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 "JSObject.h"
26#include "NumericStrings.h"
27#include "ScopeChain.h"
28#include <new> // for placement new
29#include <string.h> // for strlen
30#include <wtf/Assertions.h>
31#include <wtf/FastMalloc.h>
32#include <wtf/HashSet.h>
33#include <wtf/WTFThreadData.h>
34#include <wtf/text/StringHash.h>
35
36using WTF::ThreadSpecific;
37
38namespace JSC {
39
40IdentifierTable::~IdentifierTable()
41{
42    HashSet<StringImpl*>::iterator end = m_table.end();
43    for (HashSet<StringImpl*>::iterator iter = m_table.begin(); iter != end; ++iter)
44        (*iter)->setIsIdentifier(false);
45}
46std::pair<HashSet<StringImpl*>::iterator, bool> IdentifierTable::add(StringImpl* value)
47{
48    std::pair<HashSet<StringImpl*>::iterator, bool> result = m_table.add(value);
49    (*result.first)->setIsIdentifier(true);
50    return result;
51}
52template<typename U, typename V>
53std::pair<HashSet<StringImpl*>::iterator, bool> IdentifierTable::add(U value)
54{
55    std::pair<HashSet<StringImpl*>::iterator, bool> result = m_table.add<U, V>(value);
56    (*result.first)->setIsIdentifier(true);
57    return result;
58}
59
60IdentifierTable* createIdentifierTable()
61{
62    return new IdentifierTable;
63}
64
65void deleteIdentifierTable(IdentifierTable* table)
66{
67    delete table;
68}
69
70bool Identifier::equal(const StringImpl* r, const char* s)
71{
72    int length = r->length();
73    const UChar* d = r->characters();
74    for (int i = 0; i != length; ++i)
75        if (d[i] != (unsigned char)s[i])
76            return false;
77    return s[length] == 0;
78}
79
80bool Identifier::equal(const StringImpl* r, const UChar* s, unsigned length)
81{
82    if (r->length() != length)
83        return false;
84    const UChar* d = r->characters();
85    for (unsigned i = 0; i != length; ++i)
86        if (d[i] != s[i])
87            return false;
88    return true;
89}
90
91struct IdentifierCStringTranslator {
92    static unsigned hash(const char* c)
93    {
94        return StringHasher::computeHash<char>(c);
95    }
96
97    static bool equal(StringImpl* r, const char* s)
98    {
99        return Identifier::equal(r, s);
100    }
101
102    static void translate(StringImpl*& location, const char* c, unsigned hash)
103    {
104        size_t length = strlen(c);
105        UChar* d;
106        StringImpl* r = StringImpl::createUninitialized(length, d).leakRef();
107        for (size_t i = 0; i != length; i++)
108            d[i] = static_cast<unsigned char>(c[i]); // use unsigned char to zero-extend instead of sign-extend
109        r->setHash(hash);
110        location = r;
111    }
112};
113
114PassRefPtr<StringImpl> Identifier::add(JSGlobalData* globalData, const char* c)
115{
116    if (!c)
117        return 0;
118    if (!c[0])
119        return StringImpl::empty();
120    if (!c[1])
121        return add(globalData, globalData->smallStrings.singleCharacterStringRep(static_cast<unsigned char>(c[0])));
122
123    IdentifierTable& identifierTable = *globalData->identifierTable;
124    LiteralIdentifierTable& literalIdentifierTable = identifierTable.literalTable();
125
126    const LiteralIdentifierTable::iterator& iter = literalIdentifierTable.find(c);
127    if (iter != literalIdentifierTable.end())
128        return iter->second;
129
130    pair<HashSet<StringImpl*>::iterator, bool> addResult = identifierTable.add<const char*, IdentifierCStringTranslator>(c);
131
132    // If the string is newly-translated, then we need to adopt it.
133    // The boolean in the pair tells us if that is so.
134    RefPtr<StringImpl> addedString = addResult.second ? adoptRef(*addResult.first) : *addResult.first;
135
136    literalIdentifierTable.add(c, addedString.get());
137
138    return addedString.release();
139}
140
141PassRefPtr<StringImpl> Identifier::add(ExecState* exec, const char* c)
142{
143    return add(&exec->globalData(), c);
144}
145
146struct UCharBuffer {
147    const UChar* s;
148    unsigned int length;
149};
150
151struct IdentifierUCharBufferTranslator {
152    static unsigned hash(const UCharBuffer& buf)
153    {
154        return StringHasher::computeHash<UChar>(buf.s, buf.length);
155    }
156
157    static bool equal(StringImpl* str, const UCharBuffer& buf)
158    {
159        return Identifier::equal(str, buf.s, buf.length);
160    }
161
162    static void translate(StringImpl*& location, const UCharBuffer& buf, unsigned hash)
163    {
164        UChar* d;
165        StringImpl* r = StringImpl::createUninitialized(buf.length, d).leakRef();
166        for (unsigned i = 0; i != buf.length; i++)
167            d[i] = buf.s[i];
168        r->setHash(hash);
169        location = r;
170    }
171};
172
173uint32_t Identifier::toUInt32(const UString& string, bool& ok)
174{
175    ok = false;
176
177    unsigned length = string.length();
178    const UChar* characters = string.characters();
179
180    // An empty string is not a number.
181    if (!length)
182        return 0;
183
184    // Get the first character, turning it into a digit.
185    uint32_t value = characters[0] - '0';
186    if (value > 9)
187        return 0;
188
189    // Check for leading zeros. If the first characher is 0, then the
190    // length of the string must be one - e.g. "042" is not equal to "42".
191    if (!value && length > 1)
192        return 0;
193
194    while (--length) {
195        // Multiply value by 10, checking for overflow out of 32 bits.
196        if (value > 0xFFFFFFFFU / 10)
197            return 0;
198        value *= 10;
199
200        // Get the next character, turning it into a digit.
201        uint32_t newValue = *(++characters) - '0';
202        if (newValue > 9)
203            return 0;
204
205        // Add in the old value, checking for overflow out of 32 bits.
206        newValue += value;
207        if (newValue < value)
208            return 0;
209        value = newValue;
210    }
211
212    ok = true;
213    return value;
214}
215
216PassRefPtr<StringImpl> Identifier::add(JSGlobalData* globalData, const UChar* s, int length)
217{
218    if (length == 1) {
219        UChar c = s[0];
220        if (c <= maxSingleCharacterString)
221            return add(globalData, globalData->smallStrings.singleCharacterStringRep(c));
222    }
223    if (!length)
224        return StringImpl::empty();
225    UCharBuffer buf = {s, length};
226    pair<HashSet<StringImpl*>::iterator, bool> addResult = globalData->identifierTable->add<UCharBuffer, IdentifierUCharBufferTranslator>(buf);
227
228    // If the string is newly-translated, then we need to adopt it.
229    // The boolean in the pair tells us if that is so.
230    return addResult.second ? adoptRef(*addResult.first) : *addResult.first;
231}
232
233PassRefPtr<StringImpl> Identifier::add(ExecState* exec, const UChar* s, int length)
234{
235    return add(&exec->globalData(), s, length);
236}
237
238PassRefPtr<StringImpl> Identifier::addSlowCase(JSGlobalData* globalData, StringImpl* r)
239{
240    ASSERT(!r->isIdentifier());
241    // The empty & null strings are static singletons, and static strings are handled
242    // in ::add() in the header, so we should never get here with a zero length string.
243    ASSERT(r->length());
244
245    if (r->length() == 1) {
246        UChar c = r->characters()[0];
247        if (c <= maxSingleCharacterString)
248            r = globalData->smallStrings.singleCharacterStringRep(c);
249            if (r->isIdentifier())
250                return r;
251    }
252
253    return *globalData->identifierTable->add(r).first;
254}
255
256PassRefPtr<StringImpl> Identifier::addSlowCase(ExecState* exec, StringImpl* r)
257{
258    return addSlowCase(&exec->globalData(), r);
259}
260
261Identifier Identifier::from(ExecState* exec, unsigned value)
262{
263    return Identifier(exec, exec->globalData().numericStrings.add(value));
264}
265
266Identifier Identifier::from(ExecState* exec, int value)
267{
268    return Identifier(exec, exec->globalData().numericStrings.add(value));
269}
270
271Identifier Identifier::from(ExecState* exec, double value)
272{
273    return Identifier(exec, exec->globalData().numericStrings.add(value));
274}
275
276Identifier Identifier::from(JSGlobalData* globalData, unsigned value)
277{
278    return Identifier(globalData, globalData->numericStrings.add(value));
279}
280
281Identifier Identifier::from(JSGlobalData* globalData, int value)
282{
283    return Identifier(globalData, globalData->numericStrings.add(value));
284}
285
286Identifier Identifier::from(JSGlobalData* globalData, double value)
287{
288    return Identifier(globalData, globalData->numericStrings.add(value));
289}
290
291#ifndef NDEBUG
292
293void Identifier::checkCurrentIdentifierTable(JSGlobalData* globalData)
294{
295    // Check the identifier table accessible through the threadspecific matches the
296    // globalData's identifier table.
297    ASSERT_UNUSED(globalData, globalData->identifierTable == wtfThreadData().currentIdentifierTable());
298}
299
300void Identifier::checkCurrentIdentifierTable(ExecState* exec)
301{
302    checkCurrentIdentifierTable(&exec->globalData());
303}
304
305#else
306
307// These only exists so that our exports are the same for debug and release builds.
308// This would be an ASSERT_NOT_REACHED(), but we're in NDEBUG only code here!
309void Identifier::checkCurrentIdentifierTable(JSGlobalData*) { CRASH(); }
310void Identifier::checkCurrentIdentifierTable(ExecState*) { CRASH(); }
311
312#endif
313
314} // namespace JSC
315