WebCore/QualifiedName.h

   1 /*
   2  * This file is part of the DOM implementation for KDE.
   3  *
   4  * Copyright (C) 2005 Apple Computer, Inc.
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Library General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Library General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Library General Public License
  17  * along with this library; see the file COPYING.LIB.  If not, write to
  18  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  19  * Boston, MA 02110-1301, USA.
  20  *
  21  */
  22 #ifndef QualifiedName_h
  23 #define QualifiedName_h
  24
  25 #include "AtomicString.h"
  26 #include <wtf/HashFunctions.h>
  27
  28 namespace WebCore {
  29
  30 struct QualifiedNameComponents {
  31     StringImpl* m_prefix;
  32     StringImpl* m_localName;
  33     StringImpl* m_namespace;
  34 };
  35
  36 class QualifiedName {
  37 public:
  38     class QualifiedNameImpl : public RefCounted<QualifiedNameImpl> {
  39     public:
  40         static PassRefPtr<QualifiedNameImpl> create(const AtomicString& p, const AtomicString& l, const AtomicString& n)
  41         {
  42             return adoptRef(new QualifiedNameImpl(p, l, n));
  43         }
  44
  45         AtomicString m_prefix;
  46         AtomicString m_localName;
  47         AtomicString m_namespace;
  48
  49     private:
  50         QualifiedNameImpl(const AtomicString& p, const AtomicString& l, const AtomicString& n)
  51             : m_prefix(p)
  52             , m_localName(l)
  53             , m_namespace(n)
  54         {
  55         }
  56     };
  57
  58     QualifiedName(const AtomicString& prefix, const AtomicString& localName, const AtomicString& namespaceURI);
  59     ~QualifiedName();
  60 #ifdef QNAME_DEFAULT_CONSTRUCTOR
  61     QualifiedName() : m_impl(0) { }
  62 #endif
  63
  64     QualifiedName(const QualifiedName&);
  65     const QualifiedName& operator=(const QualifiedName&);
  66
  67     bool operator==(const QualifiedName& other) const { return m_impl == other.m_impl; }
  68     bool operator!=(const QualifiedName& other) const { return !(*this == other); }
  69
  70     bool matches(const QualifiedName& other) const { return m_impl == other.m_impl || (localName() == other.localName() && namespaceURI() == other.namespaceURI()); }
  71
  72     bool hasPrefix() const { return m_impl->m_prefix != nullAtom; }
  73     void setPrefix(const AtomicString& prefix);
  74
  75     const AtomicString& prefix() const { return m_impl->m_prefix; }
  76     const AtomicString& localName() const { return m_impl->m_localName; }
  77     const AtomicString& namespaceURI() const { return m_impl->m_namespace; }
  78
  79     String toString() const;
  80
  81     QualifiedNameImpl* impl() const { return m_impl; }
  82
  83     // Init routine for globals
  84     static void init();
  85
  86 private:
  87     void ref() { m_impl->ref(); }
  88     void deref();
  89
  90     QualifiedNameImpl* m_impl;
  91 };
  92
  93 #ifndef WEBCORE_QUALIFIEDNAME_HIDE_GLOBALS
  94 extern const QualifiedName anyName;
  95 inline const QualifiedName& anyQName() { return anyName; }
  96 #endif
  97
  98 inline bool operator==(const AtomicString& a, const QualifiedName& q) { return a == q.localName(); }
  99 inline bool operator!=(const AtomicString& a, const QualifiedName& q) { return a != q.localName(); }
 100 inline bool operator==(const QualifiedName& q, const AtomicString& a) { return a == q.localName(); }
 101 inline bool operator!=(const QualifiedName& q, const AtomicString& a) { return a != q.localName(); }
 102
 103
 104 inline unsigned hashComponents(const QualifiedNameComponents& buf)
 105 {
 106     ASSERT(sizeof(QualifiedNameComponents) % (sizeof(uint16_t) * 2) == 0);
 107
 108     unsigned l = sizeof(QualifiedNameComponents) / (sizeof(uint16_t) * 2);
 109     const uint16_t* s = reinterpret_cast<const uint16_t*>(&buf);
 110     uint32_t hash = WTF::stringHashingStartValue;
 111
 112     // Main loop
 113     for (; l > 0; l--) {
 114         hash += s[0];
 115         uint32_t tmp = (s[1] << 11) ^ hash;
 116         hash = (hash << 16) ^ tmp;
 117         s += 2;
 118         hash += hash >> 11;
 119     }
 120
 121     // Force "avalanching" of final 127 bits
 122     hash ^= hash << 3;
 123     hash += hash >> 5;
 124     hash ^= hash << 2;
 125     hash += hash >> 15;
 126     hash ^= hash << 10;
 127
 128     // this avoids ever returning a hash code of 0, since that is used to
 129     // signal "hash not computed yet", using a value that is likely to be
 130     // effectively the same as 0 when the low bits are masked
 131     if (hash == 0)
 132         hash = 0x80000000;
 133
 134     return hash;
 135 }
 136
 137 struct QualifiedNameHash {
 138     static unsigned hash(const QualifiedName& name) { return hash(name.impl()); }
 139
 140     static unsigned hash(const QualifiedName::QualifiedNameImpl* name)
 141     {
 142         QualifiedNameComponents c = { name->m_prefix.impl(), name->m_localName.impl(), name->m_namespace.impl() };
 143         return hashComponents(c);
 144     }
 145
 146     static bool equal(const QualifiedName& a, const QualifiedName& b) { return a == b; }
 147     static bool equal(const QualifiedName::QualifiedNameImpl* a, const QualifiedName::QualifiedNameImpl* b) { return a == b; }
 148
 149     static const bool safeToCompareToEmptyOrDeleted = false;
 150 };
 151
 152 }
 153
 154 namespace WTF {
 155
 156     template<typename T> struct DefaultHash;
 157     template<> struct DefaultHash<WebCore::QualifiedName> {
 158         typedef WebCore::QualifiedNameHash Hash;
 159     };
 160
 161     template<> struct HashTraits<WebCore::QualifiedName> : GenericHashTraits<WebCore::QualifiedName> {
 162         static const bool emptyValueIsZero = false;
 163         static WebCore::QualifiedName emptyValue() { return WebCore::QualifiedName(WebCore::nullAtom, WebCore::nullAtom, WebCore::nullAtom); }
 164         static void constructDeletedValue(WebCore::QualifiedName& slot) { new (&slot) WebCore::QualifiedName(WebCore::nullAtom, WebCore::AtomicString(HashTableDeletedValue), WebCore::nullAtom); }
 165         static bool isDeletedValue(const WebCore::QualifiedName& slot) { return slot.localName().isHashTableDeletedValue(); }
 166     };
 167 }
 168
 169 #endif