Introduce a PrototypeIterator class and use it for prototype access

src/accessors.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/compiler.h"
 #include "src/contexts.h"
 #include "src/deoptimizer.h"
 #include "src/execution.h"
 #include "src/factory.h"
 #include "src/frames-inl.h"
 #include "src/isolate.h"
 #include "src/list-inl.h"
 #include "src/property-details.h"
+#include "src/prototype.h"
 
 namespace v8 {
 namespace internal {
 
 
 // We have a slight impedance mismatch between the external API and the way we
 // use callbacks internally: Externally, callbacks can only be used with
 // v8::Object, but internally we even have callbacks on entities which are
 // higher in the hierarchy, so we can only return i::Object here, not
 // i::JSObject.
@@ skipping 32 matching lines @@
   info->set_expected_receiver_type(accessor->expected_receiver_type());
   info->set_getter(accessor->getter());
   info->set_setter(accessor->setter());
   info->set_data(accessor->data());
   return info;
 }
 
 
 template <class C>
 static C* FindInstanceOf(Isolate* isolate, Object* obj) {
-  for (Object* cur = obj; !cur->IsNull(); cur = cur->GetPrototype(isolate)) {
-    if (Is<C>(cur)) return C::cast(cur);
+  for (PrototypeIterator iter(isolate, obj,
+                              PrototypeIterator::START_AT_RECEIVER);
+       !iter.IsAtEnd(); iter.Advance()) {
+    if (Is<C>(iter.GetCurrent())) return C::cast(iter.GetCurrent());
   }
   return NULL;
 }
 
 
 static V8_INLINE bool CheckForName(Handle<String> name,
                                    Handle<String> property_name,
                                    int offset,
                                    int* object_offset) {
   if (String::Equals(name, property_name)) {
@@ skipping 1338 matching lines @@
   info->set_data(Smi::FromInt(index));
   Handle<Object> getter = v8::FromCData(isolate, &ModuleGetExport);
   Handle<Object> setter = v8::FromCData(isolate, &ModuleSetExport);
   info->set_getter(*getter);
   if (!(attributes & ReadOnly)) info->set_setter(*setter);
   return info;
 }
 
 
 } }  // namespace v8::internal