third_party/WebKit/Source/core/dom/QualifiedName.h

/*
 * Copyright (C) 2005, 2006, 2009 Apple Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 */

#ifndef QualifiedName_h
#define QualifiedName_h

#include "core/CoreExport.h"
#include "wtf/Allocator.h"
#include "wtf/HashTableDeletedValueType.h"
#include "wtf/HashTraits.h"
#include "wtf/RefCounted.h"
#include "wtf/text/AtomicString.h"

namespace blink {

struct QualifiedNameComponents {
  DISALLOW_NEW();
  StringImpl* m_prefix;
  StringImpl* m_localName;
  StringImpl* m_namespace;
};

// This struct is used to pass data between QualifiedName and the
// QNameTranslator.  For hashing and equality only the QualifiedNameComponents
// fields are used.
struct QualifiedNameData {
  DISALLOW_NEW();
  QualifiedNameComponents m_components;
  bool m_isStatic;
};

class CORE_EXPORT QualifiedName {
  USING_FAST_MALLOC(QualifiedName);

 public:
  class QualifiedNameImpl : public RefCounted<QualifiedNameImpl> {
   public:
    static PassRefPtr<QualifiedNameImpl> create(
        const AtomicString& prefix,
        const AtomicString& localName,
        const AtomicString& namespaceURI,
        bool isStatic) {
      return adoptRef(
          new QualifiedNameImpl(prefix, localName, namespaceURI, isStatic));
    }

    ~QualifiedNameImpl();

    unsigned computeHash() const;

    void ref() {
      if (m_isStatic)
        return;
      RefCounted<QualifiedNameImpl>::ref();
    }

    void deref() {
      if (m_isStatic)
        return;
      RefCounted<QualifiedNameImpl>::deref();
    }

    // We rely on StringHasher's hashMemory clearing out the top 8 bits when
    // doing hashing and use one of the bits for the m_isStatic value.
    mutable unsigned m_existingHash : 24;
    unsigned m_isStatic : 1;
    const AtomicString m_prefix;
    const AtomicString m_localName;
    const AtomicString m_namespace;
    mutable AtomicString m_localNameUpper;

   private:
    QualifiedNameImpl(const AtomicString& prefix,
                      const AtomicString& localName,
                      const AtomicString& namespaceURI,
                      bool isStatic)
        : m_existingHash(0),
          m_isStatic(isStatic),
          m_prefix(prefix),
          m_localName(localName),
          m_namespace(namespaceURI)

    {
      DCHECK(!namespaceURI.isEmpty() || namespaceURI.isNull());
    }
  };

  QualifiedName(const AtomicString& prefix,
                const AtomicString& localName,
                const AtomicString& namespaceURI);
  ~QualifiedName();

  QualifiedName(const QualifiedName& other) : m_impl(other.m_impl) {}
  const QualifiedName& operator=(const QualifiedName& other) {
    m_impl = other.m_impl;
    return *this;
  }

  // Hash table deleted values, which are only constructed and never copied or
  // destroyed.
  QualifiedName(WTF::HashTableDeletedValueType)
      : m_impl(WTF::HashTableDeletedValue) {}
  bool isHashTableDeletedValue() const {
    return m_impl.isHashTableDeletedValue();
  }

  bool operator==(const QualifiedName& other) const {
    return m_impl == other.m_impl;
  }
  bool operator!=(const QualifiedName& other) const {
    return !(*this == other);
  }

  bool matches(const QualifiedName& other) const {
    return m_impl == other.m_impl || (localName() == other.localName() &&
                                      namespaceURI() == other.namespaceURI());
  }

  bool matchesPossiblyIgnoringCase(const QualifiedName& other,
                                   bool shouldIgnoreCase) const {
    return m_impl == other.m_impl ||
           (equalPossiblyIgnoringCase(localName(), other.localName(),
                                      shouldIgnoreCase) &&
            namespaceURI() == other.namespaceURI());
  }

  bool hasPrefix() const { return m_impl->m_prefix != nullAtom; }
  void setPrefix(const AtomicString& prefix) {
    *this = QualifiedName(prefix, localName(), namespaceURI());
  }

  const AtomicString& prefix() const { return m_impl->m_prefix; }
  const AtomicString& localName() const { return m_impl->m_localName; }
  const AtomicString& namespaceURI() const { return m_impl->m_namespace; }

  // Uppercased localName, cached for efficiency
  const AtomicString& localNameUpper() const;

  String toString() const;

  QualifiedNameImpl* impl() const { return m_impl.get(); }

  // Init routine for globals
  static void initAndReserveCapacityForSize(unsigned size);

  static const QualifiedName& null();

  // The below methods are only for creating static global QNames that need no
  // ref counting.
  static void createStatic(void* targetAddress, StringImpl* name);
  static void createStatic(void* targetAddress,
                           StringImpl* name,
                           const AtomicString& nameNamespace);

 private:
  // This constructor is used only to create global/static QNames that don't
  // require any ref counting.
  QualifiedName(const AtomicString& prefix,
                const AtomicString& localName,
                const AtomicString& namespaceURI,
                bool isStatic);

  RefPtr<QualifiedNameImpl> m_impl;
};

extern const QualifiedName& anyName;
inline const QualifiedName& anyQName() {
  return anyName;
}

inline bool operator==(const AtomicString& a, const QualifiedName& q) {
  return a == q.localName();
}
inline bool operator!=(const AtomicString& a, const QualifiedName& q) {
  return a != q.localName();
}
inline bool operator==(const QualifiedName& q, const AtomicString& a) {
  return a == q.localName();
}
inline bool operator!=(const QualifiedName& q, const AtomicString& a) {
  return a != q.localName();
}

inline unsigned hashComponents(const QualifiedNameComponents& buf) {
  return StringHasher::hashMemory<sizeof(QualifiedNameComponents)>(&buf);
}

struct CORE_EXPORT QualifiedNameHash {
  STATIC_ONLY(QualifiedNameHash);
  static unsigned hash(const QualifiedName& name) { return hash(name.impl()); }

  static unsigned hash(const QualifiedName::QualifiedNameImpl* name) {
    if (!name->m_existingHash)
      name->m_existingHash = name->computeHash();
    return name->m_existingHash;
  }

  static bool equal(const QualifiedName& a, const QualifiedName& b) {
    return a == b;
  }
  static bool equal(const QualifiedName::QualifiedNameImpl* a,
                    const QualifiedName::QualifiedNameImpl* b) {
    return a == b;
  }

  static const bool safeToCompareToEmptyOrDeleted = false;
};

}  // namespace blink

namespace WTF {

template <>
struct DefaultHash<blink::QualifiedName> {
  typedef blink::QualifiedNameHash Hash;
};

template <>
struct HashTraits<blink::QualifiedName>
    : SimpleClassHashTraits<blink::QualifiedName> {
  static const bool emptyValueIsZero = false;
  static blink::QualifiedName emptyValue() {
    return blink::QualifiedName::null();
  }
};
}  // namespace WTF

#endif