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https://github.com/LadybirdBrowser/ladybird.git
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d1fbb7b51e
Before this change, whenever element's attributes changed, we would add a flag to "pending invalidation", indicating that all descendants whose style uses CSS custom properties needed to be recomputed. This resulted in severe overinvalidation, because we would run invalidation regardless of whether any custom property on affected element actually changed. This change takes another approach, and now we decide whether descendant's style needs to be recomputed based on whether ancestor's style recomputation results in a change of custom properties, though this approach adds a little overhead to style computation as now we have to compare old vs new hashmap of custom properties. This brings substantial improvement on discord and x.com where, before this change, advantage of using invalidation sets was lost and we had to recompute all descendants, because almost all of them use custom properties.
90 lines
3.1 KiB
C++
90 lines
3.1 KiB
C++
/*
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* Copyright (c) 2025, Aliaksandr Kalenik <kalenik.aliaksandr@gmail.com>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <LibWeb/CSS/InvalidationSet.h>
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#include <LibWeb/DOM/Element.h>
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#include <LibWeb/DOM/Node.h>
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#include <LibWeb/DOM/ShadowRoot.h>
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#include <LibWeb/DOM/StyleInvalidator.h>
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namespace Web::DOM {
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GC_DEFINE_ALLOCATOR(StyleInvalidator);
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void StyleInvalidator::visit_edges(Cell::Visitor& visitor)
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{
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Base::visit_edges(visitor);
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visitor.visit(m_pending_invalidations);
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}
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void StyleInvalidator::invalidate(Node& node)
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{
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perform_pending_style_invalidations(node, false);
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m_pending_invalidations.clear();
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}
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void StyleInvalidator::add_pending_invalidation(GC::Ref<Node> node, CSS::InvalidationSet&& invalidation_set)
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{
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auto& pending_invalidation_set = m_pending_invalidations.ensure(node, [&] {
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return CSS::InvalidationSet {};
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});
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pending_invalidation_set.include_all_from(invalidation_set);
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}
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// This function makes a full pass over the entire DOM and:
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// - converts "entire subtree needs style update" into "needs style update" for each inclusive descendant where it's found.
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// - marks nodes included into pending invalidation sets as "needs style update"
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void StyleInvalidator::perform_pending_style_invalidations(Node& node, bool invalidate_entire_subtree)
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{
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invalidate_entire_subtree |= node.entire_subtree_needs_style_update();
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if (invalidate_entire_subtree) {
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node.set_needs_style_update_internal(true);
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if (node.has_child_nodes())
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node.set_child_needs_style_update(true);
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}
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auto previous_subtree_invalidations_sets_size = m_subtree_invalidation_sets.size();
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ScopeGuard restore_state = [this, previous_subtree_invalidations_sets_size] {
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m_subtree_invalidation_sets.shrink(previous_subtree_invalidations_sets_size);
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};
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if (!invalidate_entire_subtree) {
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auto invalidation_set = m_pending_invalidations.get(node);
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if (invalidation_set.has_value()) {
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m_subtree_invalidation_sets.append(*invalidation_set);
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}
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auto affected_by_invalidation_sets_or_invalidation_flags = [this](Element const& element) {
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for (auto& invalidation_set : m_subtree_invalidation_sets) {
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if (element.includes_properties_from_invalidation_set(invalidation_set))
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return true;
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}
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return false;
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};
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if (auto* element = as_if<Element>(node); element && affected_by_invalidation_sets_or_invalidation_flags(*element)) {
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node.set_needs_style_update(true);
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}
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}
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for (auto* child = node.first_child(); child; child = child->next_sibling()) {
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perform_pending_style_invalidations(*child, invalidate_entire_subtree);
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}
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if (node.is_element()) {
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auto& element = static_cast<Element&>(node);
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if (auto shadow_root = element.shadow_root()) {
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perform_pending_style_invalidations(*shadow_root, invalidate_entire_subtree);
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if (invalidate_entire_subtree)
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node.set_child_needs_style_update(true);
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}
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}
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node.set_entire_subtree_needs_style_update(false);
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}
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}
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