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| 1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | 1 // Copyright 2014 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 WEBKIT_BROWSER_FILEAPI_TASK_RUNNER_BOUND_OBSERVER_LIST_H_ | 5 #include "storage/browser/fileapi/task_runner_bound_observer_list.h" |
| 6 #define WEBKIT_BROWSER_FILEAPI_TASK_RUNNER_BOUND_OBSERVER_LIST_H_ | |
| 7 | |
| 8 #include <map> | |
| 9 | |
| 10 #include "base/basictypes.h" | |
| 11 #include "base/bind.h" | |
| 12 #include "base/memory/ref_counted.h" | |
| 13 #include "base/sequenced_task_runner.h" | |
| 14 #include "base/threading/thread.h" | |
| 15 | |
| 16 namespace storage { | |
| 17 | |
| 18 // A wrapper for dispatching method. | |
| 19 template <class T, class Method, class Params> | |
| 20 void NotifyWrapper(T obj, Method m, const Params& p) { | |
| 21 DispatchToMethod(base::internal::UnwrapTraits<T>::Unwrap(obj), m, p); | |
| 22 } | |
| 23 | |
| 24 // An observer list helper to notify on a given task runner. | |
| 25 // Observer pointers (stored as ObserverStoreType) must be kept alive | |
| 26 // until this list dispatches all the notifications. | |
| 27 // | |
| 28 // Unlike regular ObserverList or ObserverListThreadSafe internal observer | |
| 29 // list is immutable (though not declared const) and cannot be modified after | |
| 30 // constructed. | |
| 31 // | |
| 32 // It is ok to specify scoped_refptr<Observer> as ObserverStoreType to | |
| 33 // explicitly keep references if necessary. | |
| 34 template <class Observer, class ObserverStoreType = Observer*> | |
| 35 class TaskRunnerBoundObserverList { | |
| 36 public: | |
| 37 typedef scoped_refptr<base::SequencedTaskRunner> TaskRunnerPtr; | |
| 38 typedef std::map<ObserverStoreType, TaskRunnerPtr> ObserversListMap; | |
| 39 | |
| 40 // Creates an empty list. | |
| 41 TaskRunnerBoundObserverList<Observer, ObserverStoreType>() {} | |
| 42 | |
| 43 // Creates a new list with given |observers|. | |
| 44 explicit TaskRunnerBoundObserverList<Observer, ObserverStoreType>( | |
| 45 const ObserversListMap& observers) | |
| 46 : observers_(observers) {} | |
| 47 | |
| 48 virtual ~TaskRunnerBoundObserverList<Observer, ObserverStoreType>() {} | |
| 49 | |
| 50 // Returns a new observer list with given observer. | |
| 51 // It is valid to give NULL as |runner_to_notify|, and in that case | |
| 52 // notifications are dispatched on the current runner. | |
| 53 // Note that this is a const method and does NOT change 'this' observer | |
| 54 // list but returns a new list. | |
| 55 TaskRunnerBoundObserverList<Observer, ObserverStoreType> AddObserver( | |
| 56 Observer* observer, | |
| 57 base::SequencedTaskRunner* runner_to_notify) const { | |
| 58 ObserversListMap observers = observers_; | |
| 59 observers.insert(std::make_pair(observer, runner_to_notify)); | |
| 60 return TaskRunnerBoundObserverList<Observer, ObserverStoreType>(observers); | |
| 61 } | |
| 62 | |
| 63 // Notify on the task runner that is given to AddObserver. | |
| 64 // If we're already on the runner this just dispatches the method. | |
| 65 template <class Method, class Params> | |
| 66 void Notify(Method method, const Params& params) const { | |
| 67 COMPILE_ASSERT( | |
| 68 (base::internal::ParamsUseScopedRefptrCorrectly<Params>::value), | |
| 69 badunboundmethodparams); | |
| 70 for (typename ObserversListMap::const_iterator it = observers_.begin(); | |
| 71 it != observers_.end(); ++it) { | |
| 72 if (!it->second.get() || it->second->RunsTasksOnCurrentThread()) { | |
| 73 DispatchToMethod(UnwrapTraits::Unwrap(it->first), method, params); | |
| 74 continue; | |
| 75 } | |
| 76 it->second->PostTask( | |
| 77 FROM_HERE, | |
| 78 base::Bind(&NotifyWrapper<ObserverStoreType, Method, Params>, | |
| 79 it->first, method, params)); | |
| 80 } | |
| 81 } | |
| 82 | |
| 83 private: | |
| 84 typedef base::internal::UnwrapTraits<ObserverStoreType> UnwrapTraits; | |
| 85 | |
| 86 ObserversListMap observers_; | |
| 87 }; | |
| 88 | |
| 89 class FileAccessObserver; | |
| 90 class FileChangeObserver; | |
| 91 class FileUpdateObserver; | |
| 92 | |
| 93 typedef TaskRunnerBoundObserverList<FileAccessObserver> AccessObserverList; | |
| 94 typedef TaskRunnerBoundObserverList<FileChangeObserver> ChangeObserverList; | |
| 95 typedef TaskRunnerBoundObserverList<FileUpdateObserver> UpdateObserverList; | |
| 96 | |
| 97 } // namespace storage | |
| 98 | |
| 99 #endif // WEBKIT_BROWSER_FILEAPI_TASK_RUNNER_BOUND_OBSERVER_LIST_H_ | |
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