Source/WebCore/style/IdChangeInvalidation.cpp

/*
 * Copyright (C) 2016 Apple Inc. All rights reserved.
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 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
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 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
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 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
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#include "config.h"
#include "IdChangeInvalidation.h"

#include "ElementChildIterator.h"
#include "StyleInvalidationFunctions.h"
#include "StyleInvalidator.h"

namespace WebCore {
namespace Style {

void IdChangeInvalidation::invalidateStyle(const AtomString& changedId)
{
    if (changedId.isEmpty())
        return;

    bool mayAffectStyle = false;
    bool mayAffectStyleInShadowTree = false;

    traverseRuleFeatures(m_element, [&] (const RuleFeatureSet& features, bool mayAffectShadowTree) {
        if (!features.idsInRules.contains(changedId))
            return;
        mayAffectStyle = true;
        if (mayAffectShadowTree)
            mayAffectStyleInShadowTree = true;
    });

    if (!mayAffectStyle)
        return;

    if (mayAffectStyleInShadowTree) {
        m_element.invalidateStyleForSubtree();
        return;
    }

    m_element.invalidateStyle();

    // This could be easily optimized for fine-grained descendant invalidation similar to ClassChangeInvalidation.
    // However using ids for dynamic styling is rare and this is probably not worth the memory cost of the required data structures.
    auto& ruleSets = m_element.styleResolver().ruleSets();
    bool mayAffectDescendantStyle = ruleSets.features().idsMatchingAncestorsInRules.contains(changedId);
    if (mayAffectDescendantStyle)
        m_element.invalidateStyleForSubtree();
    else
        m_element.invalidateStyle();

    // Invalidation rulesets exist for :has().
    if (auto* invalidationRuleSets = ruleSets.idInvalidationRuleSets(changedId)) {
        Invalidator::MatchElementRuleSets matchElementRuleSets;
        for (auto& invalidationRuleSet : *invalidationRuleSets)
            Invalidator::addToMatchElementRuleSets(matchElementRuleSets, invalidationRuleSet);
        Invalidator::invalidateWithMatchElementRuleSets(m_element, matchElementRuleSets);
    }
}

}
}