Add napi_finalize override to ObjectWrap

doc/object_wrap.md

@@ -190,25 +190,16 @@ property of the `Napi::CallbackInfo`.
 
 Returns a `Napi::Function` representing the constructor function for the class.
 
-### OverrideFinalizeCallback
+### Finalize
 
-Overrides default `Napi::ObjectWrap::FinalizeCallback` with a user defined finalizer.
+Hooks into `Napi::ObjectWrap::FinalizeCallback` giving access to `Napi::Env`
+before the native instance is freed.
 
 ```cpp
-static void Napi::ObjectWrap::OverrideFinalizeCallback(T* instance,
-                  napi_finalize finalizeCallback);
+virtual void Finalize(Napi::Env env);
 ```
 
-- `[in] instance`: `this` pointer from the native instance.
-- `[in] finalizeCallback`: function that implements [napi_finalize](https://nodejs.org/api/n-api.html#n_api_napi_finalize "N-API documentation for napi_finalize.").
-
-`Napi::ObjectWrap::OverrideFinalizeCallback` is protected and
-intended to be called from a native instance method; for example, in the native
-constructor.
-
-NOTE: The default `Napi::ObjectWrap::FinalizeCallback` frees
-the native instance.  A user defined finalzier is, therefore, 
-responsible for freeing the native instance.
+- `[in] env`: `Napi::Env`.
 
 ### StaticMethod
 

napi-inl.h

@@ -3260,11 +3260,7 @@ inline ClassPropertyDescriptor<T> ObjectWrap<T>::InstanceValue(
 }
 
 template <typename T>
-inline void ObjectWrap<T>::OverrideFinalizeCallback(T* instance,
-    napi_finalize finalizeCallback) {
-  ObjectWrap<T>* base = instance;
-  base->_finalizeCallbackOverride = finalizeCallback;
-}
+inline void ObjectWrap<T>::Finalize(Napi::Env env) {}
 
 template <typename T>
 inline napi_value ObjectWrap<T>::ConstructorCallbackWrapper(
@@ -3407,13 +3403,10 @@ inline napi_value ObjectWrap<T>::InstanceSetterCallbackWrapper(
 }
 
 template <typename T>
-inline void ObjectWrap<T>::FinalizeCallback(napi_env env, void* data, void* hint) {
+inline void ObjectWrap<T>::FinalizeCallback(napi_env env, void* data, void* /*hint*/) {
   T* instance = reinterpret_cast<T*>(data);
-  if(instance->_finalizeCallbackOverride == nullptr){
-    delete instance;
-  } else {
-    (*(instance->_finalizeCallbackOverride))(env, data, hint);
-  }
+  instance->Finalize(Napi::Env(env));
+  delete instance;
 }
 
 ////////////////////////////////////////////////////////////////////////////////

napi.h

@@ -1657,10 +1657,8 @@ namespace Napi {
     static PropertyDescriptor InstanceValue(Symbol name,
                                             Napi::Value value,
                                             napi_property_attributes attributes = napi_default);
-  protected:
-    static void OverrideFinalizeCallback(T* instance, napi_finalize finalizeCallback);
+    virtual void Finalize(Napi::Env env);
   private:
-    napi_finalize _finalizeCallbackOverride = nullptr;
     static napi_value ConstructorCallbackWrapper(napi_env env, napi_callback_info info);
     static napi_value StaticVoidMethodCallbackWrapper(napi_env env, napi_callback_info info);
     static napi_value StaticMethodCallbackWrapper(napi_env env, napi_callback_info info);