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

/*
 * Copyright (C) 2004, 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
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    documentation and/or other materials provided with the distribution.
 *
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 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_EDITING_VISIBLE_POSITION_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_EDITING_VISIBLE_POSITION_H_

#include <iosfwd>

#include "base/dcheck_is_on.h"
#include "third_party/blink/renderer/core/core_export.h"
#include "third_party/blink/renderer/core/editing/position_with_affinity.h"
#include "third_party/blink/renderer/core/editing/text_affinity.h"
#include "third_party/blink/renderer/platform/heap/garbage_collected.h"

namespace blink {

// |VisiblePosition| is an immutable object representing "canonical position"
// with affinity.
//
// "canonical position" is roughly equivalent to a position where we can place
// caret, see |canonicalPosition()| for actual definition.
//
// "affinity" represents a place of caret at wrapped line. UPSTREAM affinity
// means caret is placed at end of line. DOWNSTREAM affinity means caret is
// placed at start of line.
//
// Example of affinity:
//    abc^def where "^" represent |Position|
// When above text line wrapped after "abc"
//    abc|  UPSTREAM |VisiblePosition|
//    |def  DOWNSTREAM |VisiblePosition|
//
// NOTE: UPSTREAM affinity will be used only if pos is at end of a wrapped line,
// otherwise it will be converted to DOWNSTREAM.
template <typename Strategy>
class VisiblePositionTemplate final {};

extern template class CORE_EXTERN_TEMPLATE_EXPORT
    VisiblePositionTemplate<EditingStrategy>;
extern template class CORE_EXTERN_TEMPLATE_EXPORT
    VisiblePositionTemplate<EditingInFlatTreeStrategy>;

VisiblePosition;
VisiblePositionInFlatTree;

CORE_EXPORT VisiblePosition
CreateVisiblePosition(const Position&, TextAffinity = TextAffinity::kDefault);
CORE_EXPORT VisiblePosition CreateVisiblePosition(const PositionWithAffinity&);
CORE_EXPORT VisiblePositionInFlatTree
CreateVisiblePosition(const PositionInFlatTree&,
                      TextAffinity = TextAffinity::kDefault);
CORE_EXPORT VisiblePositionInFlatTree
CreateVisiblePosition(const PositionInFlatTreeWithAffinity&);

CORE_EXPORT std::ostream& operator<<(std::ostream&, const VisiblePosition&);
CORE_EXPORT std::ostream& operator<<(std::ostream&,
                                     const VisiblePositionInFlatTree&);

}  // namespace blink

#if DCHECK_IS_ON()
// Outside the blink namespace for ease of invocation from gdb.
void ShowTree(const blink::VisiblePosition*);
void ShowTree(const blink::VisiblePosition&);
#endif

#endif  // THIRD_PARTY_BLINK_RENDERER_CORE_EDITING_VISIBLE_POSITION_H_