third_party/blink/renderer/core/layout/ng/inline/ng_inline_layout_algorithm.h

// Copyright 2016 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 NGInlineLayoutAlgorithm_h
#define NGInlineLayoutAlgorithm_h

#include "third_party/blink/renderer/core/core_export.h"
#include "third_party/blink/renderer/core/layout/ng/inline/ng_inline_node.h"
#include "third_party/blink/renderer/core/layout/ng/inline/ng_line_box_fragment_builder.h"
#include "third_party/blink/renderer/core/layout/ng/ng_box_fragment_builder.h"
#include "third_party/blink/renderer/core/layout/ng/ng_constraint_space_builder.h"
#include "third_party/blink/renderer/core/layout/ng/ng_layout_algorithm.h"
#include "third_party/blink/renderer/core/layout/ng/ng_unpositioned_float.h"
#include "third_party/blink/renderer/core/layout/ng/ng_unpositioned_float_vector.h"
#include "third_party/blink/renderer/platform/fonts/font_baseline.h"
#include "third_party/blink/renderer/platform/wtf/vector.h"

namespace blink {

class NGConstraintSpace;
class NGExclusionSpace;
class NGInlineBreakToken;
class NGInlineChildLayoutContext;
class NGInlineNode;
class NGInlineItem;
class NGInlineLayoutStateStack;
class NGLineInfo;
struct NGInlineBoxState;
struct NGInlineItemResult;
struct NGPositionedFloat;

// A class for laying out an inline formatting context, i.e. a block with inline
// children.
//
// This class determines the position of NGInlineItem and build line boxes.
//
// Uses NGLineBreaker to find NGInlineItems to form a line.
class CORE_EXPORT NGInlineLayoutAlgorithm final
    : public NGLayoutAlgorithm<NGInlineNode,
                               NGLineBoxFragmentBuilder,
                               NGInlineBreakToken> {
 public:
  NGInlineLayoutAlgorithm(NGInlineNode,
                          const NGConstraintSpace&,
                          const NGInlineBreakToken*,
                          NGInlineChildLayoutContext* context);
  ~NGInlineLayoutAlgorithm() override;

  void CreateLine(NGLineInfo*, NGExclusionSpace*);

  scoped_refptr<NGLayoutResult> Layout() override;

 private:
  unsigned PositionLeadingFloats(NGExclusionSpace*);

  void PositionPendingFloats(LayoutUnit content_size, NGExclusionSpace*);

  bool IsHorizontalWritingMode() const { return is_horizontal_writing_mode_; }

  void PrepareBoxStates(const NGLineInfo&, const NGInlineBreakToken*);
  void RebuildBoxStates(const NGLineInfo&,
                        const NGInlineBreakToken*,
                        NGInlineLayoutStateStack*) const;
#if DCHECK_IS_ON()
  void CheckBoxStates(const NGLineInfo&, const NGInlineBreakToken*) const;
#endif

  NGInlineBoxState* HandleOpenTag(const NGInlineItem&,
                                  const NGInlineItemResult&,
                                  NGInlineLayoutStateStack*) const;
  NGInlineBoxState* HandleCloseTag(const NGInlineItem&,
                                   const NGInlineItemResult&,
                                   NGInlineBoxState*);

  void BidiReorder();

  void PlaceControlItem(const NGInlineItem&,
                        const NGLineInfo&,
                        NGInlineItemResult*,
                        NGInlineBoxState*);
  void PlaceGeneratedContent(scoped_refptr<const NGPhysicalFragment>,
                             UBiDiLevel,
                             NGInlineBoxState*);
  NGInlineBoxState* PlaceAtomicInline(const NGInlineItem&,
                                      const NGLineInfo&,
                                      NGInlineItemResult*);
  void PlaceLayoutResult(NGInlineItemResult*,
                         NGInlineBoxState*,
                         LayoutUnit inline_offset = LayoutUnit());
  void PlaceOutOfFlowObjects(const NGLineInfo&, const NGLineHeightMetrics&);
  void PlaceListMarker(const NGInlineItem&,
                       NGInlineItemResult*,
                       const NGLineInfo&);

  LayoutUnit OffsetForTextAlign(const NGLineInfo&, ETextAlign) const;
  bool ApplyJustify(NGLineInfo*);

  LayoutUnit ComputeContentSize(const NGLineInfo&,
                                const NGExclusionSpace&,
                                LayoutUnit line_height);

  NGLineBoxFragmentBuilder::ChildList line_box_;
  NGInlineLayoutStateStack* box_states_;
  NGInlineChildLayoutContext* context_;

  FontBaseline baseline_type_ = FontBaseline::kAlphabeticBaseline;

  unsigned is_horizontal_writing_mode_ : 1;
  unsigned quirks_mode_ : 1;

  Vector<NGPositionedFloat> positioned_floats_;
  NGUnpositionedFloatVector unpositioned_floats_;

#if DCHECK_IS_ON()
  // True if |box_states_| is taken from |context_|, to check the |box_states_|
  // is the same as when it is rebuilt.
  bool is_box_states_from_context_ = false;
#endif
};

}  // namespace blink

#endif  // NGInlineLayoutAlgorithm_h