third_party/blink/renderer/core/layout/ng/ng_layout_input_node.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 NGLayoutInputNode_h
#define NGLayoutInputNode_h

#include "base/optional.h"
#include "third_party/blink/renderer/core/core_export.h"
#include "third_party/blink/renderer/core/layout/layout_box.h"
#include "third_party/blink/renderer/core/layout/ng/geometry/ng_logical_size.h"
#include "third_party/blink/renderer/core/layout/ng/list/layout_ng_list_marker.h"
#include "third_party/blink/renderer/platform/layout_unit.h"
#include "third_party/blink/renderer/platform/text/writing_mode.h"

namespace blink {

class ComputedStyle;
class Document;
class LayoutObject;
class LayoutBox;
class NGBreakToken;
class NGConstraintSpace;
class NGInlineChildLayoutContext;
class NGLayoutResult;
struct MinMaxSize;
struct NGLogicalSize;
struct NGPhysicalSize;

enum class NGMinMaxSizeType { kContentBoxSize, kBorderBoxSize };

// Input to the min/max inline size calculation algorithm for child nodes. Child
// nodes within the same formatting context need to know which floats are beside
// them. Additionally, orthogonal writing mode roots will need the extrinsic
// block-size of the container.
struct MinMaxSizeInput {
  LayoutUnit float_left_inline_size;
  LayoutUnit float_right_inline_size;

  // Extrinsic block-size of the containing block.
  LayoutUnit extrinsic_block_size = NGSizeIndefinite;

  // Whether to return the size as a content-box size or border-box size.
  NGMinMaxSizeType size_type = NGMinMaxSizeType::kBorderBoxSize;
};

// Represents the input to a layout algorithm for a given node. The layout
// engine should use the style, node type to determine which type of layout
// algorithm to use to produce fragments for this node.
class CORE_EXPORT NGLayoutInputNode {
  DISALLOW_NEW();

 public:
  enum NGLayoutInputNodeType {
    kBlock,
    kInline
    // When adding new values, ensure type_ below has enough bits.
  };

  NGLayoutInputNode(std::nullptr_t) : box_(nullptr), type_(kBlock) {}

  bool IsInline() const { return type_ == kInline; }
  bool IsBlock() const { return type_ == kBlock; }

  bool IsColumnSpanAll() const { return IsBlock() && box_->IsColumnSpanAll(); }
  bool IsFloating() const { return IsBlock() && Style().IsFloating(); }
  bool IsOutOfFlowPositioned() const {
    return IsBlock() && Style().HasOutOfFlowPosition();
  }
  bool IsReplaced() const { return box_->IsLayoutReplaced(); }
  bool IsAbsoluteContainer() const {
    return box_->CanContainAbsolutePositionObjects();
  }
  bool IsFixedContainer() const {
    return box_->CanContainFixedPositionObjects();
  }
  bool IsBody() const { return IsBlock() && box_->IsBody(); }
  bool IsDocumentElement() const { return box_->IsDocumentElement(); }
  bool IsFlexItem() const { return IsBlock() && box_->IsFlexItem(); }
  bool ShouldBeConsideredAsReplaced() const {
    return box_->ShouldBeConsideredAsReplaced();
  }
  bool IsListItem() const { return IsBlock() && box_->IsLayoutNGListItem(); }
  bool IsListMarker() const {
    return IsBlock() && box_->IsLayoutNGListMarker();
  }
  bool ListMarkerOccupiesWholeLine() const {
    DCHECK(IsListMarker());
    return ToLayoutNGListMarker(box_)->NeedsOccupyWholeLine();
  }
  bool IsTableCell() const { return IsBlock() && box_->IsTableCell(); }
  bool IsFieldsetContainer() const {
    return IsBlock() && box_->IsLayoutNGFieldset();
  }

  // Return true if this is the legend child of a fieldset that gets special
  // treatment (i.e. placed over the block-start border).
  bool IsRenderedLegend() const {
    return IsBlock() && box_->IsRenderedLegend();
  }

  bool IsAnonymousBlock() const { return box_->IsAnonymousBlock(); }

  // If the node is a quirky container for margin collapsing, see:
  // https://html.spec.whatwg.org/#margin-collapsing-quirks
  // NOTE: The spec appears to only somewhat match reality.
  bool IsQuirkyContainer() const {
    return box_->GetDocument().InQuirksMode() &&
           (box_->IsBody() || box_->IsTableCell());
  }

  bool CreatesNewFormattingContext() const {
    return IsBlock() && box_->AvoidsFloats();
  }

  // Performs layout on this input node, will return the layout result.
  scoped_refptr<NGLayoutResult> Layout(const NGConstraintSpace&,
                                       const NGBreakToken*,
                                       NGInlineChildLayoutContext*);

  // Returns border box.
  MinMaxSize ComputeMinMaxSize(WritingMode,
                               const MinMaxSizeInput&,
                               const NGConstraintSpace* = nullptr);

  // Returns intrinsic sizing information for replaced elements.
  // ComputeReplacedSize can use it to compute actual replaced size.
  // The function arguments return values from LegacyLayout intrinsic size
  // computations: LayoutReplaced::IntrinsicSizingInfo,
  // and LayoutReplaced::IntrinsicSize.
  void IntrinsicSize(NGLogicalSize* default_intrinsic_size,
                     base::Optional<LayoutUnit>* computed_inline_size,
                     base::Optional<LayoutUnit>* computed_block_size,
                     NGLogicalSize* aspect_ratio) const;

  LayoutUnit IntrinsicPaddingBlockStart() const;
  LayoutUnit IntrinsicPaddingBlockEnd() const;

  // Returns the next sibling.
  NGLayoutInputNode NextSibling();

  Document& GetDocument() const { return box_->GetDocument(); }

  NGPhysicalSize InitialContainingBlockSize() const;

  // Returns the LayoutObject which is associated with this node.
  LayoutBox* GetLayoutBox() const { return box_; };

  const ComputedStyle& Style() const { return box_->StyleRef(); }

  bool ShouldApplySizeContainment() const {
    return box_->ShouldApplySizeContainment();
  }

  String ToString() const;

  explicit operator bool() const { return box_ != nullptr; }

  bool operator==(const NGLayoutInputNode& other) const {
    return box_ == other.box_;
  }

  bool operator!=(const NGLayoutInputNode& other) const {
    return !(*this == other);
  }

#ifndef NDEBUG
  void ShowNodeTree() const;
#endif

 protected:
  NGLayoutInputNode(LayoutBox* box, NGLayoutInputNodeType type)
      : box_(box), type_(type) {}

  LayoutBox* box_;

  unsigned type_ : 1;  // NGLayoutInputNodeType
};

}  // namespace blink

#endif  // NGLayoutInputNode_h