runtime/Identifier.cpp

   1 /*
   2  *  Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2012 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 "JSScope.h"
  27 #include "NumericStrings.h"
  28 #include "Operations.h"
  29 #include <new>
  30 #include <string.h>
  31 #include <wtf/Assertions.h>
  32 #include <wtf/FastMalloc.h>
  33 #include <wtf/HashSet.h>
  34 #include <wtf/text/ASCIIFastPath.h>
  35 #include <wtf/text/StringHash.h>
  36
  37 using WTF::ThreadSpecific;
  38
  39 namespace JSC {
  40
  41 IdentifierTable* createIdentifierTable()
  42 {
  43     return new IdentifierTable;
  44 }
  45
  46 void deleteIdentifierTable(IdentifierTable* table)
  47 {
  48     delete table;
  49 }
  50
  51 struct IdentifierASCIIStringTranslator {
  52     static unsigned hash(const LChar* c)
  53     {
  54         return StringHasher::computeHashAndMaskTop8Bits(c);
  55     }
  56
  57     static bool equal(StringImpl* r, const LChar* s)
  58     {
  59         return Identifier::equal(r, s);
  60     }
  61
  62     static void translate(StringImpl*& location, const LChar* c, unsigned hash)
  63     {
  64         size_t length = strlen(reinterpret_cast<const char*>(c));
  65         location = StringImpl::createFromLiteral(reinterpret_cast<const char*>(c), length).leakRef();
  66         location->setHash(hash);
  67     }
  68 };
  69
  70 struct IdentifierLCharFromUCharTranslator {
  71     static unsigned hash(const CharBuffer<UChar>& buf)
  72     {
  73         return StringHasher::computeHashAndMaskTop8Bits(buf.s, buf.length);
  74     }
  75
  76     static bool equal(StringImpl* str, const CharBuffer<UChar>& buf)
  77     {
  78         return Identifier::equal(str, buf.s, buf.length);
  79     }
  80
  81     static void translate(StringImpl*& location, const CharBuffer<UChar>& buf, unsigned hash)
  82     {
  83         LChar* d;
  84         StringImpl* r = StringImpl::createUninitialized(buf.length, d).leakRef();
  85         WTF::copyLCharsFromUCharSource(d, buf.s, buf.length);
  86         r->setHash(hash);
  87         location = r;
  88     }
  89 };
  90
  91 PassRefPtr<StringImpl> Identifier::add(VM* vm, const char* c)
  92 {
  93     ASSERT(c);
  94     ASSERT(c[0]);
  95     if (!c[1])
  96         return add(vm, vm->smallStrings.singleCharacterStringRep(c[0]));
  97
  98     IdentifierTable& identifierTable = *vm->identifierTable;
  99
 100     HashSet<StringImpl*>::AddResult addResult = identifierTable.add<const LChar*, IdentifierASCIIStringTranslator>(reinterpret_cast<const LChar*>(c));
 101
 102     // If the string is newly-translated, then we need to adopt it.
 103     // The boolean in the pair tells us if that is so.
 104     RefPtr<StringImpl> addedString = addResult.isNewEntry ? adoptRef(*addResult.iterator) : *addResult.iterator;
 105
 106     return addedString.release();
 107 }
 108
 109 PassRefPtr<StringImpl> Identifier::add(ExecState* exec, const char* c)
 110 {
 111     return add(&exec->vm(), c);
 112 }
 113
 114 PassRefPtr<StringImpl> Identifier::add8(VM* vm, const UChar* s, int length)
 115 {
 116     if (length == 1) {
 117         UChar c = s[0];
 118         ASSERT(c <= 0xff);
 119         if (canUseSingleCharacterString(c))
 120             return add(vm, vm->smallStrings.singleCharacterStringRep(c));
 121     }
 122
 123     if (!length)
 124         return StringImpl::empty();
 125     CharBuffer<UChar> buf = { s, static_cast<unsigned>(length) };
 126     HashSet<StringImpl*>::AddResult addResult = vm->identifierTable->add<CharBuffer<UChar>, IdentifierLCharFromUCharTranslator >(buf);
 127
 128     // If the string is newly-translated, then we need to adopt it.
 129     // The boolean in the pair tells us if that is so.
 130     return addResult.isNewEntry ? adoptRef(*addResult.iterator) : *addResult.iterator;
 131 }
 132
 133 PassRefPtr<StringImpl> Identifier::addSlowCase(VM* vm, StringImpl* r)
 134 {
 135     ASSERT(!r->isIdentifier());
 136     // The empty & null strings are static singletons, and static strings are handled
 137     // in ::add() in the header, so we should never get here with a zero length string.
 138     ASSERT(r->length());
 139
 140     if (r->length() == 1) {
 141         UChar c = (*r)[0];
 142         if (c <= maxSingleCharacterString)
 143             r = vm->smallStrings.singleCharacterStringRep(c);
 144             if (r->isIdentifier())
 145                 return r;
 146     }
 147
 148     return *vm->identifierTable->add(r).iterator;
 149 }
 150
 151 PassRefPtr<StringImpl> Identifier::addSlowCase(ExecState* exec, StringImpl* r)
 152 {
 153     return addSlowCase(&exec->vm(), r);
 154 }
 155
 156 Identifier Identifier::from(ExecState* exec, unsigned value)
 157 {
 158     return Identifier(exec, exec->vm().numericStrings.add(value));
 159 }
 160
 161 Identifier Identifier::from(ExecState* exec, int value)
 162 {
 163     return Identifier(exec, exec->vm().numericStrings.add(value));
 164 }
 165
 166 Identifier Identifier::from(ExecState* exec, double value)
 167 {
 168     return Identifier(exec, exec->vm().numericStrings.add(value));
 169 }
 170
 171 Identifier Identifier::from(VM* vm, unsigned value)
 172 {
 173     return Identifier(vm, vm->numericStrings.add(value));
 174 }
 175
 176 Identifier Identifier::from(VM* vm, int value)
 177 {
 178     return Identifier(vm, vm->numericStrings.add(value));
 179 }
 180
 181 Identifier Identifier::from(VM* vm, double value)
 182 {
 183     return Identifier(vm, vm->numericStrings.add(value));
 184 }
 185
 186 #ifndef NDEBUG
 187
 188 void Identifier::checkCurrentIdentifierTable(VM* vm)
 189 {
 190     // Check the identifier table accessible through the threadspecific matches the
 191     // vm's identifier table.
 192     ASSERT_UNUSED(vm, vm->identifierTable == wtfThreadData().currentIdentifierTable());
 193 }
 194
 195 void Identifier::checkCurrentIdentifierTable(ExecState* exec)
 196 {
 197     checkCurrentIdentifierTable(&exec->vm());
 198 }
 199
 200 #else
 201
 202 // These only exists so that our exports are the same for debug and release builds.
 203 // This would be an RELEASE_ASSERT_NOT_REACHED(), but we're in NDEBUG only code here!
 204 NO_RETURN_DUE_TO_CRASH void Identifier::checkCurrentIdentifierTable(VM*) { CRASH(); }
 205 NO_RETURN_DUE_TO_CRASH void Identifier::checkCurrentIdentifierTable(ExecState*) { CRASH(); }
 206
 207 #endif
 208
 209 } // namespace JSC