_.end(); ++it) { | 170 for (it = observer_lists_.begin(); it != observer_lists_.end(); ++it) { |
171 MessageLoop* loop = (*it).first; | 171 MessageLoop* loop = (*it).first; |
172 ObserverList<ObserverType>* list = (*it).second; | 172 ObserverList<ObserverType>* list = (*it).second; |
173 loop->PostTask( | 173 loop->PostTask( |
174 FROM_HERE, | 174 FROM_HERE, |
175 NewRunnableMethod(this, | 175 NewRunnableMethod(this, |
176 &ObserverListThreadSafe<ObserverType>:: | 176 &ObserverListThreadSafe<ObserverType>:: |
177 template NotifyWrapper<Method, Params>, list, method)); | 177 template NotifyWrapper<Method, Params>, list, method)); |
178 } | 178 } |
179 } | 179 } |
180 | 180 |
181 // Wrapper which is called to fire the notifications for each thread's | 181 // Wrapper which is called to fire the notifications for each thread's |
182 // ObserverList. This function MUST be called on the thread which owns | 182 // ObserverList. This function MUST be called on the thread which owns |
183 // the unsafe ObserverList. | 183 // the unsafe ObserverList. |
184 template <class Method, class Params> | 184 template <class Method, class Params> |
185 void NotifyWrapper(ObserverList<ObserverType>* list, | 185 void NotifyWrapper(ObserverList<ObserverType>* list, |
186 const UnboundMethod<ObserverType, Method, Params>& method) { | 186 const UnboundMethod<ObserverType, Method, Params>& method) { |
187 | 187 |
188 // Check that this list still needs notifications. | 188 // Check that this list still needs notifications. |
189 { | 189 { |
190 AutoLock lock(list_lock_); | 190 base::AutoLock lock(list_lock_); |
191 typename ObserversListMap::iterator it = | 191 typename ObserversListMap::iterator it = |
192 observer_lists_.find(MessageLoop::current()); | 192 observer_lists_.find(MessageLoop::current()); |
193 | 193 |
194 // The ObserverList could have been removed already. In fact, it could | 194 // The ObserverList could have been removed already. In fact, it could |
195 // have been removed and then re-added! If the master list's loop | 195 // have been removed and then re-added! If the master list's loop |
196 // does not match this one, then we do not need to finish this | 196 // does not match this one, then we do not need to finish this |
197 // notification. | 197 // notification. |
198 if (it == observer_lists_.end() || it->second != list) | 198 if (it == observer_lists_.end() || it->second != list) |
199 return; | 199 return; |
200 } | 200 } |
201 | 201 |
202 { | 202 { |
203 typename ObserverList<ObserverType>::Iterator it(*list); | 203 typename ObserverList<ObserverType>::Iterator it(*list); |
204 ObserverType* obs; | 204 ObserverType* obs; |
205 while ((obs = it.GetNext()) != NULL) | 205 while ((obs = it.GetNext()) != NULL) |
206 method.Run(obs); | 206 method.Run(obs); |
207 } | 207 } |
208 | 208 |
209 // If there are no more observers on the list, we can now delete it. | 209 // If there are no more observers on the list, we can now delete it. |
210 if (list->size() == 0) { | 210 if (list->size() == 0) { |
211 { | 211 { |
212 AutoLock lock(list_lock_); | 212 base::AutoLock lock(list_lock_); |
213 // Remove |list| if it's not already removed. | 213 // Remove |list| if it's not already removed. |
214 // This can happen if multiple observers got removed in a notification. | 214 // This can happen if multiple observers got removed in a notification. |
215 // See http://crbug.com/55725. | 215 // See http://crbug.com/55725. |
216 typename ObserversListMap::iterator it = | 216 typename ObserversListMap::iterator it = |
217 observer_lists_.find(MessageLoop::current()); | 217 observer_lists_.find(MessageLoop::current()); |
218 if (it != observer_lists_.end() && it->second == list) | 218 if (it != observer_lists_.end() && it->second == list) |
219 observer_lists_.erase(it); | 219 observer_lists_.erase(it); |
220 } | 220 } |
221 delete list; | 221 delete list; |
222 } | 222 } |
223 } | 223 } |
224 | 224 |
225 typedef std::map<MessageLoop*, ObserverList<ObserverType>*> ObserversListMap; | 225 typedef std::map<MessageLoop*, ObserverList<ObserverType>*> ObserversListMap; |
226 | 226 |
227 // These are marked mutable to facilitate having NotifyAll be const. | 227 // These are marked mutable to facilitate having NotifyAll be const. |
228 Lock list_lock_; // Protects the observer_lists_. | 228 base::Lock list_lock_; // Protects the observer_lists_. |
229 ObserversListMap observer_lists_; | 229 ObserversListMap observer_lists_; |
230 const NotificationType type_; | 230 const NotificationType type_; |
231 | 231 |
232 DISALLOW_COPY_AND_ASSIGN(ObserverListThreadSafe); | 232 DISALLOW_COPY_AND_ASSIGN(ObserverListThreadSafe); |
233 }; | 233 }; |
234 | 234 |
235 #endif // BASE_OBSERVER_LIST_THREADSAFE_H_ | 235 #endif // BASE_OBSERVER_LIST_THREADSAFE_H_ |
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