646b37d1a9
This patch introduces the StyleComputer::RuleCache, which divides all of our (author) CSS rules into buckets. Currently, there are two buckets: - Rules where a specific class must be present. - All other rules. This allows us to check a significantly smaller set of rules for each element, since we can skip over any rule that requires a class attribute not present on the element. This takes the typical numer of rules tested per element on Discord from ~16000 to ~550. :^) We can definitely improve the cache invalidation. It currently happens too often due to media queries. And we also need to make sure we invalidate when mutating style through CSSOM APIs.
106 lines
3.5 KiB
C++
106 lines
3.5 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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* Copyright (c) 2021, Sam Atkins <atkinssj@serenityos.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/HashMap.h>
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#include <AK/NonnullRefPtrVector.h>
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#include <AK/OwnPtr.h>
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#include <LibWeb/CSS/CSSStyleDeclaration.h>
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#include <LibWeb/CSS/Parser/StyleComponentValueRule.h>
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#include <LibWeb/CSS/StyleProperties.h>
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#include <LibWeb/Forward.h>
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namespace Web::CSS {
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struct MatchingRule {
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RefPtr<CSSStyleRule> rule;
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size_t style_sheet_index { 0 };
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size_t rule_index { 0 };
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size_t selector_index { 0 };
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u32 specificity { 0 };
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};
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class PropertyDependencyNode : public RefCounted<PropertyDependencyNode> {
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public:
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static NonnullRefPtr<PropertyDependencyNode> create(String name)
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{
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return adopt_ref(*new PropertyDependencyNode(move(name)));
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}
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void add_child(NonnullRefPtr<PropertyDependencyNode>);
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bool has_cycles();
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private:
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explicit PropertyDependencyNode(String name);
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String m_name;
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NonnullRefPtrVector<PropertyDependencyNode> m_children;
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bool m_marked { false };
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};
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class StyleComputer {
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public:
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explicit StyleComputer(DOM::Document&);
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~StyleComputer();
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DOM::Document& document() { return m_document; }
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DOM::Document const& document() const { return m_document; }
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NonnullRefPtr<StyleProperties> create_document_style() const;
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NonnullRefPtr<StyleProperties> compute_style(DOM::Element&) const;
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// https://www.w3.org/TR/css-cascade/#origin
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enum class CascadeOrigin {
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Any, // FIXME: This is not part of the spec. Get rid of it.
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Author,
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User,
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UserAgent,
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Animation,
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Transition,
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};
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Vector<MatchingRule> collect_matching_rules(DOM::Element const&, CascadeOrigin = CascadeOrigin::Any) const;
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void invalidate_rule_cache();
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private:
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void compute_cascaded_values(StyleProperties&, DOM::Element&) const;
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void compute_font(StyleProperties&, DOM::Element const*) const;
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void compute_defaulted_values(StyleProperties&, DOM::Element const*) const;
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void absolutize_values(StyleProperties&, DOM::Element const*) const;
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void transform_box_type_if_needed(StyleProperties&, DOM::Element const&) const;
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void compute_defaulted_property_value(StyleProperties&, DOM::Element const*, CSS::PropertyID) const;
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RefPtr<StyleValue> resolve_unresolved_style_value(DOM::Element&, PropertyID, UnresolvedStyleValue const&, HashMap<String, StyleProperty const*> const&) const;
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bool expand_unresolved_values(DOM::Element&, StringView property_name, HashMap<String, NonnullRefPtr<PropertyDependencyNode>>& dependencies, Vector<StyleComponentValueRule> const& source, Vector<StyleComponentValueRule>& dest, size_t source_start_index, HashMap<String, StyleProperty const*> const& custom_properties) const;
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template<typename Callback>
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void for_each_stylesheet(CascadeOrigin, Callback) const;
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struct MatchingRuleSet {
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Vector<MatchingRule> user_agent_rules;
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Vector<MatchingRule> author_rules;
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};
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void cascade_declarations(StyleProperties&, DOM::Element&, Vector<MatchingRule> const&, CascadeOrigin, bool important, HashMap<String, StyleProperty const*> const&) const;
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void build_rule_cache();
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void build_rule_cache_if_needed() const;
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DOM::Document& m_document;
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struct RuleCache {
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HashMap<FlyString, Vector<MatchingRule>> rules_by_class;
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Vector<MatchingRule> other_rules;
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int generation { 0 };
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};
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OwnPtr<RuleCache> m_rule_cache;
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};
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}
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