Ensure JSProxy correctness for PrototypeIterator uses

src/api.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/api.h"
 
 #include <string.h>  // For memcpy, strlen.
 #ifdef V8_USE_ADDRESS_SANITIZER
 #include <sanitizer/asan_interface.h>
 #endif  // V8_USE_ADDRESS_SANITIZER
@@ skipping 3729 matching lines @@
   auto isolate = Utils::OpenHandle(this)->GetIsolate();
   i::PrototypeIterator iter(isolate, *Utils::OpenHandle(this),
                             i::PrototypeIterator::START_AT_RECEIVER);
   auto tmpl_info = *Utils::OpenHandle(*tmpl);
   while (!tmpl_info->IsTemplateFor(iter.GetCurrent())) {
     iter.Advance();
     if (iter.IsAtEnd()) {
       return Local<Object>();
     }
   }
+  // IsTemplateFor() ensures that iter.GetCurrent() can't be a Proxy here.
   return Utils::ToLocal(i::handle(iter.GetCurrent<i::JSObject>(), isolate));
 }
 
 
 MaybeLocal<Array> v8::Object::GetPropertyNames(Local<Context> context) {
   PREPARE_FOR_EXECUTION(context, "v8::Object::GetPropertyNames()", Array);
   auto self = Utils::OpenHandle(this);
   i::Handle<i::FixedArray> value;
   has_pending_exception = !i::JSReceiver::GetKeys(
       self, i::JSReceiver::INCLUDE_PROTOS).ToHandle(&value);
@@ skipping 358 matching lines @@
 bool v8::Object::HasIndexedLookupInterceptor() {
   auto self = Utils::OpenHandle(this);
   return self->HasIndexedInterceptor();
 }
 
 
 MaybeLocal<Value> v8::Object::GetRealNamedPropertyInPrototypeChain(
     Local<Context> context, Local<Name> key) {
   PREPARE_FOR_EXECUTION(
       context, "v8::Object::GetRealNamedPropertyInPrototypeChain()", Value);
-  auto self = Utils::OpenHandle(this);
-  auto key_obj = Utils::OpenHandle(*key);
+  i::Handle<i::JSObject> self = Utils::OpenHandle(this);
+  i::Handle<i::Name> key_obj = Utils::OpenHandle(*key);
   i::PrototypeIterator iter(isolate, self);
   if (iter.IsAtEnd()) return MaybeLocal<Value>();
-  auto proto = i::PrototypeIterator::GetCurrent(iter);
+  i::Handle<i::JSReceiver> proto =
+      i::PrototypeIterator::GetCurrent<i::JSReceiver>(iter);
   i::LookupIterator it = i::LookupIterator::PropertyOrElement(
-      isolate, self, key_obj, i::Handle<i::JSReceiver>::cast(proto),
+      isolate, self, key_obj, proto,
       i::LookupIterator::PROTOTYPE_CHAIN_SKIP_INTERCEPTOR);
   Local<Value> result;
   has_pending_exception = !ToLocal<Value>(i::Object::GetProperty(&it), &result);
   RETURN_ON_FAILED_EXECUTION(Value);
   if (!it.IsFound()) return MaybeLocal<Value>();
   RETURN_ESCAPED(result);
 }
 
 
 Local<Value> v8::Object::GetRealNamedPropertyInPrototypeChain(
     Local<String> key) {
   auto context = ContextFromHeapObject(Utils::OpenHandle(this));
   RETURN_TO_LOCAL_UNCHECKED(GetRealNamedPropertyInPrototypeChain(context, key),
                             Value);
 }
 
 
 Maybe<PropertyAttribute>
 v8::Object::GetRealNamedPropertyAttributesInPrototypeChain(
     Local<Context> context, Local<Name> key) {
   PREPARE_FOR_EXECUTION_PRIMITIVE(
       context, "v8::Object::GetRealNamedPropertyAttributesInPrototypeChain()",
       PropertyAttribute);
-  auto self = Utils::OpenHandle(this);
-  auto key_obj = Utils::OpenHandle(*key);
+  i::Handle<i::JSObject> self = Utils::OpenHandle(this);
+  i::Handle<i::Name> key_obj = Utils::OpenHandle(*key);
   i::PrototypeIterator iter(isolate, self);
   if (iter.IsAtEnd()) return Nothing<PropertyAttribute>();
-  auto proto = i::PrototypeIterator::GetCurrent(iter);
+  i::Handle<i::JSReceiver> proto =
+      i::PrototypeIterator::GetCurrent<i::JSReceiver>(iter);
   i::LookupIterator it = i::LookupIterator::PropertyOrElement(
-      isolate, self, key_obj, i::Handle<i::JSReceiver>::cast(proto),
+      isolate, self, key_obj, proto,
       i::LookupIterator::PROTOTYPE_CHAIN_SKIP_INTERCEPTOR);
-  auto result = i::JSReceiver::GetPropertyAttributes(&it);
+  Maybe<PropertyAttributes> result = i::JSReceiver::GetPropertyAttributes(&it);
   RETURN_ON_FAILED_EXECUTION_PRIMITIVE(PropertyAttribute);
   if (!it.IsFound()) return Nothing<PropertyAttribute>();
-  if (result.FromJust() == ABSENT) {
-    return Just(static_cast<PropertyAttribute>(NONE));
-  }
-  return Just<PropertyAttribute>(
-      static_cast<PropertyAttribute>(result.FromJust()));
+  if (result.FromJust() == ABSENT) return Just(None);
+  return Just(static_cast<PropertyAttribute>(result.FromJust()));
 }
 
 
 Maybe<PropertyAttribute>
 v8::Object::GetRealNamedPropertyAttributesInPrototypeChain(Local<String> key) {
   auto context = ContextFromHeapObject(Utils::OpenHandle(this));
   return GetRealNamedPropertyAttributesInPrototypeChain(context, key);
 }
 
 
@@ skipping 4332 matching lines @@
   Address callback_address =
       reinterpret_cast<Address>(reinterpret_cast<intptr_t>(callback));
   VMState<EXTERNAL> state(isolate);
   ExternalCallbackScope call_scope(isolate, callback_address);
   callback(info);
 }
 
 
 }  // namespace internal
 }  // namespace v8