Create pre-frozen change records for Object.observe

src/objects.cc

 // 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 1732 matching lines @@
 }
 
 
 void JSObject::EnqueueChangeRecord(Handle<JSObject> object,
                                    const char* type_str,
                                    Handle<String> name,
                                    Handle<Object> old_value) {
   Isolate* isolate = object->GetIsolate();
   HandleScope scope;
   Handle<String> type = isolate->factory()->LookupUtf8Symbol(type_str);
-  if (object->IsJSGlobalObject()) {
+  EnqueueChangeRecord(object, type, name, old_value);
+}
+
+void JSObject::EnqueueChangeRecord(Handle<JSObject> object,
+                                   Handle<String> type,
+                                   Handle<String> name,
+                                   Handle<Object> old_value) {
+  Isolate* isolate = object->GetIsolate();
+  HandleScope scope;
+  if (object->IsJSGlobalObject())
     object = handle(JSGlobalObject::cast(*object)->global_receiver(), isolate);
+  Handle<JSObject> change_record = isolate->factory()->NewJSObjectFromMap(
+      old_value->IsTheHole()
+      ? isolate->change_record_map()
+      : isolate->change_record_oldvalue_map());
+
+  // Make sure both properties and elements are frozen.
+  ASSERT(!change_record->map()->is_extensible());
+  Handle<SeededNumberDictionary> elements = NormalizeElements(change_record);
+  elements->set_requires_slow_elements();
+
+  change_record->InObjectPropertyAtPut(JSChangeRecord::kTypeIndex, *type);
+  change_record->InObjectPropertyAtPut(JSChangeRecord::kObjectIndex, *object);
+  change_record->InObjectPropertyAtPut(JSChangeRecord::kNameIndex, *name);
+  if (!old_value->IsTheHole()) {
+    change_record->InObjectPropertyAtPut(
+        JSChangeRecord::kOldValueIndex, *old_value);
   }
-  Handle<Object> args[] = { type, object, name, old_value };
+
+  Handle<Object> args[] = { change_record };
   bool threw;
-  Execution::Call(Handle<JSFunction>(isolate->observers_notify_change()),
-                  Handle<Object>(isolate->heap()->undefined_value()),
-                  old_value->IsTheHole() ? 3 : 4, args,
-                  &threw);
+  Execution::Call(isolate->observers_notify_change(),
+                  isolate->factory()->undefined_value(),
+                  1, args, &threw);
   ASSERT(!threw);
 }
 
 
 void JSObject::DeliverChangeRecords(Isolate* isolate) {
   ASSERT(isolate->observer_delivery_pending());
   bool threw = false;
   Execution::Call(
       isolate->observers_deliver_changes(),
       isolate->factory()->undefined_value(),
@@ skipping 7635 matching lines @@
   }
 
   MaybeObject* result =
       self->GetElementsAccessor()->SetLength(*self, *new_length_handle);
   Handle<Object> hresult;
   if (!result->ToHandle(&hresult, isolate)) return result;
 
   CHECK(self->length()->ToArrayIndex(&new_length));
   if (old_length != new_length) {
     for (int i = 0; i < indices.length(); ++i) {
-      JSObject::EnqueueChangeRecord(
-          self, "deleted", indices[i], old_values[i]);
+      EnqueueChangeRecord(self, "deleted", indices[i], old_values[i]);
     }
-    JSObject::EnqueueChangeRecord(
-        self, "updated", isolate->factory()->length_symbol(),
-        old_length_handle);
+    EnqueueChangeRecord(self, "updated", isolate->factory()->length_symbol(),
+                        old_length_handle);
   }
   return *hresult;
 }
 
 
 Map* Map::GetPrototypeTransition(Object* prototype) {
   FixedArray* cache = GetPrototypeTransitions();
   int number_of_transitions = NumberOfProtoTransitions();
   const int proto_offset =
       kProtoTransitionHeaderSize + kProtoTransitionPrototypeOffset;
@@ skipping 4459 matching lines @@
   set_year(Smi::FromInt(year), SKIP_WRITE_BARRIER);
   set_month(Smi::FromInt(month), SKIP_WRITE_BARRIER);
   set_day(Smi::FromInt(day), SKIP_WRITE_BARRIER);
   set_weekday(Smi::FromInt(weekday), SKIP_WRITE_BARRIER);
   set_hour(Smi::FromInt(hour), SKIP_WRITE_BARRIER);
   set_min(Smi::FromInt(min), SKIP_WRITE_BARRIER);
   set_sec(Smi::FromInt(sec), SKIP_WRITE_BARRIER);
 }
 
 } }  // namespace v8::internal