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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 THIRD_PARTY_BLINK_RENDERER_CORE_LAYOUT_NG_LIST_NG_UNPOSITIONED_LIST_MARKER_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_LAYOUT_NG_LIST_NG_UNPOSITIONED_LIST_MARKER_H_
#include "base/memory/scoped_refptr.h"
#include "third_party/blink/renderer/core/core_export.h"
#include "third_party/blink/renderer/core/layout/ng/geometry/ng_box_strut.h"
#include "third_party/blink/renderer/platform/fonts/font_baseline.h"
#include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"
namespace blink {
class ComputedStyle;
class LayoutNGListMarker;
class LayoutUnit;
class NGBlockNode;
class NGConstraintSpace;
class NGBoxFragmentBuilder;
class NGLayoutResult;
class NGPhysicalFragment;
struct LogicalOffset;
struct NGLineHeightMetrics;
// Represents an unpositioned list marker.
//
// A list item can have either block children or inline children. Because
// NGBLockLayoutAlgorithm handles the former while NGInlineLayoutAlgorithm
// handles the latter, list marker can appear in either algorithm.
//
// To handle these two cases consistently, when list markers appear in these
// algorithm, they are set as "unpositioned", and are propagated to ancestors
// through NGLayoutResult until they meet the corresponding list items.
//
// In order to adjust with the other content of LI, marker will be handled
// after other children.
// First, try to find the adjusted content_metrics for the marker. See
// |CanAddToBox()| for details.
// If found, layout marker, compute the content adjusted offset and float
// intuded offset. See |AddToBox()| for details.
// If not, layout marker and deal with it in |AddToBoxWithoutLineBoxes()|.
//
// In addition, marker makes LI non self-collapsing. If the BFC block-offset of
// LI isn't resolved after layout marker, we'll resolve it. See
// |NGBlockLayoutAlgorithm::PositionOrPropagateListMarker()| and
// |NGBlockLayoutAlgorithm::PositionListMarkerWithoutLineBoxes()| for details.
class CORE_EXPORT NGUnpositionedListMarker final {
DISALLOW_NEW();
public:
NGUnpositionedListMarker() : marker_layout_object_(nullptr) {}
explicit NGUnpositionedListMarker(LayoutNGListMarker*);
explicit NGUnpositionedListMarker(const NGBlockNode&);
explicit operator bool() const { return marker_layout_object_; }
// Returns true if the list marker can be added to box. False indicates
// that the child content does not have a baseline to align to, and that
// caller should try next child, or "WithoutLineBoxes" version.
bool CanAddToBox(const NGConstraintSpace&,
FontBaseline,
const NGPhysicalFragment& content,
NGLineHeightMetrics* content_metrics) const;
// Add a fragment for an outside list marker.
void AddToBox(const NGConstraintSpace&,
FontBaseline,
const NGPhysicalFragment& content,
const NGBoxStrut&,
const NGLineHeightMetrics& content_metrics,
const NGLayoutResult& marker_layout_result,
LogicalOffset* content_offset,
NGBoxFragmentBuilder*) const;
// Add a fragment for an outside list marker when the list item has no line
// boxes.
// Returns the block size of the list marker.
LayoutUnit AddToBoxWithoutLineBoxes(
const NGConstraintSpace&,
FontBaseline,
const NGLayoutResult& marker_layout_result,
NGBoxFragmentBuilder*) const;
LayoutUnit InlineOffset(const LayoutUnit marker_inline_size) const;
bool operator==(const NGUnpositionedListMarker& other) const {
return marker_layout_object_ == other.marker_layout_object_;
}
scoped_refptr<const NGLayoutResult> Layout(
const NGConstraintSpace& parent_space,
const ComputedStyle& parent_style,
FontBaseline) const;
#if DCHECK_IS_ON()
void CheckMargin() const;
#endif
private:
bool IsImage() const;
LayoutUnit ComputeIntrudedFloatOffset(const NGConstraintSpace&,
const NGBoxFragmentBuilder*,
const NGBoxStrut&,
LayoutUnit) const;
LayoutNGListMarker* marker_layout_object_;
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_CORE_LAYOUT_NG_LIST_NG_UNPOSITIONED_LIST_MARKER_H_
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