55 lines
1.5 KiB
C
55 lines
1.5 KiB
C
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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef BASE_SCOPED_OBSERVER_H_
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#define BASE_SCOPED_OBSERVER_H_
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#include <algorithm>
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#include <vector>
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#include "base/basictypes.h"
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// ScopedObserver is used to keep track of the set of sources an object has
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// attached itself to as an observer. When ScopedObserver is destroyed it
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// removes the object as an observer from all sources it has been added to.
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template <class Source, class Observer>
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class ScopedObserver {
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public:
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explicit ScopedObserver(Observer* observer) : observer_(observer) {}
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~ScopedObserver() {
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for (size_t i = 0; i < sources_.size(); ++i)
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sources_[i]->RemoveObserver(observer_);
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}
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// Adds the object passed to the constructor as an observer on |source|.
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void Add(Source* source) {
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sources_.push_back(source);
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source->AddObserver(observer_);
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}
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// Remove the object passed to the constructor as an observer from |source|.
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void Remove(Source* source) {
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sources_.erase(std::find(sources_.begin(), sources_.end(), source));
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source->RemoveObserver(observer_);
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}
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bool IsObserving(Source* source) const {
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for (size_t i = 0; i < sources_.size(); ++i) {
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if (sources_[i] == source)
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return true;
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}
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return false;
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}
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private:
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Observer* observer_;
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std::vector<Source*> sources_;
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DISALLOW_COPY_AND_ASSIGN(ScopedObserver);
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};
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#endif // BASE_SCOPED_OBSERVER_H_
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