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 "NumericStrings.h"
  26 #include <new> // for placement new
  27 #include <string.h> // for strlen
  28 #include <wtf/Assertions.h>
  29 #include <wtf/FastMalloc.h>
  30 #include <wtf/HashSet.h>
  31 #include <wtf/WTFThreadData.h>
  32 #include <wtf/text/StringHash.h>
  33
  34 using WTF::ThreadSpecific;
  35
  36 namespace JSC {
  37
  38 IdentifierTable::~IdentifierTable()
  39 {
  40     HashSet<StringImpl*>::iterator end = m_table.end();
  41     for (HashSet<StringImpl*>::iterator iter = m_table.begin(); iter != end; ++iter)
  42         (*iter)->setIsIdentifier(false);
  43 }
  44 std::pair<HashSet<StringImpl*>::iterator, bool> IdentifierTable::add(StringImpl* value)
  45 {
  46     std::pair<HashSet<StringImpl*>::iterator, bool> result = m_table.add(value);
  47     (*result.first)->setIsIdentifier(true);
  48     return result;
  49 }
  50 template<typename U, typename V>
  51 std::pair<HashSet<StringImpl*>::iterator, bool> IdentifierTable::add(U value)
  52 {
  53     std::pair<HashSet<StringImpl*>::iterator, bool> result = m_table.add<U, V>(value);
  54     (*result.first)->setIsIdentifier(true);
  55     return result;
  56 }
  57
  58 IdentifierTable* createIdentifierTable()
  59 {
  60     return new IdentifierTable;
  61 }
  62
  63 void deleteIdentifierTable(IdentifierTable* table)
  64 {
  65     delete table;
  66 }
  67
  68 bool Identifier::equal(const UString::Rep* r, const char* s)
  69 {
  70     int length = r->length();
  71     const UChar* d = r->characters();
  72     for (int i = 0; i != length; ++i)
  73         if (d[i] != (unsigned char)s[i])
  74             return false;
  75     return s[length] == 0;
  76 }
  77
  78 bool Identifier::equal(const UString::Rep* r, const UChar* s, unsigned length)
  79 {
  80     if (r->length() != length)
  81         return false;
  82     const UChar* d = r->characters();
  83     for (unsigned i = 0; i != length; ++i)
  84         if (d[i] != s[i])
  85             return false;
  86     return true;
  87 }
  88
  89 struct IdentifierCStringTranslator {
  90     static unsigned hash(const char* c)
  91     {
  92         return UString::Rep::computeHash(c);
  93     }
  94
  95     static bool equal(UString::Rep* r, const char* s)
  96     {
  97         return Identifier::equal(r, s);
  98     }
  99
 100     static void translate(UString::Rep*& location, const char* c, unsigned hash)
 101     {
 102         size_t length = strlen(c);
 103         UChar* d;
 104         UString::Rep* r = UString::Rep::createUninitialized(length, d).releaseRef();
 105         for (size_t i = 0; i != length; i++)
 106             d[i] = static_cast<unsigned char>(c[i]); // use unsigned char to zero-extend instead of sign-extend
 107         r->setHash(hash);
 108         location = r;
 109     }
 110 };
 111
 112 PassRefPtr<UString::Rep> Identifier::add(JSGlobalData* globalData, const char* c)
 113 {
 114     if (!c)
 115         return UString::null().rep();
 116     if (!c[0])
 117         return UString::Rep::empty();
 118     if (!c[1])
 119         return add(globalData, globalData->smallStrings.singleCharacterStringRep(static_cast<unsigned char>(c[0])));
 120
 121     IdentifierTable& identifierTable = *globalData->identifierTable;
 122     LiteralIdentifierTable& literalIdentifierTable = identifierTable.literalTable();
 123
 124     const LiteralIdentifierTable::iterator& iter = literalIdentifierTable.find(c);
 125     if (iter != literalIdentifierTable.end())
 126         return iter->second;
 127
 128     pair<HashSet<UString::Rep*>::iterator, bool> addResult = identifierTable.add<const char*, IdentifierCStringTranslator>(c);
 129
 130     // If the string is newly-translated, then we need to adopt it.
 131     // The boolean in the pair tells us if that is so.
 132     RefPtr<UString::Rep> addedString = addResult.second ? adoptRef(*addResult.first) : *addResult.first;
 133
 134     literalIdentifierTable.add(c, addedString.get());
 135
 136     return addedString.release();
 137 }
 138
 139 PassRefPtr<UString::Rep> Identifier::add(ExecState* exec, const char* c)
 140 {
 141     return add(&exec->globalData(), c);
 142 }
 143
 144 struct UCharBuffer {
 145     const UChar* s;
 146     unsigned int length;
 147 };
 148
 149 struct IdentifierUCharBufferTranslator {
 150     static unsigned hash(const UCharBuffer& buf)
 151     {
 152         return UString::Rep::computeHash(buf.s, buf.length);
 153     }
 154
 155     static bool equal(UString::Rep* str, const UCharBuffer& buf)
 156     {
 157         return Identifier::equal(str, buf.s, buf.length);
 158     }
 159
 160     static void translate(UString::Rep*& location, const UCharBuffer& buf, unsigned hash)
 161     {
 162         UChar* d;
 163         UString::Rep* r = UString::Rep::createUninitialized(buf.length, d).releaseRef();
 164         for (unsigned i = 0; i != buf.length; i++)
 165             d[i] = buf.s[i];
 166         r->setHash(hash);
 167         location = r;
 168     }
 169 };
 170
 171 PassRefPtr<UString::Rep> Identifier::add(JSGlobalData* globalData, const UChar* s, int length)
 172 {
 173     if (length == 1) {
 174         UChar c = s[0];
 175         if (c <= 0xFF)
 176             return add(globalData, globalData->smallStrings.singleCharacterStringRep(c));
 177     }
 178     if (!length)
 179         return UString::Rep::empty();
 180     UCharBuffer buf = {s, length};
 181     pair<HashSet<UString::Rep*>::iterator, bool> addResult = globalData->identifierTable->add<UCharBuffer, IdentifierUCharBufferTranslator>(buf);
 182
 183     // If the string is newly-translated, then we need to adopt it.
 184     // The boolean in the pair tells us if that is so.
 185     return addResult.second ? adoptRef(*addResult.first) : *addResult.first;
 186 }
 187
 188 PassRefPtr<UString::Rep> Identifier::add(ExecState* exec, const UChar* s, int length)
 189 {
 190     return add(&exec->globalData(), s, length);
 191 }
 192
 193 PassRefPtr<UString::Rep> Identifier::addSlowCase(JSGlobalData* globalData, UString::Rep* r)
 194 {
 195     ASSERT(!r->isIdentifier());
 196     // The empty & null strings are static singletons, and static strings are handled
 197     // in ::add() in the header, so we should never get here with a zero length string.
 198     ASSERT(r->length());
 199
 200     if (r->length() == 1) {
 201         UChar c = r->characters()[0];
 202         if (c <= 0xFF)
 203             r = globalData->smallStrings.singleCharacterStringRep(c);
 204             if (r->isIdentifier())
 205                 return r;
 206     }
 207
 208     return *globalData->identifierTable->add(r).first;
 209 }
 210
 211 PassRefPtr<UString::Rep> Identifier::addSlowCase(ExecState* exec, UString::Rep* r)
 212 {
 213     return addSlowCase(&exec->globalData(), r);
 214 }
 215
 216 Identifier Identifier::from(ExecState* exec, unsigned value)
 217 {
 218     return Identifier(exec, exec->globalData().numericStrings.add(value));
 219 }
 220
 221 Identifier Identifier::from(ExecState* exec, int value)
 222 {
 223     return Identifier(exec, exec->globalData().numericStrings.add(value));
 224 }
 225
 226 Identifier Identifier::from(ExecState* exec, double value)
 227 {
 228     return Identifier(exec, exec->globalData().numericStrings.add(value));
 229 }
 230
 231 #ifndef NDEBUG
 232
 233 void Identifier::checkCurrentIdentifierTable(JSGlobalData* globalData)
 234 {
 235     // Check the identifier table accessible through the threadspecific matches the
 236     // globalData's identifier table.
 237     ASSERT_UNUSED(globalData, globalData->identifierTable == wtfThreadData().currentIdentifierTable());
 238 }
 239
 240 void Identifier::checkCurrentIdentifierTable(ExecState* exec)
 241 {
 242     checkCurrentIdentifierTable(&exec->globalData());
 243 }
 244
 245 #else
 246
 247 // These only exists so that our exports are the same for debug and release builds.
 248 // This would be an ASSERT_NOT_REACHED(), but we're in NDEBUG only code here!
 249 void Identifier::checkCurrentIdentifierTable(JSGlobalData*) { CRASH(); }
 250 void Identifier::checkCurrentIdentifierTable(ExecState*) { CRASH(); }
 251
 252 #endif
 253
 254 } // namespace JSC