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// Copyright 2017 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 NGInlineItem_h
#define NGInlineItem_h
#include "third_party/blink/renderer/core/core_export.h"
#include "third_party/blink/renderer/core/layout/ng/inline/ng_offset_mapping.h"
#include "third_party/blink/renderer/core/layout/ng/ng_style_variant.h"
#include "third_party/blink/renderer/core/style/computed_style.h"
#include "third_party/blink/renderer/platform/fonts/shaping/shape_result.h"
#include "third_party/blink/renderer/platform/text/text_direction.h"
#include <unicode/ubidi.h>
#include <unicode/uscript.h>
namespace blink {
class LayoutObject;
// Class representing a single text node or styled inline element with text
// content segmented by style, text direction, sideways rotation, font fallback
// priority (text, symbol, emoji, etc), and script (but not by font).
// In this representation TextNodes are merged up into their parent inline
// element where possible.
class CORE_EXPORT NGInlineItem {
public:
enum NGInlineItemType {
kText,
kControl,
kAtomicInline,
kOpenTag,
kCloseTag,
kFloating,
kOutOfFlowPositioned,
kListMarker,
kBidiControl
// When adding new values, make sure the bit size of |type_| is large
// enough to store.
};
// Whether pre- and post-context should be used for shaping.
enum NGLayoutInlineShapeOptions {
kNoContext = 0,
kPreContext = 1,
kPostContext = 2
};
enum NGCollapseType {
// No collapsible spaces.
kNotCollapsible,
// A collapsible space run that does not contain segment breaks.
kCollapsibleSpace,
// A collapsible space run that contains segment breaks.
kCollapsibleNewline,
// This item is opaque to whitespace collapsing.
kOpaqueToCollapsing
};
// The constructor and destructor can't be implicit or inlined, because they
// require full definition of ComputedStyle.
NGInlineItem(NGInlineItemType type,
unsigned start,
unsigned end,
const ComputedStyle* style = nullptr,
LayoutObject* layout_object = nullptr,
bool end_may_collapse = false);
~NGInlineItem();
// Copy constructor adjusting start/end and shape results.
NGInlineItem(const NGInlineItem&,
unsigned adjusted_start,
unsigned adjusted_end,
scoped_refptr<const ShapeResult>);
NGInlineItemType Type() const { return static_cast<NGInlineItemType>(type_); }
const char* NGInlineItemTypeToString(int val) const;
const ShapeResult* TextShapeResult() const { return shape_result_.get(); }
NGLayoutInlineShapeOptions ShapeOptions() const {
return static_cast<NGLayoutInlineShapeOptions>(shape_options_);
}
// If this item is "empty" for the purpose of empty block calculation.
bool IsEmptyItem() const { return is_empty_item_; }
// If this item should create a box fragment. Box fragments can be omitted for
// optimization if this is false.
bool ShouldCreateBoxFragment() const { return should_create_box_fragment_; }
unsigned StartOffset() const { return start_offset_; }
unsigned EndOffset() const { return end_offset_; }
unsigned Length() const { return end_offset_ - start_offset_; }
TextDirection Direction() const { return DirectionFromLevel(BidiLevel()); }
UBiDiLevel BidiLevel() const { return static_cast<UBiDiLevel>(bidi_level_); }
// Resolved bidi level for the reordering algorithm. Certain items have
// artificial bidi level for the reordering algorithm without affecting its
// direction.
UBiDiLevel BidiLevelForReorder() const;
UScriptCode GetScript() const { return script_; }
const ComputedStyle* Style() const { return style_.get(); }
LayoutObject* GetLayoutObject() const { return layout_object_; }
void SetOffset(unsigned start, unsigned end);
void SetEndOffset(unsigned);
bool HasStartEdge() const;
bool HasEndEdge() const;
void SetStyleVariant(NGStyleVariant style_variant) {
style_variant_ = static_cast<unsigned>(style_variant);
}
NGStyleVariant StyleVariant() const {
return static_cast<NGStyleVariant>(style_variant_);
}
// Get or set the whitespace collapse type at the end of this item.
NGCollapseType EndCollapseType() const {
return static_cast<NGCollapseType>(end_collapse_type_);
}
void SetEndCollapseType(NGCollapseType type) { end_collapse_type_ = type; }
// Whether the item may be affected by whitespace collapsing. Unlike the
// EndCollapseType() method this returns true even if a trailing space has
// been removed.
bool EndMayCollapse() const { return end_may_collapse_; }
static void Split(Vector<NGInlineItem>&, unsigned index, unsigned offset);
void SetBidiLevel(UBiDiLevel);
static unsigned SetBidiLevel(Vector<NGInlineItem>&,
unsigned index,
unsigned end_offset,
UBiDiLevel);
void AssertOffset(unsigned offset) const;
void AssertEndOffset(unsigned offset) const;
String ToString() const;
private:
void ComputeBoxProperties();
unsigned start_offset_;
unsigned end_offset_;
UScriptCode script_;
scoped_refptr<const ShapeResult> shape_result_;
scoped_refptr<const ComputedStyle> style_;
LayoutObject* layout_object_;
unsigned type_ : 4;
unsigned bidi_level_ : 8; // UBiDiLevel is defined as uint8_t.
unsigned shape_options_ : 2;
unsigned is_empty_item_ : 1;
unsigned should_create_box_fragment_ : 1;
unsigned style_variant_ : 2;
unsigned end_collapse_type_ : 2; // NGCollapseType
unsigned end_may_collapse_ : 1;
friend class NGInlineNode;
};
inline void NGInlineItem::AssertOffset(unsigned offset) const {
DCHECK((offset >= start_offset_ && offset < end_offset_) ||
(offset == start_offset_ && start_offset_ == end_offset_));
}
inline void NGInlineItem::AssertEndOffset(unsigned offset) const {
DCHECK_GE(offset, start_offset_);
DCHECK_LE(offset, end_offset_);
}
// Represents a text content with a list of NGInlineItem. A node may have an
// additional NGInlineItemsData for ::first-line pseudo element.
struct CORE_EXPORT NGInlineItemsData {
// Text content for all inline items represented by a single NGInlineNode.
// Encoded either as UTF-16 or latin-1 depending on the content.
String text_content;
Vector<NGInlineItem> items;
// The DOM to text content offset mapping of this inline node.
std::unique_ptr<NGOffsetMapping> offset_mapping;
void AssertOffset(unsigned index, unsigned offset) const {
items[index].AssertOffset(offset);
}
void AssertEndOffset(unsigned index, unsigned offset) const {
items[index].AssertEndOffset(offset);
}
};
} // namespace blink
#endif // NGInlineItem_h
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