| // 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_ |