// Copyright 2014 The Chromium Authors. All rights reserved.
// Copyright (C) 2016-2020 Apple Inc. All rights reserved.
//
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#pragma once

#include "CSSParserContext.h"
#include "CSSParserEnum.h"
#include "CSSParserSelector.h"
#include "CSSParserTokenRange.h"
#include "CSSSelectorList.h"
#include "StyleSheetContents.h"
#include <wtf/HashFunctions.h>
#include <wtf/Hasher.h>

namespace WebCore {

class CSSParserTokenRange;
class CSSSelectorList;
class StyleSheetContents;
class StyleRule;

struct CSSSelectorParserContext {
    CSSParserMode mode { CSSParserMode::HTMLStandardMode };
    bool cssNestingEnabled { false };
    bool focusVisibleEnabled { false };
    bool hasPseudoClassEnabled { false };

    bool isHashTableDeletedValue { false };

    CSSSelectorParserContext() = default;
    CSSSelectorParserContext(const CSSParserContext&);
    explicit CSSSelectorParserContext(const Document&);

    bool operator==(const CSSSelectorParserContext&) const = default;
};

class CSSSelectorParser {
public:
    CSSSelectorParser(const CSSSelectorParserContext&, StyleSheetContents*, CSSParserEnum::IsNestedContext = CSSParserEnum::IsNestedContext::No);

    CSSSelectorList consumeComplexSelectorList(CSSParserTokenRange&);
    CSSSelectorList consumeNestedSelectorList(CSSParserTokenRange&);

    static bool supportsComplexSelector(CSSParserTokenRange, const CSSSelectorParserContext&, CSSParserEnum::IsNestedContext);
    static CSSSelectorList resolveNestingParent(const CSSSelectorList& nestedSelectorList, const CSSSelectorList* parentResolvedSelectorList);

private:
    template<typename ConsumeSelector> CSSSelectorList consumeSelectorList(CSSParserTokenRange&, ConsumeSelector&&);
    template<typename ConsumeSelector> CSSSelectorList consumeForgivingSelectorList(CSSParserTokenRange&, ConsumeSelector&&);

    CSSSelectorList consumeForgivingComplexSelectorList(CSSParserTokenRange&);
    CSSSelectorList consumeCompoundSelectorList(CSSParserTokenRange&);
    CSSSelectorList consumeRelativeSelectorList(CSSParserTokenRange&);

    std::unique_ptr<CSSParserSelector> consumeComplexSelector(CSSParserTokenRange&);
    std::unique_ptr<CSSParserSelector> consumeNestedComplexSelector(CSSParserTokenRange&);
    std::unique_ptr<CSSParserSelector> consumeCompoundSelector(CSSParserTokenRange&);
    std::unique_ptr<CSSParserSelector> consumeRelativeScopeSelector(CSSParserTokenRange&);
    std::unique_ptr<CSSParserSelector> consumeRelativeNestedSelector(CSSParserTokenRange&);

    // This doesn't include element names, since they're handled specially.
    std::unique_ptr<CSSParserSelector> consumeSimpleSelector(CSSParserTokenRange&);

    bool consumeName(CSSParserTokenRange&, AtomString& name, AtomString& namespacePrefix);

    // These will return nullptr when the selector is invalid.
    std::unique_ptr<CSSParserSelector> consumeId(CSSParserTokenRange&);
    std::unique_ptr<CSSParserSelector> consumeClass(CSSParserTokenRange&);
    std::unique_ptr<CSSParserSelector> consumePseudo(CSSParserTokenRange&);
    std::unique_ptr<CSSParserSelector> consumeAttribute(CSSParserTokenRange&);
    std::unique_ptr<CSSParserSelector> consumeNesting(CSSParserTokenRange&);

    CSSSelector::RelationType consumeCombinator(CSSParserTokenRange&);
    CSSSelector::Match consumeAttributeMatch(CSSParserTokenRange&);
    CSSSelector::AttributeMatchType consumeAttributeFlags(CSSParserTokenRange&);

    const AtomString& defaultNamespace() const;
    const AtomString& determineNamespace(const AtomString& prefix);
    void prependTypeSelectorIfNeeded(const AtomString& namespacePrefix, const AtomString& elementName, CSSParserSelector&);
    static std::unique_ptr<CSSParserSelector> splitCompoundAtImplicitShadowCrossingCombinator(std::unique_ptr<CSSParserSelector> compoundSelector, const CSSSelectorParserContext&);
    static bool containsUnknownWebKitPseudoElements(const CSSSelector& complexSelector);

    class DisallowPseudoElementsScope;

    const CSSSelectorParserContext m_context;
    const RefPtr<StyleSheetContents> m_styleSheet;
    CSSParserEnum::IsNestedContext m_isNestedContext { CSSParserEnum::IsNestedContext::No };

    // FIXME: This m_failedParsing is ugly and confusing, we should look into removing it (the return value of each function already convey this information).
    bool m_failedParsing { false };

    bool m_disallowPseudoElements { false };
    bool m_disallowHasPseudoClass { false };
    bool m_resistDefaultNamespace { false };
    bool m_ignoreDefaultNamespace { false };
    bool m_disableForgivingParsing { false };
    std::optional<CSSSelector::PseudoElementType> m_precedingPseudoElement;
};

std::optional<CSSSelectorList> parseCSSSelector(CSSParserTokenRange, const CSSSelectorParserContext&, StyleSheetContents* = nullptr, CSSParserEnum::IsNestedContext = CSSParserEnum::IsNestedContext::No);

void add(Hasher&, const CSSSelectorParserContext&);

struct CSSSelectorParserContextHash {
    static unsigned hash(const CSSSelectorParserContext& context) { return computeHash(context); }
    static bool equal(const CSSSelectorParserContext& a, const CSSSelectorParserContext& b) { return a == b; }
    static const bool safeToCompareToEmptyOrDeleted = false;
};

} // namespace WebCore

namespace WTF {

template<> struct HashTraits<WebCore::CSSSelectorParserContext> : GenericHashTraits<WebCore::CSSSelectorParserContext> {
    static void constructDeletedValue(WebCore::CSSSelectorParserContext& slot) { slot.isHashTableDeletedValue = true; }
    static bool isDeletedValue(const WebCore::CSSSelectorParserContext& value) { return value.isHashTableDeletedValue; }
    static WebCore::CSSSelectorParserContext emptyValue() { return { }; }
};

template<> struct DefaultHash<WebCore::CSSSelectorParserContext> : WebCore::CSSSelectorParserContextHash { };

} // namespace WTF
