Enable correct interceptor return values

This requires minor changes in user code due to the need to call
and return from Intercepted::No or Intercepted::Yes. While an
operator conversion on classes would have been nicer,
implicit conversion to void is not possible.

nan_callbacks.h

@@ -13,6 +13,19 @@ template<typename T> class FunctionCallbackInfo;
 template<typename T> class PropertyCallbackInfo;
 template<typename T> class Global;
 
+#if defined(V8_MAJOR_VERSION) && (V8_MAJOR_VERSION > 12 ||                     \
+  (V8_MAJOR_VERSION == 12 && defined(V8_MINOR_VERSION) && V8_MINOR_VERSION > 4))
+namespace Intercepted {
+  constexpr v8::Intercepted No() { return v8::Intercepted::kNo; }
+  constexpr v8::Intercepted Yes() { return v8::Intercepted::kYes; }
+};
+#else
+namespace Intercepted {
+  inline void No() {}
+  inline void Yes() {}
+};
+#endif
+
 typedef void(*FunctionCallback)(const FunctionCallbackInfo<v8::Value>&);
 typedef void(*GetterCallback)
     (v8::Local<v8::String>, const PropertyCallbackInfo<v8::Value>&);

test/cpp/indexedinterceptors.cpp

@@ -80,6 +80,7 @@ NAN_INDEX_GETTER(IndexedInterceptor::PropertyGetter) {
   } else {
     info.GetReturnValue().Set(Nan::New("bar").ToLocalChecked());
   }
+  return Intercepted::Yes();
 }
 
 NAN_INDEX_SETTER(IndexedInterceptor::PropertySetter) {
@@ -94,28 +95,34 @@ NAN_INDEX_SETTER(IndexedInterceptor::PropertySetter) {
   } else {
     info.GetReturnValue().Set(info.This());
   }
+  return Intercepted::Yes();
 }
 
 NAN_INDEX_ENUMERATOR(IndexedInterceptor::PropertyEnumerator) {
   v8::Local<v8::Array> arr = Nan::New<v8::Array>();
   Set(arr, 0, Nan::New(42));
   info.GetReturnValue().Set(arr);
+  return Intercepted::Yes();
 }
 
 NAN_INDEX_DELETER(IndexedInterceptor::PropertyDeleter) {
   IndexedInterceptor* interceptor =
     ObjectWrap::Unwrap<IndexedInterceptor>(info.Holder());
   std::strncpy(interceptor->buf, "goober", sizeof (interceptor->buf));
   info.GetReturnValue().Set(True());
+  return Intercepted::Yes();
 }
 
 NAN_INDEX_QUERY(IndexedInterceptor::PropertyQuery) {
   if (index == 1) {
     info.GetReturnValue().Set(Nan::New<v8::Integer>(v8::DontEnum));
+    return Intercepted::Yes();
   }
   if (index == 42) {
     info.GetReturnValue().Set(Nan::New(0));
+    return Intercepted::Yes();
   }
+  return Intercepted::No();
 }
 
 NODE_MODULE(indexedinterceptors, IndexedInterceptor::Init)

test/cpp/namedinterceptors.cpp

@@ -80,6 +80,7 @@ NAN_PROPERTY_GETTER(NamedInterceptor::PropertyGetter) {
   } else {
     info.GetReturnValue().Set(Nan::New("bar").ToLocalChecked());
   }
+  return Intercepted::Yes();
 }
 
 NAN_PROPERTY_SETTER(NamedInterceptor::PropertySetter) {
@@ -94,6 +95,7 @@ NAN_PROPERTY_SETTER(NamedInterceptor::PropertySetter) {
   } else {
     info.GetReturnValue().Set(info.This());
   }
+  return Intercepted::Yes();
 }
 
 NAN_PROPERTY_ENUMERATOR(NamedInterceptor::PropertyEnumerator) {
@@ -107,16 +109,20 @@ NAN_PROPERTY_DELETER(NamedInterceptor::PropertyDeleter) {
     ObjectWrap::Unwrap<NamedInterceptor>(info.Holder());
   std::strncpy(interceptor->buf, "goober", sizeof (interceptor->buf));
   info.GetReturnValue().Set(True());
+  return Intercepted::Yes();
 }
 
 NAN_PROPERTY_QUERY(NamedInterceptor::PropertyQuery) {
   Nan::Utf8String s(property);
   if (!std::strcmp(*s, "thing")) {
-    return info.GetReturnValue().Set(Nan::New<v8::Integer>(v8::DontEnum));
+    info.GetReturnValue().Set(Nan::New<v8::Integer>(v8::DontEnum));
+    return Intercepted::Yes();
   }
   if (!std::strcmp(*s, "value")) {
-    return info.GetReturnValue().Set(Nan::New(0));
+    info.GetReturnValue().Set(Nan::New(0));
+    return Intercepted::Yes();
   }
+  return Intercepted::No();
 }
 
 NODE_MODULE(namedinterceptors, NamedInterceptor::Init)