1/*
2 * Copyright (C) 2005, 2006, 2009 Apple Inc. All rights reserved.
3 *
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Library General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12 * Library General Public License for more details.
13 *
14 * You should have received a copy of the GNU Library General Public License
15 * along with this library; see the file COPYING.LIB.  If not, write to
16 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
17 * Boston, MA 02110-1301, USA.
18 *
19 */
20
21#ifndef QualifiedName_h
22#define QualifiedName_h
23
24#include "AtomicString.h"
25#include <wtf/HashTraits.h>
26
27namespace WebCore {
28
29struct QualifiedNameComponents {
30    StringImpl* m_prefix;
31    StringImpl* m_localName;
32    StringImpl* m_namespace;
33};
34
35class QualifiedName : public FastAllocBase {
36public:
37    class QualifiedNameImpl : public RefCounted<QualifiedNameImpl> {
38    public:
39        static PassRefPtr<QualifiedNameImpl> create(const AtomicString& prefix, const AtomicString& localName, const AtomicString& namespaceURI)
40        {
41            return adoptRef(new QualifiedNameImpl(prefix, localName, namespaceURI));
42        }
43
44        const AtomicString m_prefix;
45        const AtomicString m_localName;
46        const AtomicString m_namespace;
47        mutable AtomicString m_localNameUpper;
48
49    private:
50        QualifiedNameImpl(const AtomicString& prefix, const AtomicString& localName, const AtomicString& namespaceURI)
51            : m_prefix(prefix)
52            , m_localName(localName)
53            , m_namespace(namespaceURI)
54        {
55            ASSERT(!namespaceURI.isEmpty() || namespaceURI.isNull());
56        }
57    };
58
59    QualifiedName(const AtomicString& prefix, const AtomicString& localName, const AtomicString& namespaceURI);
60    QualifiedName(const AtomicString& prefix, const char* localName, const AtomicString& namespaceURI);
61    ~QualifiedName() { deref(); }
62#ifdef QNAME_DEFAULT_CONSTRUCTOR
63    QualifiedName() : m_impl(0) { }
64#endif
65
66    QualifiedName(const QualifiedName& other) : m_impl(other.m_impl) { ref(); }
67    const QualifiedName& operator=(const QualifiedName& other) { other.ref(); deref(); m_impl = other.m_impl; return *this; }
68
69    bool operator==(const QualifiedName& other) const { return m_impl == other.m_impl; }
70    bool operator!=(const QualifiedName& other) const { return !(*this == other); }
71
72    bool matches(const QualifiedName& other) const { return m_impl == other.m_impl || (localName() == other.localName() && namespaceURI() == other.namespaceURI()); }
73
74    bool hasPrefix() const { return m_impl->m_prefix != nullAtom; }
75    void setPrefix(const AtomicString& prefix) { *this = QualifiedName(prefix, localName(), namespaceURI()); }
76
77    const AtomicString& prefix() const { return m_impl->m_prefix; }
78    const AtomicString& localName() const { return m_impl->m_localName; }
79    const AtomicString& namespaceURI() const { return m_impl->m_namespace; }
80
81    // Uppercased localName, cached for efficiency
82    const AtomicString& localNameUpper() const;
83
84    String toString() const;
85
86    QualifiedNameImpl* impl() const { return m_impl; }
87
88    // Init routine for globals
89    static void init();
90
91private:
92    void init(const AtomicString& prefix, const AtomicString& localName, const AtomicString& namespaceURI);
93    void ref() const { m_impl->ref(); }
94    void deref();
95
96    QualifiedNameImpl* m_impl;
97};
98
99#ifndef WEBCORE_QUALIFIEDNAME_HIDE_GLOBALS
100extern const QualifiedName anyName;
101inline const QualifiedName& anyQName() { return anyName; }
102#endif
103
104inline bool operator==(const AtomicString& a, const QualifiedName& q) { return a == q.localName(); }
105inline bool operator!=(const AtomicString& a, const QualifiedName& q) { return a != q.localName(); }
106inline bool operator==(const QualifiedName& q, const AtomicString& a) { return a == q.localName(); }
107inline bool operator!=(const QualifiedName& q, const AtomicString& a) { return a != q.localName(); }
108
109inline unsigned hashComponents(const QualifiedNameComponents& buf)
110{
111    ASSERT(sizeof(QualifiedNameComponents) % (sizeof(uint16_t) * 2) == 0);
112
113    unsigned l = sizeof(QualifiedNameComponents) / (sizeof(uint16_t) * 2);
114    const uint16_t* s = reinterpret_cast<const uint16_t*>(&buf);
115    uint32_t hash = WTF::stringHashingStartValue;
116
117    // Main loop
118    for (; l > 0; l--) {
119        hash += s[0];
120        uint32_t tmp = (s[1] << 11) ^ hash;
121        hash = (hash << 16) ^ tmp;
122        s += 2;
123        hash += hash >> 11;
124    }
125
126    // Force "avalanching" of final 127 bits
127    hash ^= hash << 3;
128    hash += hash >> 5;
129    hash ^= hash << 2;
130    hash += hash >> 15;
131    hash ^= hash << 10;
132
133    // this avoids ever returning a hash code of 0, since that is used to
134    // signal "hash not computed yet", using a value that is likely to be
135    // effectively the same as 0 when the low bits are masked
136    if (hash == 0)
137        hash = 0x80000000;
138
139    return hash;
140}
141
142struct QualifiedNameHash {
143    static unsigned hash(const QualifiedName& name) { return hash(name.impl()); }
144
145    static unsigned hash(const QualifiedName::QualifiedNameImpl* name)
146    {
147        QualifiedNameComponents c = { name->m_prefix.impl(), name->m_localName.impl(), name->m_namespace.impl() };
148        return hashComponents(c);
149    }
150
151    static bool equal(const QualifiedName& a, const QualifiedName& b) { return a == b; }
152    static bool equal(const QualifiedName::QualifiedNameImpl* a, const QualifiedName::QualifiedNameImpl* b) { return a == b; }
153
154    static const bool safeToCompareToEmptyOrDeleted = false;
155};
156
157}
158
159namespace WTF {
160
161    template<typename T> struct DefaultHash;
162
163    template<> struct DefaultHash<WebCore::QualifiedName> {
164        typedef WebCore::QualifiedNameHash Hash;
165    };
166
167    template<> struct HashTraits<WebCore::QualifiedName> : GenericHashTraits<WebCore::QualifiedName> {
168        static const bool emptyValueIsZero = false;
169        static WebCore::QualifiedName emptyValue() { return WebCore::QualifiedName(WebCore::nullAtom, WebCore::nullAtom, WebCore::nullAtom); }
170        static void constructDeletedValue(WebCore::QualifiedName& slot) { new (&slot) WebCore::QualifiedName(WebCore::nullAtom, WebCore::AtomicString(HashTableDeletedValue), WebCore::nullAtom); }
171        static bool isDeletedValue(const WebCore::QualifiedName& slot) { return slot.localName().isHashTableDeletedValue(); }
172    };
173}
174
175#endif
176