1/*
2 *  Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008 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#include "config.h"
22#include "Identifier.h"
23
24#include "CallFrame.h"
25#include <new> // for placement new
26#include <string.h> // for strlen
27#include <wtf/Assertions.h>
28#include <wtf/FastMalloc.h>
29#include <wtf/HashSet.h>
30
31using WTF::ThreadSpecific;
32
33namespace JSC {
34
35typedef HashMap<const char*, RefPtr<UString::Rep>, PtrHash<const char*> > LiteralIdentifierTable;
36
37class IdentifierTable : public FastAllocBase {
38public:
39    ~IdentifierTable()
40    {
41        HashSet<UString::Rep*>::iterator end = m_table.end();
42        for (HashSet<UString::Rep*>::iterator iter = m_table.begin(); iter != end; ++iter)
43            (*iter)->setIsIdentifier(false);
44    }
45
46    std::pair<HashSet<UString::Rep*>::iterator, bool> add(UString::Rep* value)
47    {
48        std::pair<HashSet<UString::Rep*>::iterator, bool> result = m_table.add(value);
49        (*result.first)->setIsIdentifier(true);
50        return result;
51    }
52
53    template<typename U, typename V>
54    std::pair<HashSet<UString::Rep*>::iterator, bool> add(U value)
55    {
56        std::pair<HashSet<UString::Rep*>::iterator, bool> result = m_table.add<U, V>(value);
57        (*result.first)->setIsIdentifier(true);
58        return result;
59    }
60
61    void remove(UString::Rep* r) { m_table.remove(r); }
62
63    LiteralIdentifierTable& literalTable() { return m_literalTable; }
64
65private:
66    HashSet<UString::Rep*> m_table;
67    LiteralIdentifierTable m_literalTable;
68};
69
70IdentifierTable* createIdentifierTable()
71{
72    return new IdentifierTable;
73}
74
75void deleteIdentifierTable(IdentifierTable* table)
76{
77    delete table;
78}
79
80bool Identifier::equal(const UString::Rep* r, const char* s)
81{
82    int length = r->size();
83    const UChar* d = r->data();
84    for (int i = 0; i != length; ++i)
85        if (d[i] != (unsigned char)s[i])
86            return false;
87    return s[length] == 0;
88}
89
90bool Identifier::equal(const UString::Rep* r, const UChar* s, int length)
91{
92    if (r->size() != length)
93        return false;
94    const UChar* d = r->data();
95    for (int i = 0; i != length; ++i)
96        if (d[i] != s[i])
97            return false;
98    return true;
99}
100
101struct CStringTranslator {
102    static unsigned hash(const char* c)
103    {
104        return UString::Rep::computeHash(c);
105    }
106
107    static bool equal(UString::Rep* r, const char* s)
108    {
109        return Identifier::equal(r, s);
110    }
111
112    static void translate(UString::Rep*& location, const char* c, unsigned hash)
113    {
114        size_t length = strlen(c);
115        UChar* d;
116        UString::Rep* r = UString::Rep::createUninitialized(length, d).releaseRef();
117        for (size_t i = 0; i != length; i++)
118            d[i] = static_cast<unsigned char>(c[i]); // use unsigned char to zero-extend instead of sign-extend
119        r->setHash(hash);
120        location = r;
121    }
122};
123
124PassRefPtr<UString::Rep> Identifier::add(JSGlobalData* globalData, const char* c)
125{
126    ASSERT(c);
127
128    if (!c[0]) {
129        UString::Rep::empty().hash();
130        return &UString::Rep::empty();
131    }
132    if (!c[1])
133        return add(globalData, globalData->smallStrings.singleCharacterStringRep(static_cast<unsigned char>(c[0])));
134
135    IdentifierTable& identifierTable = *globalData->identifierTable;
136    LiteralIdentifierTable& literalIdentifierTable = identifierTable.literalTable();
137
138    const LiteralIdentifierTable::iterator& iter = literalIdentifierTable.find(c);
139    if (iter != literalIdentifierTable.end())
140        return iter->second;
141
142    pair<HashSet<UString::Rep*>::iterator, bool> addResult = identifierTable.add<const char*, CStringTranslator>(c);
143
144    // If the string is newly-translated, then we need to adopt it.
145    // The boolean in the pair tells us if that is so.
146    RefPtr<UString::Rep> addedString = addResult.second ? adoptRef(*addResult.first) : *addResult.first;
147
148    literalIdentifierTable.add(c, addedString.get());
149
150    return addedString.release();
151}
152
153PassRefPtr<UString::Rep> Identifier::add(ExecState* exec, const char* c)
154{
155    return add(&exec->globalData(), c);
156}
157
158struct UCharBuffer {
159    const UChar* s;
160    unsigned int length;
161};
162
163struct UCharBufferTranslator {
164    static unsigned hash(const UCharBuffer& buf)
165    {
166        return UString::Rep::computeHash(buf.s, buf.length);
167    }
168
169    static bool equal(UString::Rep* str, const UCharBuffer& buf)
170    {
171        return Identifier::equal(str, buf.s, buf.length);
172    }
173
174    static void translate(UString::Rep*& location, const UCharBuffer& buf, unsigned hash)
175    {
176        UChar* d;
177        UString::Rep* r = UString::Rep::createUninitialized(buf.length, d).releaseRef();
178        for (unsigned i = 0; i != buf.length; i++)
179            d[i] = buf.s[i];
180        r->setHash(hash);
181        location = r;
182    }
183};
184
185PassRefPtr<UString::Rep> Identifier::add(JSGlobalData* globalData, const UChar* s, int length)
186{
187    if (length == 1) {
188        UChar c = s[0];
189        if (c <= 0xFF)
190            return add(globalData, globalData->smallStrings.singleCharacterStringRep(c));
191    }
192    if (!length) {
193        UString::Rep::empty().hash();
194        return &UString::Rep::empty();
195    }
196    UCharBuffer buf = {s, length};
197    pair<HashSet<UString::Rep*>::iterator, bool> addResult = globalData->identifierTable->add<UCharBuffer, UCharBufferTranslator>(buf);
198
199    // If the string is newly-translated, then we need to adopt it.
200    // The boolean in the pair tells us if that is so.
201    return addResult.second ? adoptRef(*addResult.first) : *addResult.first;
202}
203
204PassRefPtr<UString::Rep> Identifier::add(ExecState* exec, const UChar* s, int length)
205{
206    return add(&exec->globalData(), s, length);
207}
208
209PassRefPtr<UString::Rep> Identifier::addSlowCase(JSGlobalData* globalData, UString::Rep* r)
210{
211    ASSERT(!r->isIdentifier());
212    if (r->size() == 1) {
213        UChar c = r->data()[0];
214        if (c <= 0xFF)
215            r = globalData->smallStrings.singleCharacterStringRep(c);
216            if (r->isIdentifier()) {
217#ifndef NDEBUG
218                checkSameIdentifierTable(globalData, r);
219#endif
220                return r;
221            }
222    }
223    if (!r->size()) {
224        UString::Rep::empty().hash();
225        return &UString::Rep::empty();
226    }
227    return *globalData->identifierTable->add(r).first;
228}
229
230PassRefPtr<UString::Rep> Identifier::addSlowCase(ExecState* exec, UString::Rep* r)
231{
232    return addSlowCase(&exec->globalData(), r);
233}
234
235void Identifier::remove(UString::Rep* r)
236{
237    currentIdentifierTable()->remove(r);
238}
239
240#ifndef NDEBUG
241
242void Identifier::checkSameIdentifierTable(ExecState* exec, UString::Rep*)
243{
244    ASSERT_UNUSED(exec, exec->globalData().identifierTable == currentIdentifierTable());
245}
246
247void Identifier::checkSameIdentifierTable(JSGlobalData* globalData, UString::Rep*)
248{
249    ASSERT_UNUSED(globalData, globalData->identifierTable == currentIdentifierTable());
250}
251
252#else
253
254void Identifier::checkSameIdentifierTable(ExecState*, UString::Rep*)
255{
256}
257
258void Identifier::checkSameIdentifierTable(JSGlobalData*, UString::Rep*)
259{
260}
261
262#endif
263
264ThreadSpecific<ThreadIdentifierTableData>* g_identifierTableSpecific = 0;
265
266#if ENABLE(JSC_MULTIPLE_THREADS)
267
268pthread_once_t createIdentifierTableSpecificOnce = PTHREAD_ONCE_INIT;
269static void createIdentifierTableSpecificCallback()
270{
271    ASSERT(!g_identifierTableSpecific);
272    g_identifierTableSpecific = new ThreadSpecific<ThreadIdentifierTableData>();
273}
274void createIdentifierTableSpecific()
275{
276    pthread_once(&createIdentifierTableSpecificOnce, createIdentifierTableSpecificCallback);
277    ASSERT(g_identifierTableSpecific);
278}
279
280#else
281
282void createIdentifierTableSpecific()
283{
284    ASSERT(!g_identifierTableSpecific);
285    g_identifierTableSpecific = new ThreadSpecific<ThreadIdentifierTableData>();
286}
287
288#endif
289
290} // namespace JSC
291