Adding template parameter to PrototypeIterator GetCurrent for casting

src/prototype.h

 // Copyright 2014 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.
 
 #ifndef V8_PROTOTYPE_H_
 #define V8_PROTOTYPE_H_
 
 #include "src/isolate.h"
 #include "src/objects.h"
 
@@ skipping 21 matching lines @@
                     WhereToStart where_to_start = START_AT_PROTOTYPE)
       : did_jump_to_prototype_chain_(false),
         object_(NULL),
         handle_(receiver),
         isolate_(isolate) {
     CHECK(!handle_.is_null());
     if (where_to_start == START_AT_PROTOTYPE) {
       Advance();
     }
   }
+
   PrototypeIterator(Isolate* isolate, Object* receiver,
                     WhereToStart where_to_start = START_AT_PROTOTYPE)
       : did_jump_to_prototype_chain_(false),
         object_(receiver),
         isolate_(isolate) {
     if (where_to_start == START_AT_PROTOTYPE) {
       Advance();
     }
   }
+
   explicit PrototypeIterator(Map* receiver_map)
       : did_jump_to_prototype_chain_(true),
         object_(receiver_map->prototype()),
         isolate_(receiver_map->GetIsolate()) {}
+
   explicit PrototypeIterator(Handle<Map> receiver_map)
       : did_jump_to_prototype_chain_(true),
         object_(NULL),
         handle_(handle(receiver_map->prototype(), receiver_map->GetIsolate())),
         isolate_(receiver_map->GetIsolate()) {}
+
   ~PrototypeIterator() {}
 
-  Object* GetCurrent() const {
+  template <typename T = Object>
+  T* GetCurrent() const {
     DCHECK(handle_.is_null());
-    return object_;
+    return T::cast(object_);
   }
-  static Handle<Object> GetCurrent(const PrototypeIterator& iterator) {
+
+  template <typename T = Object>
+  static Handle<T> GetCurrent(const PrototypeIterator& iterator) {
     DCHECK(!iterator.handle_.is_null());
-    return iterator.handle_;
+    return Handle<T>::cast(iterator.handle_);
   }
+
   void Advance() {
     if (handle_.is_null() && object_->IsJSProxy()) {
       did_jump_to_prototype_chain_ = true;
       object_ = isolate_->heap()->null_value();
       return;
     } else if (!handle_.is_null() && handle_->IsJSProxy()) {
       did_jump_to_prototype_chain_ = true;
       handle_ = handle(isolate_->heap()->null_value(), isolate_);
       return;
     }
     AdvanceIgnoringProxies();
   }
+
   void AdvanceIgnoringProxies() {
     if (!did_jump_to_prototype_chain_) {
       did_jump_to_prototype_chain_ = true;
       if (handle_.is_null()) {
         object_ = object_->GetRootMap(isolate_)->prototype();
       } else {
         handle_ = handle(handle_->GetRootMap(isolate_)->prototype(), isolate_);
       }
     } else {
       if (handle_.is_null()) {
         object_ = HeapObject::cast(object_)->map()->prototype();
       } else {
         handle_ =
             handle(HeapObject::cast(*handle_)->map()->prototype(), isolate_);
       }
     }
   }
+
   bool IsAtEnd(WhereToEnd where_to_end = END_AT_NULL) const {
     if (handle_.is_null()) {
       return object_->IsNull() ||
              (did_jump_to_prototype_chain_ &&
               where_to_end == END_AT_NON_HIDDEN &&
               !HeapObject::cast(object_)->map()->is_hidden_prototype());
     } else {
       return handle_->IsNull() ||
              (did_jump_to_prototype_chain_ &&
               where_to_end == END_AT_NON_HIDDEN &&
               !Handle<HeapObject>::cast(handle_)->map()->is_hidden_prototype());
     }
   }
+
   bool IsAtEnd(Object* final_object) {
     DCHECK(handle_.is_null());
     return object_->IsNull() || object_ == final_object;
   }
+
   bool IsAtEnd(Handle<Object> final_object) {
     DCHECK(!handle_.is_null());
     return handle_->IsNull() || *handle_ == *final_object;
   }
 
  private:
   bool did_jump_to_prototype_chain_;
   Object* object_;
   Handle<Object> handle_;
   Isolate* isolate_;
 
   DISALLOW_COPY_AND_ASSIGN(PrototypeIterator);
 };
 
 
 }  // namespace internal
 
 }  // namespace v8
 
 #endif  // V8_PROTOTYPE_H_