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// Copyright 2013 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 UI_EVENTS_EVENT_TARGET_ITERATOR_H_
#define UI_EVENTS_EVENT_TARGET_ITERATOR_H_
#include <vector>
namespace ui {
class EventTarget;
// An interface that allows iterating over a set of EventTargets.
class EventTargetIterator {
public:
virtual ~EventTargetIterator() {}
virtual EventTarget* GetNextTarget() = 0;
};
// Provides an EventTargetIterator implementation for iterating over a list of
// EventTargets. The list is iterated in the reverse order, since typically the
// EventTargets are maintained in increasing z-order in the lists.
template<typename T>
class EventTargetIteratorImpl : public EventTargetIterator {
public:
explicit EventTargetIteratorImpl(const std::vector<T*>& children)
: begin_(children.rbegin()),
end_(children.rend()) {
}
~EventTargetIteratorImpl() override {}
EventTarget* GetNextTarget() override {
if (begin_ == end_)
return NULL;
EventTarget* target = *(begin_);
++begin_;
return target;
}
private:
typename std::vector<T*>::const_reverse_iterator begin_;
typename std::vector<T*>::const_reverse_iterator end_;
};
} // namespace ui
#endif // UI_EVENTS_EVENT_TARGET_ITERATOR_H_
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