LibWeb: Avoid full tree traversal for non-subject :has() invalidation

Instead of checking all elements in a document for containment in
`:has()` invalidation set, we could narrow this down to ancestors and
ancestor siblings, like we already do for subject `:has()` invalidation.

This change brings great improvement on GitHub that has selectors with
non-subject `:has()` and sibling combinators (e.g., `.a:has(.b) ~ .c`)
which prior to this change meant style invalidation for whole document.
This commit is contained in:
Aliaksandr Kalenik 2025-02-12 16:33:24 +01:00 committed by Andreas Kling
commit 327dc8e82a
Notes: github-actions[bot] 2025-02-13 15:25:48 +00:00
6 changed files with 42 additions and 54 deletions

View file

@ -1679,30 +1679,25 @@ void Document::invalidate_style_of_elements_affected_by_has()
for (auto const& node : m_pending_nodes_for_style_invalidation_due_to_presence_of_has) {
if (node.is_null())
continue;
node->invalidate_ancestors_affected_by_has_in_subject_position();
}
for (auto* ancestor = node.ptr(); ancestor; ancestor = ancestor->parent_or_shadow_host()) {
if (!ancestor->is_element())
continue;
auto& element = static_cast<Element&>(*ancestor);
element.invalidate_style_if_affected_by_has();
// Take care of elements that affected by :has() in non-subject position, i.e., ".a:has(.b) > .c".
// Elements affected by :has() in subject position, i.e., ".a:has(.b)", are handled by
// Node::invalidate_style() and should already be marked for style update by now.
Vector<CSS::InvalidationSet::Property, 1> changed_properties;
changed_properties.append({ .type = CSS::InvalidationSet::Property::Type::PseudoClass, .value = CSS::PseudoClass::Has });
auto invalidation_set = style_computer().invalidation_set_for_properties(changed_properties);
for_each_shadow_including_inclusive_descendant([&](Node& node) {
if (!node.is_element())
return TraversalDecision::Continue;
auto& element = static_cast<Element&>(node);
bool needs_style_recalculation = false;
if (invalidation_set.needs_invalidate_whole_subtree()) {
needs_style_recalculation = true;
} else if (element.includes_properties_from_invalidation_set(invalidation_set)) {
needs_style_recalculation = true;
auto* parent = ancestor->parent_or_shadow_host();
if (!parent)
return;
// If any ancestor's sibling was tested against selectors like ".a:has(+ .b)" or ".a:has(~ .b)"
// its style might be affected by the change in descendant node.
parent->for_each_child_of_type<Element>([&](auto& ancestor_sibling_element) {
if (ancestor_sibling_element.affected_by_has_pseudo_class_with_relative_selector_that_has_sibling_combinator())
ancestor_sibling_element.invalidate_style_if_affected_by_has();
return IterationDecision::Continue;
});
}
if (needs_style_recalculation)
element.set_needs_style_update(true);
return TraversalDecision::Continue;
});
}
}
void Document::invalidate_style_for_elements_affected_by_hover_change(Node& old_new_hovered_common_ancestor, GC::Ptr<Node> hovered_node)