erg@chromium.org | 7827c53 | 2012-06-23 06:47:30 +0900 | [diff] [blame] | 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 |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | #ifndef BASE_SCOPED_OBSERVER_H_ |
| 6 | #define BASE_SCOPED_OBSERVER_H_ |
erg@chromium.org | 7827c53 | 2012-06-23 06:47:30 +0900 | [diff] [blame] | 7 | |
| 8 | #include <algorithm> |
| 9 | #include <vector> |
| 10 | |
| 11 | #include "base/basictypes.h" |
| 12 | |
| 13 | // ScopedObserver is used to keep track of the set of sources an object has |
| 14 | // attached itself to as an observer. When ScopedObserver is destroyed it |
| 15 | // removes the object as an observer from all sources it has been added to. |
| 16 | template <class Source, class Observer> |
| 17 | class ScopedObserver { |
| 18 | public: |
| 19 | explicit ScopedObserver(Observer* observer) : observer_(observer) {} |
| 20 | |
| 21 | ~ScopedObserver() { |
thestig@chromium.org | c6baf06 | 2014-04-08 13:01:06 +0900 | [diff] [blame] | 22 | RemoveAll(); |
erg@chromium.org | 7827c53 | 2012-06-23 06:47:30 +0900 | [diff] [blame] | 23 | } |
| 24 | |
| 25 | // Adds the object passed to the constructor as an observer on |source|. |
| 26 | void Add(Source* source) { |
| 27 | sources_.push_back(source); |
| 28 | source->AddObserver(observer_); |
| 29 | } |
| 30 | |
jam@chromium.org | 7bf65a7 | 2012-10-06 01:01:57 +0900 | [diff] [blame] | 31 | // Remove the object passed to the constructor as an observer from |source|. |
erg@chromium.org | 7827c53 | 2012-06-23 06:47:30 +0900 | [diff] [blame] | 32 | void Remove(Source* source) { |
| 33 | sources_.erase(std::find(sources_.begin(), sources_.end(), source)); |
| 34 | source->RemoveObserver(observer_); |
| 35 | } |
| 36 | |
thestig@chromium.org | c6baf06 | 2014-04-08 13:01:06 +0900 | [diff] [blame] | 37 | void RemoveAll() { |
| 38 | for (size_t i = 0; i < sources_.size(); ++i) |
| 39 | sources_[i]->RemoveObserver(observer_); |
| 40 | sources_.clear(); |
| 41 | } |
| 42 | |
jam@chromium.org | 7bf65a7 | 2012-10-06 01:01:57 +0900 | [diff] [blame] | 43 | bool IsObserving(Source* source) const { |
thestig@chromium.org | c6baf06 | 2014-04-08 13:01:06 +0900 | [diff] [blame] | 44 | return std::find(sources_.begin(), sources_.end(), source) != |
| 45 | sources_.end(); |
jam@chromium.org | 7bf65a7 | 2012-10-06 01:01:57 +0900 | [diff] [blame] | 46 | } |
| 47 | |
erg@chromium.org | 7827c53 | 2012-06-23 06:47:30 +0900 | [diff] [blame] | 48 | private: |
| 49 | Observer* observer_; |
| 50 | |
| 51 | std::vector<Source*> sources_; |
| 52 | |
| 53 | DISALLOW_COPY_AND_ASSIGN(ScopedObserver); |
| 54 | }; |
| 55 | |
| 56 | #endif // BASE_SCOPED_OBSERVER_H_ |