Source/core/css/analyzer/DescendantInvalidationSet.h

/*
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#ifndef DescendantInvalidationSet_h
#define DescendantInvalidationSet_h

#include "wtf/Forward.h"
#include "wtf/HashSet.h"
#include "wtf/RefCounted.h"
#include "wtf/RefPtr.h"
#include "wtf/text/AtomicStringHash.h"
#include "wtf/text/StringHash.h"

namespace WebCore {

class Element;

// Tracks data to determine which elements of a DOM subtree need to have style
// recalculated.
class DescendantInvalidationSet FINAL : public RefCounted<DescendantInvalidationSet> {
public:
    static PassRefPtr<DescendantInvalidationSet> create()
    {
        return adoptRef(new DescendantInvalidationSet);
    }

    void combine(const DescendantInvalidationSet& other);

    void addClass(const AtomicString& className);
    void addId(const AtomicString& id);
    void addTagName(const AtomicString& tagName);

    // Appends the classes in this DescendantInvalidationSet to the vector.
    void getClasses(Vector<AtomicString>& classes) const;

    void setWholeSubtreeInvalid();
    bool wholeSubtreeInvalid() const { return m_allDescendantsMightBeInvalid; }
private:
    DescendantInvalidationSet();

    HashSet<AtomicString>& ensureClassSet();
    HashSet<AtomicString>& ensureIdSet();
    HashSet<AtomicString>& ensureTagNameSet();

    // If true, all descendants might be invalidated, so a full subtree recalc is required.
    bool m_allDescendantsMightBeInvalid;

    // FIXME: optimize this if it becomes a memory issue.
    OwnPtr<HashSet<AtomicString> > m_classes;
    OwnPtr<HashSet<AtomicString> > m_ids;
    OwnPtr<HashSet<AtomicString> > m_tagNames;
};

} // namespace WebCore

#endif // DescendantInvalidationSet_h