9340d2d1a3
Move the layout tree from GC allocation to refcounted ownership so removed layout and paint subtrees are destroyed synchronously instead of waiting for the next GC sweep. This dramatically reduces GC memory usage peaks after layout tree churn and makes it easier for memory use to fall back after large document updates. Update layout factories, tree traversal, SVG layout node creation, paintable back-pointers, and pseudo-element layout links to use RefPtr ownership. Make display: contents follow the same shape as Blink and WebKit: the element itself does not create a layout node, and its children are flattened into the nearest layout parent. Wrap direct non-whitespace text in an anonymous inline node when the boxless element contributes inherited style to that text. Use an internal inline wrapper for display: contents pseudo-elements so generated content can still participate in layout, painting, hit testing, and pseudo-element queries. Keep CSSOM reporting the computed display value from the pseudo style, not the internal wrapper. Remove the retained out-of-tree layout node list and its testing hook, since the flattened model does not need a side owner for boxless elements. Add coverage for inherited text style, dynamic insertion order, pseudo-element hit testing, and computed style queries.
114 lines
3.8 KiB
C++
114 lines
3.8 KiB
C++
/*
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* Copyright (c) 2022, Andreas Kling <andreas@ladybird.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/Noncopyable.h>
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#include <LibWeb/Layout/BlockContainer.h>
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#include <LibWeb/Layout/LayoutState.h>
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#include <LibWeb/Layout/TextNode.h>
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namespace Web::Layout {
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// This class iterates over all the inline-level objects within an inline formatting context.
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// By repeatedly calling next() with the remaining available width on the current line,
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// it returns an "Item" representing the next piece of inline-level content to be placed on the line.
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class InlineLevelIterator {
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AK_MAKE_NONCOPYABLE(InlineLevelIterator);
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AK_MAKE_NONMOVABLE(InlineLevelIterator);
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public:
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struct Item {
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enum class Type {
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Text,
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Element,
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ForcedBreak,
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AbsolutelyPositionedElement,
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FloatingElement,
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};
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Type type {};
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Layout::Node const* node { nullptr };
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RefPtr<Gfx::GlyphRun> glyph_run {};
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size_t offset_in_node { 0 };
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size_t length_in_node { 0 };
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CSSPixels width { 0.0f };
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CSSPixels padding_start { 0.0f };
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CSSPixels padding_end { 0.0f };
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CSSPixels border_start { 0.0f };
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CSSPixels border_end { 0.0f };
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CSSPixels margin_start { 0.0f };
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CSSPixels margin_end { 0.0f };
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bool is_collapsible_whitespace { false };
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bool can_break_before { false };
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CSSPixels border_box_width() const
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{
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return border_start + padding_start + width + padding_end + border_end;
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}
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};
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InlineLevelIterator(Layout::InlineFormattingContext&, LayoutState&, Layout::BlockContainer const& containing_block, LayoutState::UsedValues const& containing_block_used_values, LayoutMode);
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Optional<Item&> next();
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CSSPixels next_non_whitespace_sequence_width();
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private:
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void generate_all_items();
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Optional<Item> generate_next_item();
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Gfx::GlyphRun::TextType resolve_text_direction_from_context();
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void skip_to_next();
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void compute_next();
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void enter_text_node(Layout::TextNode const&);
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void enter_node_with_box_model_metrics(Layout::NodeWithStyleAndBoxModelMetrics const&);
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void exit_node_with_box_model_metrics();
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void add_extra_box_model_metrics_to_item(Item&, bool add_leading_metrics, bool add_trailing_metrics);
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Layout::Node const* next_inline_node_in_pre_order(Layout::Node const& current, Layout::Node const* stay_within);
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Layout::InlineFormattingContext& m_inline_formatting_context;
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Layout::LayoutState& m_layout_state;
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BlockContainer const& m_containing_block;
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LayoutState::UsedValues const& m_containing_block_used_values;
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Layout::Node const* m_current_node { nullptr };
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Layout::Node const* m_next_node { nullptr };
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LayoutMode const m_layout_mode;
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struct TextNodeContext {
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TextNode::ChunkList const* chunk_list { nullptr };
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size_t next_chunk_index { 0 };
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bool should_collapse_whitespace {};
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bool should_wrap_lines {};
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bool should_respect_linebreaks {};
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Optional<Gfx::GlyphRun::TextType> last_known_direction {};
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};
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Optional<TextNodeContext> m_text_node_context;
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struct ExtraBoxMetrics {
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CSSPixels margin { 0 };
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CSSPixels border { 0 };
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CSSPixels padding { 0 };
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};
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Optional<ExtraBoxMetrics> m_extra_leading_metrics;
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Optional<ExtraBoxMetrics> m_extra_trailing_metrics;
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Vector<NodeWithStyleAndBoxModelMetrics const*> m_box_model_node_stack;
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// Pre-generated items for O(1) iteration and lookahead.
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Vector<Item> m_items;
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size_t m_next_item_index { 0 };
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// Accumulated width tracking for tab calculations during pre-generation.
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CSSPixels m_accumulated_width_for_tabs { 0 };
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bool m_previous_chunk_can_break_after { false };
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};
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}
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