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layer_list_iterator.h
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layer_list_iterator.h
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// Copyright 2016 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 CC_LAYERS_LAYER_LIST_ITERATOR_H_
#define CC_LAYERS_LAYER_LIST_ITERATOR_H_
#include <stdlib.h>
#include <vector>
#include "cc/cc_export.h"
namespace cc {
// This visits a tree of layers in drawing order. For LayerImpls, this is only
// useful for tests, since there's no LayerImpl tree outside unit tests.
template <typename LayerType>
class CC_EXPORT LayerListIterator {
public:
explicit LayerListIterator(LayerType* root_layer);
LayerListIterator(const LayerListIterator<LayerType>& other);
virtual ~LayerListIterator();
bool operator==(const LayerListIterator<LayerType>& other) const {
return current_layer_ == other.current_layer_;
}
bool operator!=(const LayerListIterator<LayerType>& other) const {
return !(*this == other);
}
// We will only support prefix increment.
virtual LayerListIterator& operator++();
LayerType* operator->() const { return current_layer_; }
LayerType* operator*() const { return current_layer_; }
protected:
// The implementation of this iterator is currently tied tightly to the layer
// tree, but it should be straightforward to reimplement in terms of a list
// when it's ready.
LayerType* current_layer_;
std::vector<size_t> list_indices_;
};
template <typename LayerType>
class CC_EXPORT LayerListReverseIterator : public LayerListIterator<LayerType> {
public:
explicit LayerListReverseIterator(LayerType* root_layer);
~LayerListReverseIterator() override;
// We will only support prefix increment.
LayerListIterator<LayerType>& operator++() override;
private:
void DescendToRightmostInSubtree();
LayerType* current_layer() { return this->current_layer_; }
std::vector<size_t>& list_indices() { return this->list_indices_; }
};
} // namespace cc
#endif // CC_LAYERS_LAYER_LIST_ITERATOR_H_