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 <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
  31 using WTF::ThreadSpecific;
  32
  33 namespace JSC {
  34
  35 typedef HashMap<const char*, RefPtr<UString::Rep>, PtrHash<const char*> > LiteralIdentifierTable;
  36
  37 class IdentifierTable : public FastAllocBase {
  38 public:
  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
  65 private:
  66     HashSet<UString::Rep*> m_table;
  67     LiteralIdentifierTable m_literalTable;
  68 };
  69
  70 IdentifierTable* createIdentifierTable()
  71 {
  72     return new IdentifierTable;
  73 }
  74
  75 void deleteIdentifierTable(IdentifierTable* table)
  76 {
  77     delete table;
  78 }
  79
  80 bool 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
  90 bool 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
 101 struct 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
 124 PassRefPtr<UString::Rep> Identifier::add(JSGlobalData* globalData, const char* c)
 125 {
 126     if (!c) {
 127         UString::Rep::null().hash();
 128         return &UString::Rep::null();
 129     }
 130     if (!c[0]) {
 131         UString::Rep::empty().hash();
 132         return &UString::Rep::empty();
 133     }
 134     if (!c[1])
 135         return add(globalData, globalData->smallStrings.singleCharacterStringRep(static_cast<unsigned char>(c[0])));
 136
 137     IdentifierTable& identifierTable = *globalData->identifierTable;
 138     LiteralIdentifierTable& literalIdentifierTable = identifierTable.literalTable();
 139
 140     const LiteralIdentifierTable::iterator& iter = literalIdentifierTable.find(c);
 141     if (iter != literalIdentifierTable.end())
 142         return iter->second;
 143
 144     pair<HashSet<UString::Rep*>::iterator, bool> addResult = identifierTable.add<const char*, CStringTranslator>(c);
 145
 146     // If the string is newly-translated, then we need to adopt it.
 147     // The boolean in the pair tells us if that is so.
 148     RefPtr<UString::Rep> addedString = addResult.second ? adoptRef(*addResult.first) : *addResult.first;
 149
 150     literalIdentifierTable.add(c, addedString.get());
 151
 152     return addedString.release();
 153 }
 154
 155 PassRefPtr<UString::Rep> Identifier::add(ExecState* exec, const char* c)
 156 {
 157     return add(&exec->globalData(), c);
 158 }
 159
 160 struct UCharBuffer {
 161     const UChar* s;
 162     unsigned int length;
 163 };
 164
 165 struct UCharBufferTranslator {
 166     static unsigned hash(const UCharBuffer& buf)
 167     {
 168         return UString::Rep::computeHash(buf.s, buf.length);
 169     }
 170
 171     static bool equal(UString::Rep* str, const UCharBuffer& buf)
 172     {
 173         return Identifier::equal(str, buf.s, buf.length);
 174     }
 175
 176     static void translate(UString::Rep*& location, const UCharBuffer& buf, unsigned hash)
 177     {
 178         UChar* d;
 179         UString::Rep* r = UString::Rep::createUninitialized(buf.length, d).releaseRef();
 180         for (unsigned i = 0; i != buf.length; i++)
 181             d[i] = buf.s[i];
 182         r->setHash(hash);
 183         location = r;
 184     }
 185 };
 186
 187 PassRefPtr<UString::Rep> Identifier::add(JSGlobalData* globalData, const UChar* s, int length)
 188 {
 189     if (length == 1) {
 190         UChar c = s[0];
 191         if (c <= 0xFF)
 192             return add(globalData, globalData->smallStrings.singleCharacterStringRep(c));
 193     }
 194     if (!length) {
 195         UString::Rep::empty().hash();
 196         return &UString::Rep::empty();
 197     }
 198     UCharBuffer buf = {s, length};
 199     pair<HashSet<UString::Rep*>::iterator, bool> addResult = globalData->identifierTable->add<UCharBuffer, UCharBufferTranslator>(buf);
 200
 201     // If the string is newly-translated, then we need to adopt it.
 202     // The boolean in the pair tells us if that is so.
 203     return addResult.second ? adoptRef(*addResult.first) : *addResult.first;
 204 }
 205
 206 PassRefPtr<UString::Rep> Identifier::add(ExecState* exec, const UChar* s, int length)
 207 {
 208     return add(&exec->globalData(), s, length);
 209 }
 210
 211 PassRefPtr<UString::Rep> Identifier::addSlowCase(JSGlobalData* globalData, UString::Rep* r)
 212 {
 213     ASSERT(!r->isIdentifier());
 214     if (r->size() == 1) {
 215         UChar c = r->data()[0];
 216         if (c <= 0xFF)
 217             r = globalData->smallStrings.singleCharacterStringRep(c);
 218             if (r->isIdentifier()) {
 219 #ifndef NDEBUG
 220                 checkSameIdentifierTable(globalData, r);
 221 #endif
 222                 return r;
 223             }
 224     }
 225     if (!r->size()) {
 226         UString::Rep::empty().hash();
 227         return &UString::Rep::empty();
 228     }
 229     return *globalData->identifierTable->add(r).first;
 230 }
 231
 232 PassRefPtr<UString::Rep> Identifier::addSlowCase(ExecState* exec, UString::Rep* r)
 233 {
 234     return addSlowCase(&exec->globalData(), r);
 235 }
 236
 237 void Identifier::remove(UString::Rep* r)
 238 {
 239     currentIdentifierTable()->remove(r);
 240 }
 241
 242 #ifndef NDEBUG
 243
 244 void Identifier::checkSameIdentifierTable(ExecState* exec, UString::Rep*)
 245 {
 246     ASSERT_UNUSED(exec, exec->globalData().identifierTable == currentIdentifierTable());
 247 }
 248
 249 void Identifier::checkSameIdentifierTable(JSGlobalData* globalData, UString::Rep*)
 250 {
 251     ASSERT_UNUSED(globalData, globalData->identifierTable == currentIdentifierTable());
 252 }
 253
 254 #else
 255
 256 void Identifier::checkSameIdentifierTable(ExecState*, UString::Rep*)
 257 {
 258 }
 259
 260 void Identifier::checkSameIdentifierTable(JSGlobalData*, UString::Rep*)
 261 {
 262 }
 263
 264 #endif
 265
 266 ThreadSpecific<ThreadIdentifierTableData>* g_identifierTableSpecific = 0;
 267 ThreadIdentifierTableData* g_identifierTableMain = 0;
 268
 269 #if ENABLE(JSC_MULTIPLE_THREADS)
 270
 271 pthread_once_t createIdentifierTableSpecificOnce = PTHREAD_ONCE_INIT;
 272 static void createIdentifierTableSpecificCallback()
 273 {
 274     ASSERT(!g_identifierTableSpecific);
 275     g_identifierTableSpecific = new ThreadSpecific<ThreadIdentifierTableData>();
 276     ASSERT(!g_identifierTableMain);
 277     g_identifierTableMain = new ThreadIdentifierTableData();
 278 }
 279 void createIdentifierTableSpecific()
 280 {
 281     pthread_once(&createIdentifierTableSpecificOnce, createIdentifierTableSpecificCallback);
 282     ASSERT(g_identifierTableSpecific);
 283     ASSERT(g_identifierTableMain);
 284 }
 285
 286 #else
 287
 288 void createIdentifierTableSpecific()
 289 {
 290     ASSERT(!g_identifierTableSpecific);
 291     g_identifierTableSpecific = new ThreadSpecific<ThreadIdentifierTableData>();
 292     ASSERT(!g_identifierTableMain);
 293     g_identifierTableMain = new ThreadIdentifierTableData();
 294 }
 295
 296 #endif
 297
 298 } // namespace JSC