runtime.cc.svn-base

Google浏览器V8内核代码

  return Top::initial_object_prototype()->GetProperty(*key);
}


static Object* Runtime_ToBool(Arguments args) {
  NoHandleAllocation ha;
  ASSERT(args.length() == 1);

  return args[0]->ToBoolean();
}


// Returns the type string of a value; see ECMA-262, 11.4.3 (p 47).
// Possible optimizations: put the type string into the oddballs.
static Object* Runtime_Typeof(Arguments args) {
  NoHandleAllocation ha;

  Object* obj = args[0];
  if (obj->IsNumber()) return Heap::number_symbol();
  HeapObject* heap_obj = HeapObject::cast(obj);

  // typeof an undetectable object is 'undefined'
  if (heap_obj->map()->is_undetectable()) return Heap::undefined_symbol();

  InstanceType instance_type = heap_obj->map()->instance_type();
  if (instance_type < FIRST_NONSTRING_TYPE) {
    return Heap::string_symbol();
  }

  switch (instance_type) {
    case ODDBALL_TYPE:
      if (heap_obj->IsTrue() || heap_obj->IsFalse()) {
        return Heap::boolean_symbol();
      }
      if (heap_obj->IsNull()) {
        return Heap::object_symbol();
      }
      ASSERT(heap_obj->IsUndefined());
      return Heap::undefined_symbol();
    case JS_FUNCTION_TYPE:
      return Heap::function_symbol();
    default:
      // For any kind of object not handled above, the spec rule for
      // host objects gives that it is okay to return "object"
      return Heap::object_symbol();
  }
}


static Object* Runtime_StringToNumber(Arguments args) {
  NoHandleAllocation ha;
  ASSERT(args.length() == 1);
  CONVERT_CHECKED(String, subject, args[0]);
  subject->TryFlatten();
  return Heap::NumberFromDouble(StringToDouble(subject, ALLOW_HEX));
}


static Object* Runtime_StringFromCharCodeArray(Arguments args) {
  NoHandleAllocation ha;
  ASSERT(args.length() == 1);

  CONVERT_CHECKED(JSArray, codes, args[0]);
  int length = Smi::cast(codes->length())->value();

  // Check if the string can be ASCII.
  int i;
  for (i = 0; i < length; i++) {
    Object* element = codes->GetElement(i);
    CONVERT_NUMBER_CHECKED(int, chr, Int32, element);
    if ((chr & 0xffff) > String::kMaxAsciiCharCode)
      break;
  }

  Object* object = NULL;
  if (i == length) {  // The string is ASCII.
    object = Heap::AllocateRawAsciiString(length);
  } else {  // The string is not ASCII.
    object = Heap::AllocateRawTwoByteString(length);
  }

  if (object->IsFailure()) return object;
  String* result = String::cast(object);
  for (int i = 0; i < length; i++) {
    Object* element = codes->GetElement(i);
    CONVERT_NUMBER_CHECKED(int, chr, Int32, element);
    result->Set(i, chr & 0xffff);
  }
  return result;
}


// kNotEscaped is generated by the following:
//
// #!/bin/perl
// for (my $i = 0; $i < 256; $i++) {
//   print "\n" if $i % 16 == 0;
//   my $c = chr($i);
//   my $escaped = 1;
//   $escaped = 0 if $c =~ m#[A-Za-z0-9@*_+./-]#;
//   print $escaped ? "0, " : "1, ";
// }


static bool IsNotEscaped(uint16_t character) {
  // Only for 8 bit characters, the rest are always escaped (in a different way)
  ASSERT(character < 256);
  static const char kNotEscaped[256] = {
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1,
    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  };
  return kNotEscaped[character] != 0;
}


static Object* Runtime_URIEscape(Arguments args) {
  const char hex_chars[] = "0123456789ABCDEF";
  NoHandleAllocation ha;
  ASSERT(args.length() == 1);
  CONVERT_CHECKED(String, source, args[0]);

  source->TryFlatten();

  int escaped_length = 0;
  int length = source->length();
  {
    Access<StringInputBuffer> buffer(&string_input_buffer);
    buffer->Reset(source);
    while (buffer->has_more()) {
      uint16_t character = buffer->GetNext();
      if (character >= 256) {
        escaped_length += 6;
      } else if (IsNotEscaped(character)) {
        escaped_length++;
      } else {
        escaped_length += 3;
      }
      // We don't allow strings that are longer than Smi range.
      if (!Smi::IsValid(escaped_length)) {
        Top::context()->mark_out_of_memory();
        return Failure::OutOfMemoryException();
      }
    }
  }
  // No length change implies no change.  Return original string if no change.
  if (escaped_length == length) {
    return source;
  }
  Object* o = Heap::AllocateRawAsciiString(escaped_length);
  if (o->IsFailure()) return o;
  String* destination = String::cast(o);
  int dest_position = 0;

  Access<StringInputBuffer> buffer(&string_input_buffer);
  buffer->Rewind();
  while (buffer->has_more()) {
    uint16_t character = buffer->GetNext();
    if (character >= 256) {
      destination->Set(dest_position, '%');
      destination->Set(dest_position+1, 'u');
      destination->Set(dest_position+2, hex_chars[character >> 12]);
      destination->Set(dest_position+3, hex_chars[(character >> 8) & 0xf]);
      destination->Set(dest_position+4, hex_chars[(character >> 4) & 0xf]);
      destination->Set(dest_position+5, hex_chars[character & 0xf]);
      dest_position += 6;
    } else if (IsNotEscaped(character)) {
      destination->Set(dest_position, character);
      dest_position++;
    } else {
      destination->Set(dest_position, '%');
      destination->Set(dest_position+1, hex_chars[character >> 4]);
      destination->Set(dest_position+2, hex_chars[character & 0xf]);
      dest_position += 3;
    }
  }
  return destination;
}


static inline int TwoDigitHex(uint16_t character1, uint16_t character2) {
  static const signed char kHexValue['g'] = {
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    0,  1,  2,   3,  4,  5,  6,  7,  8,  9, -1, -1, -1, -1, -1, -1,
    -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, 10, 11, 12, 13, 14, 15 };

  if (character1 > 'f') return -1;
  int hi = kHexValue[character1];
  if (hi == -1) return -1;
  if (character2 > 'f') return -1;
  int lo = kHexValue[character2];
  if (lo == -1) return -1;
  return (hi << 4) + lo;
}


static inline int Unescape(String* source, int i, int length, int* step) {
  uint16_t character = source->Get(i);
  int32_t hi, lo;
  if (character == '%' &&
      i <= length - 6 &&
      source->Get(i + 1) == 'u' &&
      (hi = TwoDigitHex(source->Get(i + 2), source->Get(i + 3))) != -1 &&
      (lo = TwoDigitHex(source->Get(i + 4), source->Get(i + 5))) != -1) {
    *step = 6;
    return (hi << 8) + lo;
  } else if (character == '%' &&
      i <= length - 3 &&
      (lo = TwoDigitHex(source->Get(i + 1), source->Get(i + 2))) != -1) {
    *step = 3;
    return lo;
  } else {
    *step = 1;
    return character;
  }
}


static Object* Runtime_URIUnescape(Arguments args) {
  NoHandleAllocation ha;
  ASSERT(args.length() == 1);
  CONVERT_CHECKED(String, source, args[0]);

  source->TryFlatten();

  bool ascii = true;
  int length = source->length();

  int unescaped_length = 0;
  for (int i = 0; i < length; unescaped_length++) {
    int step;
    if (Unescape(source, i, length, &step) > String::kMaxAsciiCharCode)
      ascii = false;
    i += step;
  }

  // No length change implies no change.  Return original string if no change.
  if (unescaped_length == length)
    return source;

  Object* o = ascii ?
              Heap::AllocateRawAsciiString(unescaped_length) :
              Heap::AllocateRawTwoByteString(unescaped_length);
  if (o->IsFailure()) return o;
  String* destination = String::cast(o);

  int dest_position = 0;
  for (int i = 0; i < length; dest_position++) {
    int step;
    destination->Set(dest_position, Unescape(source, i, length, &step));
    i += step;
  }
  return destination;
}


static Object* Runtime_StringParseInt(Arguments args) {
  NoHandleAllocation ha;

  CONVERT_CHECKED(String, s, args[0]);
  CONVERT_DOUBLE_CHECKED(n, args[1]);
  int radix = FastD2I(n);

  s->TryFlatten();

  int len = s->length();
  int i;

  // Skip leading white space.
  for (i = 0; i < len && Scanner::kIsWhiteSpace.get(s->Get(i)); i++) ;
  if (i == len) return Heap::nan_value();

  // Compute the sign (default to +).
  int sign = 1;
  if (s->Get(i) == '-') {
    sign = -1;
    i++;
  } else if (s->Get(i) == '+') {
    i++;
  }

  // Compute the radix if 0.
  if (radix == 0) {
    radix = 10;
    if (i < len && s->Get(i) == '0') {
      radix = 8;
      if (i + 1 < len) {
        int c = s->Get(i + 1);
        if (c == 'x' || c == 'X') {
          radix = 16;
          i += 2;
        }
      }
    }
  } else if (radix == 16) {
    // Allow 0x or 0X prefix if radix is 16.
    if (i + 1 < len && s->Get(i) == '0') {
      int c = s->Get(i + 1);
      if (c == 'x' || c == 'X') i += 2;
    }
  }

  RUNTIME_ASSERT(2 <= radix && radix <= 36);
  double value;
  int end_index = StringToInt(s, i, radix, &value);
  if (end_index != i) {
    return Heap::NumberFromDouble(sign * value);
  }
  return Heap::nan_value();
}


static Object* Runtime_StringParseFloat(Arguments args) {
  NoHandleAllocation ha;
  CONVERT_CHECKED(String, str, args[0]);

  // ECMA-262 section 15.1.2.3, empty string is NaN
  double value = StringToDouble(str, ALLOW_TRAILING_JUNK, OS::nan_value());

  // Create a number object from the value.
  return Heap::NumberFromDouble(value);
}


static unibrow::Mapping<unibrow::ToUppercase, 128> to_upper_mapping;
static unibrow::Mapping<unibrow::ToLowercase, 128> to_lower_mapping;


template <class Converter>
static Object* ConvertCase(Arguments args,
                           unibrow::Mapping<Converter, 128>* mapping) {
  NoHandleAllocation ha;

  CONVERT_CHECKED(String, s, args[0]);
  int raw_string_length = s->length();
  // Assume that the string is not empty; we need this assumption later
  if (raw_string_length == 0) return s;
  int length = raw_string_length;

  s->TryFlatten();

  // We try this twice, once with the assumption that the result is
  // no longer than the input and, if that assumption breaks, again
  // with the exact length.  This is implemented using a goto back
  // to this label if we discover that the assumption doesn't hold.
  // I apologize sincerely for this and will give a vaffel-is to
  // the first person who can implement it in a nicer way.
 try_convert:

  // Allocate the resulting string.
  //
  // NOTE: This assumes that the upper/lower case of an ascii
  // character is also ascii.  This is currently the case, but it
  // might break in the future if we implement more context and locale
  // dependent upper/lower conversions.
  Object* o = s->IsAscii()
      ? Heap::AllocateRawAsciiString(length)
      : Heap::AllocateRawTwoByteString(length);
  if (o->IsFailure()) return o;
  String* result = String::cast(o);
  bool has_changed_character = false;

  // Convert all characters to upper case, assuming that they will fit
  // in the buffer
  Access<StringInputBuffer> buffer(&string_input_buffer);
  buffer->Reset(s);
  unibrow::uchar chars[unibrow::kMaxCaseConvertedSize];
  int i = 0;
  // We can assume that the string is not empty
  uc32 current = buffer->GetNext();
  while (i < length) {
    uc32 next = buffer->has_more() ? buffer->GetNext() : 0;
    int char_length = mapping->get(current, next, chars);
    if (char_length == 0) {