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