Source/WebCore/dom/DocumentOrderedMap.h

/*
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#ifndef DocumentOrderedMap_h
#define DocumentOrderedMap_h

#include <wtf/HashCountedSet.h>
#include <wtf/HashMap.h>
#include <wtf/text/AtomicStringImpl.h>

namespace WebCore {

class Element;
class TreeScope;

class DocumentOrderedMap {
public:
    void add(AtomicStringImpl*, Element*);
    void remove(AtomicStringImpl*, Element*);
    void clear();

    bool contains(AtomicStringImpl*) const;
    bool containsMultiple(AtomicStringImpl*) const;
    // concrete instantiations of the get<>() method template
    Element* getElementById(AtomicStringImpl*, const TreeScope*) const;
    Element* getElementByMapName(AtomicStringImpl*, const TreeScope*) const;
    Element* getElementByLowercasedMapName(AtomicStringImpl*, const TreeScope*) const;

    void checkConsistency() const;

private:
    template<bool keyMatches(AtomicStringImpl*, Element*)> Element* get(AtomicStringImpl*, const TreeScope*) const;

    typedef HashMap<AtomicStringImpl*, Element*> Map;

    // We maintain the invariant that m_duplicateCounts is the count of all elements with a given key
    // excluding the one referenced in m_map, if any. This means it one less than the total count
    // when the first node with a given key is cached, otherwise the same as the total count.
    mutable Map m_map;
    mutable HashCountedSet<AtomicStringImpl*> m_duplicateCounts;
};

inline bool DocumentOrderedMap::contains(AtomicStringImpl* id) const
{
    return m_map.contains(id) || m_duplicateCounts.contains(id);
}

inline bool DocumentOrderedMap::containsMultiple(AtomicStringImpl* id) const
{
    return m_duplicateCounts.contains(id);
}

} // namespace WebCore

#endif // DocumentOrderedMap_h