objects.cc.svn-base

Google浏览器V8内核代码

      ASSERT(!value->IsTheHole() || result->IsReadOnly());
      return value->IsTheHole() ? Heap::undefined_value() : value;
    case CONSTANT_FUNCTION:
      return result->GetConstantFunction();
    case CALLBACKS:
      return GetPropertyWithCallback(receiver,
                                     result->GetCallbackObject(),
                                     name,
                                     holder);
    case INTERCEPTOR: {
      JSObject* recvr = JSObject::cast(receiver);
      return holder->GetPropertyWithInterceptor(recvr, name, attributes);
    }
    default:
      UNREACHABLE();
      return NULL;
  }
}


Object* Object::GetElementWithReceiver(Object* receiver, uint32_t index) {
  // Non-JS objects do not have integer indexed properties.
  if (!IsJSObject()) return Heap::undefined_value();
  return JSObject::cast(this)->GetElementWithReceiver(JSObject::cast(receiver),
                                                      index);
}


Object* Object::GetPrototype() {
  // The object is either a number, a string, a boolean, or a real JS object.
  if (IsJSObject()) return JSObject::cast(this)->map()->prototype();
  Context* context = Top::context()->global_context();

  if (IsNumber()) return context->number_function()->instance_prototype();
  if (IsString()) return context->string_function()->instance_prototype();
  if (IsBoolean()) {
    return context->boolean_function()->instance_prototype();
  } else {
    return Heap::null_value();
  }
}


void Object::ShortPrint() {
  HeapStringAllocator allocator;
  StringStream accumulator(&allocator);
  ShortPrint(&accumulator);
  accumulator.OutputToStdOut();
}


void Object::ShortPrint(StringStream* accumulator) {
  if (IsSmi()) {
    Smi::cast(this)->SmiPrint(accumulator);
  } else if (IsFailure()) {
    Failure::cast(this)->FailurePrint(accumulator);
  } else {
    HeapObject::cast(this)->HeapObjectShortPrint(accumulator);
  }
}


void Smi::SmiPrint() {
  PrintF("%d", value());
}


void Smi::SmiPrint(StringStream* accumulator) {
  accumulator->Add("%d", value());
}


void Failure::FailurePrint(StringStream* accumulator) {
  accumulator->Add("Failure(%d)", value());
}


void Failure::FailurePrint() {
  PrintF("Failure(%d)", value());
}


Failure* Failure::RetryAfterGC(int requested_bytes, AllocationSpace space) {
  ASSERT((space & ~kSpaceTagMask) == 0);
  int requested = requested_bytes >> kObjectAlignmentBits;
  int value = (requested << kSpaceTagSize) | space;
  // We can't very well allocate a heap number in this situation, and if the
  // requested memory is so large it seems reasonable to say that this is an
  // out of memory situation.  This fixes a crash in
  // js1_5/Regress/regress-303213.js.
  if (value >> kSpaceTagSize != requested ||
      !Smi::IsValid(value) ||
      value != ((value << kFailureTypeTagSize) >> kFailureTypeTagSize) ||
      !Smi::IsValid(value << kFailureTypeTagSize)) {
    Top::context()->mark_out_of_memory();
    return Failure::OutOfMemoryException();
  }
  return Construct(RETRY_AFTER_GC, value);
}


// Should a word be prefixed by 'a' or 'an' in order to read naturally in
// English?  Returns false for non-ASCII or words that don't start with
// a capital letter.  The a/an rule follows pronunciation in English.
// We don't use the BBC's overcorrect "an historic occasion" though if
// you speak a dialect you may well say "an 'istoric occasion".
static bool AnWord(String* str) {
  if (str->length() == 0) return false;  // a nothing
  int c0 = str->Get(0);
  int c1 = str->length() > 1 ? str->Get(1) : 0;
  if (c0 == 'U') {
    if (c1 > 'Z') {
      return true;  // an Umpire, but a UTF8String, a U
    }
  } else if (c0 == 'A' || c0 == 'E' || c0 == 'I' || c0 == 'O') {
    return true;   // an Ape, an ABCBook
  } else if ((c1 == 0 || (c1 >= 'A' && c1 <= 'Z')) &&
           (c0 == 'F' || c0 == 'H' || c0 == 'M' || c0 == 'N' || c0 == 'R' ||
            c0 == 'S' || c0 == 'X')) {
    return true;   // an MP3File, an M
  }
  return false;
}


Object* String::Flatten() {
#ifdef DEBUG
  // Do not attempt to flatten in debug mode when allocation is not
  // allowed.  This is to avoid an assertion failure when allocating.
  // Flattening strings is the only case where we always allow
  // allocation because no GC is performed if the allocation fails.
  if (!Heap::IsAllocationAllowed()) return this;
#endif

  switch (representation_tag()) {
    case kSlicedStringTag: {
      SlicedString* ss = SlicedString::cast(this);
      // The SlicedString constructor should ensure that there are no
      // SlicedStrings that are constructed directly on top of other
      // SlicedStrings.
      ASSERT(!ss->buffer()->IsSlicedString());
      Object* ok = String::cast(ss->buffer())->Flatten();
      if (ok->IsFailure()) return ok;
      return this;
    }
    case kConsStringTag: {
      ConsString* cs = ConsString::cast(this);
      if (String::cast(cs->second())->length() == 0) {
        return this;
      }
      // There's little point in putting the flat string in new space if the
      // cons string is in old space.  It can never get GCed until there is
      // an old space GC.
      PretenureFlag tenure = Heap::InNewSpace(this) ? NOT_TENURED : TENURED;
      Object* object = IsAscii() ?
          Heap::AllocateRawAsciiString(length(), tenure) :
          Heap::AllocateRawTwoByteString(length(), tenure);
      if (object->IsFailure()) return object;
      String* result = String::cast(object);
      Flatten(this, result, 0, length(), 0);
      cs->set_first(result);
      cs->set_second(Heap::empty_string());
      return this;
    }
    default:
      return this;
  }
}


void String::StringShortPrint(StringStream* accumulator) {
  int len = length();
  if (len > kMaxMediumStringSize) {
    accumulator->Add("<Very long string[%u]>", len);
    return;
  }

  if (!LooksValid()) {
    accumulator->Add("<Invalid String>");
    return;
  }

  StringInputBuffer buf(this);

  bool truncated = false;
  if (len > kMaxShortPrintLength) {
    len = kMaxShortPrintLength;
    truncated = true;
  }
  bool ascii = true;
  for (int i = 0; i < len; i++) {
    int c = buf.GetNext();

    if (c < 32 || c >= 127) {
      ascii = false;
    }
  }
  buf.Reset(this);
  if (ascii) {
    accumulator->Add("<String[%u]: ", length());
    for (int i = 0; i < len; i++) {
      accumulator->Put(buf.GetNext());
    }
    accumulator->Put('>');
  } else {
    // Backslash indicates that the string contains control
    // characters and that backslashes are therefore escaped.
    accumulator->Add("<String[%u]\\: ", length());
    for (int i = 0; i < len; i++) {
      int c = buf.GetNext();
      if (c == '\n') {
        accumulator->Add("\\n");
      } else if (c == '\r') {
        accumulator->Add("\\r");
      } else if (c == '\\') {
        accumulator->Add("\\\\");
      } else if (c < 32 || c > 126) {
        accumulator->Add("\\x%02x", c);
      } else {
        accumulator->Put(c);
      }
    }
    if (truncated) {
      accumulator->Put('.');
      accumulator->Put('.');
      accumulator->Put('.');
    }
    accumulator->Put('>');
  }
  return;
}


void JSObject::JSObjectShortPrint(StringStream* accumulator) {
  switch (map()->instance_type()) {
    case JS_ARRAY_TYPE: {
      double length = JSArray::cast(this)->length()->Number();
      accumulator->Add("<JS array[%u]>", static_cast<uint32_t>(length));
      break;
    }
    case JS_REGEXP_TYPE: {
      accumulator->Add("<JS RegExp>");
      break;
    }
    case JS_FUNCTION_TYPE: {
      Object* fun_name = JSFunction::cast(this)->shared()->name();
      bool printed = false;
      if (fun_name->IsString()) {
        String* str = String::cast(fun_name);
        if (str->length() > 0) {
          accumulator->Add("<JS Function ");
          accumulator->Put(str);
          accumulator->Put('>');
          printed = true;
        }
      }
      if (!printed) {
        accumulator->Add("<JS Function>");
      }
      break;
    }
    // All other JSObjects are rather similar to each other (JSObject,
    // JSGlobalObject, JSUndetectableObject, JSValue).
    default: {
      Object* constructor = map()->constructor();
      bool printed = false;
      if (constructor->IsHeapObject() &&
          !Heap::Contains(HeapObject::cast(constructor))) {
        accumulator->Add("!!!INVALID CONSTRUCTOR!!!");
      } else {
        bool global_object = IsJSGlobalObject();
        if (constructor->IsJSFunction()) {
          if (!Heap::Contains(JSFunction::cast(constructor)->shared())) {
            accumulator->Add("!!!INVALID SHARED ON CONSTRUCTOR!!!");
          } else {
            Object* constructor_name =
                JSFunction::cast(constructor)->shared()->name();
            if (constructor_name->IsString()) {
              String* str = String::cast(constructor_name);
              if (str->length() > 0) {
                bool vowel = AnWord(str);
                accumulator->Add("<%sa%s ",
                       global_object ? "JS Global Object: " : "",
                       vowel ? "n" : "");
                accumulator->Put(str);
                accumulator->Put('>');
                printed = true;
              }
            }
          }
        }
        if (!printed) {
          accumulator->Add("<JS %sObject", global_object ? "Global " : "");
        }
      }
      if (IsJSValue()) {
        accumulator->Add(" value = ");
        JSValue::cast(this)->value()->ShortPrint(accumulator);
      }
      accumulator->Put('>');
      break;
    }
  }
}


void HeapObject::HeapObjectShortPrint(StringStream* accumulator) {
  // if (!Heap::InNewSpace(this)) PrintF("*", this);
  if (!Heap::Contains(this)) {
    accumulator->Add("!!!INVALID POINTER!!!");
    return;
  }
  if (!Heap::Contains(map())) {
    accumulator->Add("!!!INVALID MAP!!!");
    return;
  }

  accumulator->Add("%p ", this);

  if (IsString()) {
    String::cast(this)->StringShortPrint(accumulator);
    return;
  }
  if (IsJSObject()) {
    JSObject::cast(this)->JSObjectShortPrint(accumulator);
    return;
  }
  switch (map()->instance_type()) {
    case MAP_TYPE:
      accumulator->Add("<Map>");
      break;
    case FIXED_ARRAY_TYPE:
      accumulator->Add("<FixedArray[%u]>", FixedArray::cast(this)->length());
      break;
    case BYTE_ARRAY_TYPE:
      accumulator->Add("<ByteArray[%u]>", ByteArray::cast(this)->length());
      break;
    case SHARED_FUNCTION_INFO_TYPE:
      accumulator->Add("<SharedFunctionInfo>");
      break;
#define MAKE_STRUCT_CASE(NAME, Name, name) \
  case NAME##_TYPE:                        \
    accumulator->Add(#Name);               \
    break;
  STRUCT_LIST(MAKE_STRUCT_CASE)
#undef MAKE_STRUCT_CASE
    case CODE_TYPE:
      accumulator->Add("<Code>");
      break;
    case ODDBALL_TYPE: {
      if (IsUndefined())
        accumulator->Add("<undefined>");
      else if (IsTheHole())
        accumulator->Add("<the hole>");
      else if (IsNull())
        accumulator->Add("<null>");
      else if (IsTrue())
        accumulator->Add("<true>");
      else if (IsFalse())
        accumulator->Add("<false>");
      else
        accumulator->Add("<Odd Oddball>");
      break;
    }
    case HEAP_NUMBER_TYPE:
      accumulator->Add("<Number: ");
      HeapNumber::cast(this)->HeapNumberPrint(accumulator);
      accumulator->Put('>');
      break;
    case PROXY_TYPE:
      accumulator->Add("<Proxy>");
      break;
    default:
      accumulator->Add("<Other heap object (%d)>", map()->instance_type());
      break;
  }
}


int HeapObject::SlowSizeFromMap(Map* map) {
  // Avoid calling functions such as FixedArray::cast during GC, which
  // read map pointer of this object again.