chromium/third_party/blink/renderer/core/editing/ephemeral_range.h

// Copyright 2015 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_EDITING_EPHEMERAL_RANGE_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_EDITING_EPHEMERAL_RANGE_H_

#include "base/dcheck_is_on.h"
#include "third_party/blink/renderer/core/core_export.h"
#include "third_party/blink/renderer/core/editing/position.h"

namespace blink {

class Document;
class AbstractRange;
class Range;

// We should restrict access to the unwanted version of |TraversalRange::end()|
// function.
template <class Iterator>
class TraversalRangeNodes : private TraversalRange<Iterator> { … };

// This class acts like |TraversalNextIterator| but in addition
// it allows to set current position and checks |current_| pointer before
// dereferencing.
template <class TraversalNext>
class CheckedTraversalNextIterator
    : public TraversalIteratorBase<TraversalNext> { … };

// Unlike |Range| objects, |EphemeralRangeTemplate| objects aren't relocated.
// You should not use |EphemeralRangeTemplate| objects after DOM modification.
//
// EphemeralRangeTemplate is supposed to use returning or passing start and end
// position.
//
//  Example usage:
//    Range* range = produceRange();
//    consumeRange(range);
//    ... no DOM modification ...
//    consumeRange2(range);
//
//  Above code should be:
//    EphemeralRangeTemplate range = produceRange();
//    consumeRange(range);
//    ... no DOM modification ...
//    consumeRange2(range);
//
//  Because of |Range| objects consume heap memory and inserted into |Range|
//  object list in |Document| for relocation. These operations are redundant
//  if |Range| objects doesn't live after DOM mutation.
//
template <typename Strategy>
class EphemeralRangeTemplate final { … };

extern template class CORE_EXTERN_TEMPLATE_EXPORT
    EphemeralRangeTemplate<EditingStrategy>;
EphemeralRange;

extern template class CORE_EXTERN_TEMPLATE_EXPORT
    EphemeralRangeTemplate<EditingInFlatTreeStrategy>;
EphemeralRangeInFlatTree;

// Returns a newly created |Range| object from |range| or |nullptr| if
// |range.isNull()| returns true.
CORE_EXPORT Range* CreateRange(const EphemeralRange& /* range */);

CORE_EXPORT std::ostream& operator<<(std::ostream&, const EphemeralRange&);
CORE_EXPORT std::ostream& operator<<(std::ostream&,
                                     const EphemeralRangeInFlatTree&);

CORE_EXPORT EphemeralRangeInFlatTree
ToEphemeralRangeInFlatTree(const EphemeralRange&);

}  // namespace blink

#endif  // THIRD_PARTY_BLINK_RENDERER_CORE_EDITING_EPHEMERAL_RANGE_H_