offset_mapping.h | Explore in Territory

// Copyright 2017 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_LAYOUT_INLINE_OFFSET_MAPPING_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_LAYOUT_INLINE_OFFSET_MAPPING_H_

#include <optional>

#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/forward.h"
#include "third_party/blink/renderer/platform/heap/collection_support/heap_hash_map.h"
#include "third_party/blink/renderer/platform/heap/garbage_collected.h"
#include "third_party/blink/renderer/platform/heap/persistent.h"
#include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"
#include "third_party/blink/renderer/platform/wtf/text/wtf_string.h"
#include "third_party/blink/renderer/platform/wtf/vector.h"

namespace blink {

class LayoutBlockFlow;
class LayoutObject;

enum class OffsetMappingUnitType { … };

// An OffsetMappingUnit indicates a "simple" offset mapping between dom offset
// range [dom_start, dom_end] on node |owner| and text content offset range
// [text_content_start, text_content_end]. The mapping between them falls in one
// of the following categories, depending on |type|:
// - kIdentity: The mapping between the two ranges is the identity mapping. In
//   other words, the two ranges have the same length, and the offsets are
//   mapped one-to-one.
// - kCollapsed: The mapping is collapsed, namely, |text_content_start| and
//   |text_content_end| are the same, and characters in the dom range are
//   collapsed.
// - kVariable: The mapping is expanded or shrunk, namely.
//   -- |dom_end == dom_start + 1|, and
//      |text_content_end > text_content_start + 1|, indicating that the
//      character in the dom range is expanded into multiple characters, or
//   -- |dom_end > dom_start + 1|, and
//      |text_content_end == text_content_start + 1|, indicating that multiple
//      characters in the dom range is shrunk into a single character.
// See design doc https://goo.gl/CJbxky for details.
class CORE_EXPORT OffsetMappingUnit { … };

// Each inline formatting context laid out with LayoutNG has an OffsetMapping
// object that stores the mapping information between DOM positions and offsets
// in the text content string of the context.
// See design doc https://goo.gl/CJbxky for details.
class CORE_EXPORT OffsetMapping final : public GarbageCollected<OffsetMapping> { … };

CORE_EXPORT LayoutBlockFlow* NGInlineFormattingContextOf(const Position&);

}  // namespace blink

namespace WTF {

template <>
struct VectorTraits<blink::OffsetMappingUnit>
    : VectorTraitsBase<blink::OffsetMappingUnit> { … };

}  // namespace WTF

#endif  // THIRD_PARTY_BLINK_RENDERER_CORE_LAYOUT_INLINE_OFFSET_MAPPING_H_
chromium/third_party/blink/renderer/core/layout/inline/offset_mapping.h
