LibWeb: Use invalidation sets to reduce style recalculation

Implements idea described in https://docs.google.com/document/d/1vEW86DaeVs4uQzNFI5R-_xS9TcS1Cs_EUsHRSgCHGu8 Invalidation sets are used to reduce the number of elements marked for style recalculation by collecting metadata from style rules about the dependencies between properties that could affect an element’s style. Currently, this optimization is only applied to style invalidation triggered by class list mutations on an element.
Author: https://github.com/kalenikaliaksandr Commit: c5f2a88f69 Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/3292 Reviewed-by: https://github.com/awesomekling
2025-06-17 15:51:55 +00:00 · 2025-01-12 18:38:05 +03:00 · 2025-01-12 18:38:05 +03:00 · c5f2a88f69 · 2025-01-19 18:55:55 +00:00
commit c5f2a88f69
parent 58c78cb003
11 changed files with 549 additions and 3 deletions
--- a/Libraries/LibWeb/CSS/InvalidationSet.cpp
+++ b/Libraries/LibWeb/CSS/InvalidationSet.cpp
@ -0,0 +1,90 @@
+/*
+ * Copyright (c) 2025, Aliaksandr Kalenik <kalenik.aliaksandr@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibWeb/CSS/InvalidationSet.h>
+
+namespace Web::CSS {
+
+void InvalidationSet::include_all_from(InvalidationSet const& other)
+{
+    m_needs_invalidate_self |= other.m_needs_invalidate_self;
+    m_needs_invalidate_whole_subtree |= other.m_needs_invalidate_whole_subtree;
+    for (auto const& property : other.m_properties)
+        m_properties.set(property);
+}
+
+bool InvalidationSet::is_empty() const
+{
+    return !m_needs_invalidate_self && !m_needs_invalidate_whole_subtree && m_properties.is_empty();
+}
+
+void InvalidationSet::for_each_property(Function<void(Property const&)> const& callback) const
+{
+    if (m_needs_invalidate_self)
+        callback({ Property::Type::InvalidateSelf });
+    if (m_needs_invalidate_whole_subtree)
+        callback({ Property::Type::InvalidateWholeSubtree });
+    for (auto const& property : m_properties)
+        callback(property);
+}
+
+}
+
+namespace AK {
+
+unsigned Traits<Web::CSS::InvalidationSet::Property>::hash(Web::CSS::InvalidationSet::Property const& invalidation_set_property)
+{
+    return pair_int_hash(to_underlying(invalidation_set_property.type), invalidation_set_property.name.hash());
+}
+
+ErrorOr<void> Formatter<Web::CSS::InvalidationSet::Property>::format(FormatBuilder& builder, Web::CSS::InvalidationSet::Property const& invalidation_set_property)
+{
+    switch (invalidation_set_property.type) {
+    case Web::CSS::InvalidationSet::Property::Type::InvalidateSelf: {
+        TRY(builder.put_string("$"sv));
+        return {};
+    }
+    case Web::CSS::InvalidationSet::Property::Type::Class: {
+        TRY(builder.put_string("."sv));
+        TRY(builder.put_string(invalidation_set_property.name));
+        return {};
+    }
+    case Web::CSS::InvalidationSet::Property::Type::Id: {
+        TRY(builder.put_string("#"sv));
+        TRY(builder.put_string(invalidation_set_property.name));
+        return {};
+    }
+    case Web::CSS::InvalidationSet::Property::Type::TagName: {
+        TRY(builder.put_string(invalidation_set_property.name));
+        return {};
+    }
+    case Web::CSS::InvalidationSet::Property::Type::Attribute: {
+        TRY(builder.put_string("["sv));
+        TRY(builder.put_string(invalidation_set_property.name));
+        TRY(builder.put_string("]"sv));
+        return {};
+    }
+    case Web::CSS::InvalidationSet::Property::Type::InvalidateWholeSubtree: {
+        TRY(builder.put_string("*"sv));
+        return {};
+    }
+    default:
+        VERIFY_NOT_REACHED();
+    }
+}
+
+ErrorOr<void> Formatter<Web::CSS::InvalidationSet>::format(FormatBuilder& builder, Web::CSS::InvalidationSet const& invalidation_set)
+{
+    bool first = true;
+    invalidation_set.for_each_property([&](auto const& property) {
+        if (!first)
+            builder.builder().append(", "sv);
+        builder.builder().appendff("{}", property);
+    });
+    return {};
+}
+
+}