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https://github.com/LadybirdBrowser/ladybird.git
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9e8e568b43
Replace per-element OrderedHashMap storage for custom properties with a RefCounted chain (CustomPropertyData) that enables structural sharing. Each chain node stores only the properties declared directly on its element, with a parent pointer to the inherited chain. Elements that don't override any custom properties share the parent's data directly (just a RefPtr copy). During cascade, only entries that actually differ from the parent are stored in own_values - the rest are inherited through the chain. During var() resolution, resolved values are compared against the parent's and matching entries are dropped, enabling further sharing. The chain uses a depth limit (max 32) with flattening, plus absorption of small parent nodes (threshold 8) to keep lookups fast. This reduces custom property memory from ~79 MB to ~5.7 MB on cloudflare.com.
45 lines
1.4 KiB
C++
45 lines
1.4 KiB
C++
/*
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* Copyright (c) 2026, 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/Function.h>
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#include <AK/HashMap.h>
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#include <AK/RefCounted.h>
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#include <AK/RefPtr.h>
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#include <LibWeb/CSS/StyleProperty.h>
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#include <LibWeb/Export.h>
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namespace Web::CSS {
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// Chain of custom property maps with structural sharing.
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// Each node stores only the properties declared directly on its element,
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// with a parent pointer to the inherited chain.
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class WEB_API CustomPropertyData : public RefCounted<CustomPropertyData> {
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public:
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static NonnullRefPtr<CustomPropertyData> create(
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OrderedHashMap<FlyString, StyleProperty> own_values,
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RefPtr<CustomPropertyData const> parent);
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StyleProperty const* get(FlyString const& name) const;
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OrderedHashMap<FlyString, StyleProperty> const& own_values() const { return m_own_values; }
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void for_each_property(Function<void(FlyString const&, StyleProperty const&)> callback) const;
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RefPtr<CustomPropertyData const> parent() const { return m_parent; }
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bool is_empty() const;
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private:
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CustomPropertyData(OrderedHashMap<FlyString, StyleProperty> own_values, RefPtr<CustomPropertyData const> parent, u8 ancestor_count);
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OrderedHashMap<FlyString, StyleProperty> m_own_values;
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RefPtr<CustomPropertyData const> m_parent;
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u8 m_ancestor_count { 0 };
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};
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}
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