Provide private symbols through internal APIs

src/objects-inl.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 171 matching lines @@
 bool Object::NonFailureIsHeapObject() {
   ASSERT(!this->IsFailure());
   return (reinterpret_cast<intptr_t>(this) & kSmiTagMask) != 0;
 }
 
 
 TYPE_CHECKER(HeapNumber, HEAP_NUMBER_TYPE)
 TYPE_CHECKER(Symbol, SYMBOL_TYPE)
 
 
+bool Object::IsPrivate() {
+  return IsSymbol() && Symbol::cast(this)->name()->IsBox();
+}
+
+
 bool Object::IsString() {
   return Object::IsHeapObject()
     && HeapObject::cast(this)->map()->instance_type() < FIRST_NONSTRING_TYPE;
 }
 
 
 bool Object::IsName() {
   return IsString() || IsSymbol();
 }
 
@@ skipping 2393 matching lines @@
 CAST_ACCESSOR(String)
 CAST_ACCESSOR(SeqString)
 CAST_ACCESSOR(SeqOneByteString)
 CAST_ACCESSOR(SeqTwoByteString)
 CAST_ACCESSOR(SlicedString)
 CAST_ACCESSOR(ConsString)
 CAST_ACCESSOR(ExternalString)
 CAST_ACCESSOR(ExternalAsciiString)
 CAST_ACCESSOR(ExternalTwoByteString)
 CAST_ACCESSOR(Symbol)
+CAST_ACCESSOR(Private)
 CAST_ACCESSOR(Name)
 CAST_ACCESSOR(JSReceiver)
 CAST_ACCESSOR(JSObject)
 CAST_ACCESSOR(Smi)
 CAST_ACCESSOR(HeapObject)
 CAST_ACCESSOR(HeapNumber)
 CAST_ACCESSOR(Oddball)
 CAST_ACCESSOR(Cell)
 CAST_ACCESSOR(PropertyCell)
 CAST_ACCESSOR(SharedFunctionInfo)
@@ skipping 70 matching lines @@
       this->IsSymbol() || other->IsSymbol()) {
     return false;
   }
   return String::cast(this)->SlowEquals(String::cast(other));
 }
 
 
 ACCESSORS(Symbol, name, Object, kNameOffset)
 
 
+Object* Private::name() {
+  ASSERT(IsPrivate());
+  return Box::cast(Symbol::name())->value();

[Yang, 2013/10/29 12:47:26]

could we assert in those accessors that the value is either undefined or a
string?

[rossberg, 2013/10/29 15:08:19]

Yeah, that is nasty. I decided to remove the whole Box hack and simply add a
flags field to the Symbol representation. Screw premature optimisation.

+}
+
+
+void Private::set_name(Object* value, WriteBarrierMode mode) {
+  ASSERT(IsPrivate());
+  return Box::cast(Symbol::name())->set_value(value, mode);
+}
+
+
 bool String::Equals(String* other) {
   if (other == this) return true;
   if (this->IsInternalizedString() && other->IsInternalizedString()) {
     return false;
   }
   return SlowEquals(other);
 }
 
 
 MaybeObject* String::TryFlatten(PretenureFlag pretenure) {
@@ skipping 3693 matching lines @@
 #undef WRITE_UINT32_FIELD
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_