Prepare DefinePropertyAccessor for callback transitions.

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 4392 matching lines @@
   AccessorPair* accessors;
   { MaybeObject* maybe_accessors = GetHeap()->AllocateAccessorPair();
     if (!maybe_accessors->To(&accessors)) return maybe_accessors;
   }
   accessors->SetComponents(getter, setter);
 
   return SetElementCallback(index, accessors, attributes);
 }
 
 
+MaybeObject* JSObject::CreateAccessorPairFor(String* name) {
+  LookupResult result(GetHeap()->isolate());
+  LocalLookupRealNamedProperty(name, &result);
+  if (result.IsProperty() && result.type() == CALLBACKS) {
+    ASSERT(!result.IsDontDelete());
+    Object* obj = result.GetCallbackObject();
+    if (obj->IsAccessorPair()) {
+      return AccessorPair::cast(obj)->CopyWithoutTransitions();
+    }
+  }
+  return GetHeap()->AllocateAccessorPair();
+}
+
+
 MaybeObject* JSObject::DefinePropertyAccessor(String* name,
                                               Object* getter,
                                               Object* setter,
                                               PropertyAttributes attributes) {
-  // Lookup the name.
-  LookupResult result(GetHeap()->isolate());
-  LocalLookupRealNamedProperty(name, &result);
-  if (result.IsFound()) {
-    if (result.type() == CALLBACKS) {
-      ASSERT(!result.IsDontDelete());
-      Object* obj = result.GetCallbackObject();
-      // Need to preserve old getters/setters.
-      if (obj->IsAccessorPair()) {
-        AccessorPair* copy;
-        { MaybeObject* maybe_copy =
-              AccessorPair::cast(obj)->CopyWithoutTransitions();
-          if (!maybe_copy->To(&copy)) return maybe_copy;
-        }
-        copy->SetComponents(getter, setter);
-        // Use set to update attributes.
-        return SetPropertyCallback(name, copy, attributes);
-      }
-    }
-  }
-
   AccessorPair* accessors;
-  { MaybeObject* maybe_accessors = GetHeap()->AllocateAccessorPair();
+  { MaybeObject* maybe_accessors = CreateAccessorPairFor(name);
     if (!maybe_accessors->To(&accessors)) return maybe_accessors;
   }
   accessors->SetComponents(getter, setter);
-
   return SetPropertyCallback(name, accessors, attributes);
 }
 
 
 bool JSObject::CanSetCallback(String* name) {
   ASSERT(!IsAccessCheckNeeded() ||
          GetIsolate()->MayNamedAccess(this, name, v8::ACCESS_SET));
 
   // Check if there is an API defined callback object which prohibits
   // callback overwriting in this object or it's prototype chain.
@@ skipping 8519 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