API: added function to find instance of template in prototype chain.

src/objects-inl.h

 // Copyright 2006-2008 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 82 matching lines @@
 
 #define BOOL_ACCESSORS(holder, field, name, offset) \
   bool holder::name() {                                    \
     return BooleanBit::get(field(), offset);               \
   }                                                        \
   void holder::set_##name(bool value) {                    \
     set_##field(BooleanBit::set(field(), offset, value));  \
   }
 
 
+bool Object::IsInstanceOf(FunctionTemplateInfo* expected) {
+  // There is a constraint on the object; check.
+  if (!this->IsJSObject()) return false;
+  // Fetch the constructor function of the object.
+  Object* cons_obj = JSObject::cast(this)->map()->constructor();
+  if (!cons_obj->IsJSFunction()) return false;
+  JSFunction* fun = JSFunction::cast(cons_obj);
+  // Iterate through the chain of inheriting function templates to
+  // see if the required one occurs.
+  for (Object* type = fun->shared()->function_data();
+       type->IsFunctionTemplateInfo();
+       type = FunctionTemplateInfo::cast(type)->parent_template()) {
+    if (type == expected) return true;
+  }
+  // Didn't find the required type in the inheritance chain.
+  return false;
+}
+
+
 bool Object::IsSmi() {
   return HAS_SMI_TAG(this);
 }
 
 
 bool Object::IsHeapObject() {
   return HAS_HEAP_OBJECT_TAG(this);
 }
 
 
@@ skipping 2716 matching lines @@
 #undef WRITE_INT_FIELD
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_