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 namespace JSC {

    32 

    33 typedef HashMap<const char*, RefPtr<UString::Rep>, PtrHash<const char*> > LiteralIdentifierTable;

    34 

    35 class IdentifierTable : public FastAllocBase {

    36 public:

    37     ~IdentifierTable()

    38     {

    39         HashSet<UString::Rep*>::iterator end = m_table.end();

    40         for (HashSet<UString::Rep*>::iterator iter = m_table.begin(); iter != end; ++iter)

    41             (*iter)->setIdentifierTable(0);

    42     }

    43     

    44     std::pair<HashSet<UString::Rep*>::iterator, bool> add(UString::Rep* value)

    45     {

    46         std::pair<HashSet<UString::Rep*>::iterator, bool> result = m_table.add(value);

    47         (*result.first)->setIdentifierTable(this);

    48         return result;

    49     }

    50 

    51     template<typename U, typename V>

    52     std::pair<HashSet<UString::Rep*>::iterator, bool> add(U value)

    53     {

    54         std::pair<HashSet<UString::Rep*>::iterator, bool> result = m_table.add<U, V>(value);

    55         (*result.first)->setIdentifierTable(this);

    56         return result;

    57     }

    58 

    59     void remove(UString::Rep* r) { m_table.remove(r); }

    60 

    61     LiteralIdentifierTable& literalTable() { return m_literalTable; }

    62 

    63 private:

    64     HashSet<UString::Rep*> m_table;

    65     LiteralIdentifierTable m_literalTable;

    66 };

    67 

    68 IdentifierTable* createIdentifierTable()

    69 {

    70     return new IdentifierTable;

    71 }

    72 

    73 void deleteIdentifierTable(IdentifierTable* table)

    74 {

    75     delete table;

    76 }

    77 

    78 bool Identifier::equal(const UString::Rep* r, const char* s)

    79 {

    80     int length = r->len;

    81     const UChar* d = r->data();

    82     for (int i = 0; i != length; ++i)

    83         if (d[i] != (unsigned char)s[i])

    84             return false;

    85     return s[length] == 0;

    86 }

    87 

    88 bool Identifier::equal(const UString::Rep* r, const UChar* s, int length)

    89 {

    90     if (r->len != length)

    91         return false;

    92     const UChar* d = r->data();

    93     for (int i = 0; i != length; ++i)

    94         if (d[i] != s[i])

    95             return false;

    96     return true;

    97 }

    98 

    99 struct CStringTranslator {

   100     static unsigned hash(const char* c)

   101     {

   102         return UString::Rep::computeHash(c);

   103     }

   104 

   105     static bool equal(UString::Rep* r, const char* s)

   106     {

   107         return Identifier::equal(r, s);

   108     }

   109 

   110     static void translate(UString::Rep*& location, const char* c, unsigned hash)

   111     {

   112         size_t length = strlen(c);

   113         UChar* d = static_cast<UChar*>(fastMalloc(sizeof(UChar) * length));

   114         for (size_t i = 0; i != length; i++)

   115             d[i] = static_cast<unsigned char>(c[i]); // use unsigned char to zero-extend instead of sign-extend

   116         

   117         UString::Rep* r = UString::Rep::create(d, static_cast<int>(length)).releaseRef();

   118         r->_hash = hash;

   119 

   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 = static_cast<UChar*>(fastMalloc(sizeof(UChar) * buf.length));

   179         for (unsigned i = 0; i != buf.length; i++)

   180             d[i] = buf.s[i];

   181         

   182         UString::Rep* r = UString::Rep::create(d, buf.length).releaseRef();

   183         r->_hash = hash;

   184         

   185         location = r; 

   186     }

   187 };

   188 

   189 PassRefPtr<UString::Rep> Identifier::add(JSGlobalData* globalData, const UChar* s, int length)

   190 {

   191     if (length == 1) {

   192         UChar c = s[0];

   193         if (c <= 0xFF)

   194             return add(globalData, globalData->smallStrings.singleCharacterStringRep(c));

   195     }

   196     if (!length) {

   197         UString::Rep::empty().hash();

   198         return &UString::Rep::empty();

   199     }

   200     UCharBuffer buf = {s, length}; 

   201     pair<HashSet<UString::Rep*>::iterator, bool> addResult = globalData->identifierTable->add<UCharBuffer, UCharBufferTranslator>(buf);

   202 

   203     // If the string is newly-translated, then we need to adopt it.

   204     // The boolean in the pair tells us if that is so.

   205     return addResult.second ? adoptRef(*addResult.first) : *addResult.first;

   206 }

   207 

   208 PassRefPtr<UString::Rep> Identifier::add(ExecState* exec, const UChar* s, int length)

   209 {

   210     return add(&exec->globalData(), s, length);

   211 }

   212 

   213 PassRefPtr<UString::Rep> Identifier::addSlowCase(JSGlobalData* globalData, UString::Rep* r)

   214 {

   215     ASSERT(!r->identifierTable());

   216     if (r->len == 1) {

   217         UChar c = r->data()[0];

   218         if (c <= 0xFF)

   219             r = globalData->smallStrings.singleCharacterStringRep(c);

   220             if (r->identifierTable()) {

   221 #ifndef NDEBUG

   222                 checkSameIdentifierTable(globalData, r);

   223 #endif

   224                 return r;

   225             }

   226     }

   227     if (!r->len) {

   228         UString::Rep::empty().hash();

   229         return &UString::Rep::empty();

   230     }

   231     return *globalData->identifierTable->add(r).first;

   232 }

   233 

   234 PassRefPtr<UString::Rep> Identifier::addSlowCase(ExecState* exec, UString::Rep* r)

   235 {

   236     return addSlowCase(&exec->globalData(), r);

   237 }

   238 

   239 void Identifier::remove(UString::Rep* r)

   240 {

   241     r->identifierTable()->remove(r);

   242 }

   243 

   244 #ifndef NDEBUG

   245 

   246 void Identifier::checkSameIdentifierTable(ExecState* exec, UString::Rep* rep)

   247 {

   248     ASSERT(rep->identifierTable() == exec->globalData().identifierTable);

   249 }

   250 

   251 void Identifier::checkSameIdentifierTable(JSGlobalData* globalData, UString::Rep* rep)

   252 {

   253     ASSERT(rep->identifierTable() == globalData->identifierTable);

   254 }

   255 

   256 #else

   257 

   258 void Identifier::checkSameIdentifierTable(ExecState*, UString::Rep*)

   259 {

   260 }

   261 

   262 void Identifier::checkSameIdentifierTable(JSGlobalData*, UString::Rep*)

   263 {

   264 }

   265 

   266 #endif

   267 

   268 } // namespace JSC