third_party/WebKit/Source/core/css/CSSSelectorList.cpp

/*
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 * Copyright (C) 2009 Google Inc. All rights reserved.
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#include "core/css/CSSSelectorList.h"

#include "core/css/parser/CSSParserSelector.h"
#include "wtf/Partitions.h"
#include "wtf/text/StringBuilder.h"

namespace {
    // CSSSelector is one of the top types that consume renderer memory,
    // so instead of using the |WTF_HEAP_PROFILER_TYPE_NAME| macro in the
    // allocations below, pass this type name constant to allow profiling
    // in official builds.
    const char kCSSSelectorTypeName[] = "blink::CSSSelector";
}

namespace blink {

CSSSelectorList CSSSelectorList::copy() const
{
    CSSSelectorList list;

    unsigned length = this->length();
    list.m_selectorArray = reinterpret_cast<CSSSelector*>(WTF::Partitions::fastMalloc(sizeof(CSSSelector) * length, kCSSSelectorTypeName));
    for (unsigned i = 0; i < length; ++i)
        new (&list.m_selectorArray[i]) CSSSelector(m_selectorArray[i]);

    return list;
}

CSSSelectorList CSSSelectorList::adoptSelectorVector(Vector<OwnPtr<CSSParserSelector>>& selectorVector)
{
    size_t flattenedSize = 0;
    for (size_t i = 0; i < selectorVector.size(); ++i) {
        for (CSSParserSelector* selector = selectorVector[i].get(); selector; selector = selector->tagHistory())
            ++flattenedSize;
    }
    ASSERT(flattenedSize);

    CSSSelectorList list;
    list.m_selectorArray = reinterpret_cast<CSSSelector*>(WTF::Partitions::fastMalloc(sizeof(CSSSelector) * flattenedSize, kCSSSelectorTypeName));
    size_t arrayIndex = 0;
    for (size_t i = 0; i < selectorVector.size(); ++i) {
        CSSParserSelector* current = selectorVector[i].get();
        while (current) {
            // Move item from the parser selector vector into m_selectorArray without invoking destructor (Ugh.)
            CSSSelector* currentSelector = current->releaseSelector().leakPtr();
            memcpy(&list.m_selectorArray[arrayIndex], currentSelector, sizeof(CSSSelector));
            WTF::Partitions::fastFree(currentSelector);

            current = current->tagHistory();
            ASSERT(!list.m_selectorArray[arrayIndex].isLastInSelectorList());
            if (current)
                list.m_selectorArray[arrayIndex].setNotLastInTagHistory();
            ++arrayIndex;
        }
        ASSERT(list.m_selectorArray[arrayIndex - 1].isLastInTagHistory());
    }
    ASSERT(flattenedSize == arrayIndex);
    list.m_selectorArray[arrayIndex - 1].setLastInSelectorList();
    selectorVector.clear();

    return list;
}

unsigned CSSSelectorList::length() const
{
    if (!m_selectorArray)
        return 0;
    CSSSelector* current = m_selectorArray;
    while (!current->isLastInSelectorList())
        ++current;
    return (current - m_selectorArray) + 1;
}

void CSSSelectorList::deleteSelectors()
{
    ASSERT(m_selectorArray);

    bool finished = false;
    for (CSSSelector* s = m_selectorArray; !finished; ++s) {
        finished = s->isLastInSelectorList();
        s->~CSSSelector();
    }

    WTF::Partitions::fastFree(m_selectorArray);
}

String CSSSelectorList::selectorsText() const
{
    StringBuilder result;

    for (const CSSSelector* s = first(); s; s = next(*s)) {
        if (s != first())
            result.appendLiteral(", ");
        result.append(s->selectorText());
    }

    return result.toString();
}

template <typename Functor>
static bool forEachTagSelector(const Functor& functor, const CSSSelector& selector)
{
    for (const CSSSelector* current = &selector; current; current = current->tagHistory()) {
        if (functor(*current))
            return true;
        if (const CSSSelectorList* selectorList = current->selectorList()) {
            for (const CSSSelector* subSelector = selectorList->first(); subSelector; subSelector = CSSSelectorList::next(*subSelector)) {
                if (forEachTagSelector(functor, *subSelector))
                    return true;
            }
        }
    }

    return false;
}

template <typename Functor>
static bool forEachSelector(const Functor& functor, const CSSSelectorList* selectorList)
{
    for (const CSSSelector* selector = selectorList->first(); selector; selector = CSSSelectorList::next(*selector)) {
        if (forEachTagSelector(functor, *selector))
            return true;
    }

    return false;
}

bool CSSSelectorList::selectorsNeedNamespaceResolution()
{
    return forEachSelector([](const CSSSelector& selector) -> bool {
        if (selector.match() != CSSSelector::Tag && !selector.isAttributeSelector())
            return false;
        const AtomicString& prefix = selector.isAttributeSelector() ? selector.attribute().prefix() : selector.tagQName().prefix();
        return prefix != nullAtom && prefix != emptyAtom && prefix != starAtom;
    }, this);
}

bool CSSSelectorList::selectorHasContentPseudo(size_t index) const
{
    return forEachTagSelector([](const CSSSelector& selector) -> bool {
        return selector.relationIsAffectedByPseudoContent();
    }, selectorAt(index));
}

bool CSSSelectorList::selectorHasSlottedPseudo(size_t index) const
{
    return forEachTagSelector([](const CSSSelector& selector) ->  bool {
        return selector.pseudoType() == CSSSelector::PseudoSlotted;
    }, selectorAt(index));
}

bool CSSSelectorList::selectorUsesDeepCombinatorOrShadowPseudo(size_t index) const
{
    return forEachTagSelector([](const CSSSelector& selector) -> bool {
        return selector.relation() == CSSSelector::ShadowDeep || selector.pseudoType() == CSSSelector::PseudoShadow;
    }, selectorAt(index));
}

bool CSSSelectorList::selectorNeedsUpdatedDistribution(size_t index) const
{
    return forEachTagSelector([](const CSSSelector& selector) -> bool {
        return selector.relationIsAffectedByPseudoContent() || selector.pseudoType() == CSSSelector::PseudoSlotted || selector.pseudoType() == CSSSelector::PseudoHostContext;
    }, selectorAt(index));
}

} // namespace blink