runtime/Identifier.h

   1 /*
   2  *  Copyright (C) 2003, 2006, 2007, 2008, 2009 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 #ifndef Identifier_h
  22 #define Identifier_h
  23
  24 #include "JSGlobalData.h"
  25 #include <wtf/ThreadSpecific.h>
  26 #include "UString.h"
  27 #include <wtf/WTFThreadData.h>
  28 #include <wtf/text/CString.h>
  29
  30 namespace JSC {
  31
  32     class ExecState;
  33
  34     class Identifier {
  35         friend class Structure;
  36     public:
  37         Identifier() { }
  38
  39         Identifier(ExecState* exec, const char* s) : m_string(add(exec, s)) { } // Only to be used with string literals.
  40         Identifier(ExecState* exec, StringImpl* rep) : m_string(add(exec, rep)) { }
  41         Identifier(ExecState* exec, const UString& s) : m_string(add(exec, s.impl())) { }
  42
  43         Identifier(JSGlobalData* globalData, const char* s) : m_string(add(globalData, s)) { } // Only to be used with string literals.
  44         Identifier(JSGlobalData* globalData, const LChar* s, int length) : m_string(add(globalData, s, length)) { }
  45         Identifier(JSGlobalData* globalData, const UChar* s, int length) : m_string(add(globalData, s, length)) { }
  46         Identifier(JSGlobalData* globalData, StringImpl* rep) : m_string(add(globalData, rep)) { }
  47         Identifier(JSGlobalData* globalData, const UString& s) : m_string(add(globalData, s.impl())) { }
  48
  49         const UString& ustring() const { return m_string; }
  50         StringImpl* impl() const { return m_string.impl(); }
  51
  52         const UChar* characters() const { return m_string.characters(); }
  53         int length() const { return m_string.length(); }
  54
  55         CString ascii() const { return m_string.ascii(); }
  56
  57         static Identifier createLCharFromUChar(JSGlobalData* globalData, const UChar* s, int length) { return Identifier(globalData, add8(globalData, s, length)); }
  58
  59         JS_EXPORT_PRIVATE static Identifier from(ExecState* exec, unsigned y);
  60         JS_EXPORT_PRIVATE static Identifier from(ExecState* exec, int y);
  61         static Identifier from(ExecState* exec, double y);
  62         static Identifier from(JSGlobalData*, unsigned y);
  63         static Identifier from(JSGlobalData*, int y);
  64         static Identifier from(JSGlobalData*, double y);
  65
  66         JS_EXPORT_PRIVATE static uint32_t toUInt32(const UString&, bool& ok);
  67         uint32_t toUInt32(bool& ok) const { return toUInt32(m_string, ok); }
  68         unsigned toArrayIndex(bool& ok) const;
  69
  70         bool isNull() const { return m_string.isNull(); }
  71         bool isEmpty() const { return m_string.isEmpty(); }
  72
  73         friend bool operator==(const Identifier&, const Identifier&);
  74         friend bool operator!=(const Identifier&, const Identifier&);
  75
  76         friend bool operator==(const Identifier&, const LChar*);
  77         friend bool operator==(const Identifier&, const char*);
  78         friend bool operator!=(const Identifier&, const LChar*);
  79         friend bool operator!=(const Identifier&, const char*);
  80
  81         static bool equal(const StringImpl*, const LChar*);
  82         static inline bool equal(const StringImpl*a, const char*b) { return Identifier::equal(a, reinterpret_cast<const LChar*>(b)); };
  83         static bool equal(const StringImpl*, const LChar*, unsigned length);
  84         static bool equal(const StringImpl*, const UChar*, unsigned length);
  85         static bool equal(const StringImpl* a, const StringImpl* b) { return ::equal(a, b); }
  86
  87         JS_EXPORT_PRIVATE static PassRefPtr<StringImpl> add(ExecState*, const char*); // Only to be used with string literals.
  88         static PassRefPtr<StringImpl> add(JSGlobalData*, const char*); // Only to be used with string literals.
  89
  90     private:
  91         UString m_string;
  92
  93         template <typename CharType>
  94         ALWAYS_INLINE static uint32_t toUInt32FromCharacters(const CharType* characters, unsigned length, bool& ok);
  95
  96         static bool equal(const Identifier& a, const Identifier& b) { return a.m_string.impl() == b.m_string.impl(); }
  97         static bool equal(const Identifier& a, const LChar* b) { return equal(a.m_string.impl(), b); }
  98
  99         template <typename T> static PassRefPtr<StringImpl> add(JSGlobalData*, const T*, int length);
 100         static PassRefPtr<StringImpl> add8(JSGlobalData*, const UChar*, int length);
 101         template <typename T> ALWAYS_INLINE static bool canUseSingleCharacterString(T);
 102
 103         static PassRefPtr<StringImpl> add(ExecState* exec, StringImpl* r)
 104         {
 105 #ifndef NDEBUG
 106             checkCurrentIdentifierTable(exec);
 107 #endif
 108             if (r->isIdentifier())
 109                 return r;
 110             return addSlowCase(exec, r);
 111         }
 112         static PassRefPtr<StringImpl> add(JSGlobalData* globalData, StringImpl* r)
 113         {
 114 #ifndef NDEBUG
 115             checkCurrentIdentifierTable(globalData);
 116 #endif
 117             if (r->isIdentifier())
 118                 return r;
 119             return addSlowCase(globalData, r);
 120         }
 121
 122         JS_EXPORT_PRIVATE static PassRefPtr<StringImpl> addSlowCase(ExecState*, StringImpl* r);
 123         JS_EXPORT_PRIVATE static PassRefPtr<StringImpl> addSlowCase(JSGlobalData*, StringImpl* r);
 124
 125         JS_EXPORT_PRIVATE static void checkCurrentIdentifierTable(ExecState*);
 126         JS_EXPORT_PRIVATE static void checkCurrentIdentifierTable(JSGlobalData*);
 127     };
 128
 129     template <> ALWAYS_INLINE bool Identifier::canUseSingleCharacterString(LChar)
 130     {
 131         ASSERT(maxSingleCharacterString == 0xff);
 132         return true;
 133     }
 134
 135     template <> ALWAYS_INLINE bool Identifier::canUseSingleCharacterString(UChar c)
 136     {
 137         return (c <= maxSingleCharacterString);
 138     }
 139
 140     template <typename T>
 141     struct CharBuffer {
 142         const T* s;
 143         unsigned int length;
 144     };
 145
 146     template <typename T>
 147     struct IdentifierCharBufferTranslator {
 148         static unsigned hash(const CharBuffer<T>& buf)
 149         {
 150             return StringHasher::computeHash<T>(buf.s, buf.length);
 151         }
 152
 153         static bool equal(StringImpl* str, const CharBuffer<T>& buf)
 154         {
 155             return Identifier::equal(str, buf.s, buf.length);
 156         }
 157
 158         static void translate(StringImpl*& location, const CharBuffer<T>& buf, unsigned hash)
 159         {
 160             T* d;
 161             StringImpl* r = StringImpl::createUninitialized(buf.length, d).leakRef();
 162             for (unsigned i = 0; i != buf.length; i++)
 163                 d[i] = buf.s[i];
 164             r->setHash(hash);
 165             location = r;
 166         }
 167     };
 168
 169     template <typename T>
 170     PassRefPtr<StringImpl> Identifier::add(JSGlobalData* globalData, const T* s, int length)
 171     {
 172         if (length == 1) {
 173             T c = s[0];
 174             if (canUseSingleCharacterString(c))
 175                 return add(globalData, globalData->smallStrings.singleCharacterStringRep(c));
 176         }
 177
 178         if (!length)
 179             return StringImpl::empty();
 180         CharBuffer<T> buf = {s, length};
 181         HashSet<StringImpl*>::AddResult addResult = globalData->identifierTable->add<CharBuffer<T>, IdentifierCharBufferTranslator<T> >(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.isNewEntry ? adoptRef(*addResult.iterator) : *addResult.iterator;
 186     }
 187
 188     inline bool operator==(const Identifier& a, const Identifier& b)
 189     {
 190         return Identifier::equal(a, b);
 191     }
 192
 193     inline bool operator!=(const Identifier& a, const Identifier& b)
 194     {
 195         return !Identifier::equal(a, b);
 196     }
 197
 198     inline bool operator==(const Identifier& a, const LChar* b)
 199     {
 200         return Identifier::equal(a, b);
 201     }
 202
 203     inline bool operator==(const Identifier& a, const char* b)
 204     {
 205         return Identifier::equal(a, reinterpret_cast<const LChar*>(b));
 206     }
 207
 208     inline bool operator!=(const Identifier& a, const LChar* b)
 209     {
 210         return !Identifier::equal(a, b);
 211     }
 212
 213     inline bool operator!=(const Identifier& a, const char* b)
 214     {
 215         return !Identifier::equal(a, reinterpret_cast<const LChar*>(b));
 216     }
 217
 218     inline bool Identifier::equal(const StringImpl* r, const LChar* s)
 219     {
 220         return WTF::equal(r, s);
 221     }
 222
 223     inline bool Identifier::equal(const StringImpl* r, const LChar* s, unsigned length)
 224     {
 225         return WTF::equal(r, s, length);
 226     }
 227
 228     inline bool Identifier::equal(const StringImpl* r, const UChar* s, unsigned length)
 229     {
 230         return WTF::equal(r, s, length);
 231     }
 232
 233     IdentifierTable* createIdentifierTable();
 234     void deleteIdentifierTable(IdentifierTable*);
 235
 236     struct IdentifierRepHash : PtrHash<RefPtr<StringImpl> > {
 237         static unsigned hash(const RefPtr<StringImpl>& key) { return key->existingHash(); }
 238         static unsigned hash(StringImpl* key) { return key->existingHash(); }
 239     };
 240
 241     struct IdentifierMapIndexHashTraits : HashTraits<int> {
 242         static int emptyValue() { return std::numeric_limits<int>::max(); }
 243         static const bool emptyValueIsZero = false;
 244     };
 245
 246     typedef HashMap<RefPtr<StringImpl>, int, IdentifierRepHash, HashTraits<RefPtr<StringImpl> >, IdentifierMapIndexHashTraits> IdentifierMap;
 247
 248     template<typename U, typename V>
 249     HashSet<StringImpl*>::AddResult IdentifierTable::add(U value)
 250     {
 251         HashSet<StringImpl*>::AddResult result = m_table.add<U, V>(value);
 252         (*result.iterator)->setIsIdentifier(true);
 253         return result;
 254     }
 255
 256 } // namespace JSC
 257
 258 #endif // Identifier_h