runtime/Identifier.h

   1 /*
   2  *  Copyright (C) 2003, 2006, 2007, 2008, 2009, 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 #ifndef Identifier_h
  22 #define Identifier_h
  23
  24 #include "VM.h"
  25 #include <wtf/ThreadSpecific.h>
  26 #include <wtf/WTFThreadData.h>
  27 #include <wtf/text/CString.h>
  28 #include <wtf/text/WTFString.h>
  29
  30 namespace JSC {
  31
  32     class ExecState;
  33
  34     class Identifier {
  35         friend class Structure;
  36     public:
  37         Identifier() { }
  38         enum EmptyIdentifierFlag { EmptyIdentifier };
  39         Identifier(EmptyIdentifierFlag) : m_string(StringImpl::empty()) { }
  40
  41         // Only to be used with string literals.
  42         template<unsigned charactersCount>
  43         Identifier(ExecState* exec, const char (&characters)[charactersCount]) : m_string(add(exec, characters)) { }
  44         template<unsigned charactersCount>
  45         Identifier(VM* vm, const char (&characters)[charactersCount]) : m_string(add(vm, characters)) { }
  46
  47         Identifier(ExecState* exec, StringImpl* rep) : m_string(add(exec, rep)) { }
  48         Identifier(ExecState* exec, const String& s) : m_string(add(exec, s.impl())) { }
  49
  50         Identifier(VM* vm, const LChar* s, int length) : m_string(add(vm, s, length)) { }
  51         Identifier(VM* vm, const UChar* s, int length) : m_string(add(vm, s, length)) { }
  52         Identifier(VM* vm, StringImpl* rep) : m_string(add(vm, rep)) { }
  53         Identifier(VM* vm, const String& s) : m_string(add(vm, s.impl())) { }
  54
  55         const String& string() const { return m_string; }
  56         StringImpl* impl() const { return m_string.impl(); }
  57
  58         const UChar* characters() const { return m_string.characters(); }
  59         int length() const { return m_string.length(); }
  60
  61         CString ascii() const { return m_string.ascii(); }
  62
  63         static Identifier createLCharFromUChar(VM* vm, const UChar* s, int length) { return Identifier(vm, add8(vm, s, length)); }
  64
  65         JS_EXPORT_PRIVATE static Identifier from(ExecState* exec, unsigned y);
  66         JS_EXPORT_PRIVATE static Identifier from(ExecState* exec, int y);
  67         static Identifier from(ExecState* exec, double y);
  68         static Identifier from(VM*, unsigned y);
  69         static Identifier from(VM*, int y);
  70         static Identifier from(VM*, double y);
  71
  72         bool isNull() const { return m_string.isNull(); }
  73         bool isEmpty() const { return m_string.isEmpty(); }
  74
  75         friend bool operator==(const Identifier&, const Identifier&);
  76         friend bool operator!=(const Identifier&, const Identifier&);
  77
  78         friend bool operator==(const Identifier&, const LChar*);
  79         friend bool operator==(const Identifier&, const char*);
  80         friend bool operator!=(const Identifier&, const LChar*);
  81         friend bool operator!=(const Identifier&, const char*);
  82
  83         static bool equal(const StringImpl*, const LChar*);
  84         static inline bool equal(const StringImpl*a, const char*b) { return Identifier::equal(a, reinterpret_cast<const LChar*>(b)); };
  85         static bool equal(const StringImpl*, const LChar*, unsigned length);
  86         static bool equal(const StringImpl*, const UChar*, unsigned length);
  87         static bool equal(const StringImpl* a, const StringImpl* b) { return ::equal(a, b); }
  88
  89         // Only to be used with string literals.
  90         static PassRefPtr<StringImpl> add(VM*, const char*);
  91         JS_EXPORT_PRIVATE static PassRefPtr<StringImpl> add(ExecState*, const char*);
  92
  93     private:
  94         String m_string;
  95
  96         template <typename CharType>
  97         ALWAYS_INLINE static uint32_t toUInt32FromCharacters(const CharType* characters, unsigned length, bool& ok);
  98
  99         static bool equal(const Identifier& a, const Identifier& b) { return a.m_string.impl() == b.m_string.impl(); }
 100         static bool equal(const Identifier& a, const LChar* b) { return equal(a.m_string.impl(), b); }
 101
 102         template <typename T> static PassRefPtr<StringImpl> add(VM*, const T*, int length);
 103         static PassRefPtr<StringImpl> add8(VM*, const UChar*, int length);
 104         template <typename T> ALWAYS_INLINE static bool canUseSingleCharacterString(T);
 105
 106         static PassRefPtr<StringImpl> add(ExecState* exec, StringImpl* r)
 107         {
 108 #ifndef NDEBUG
 109             checkCurrentIdentifierTable(exec);
 110 #endif
 111             if (r->isIdentifier())
 112                 return r;
 113             return addSlowCase(exec, r);
 114         }
 115         static PassRefPtr<StringImpl> add(VM* vm, StringImpl* r)
 116         {
 117 #ifndef NDEBUG
 118             checkCurrentIdentifierTable(vm);
 119 #endif
 120             if (r->isIdentifier())
 121                 return r;
 122             return addSlowCase(vm, r);
 123         }
 124
 125         JS_EXPORT_PRIVATE static PassRefPtr<StringImpl> addSlowCase(ExecState*, StringImpl* r);
 126         JS_EXPORT_PRIVATE static PassRefPtr<StringImpl> addSlowCase(VM*, StringImpl* r);
 127
 128         JS_EXPORT_PRIVATE static void checkCurrentIdentifierTable(ExecState*);
 129         JS_EXPORT_PRIVATE static void checkCurrentIdentifierTable(VM*);
 130     };
 131
 132     template <> ALWAYS_INLINE bool Identifier::canUseSingleCharacterString(LChar)
 133     {
 134         ASSERT(maxSingleCharacterString == 0xff);
 135         return true;
 136     }
 137
 138     template <> ALWAYS_INLINE bool Identifier::canUseSingleCharacterString(UChar c)
 139     {
 140         return (c <= maxSingleCharacterString);
 141     }
 142
 143     template <typename T>
 144     struct CharBuffer {
 145         const T* s;
 146         unsigned int length;
 147     };
 148
 149     template <typename T>
 150     struct IdentifierCharBufferTranslator {
 151         static unsigned hash(const CharBuffer<T>& buf)
 152         {
 153             return StringHasher::computeHashAndMaskTop8Bits(buf.s, buf.length);
 154         }
 155
 156         static bool equal(StringImpl* str, const CharBuffer<T>& buf)
 157         {
 158             return Identifier::equal(str, buf.s, buf.length);
 159         }
 160
 161         static void translate(StringImpl*& location, const CharBuffer<T>& buf, unsigned hash)
 162         {
 163             T* d;
 164             StringImpl* r = StringImpl::createUninitialized(buf.length, d).leakRef();
 165             for (unsigned i = 0; i != buf.length; i++)
 166                 d[i] = buf.s[i];
 167             r->setHash(hash);
 168             location = r;
 169         }
 170     };
 171
 172     template <typename T>
 173     PassRefPtr<StringImpl> Identifier::add(VM* vm, const T* s, int length)
 174     {
 175         if (length == 1) {
 176             T c = s[0];
 177             if (canUseSingleCharacterString(c))
 178                 return add(vm, vm->smallStrings.singleCharacterStringRep(c));
 179         }
 180
 181         if (!length)
 182             return StringImpl::empty();
 183         CharBuffer<T> buf = { s, static_cast<unsigned>(length) };
 184         HashSet<StringImpl*>::AddResult addResult = vm->identifierTable->add<CharBuffer<T>, IdentifierCharBufferTranslator<T> >(buf);
 185
 186         // If the string is newly-translated, then we need to adopt it.
 187         // The boolean in the pair tells us if that is so.
 188         return addResult.isNewEntry ? adoptRef(*addResult.iterator) : *addResult.iterator;
 189     }
 190
 191     inline bool operator==(const Identifier& a, const Identifier& b)
 192     {
 193         return Identifier::equal(a, b);
 194     }
 195
 196     inline bool operator!=(const Identifier& a, const Identifier& b)
 197     {
 198         return !Identifier::equal(a, b);
 199     }
 200
 201     inline bool operator==(const Identifier& a, const LChar* b)
 202     {
 203         return Identifier::equal(a, b);
 204     }
 205
 206     inline bool operator==(const Identifier& a, const char* b)
 207     {
 208         return Identifier::equal(a, reinterpret_cast<const LChar*>(b));
 209     }
 210
 211     inline bool operator!=(const Identifier& a, const LChar* b)
 212     {
 213         return !Identifier::equal(a, b);
 214     }
 215
 216     inline bool operator!=(const Identifier& a, const char* b)
 217     {
 218         return !Identifier::equal(a, reinterpret_cast<const LChar*>(b));
 219     }
 220
 221     inline bool Identifier::equal(const StringImpl* r, const LChar* s)
 222     {
 223         return WTF::equal(r, s);
 224     }
 225
 226     inline bool Identifier::equal(const StringImpl* r, const LChar* s, unsigned length)
 227     {
 228         return WTF::equal(r, s, length);
 229     }
 230
 231     inline bool Identifier::equal(const StringImpl* r, const UChar* s, unsigned length)
 232     {
 233         return WTF::equal(r, s, length);
 234     }
 235
 236     IdentifierTable* createIdentifierTable();
 237     void deleteIdentifierTable(IdentifierTable*);
 238
 239     struct IdentifierRepHash : PtrHash<RefPtr<StringImpl> > {
 240         static unsigned hash(const RefPtr<StringImpl>& key) { return key->existingHash(); }
 241         static unsigned hash(StringImpl* key) { return key->existingHash(); }
 242     };
 243
 244     struct IdentifierMapIndexHashTraits : HashTraits<int> {
 245         static int emptyValue() { return std::numeric_limits<int>::max(); }
 246         static const bool emptyValueIsZero = false;
 247     };
 248
 249     typedef HashMap<RefPtr<StringImpl>, int, IdentifierRepHash, HashTraits<RefPtr<StringImpl> >, IdentifierMapIndexHashTraits> IdentifierMap;
 250
 251     template<typename U, typename V>
 252     HashSet<StringImpl*>::AddResult IdentifierTable::add(U value)
 253     {
 254         HashSet<StringImpl*>::AddResult result = m_table.add<U, V>(value);
 255         (*result.iterator)->setIsIdentifier(true);
 256         return result;
 257     }
 258
 259 } // namespace JSC
 260
 261 namespace WTF {
 262
 263 template <> struct VectorTraits<JSC::Identifier> : SimpleClassVectorTraits { };
 264
 265 } // namespace WTF
 266
 267 #endif // Identifier_h