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/*
* Copyright (C) 2007, 2008 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_EDITING_POSITION_ITERATOR_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_EDITING_POSITION_ITERATOR_H_
#include "third_party/blink/renderer/core/core_export.h"
#include "third_party/blink/renderer/core/dom/node.h"
#include "third_party/blink/renderer/core/editing/editing_strategy.h"
#include "third_party/blink/renderer/core/editing/forward.h"
namespace blink {
// A Position iterator with nearly constant-time
// increment, decrement, and several predicates on the Position it is at.
// Conversion from Position is O(n) in the depth.
// Conversion to Position is O(1).
// PositionIteratorAlgorithm must be used without DOM tree change.
template <typename Strategy>
class PositionIteratorAlgorithm {
STACK_ALLOCATED();
public:
explicit PositionIteratorAlgorithm(const PositionTemplate<Strategy>&);
PositionIteratorAlgorithm();
// Since |deprecatedComputePosition()| is slow, new code should use
// |computePosition()| instead.
PositionTemplate<Strategy> DeprecatedComputePosition() const;
PositionTemplate<Strategy> ComputePosition() const;
// increment() takes O(1) other than incrementing to a element that has
// new parent.
// In the later case, it takes time of O(<number of childlen>) but the case
// happens at most depth-of-the-tree times over whole tree traversal.
void Increment();
// decrement() takes O(1) other than decrement into new node that has
// childlen.
// In the later case, it takes time of O(<number of childlen>).
void Decrement();
Node* GetNode() const { return anchor_node_; }
int OffsetInLeafNode() const { return offset_in_anchor_; }
bool AtStart() const;
bool AtEnd() const;
bool AtStartOfNode() const;
bool AtEndOfNode() const;
private:
PositionIteratorAlgorithm(Node* anchor_node, int offset_in_anchoror_node);
bool IsValid() const {
return !anchor_node_ ||
dom_tree_version_ == anchor_node_->GetDocument().DomTreeVersion();
}
Member<Node> anchor_node_;
// If this is non-null, Strategy::Parent(*node_after_position_in_anchor_) ==
// anchor_node_;
Member<Node> node_after_position_in_anchor_;
int offset_in_anchor_;
wtf_size_t depth_to_anchor_node_;
// If |node_after_position_in_anchor_| is not null,
// offsets_in_anchor_node_[depth_to_anchor_node_] ==
// Strategy::Index(node_after_position_in_anchor_).
Vector<int> offsets_in_anchor_node_;
uint64_t dom_tree_version_;
};
extern template class CORE_EXTERN_TEMPLATE_EXPORT
PositionIteratorAlgorithm<EditingStrategy>;
extern template class CORE_EXTERN_TEMPLATE_EXPORT
PositionIteratorAlgorithm<EditingInFlatTreeStrategy>;
using PositionIterator = PositionIteratorAlgorithm<EditingStrategy>;
using PositionIteratorInFlatTree =
PositionIteratorAlgorithm<EditingInFlatTreeStrategy>;
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_CORE_EDITING_POSITION_ITERATOR_H_
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