runtime/Identifier.cpp

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