n-api: reduce gc finalization stress

#24494 fixed a crash but resulted in increased stress on gc finalization. A leak was reported in #26667 which we are still investigating. As part of this investigation I realized we can optimize to reduce amount of deferred finalization. Regardless of the root cause of the leak this should be a good optimization. It also resolves the leak for the case being reported in #26667. The OP in 26667 has confirmed that he can still recreate the original problem that 24494 fixed and that the fix still works with this optimization PR-URL: #27085 Reviewed-By: Ben Noordhuis <[email protected]> Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: James M Snell <[email protected]>

Author: mhdawson

src/js_native_api_v8.cc

@@ -227,24 +227,26 @@ class Reference : private Finalizer{
 // from one of Unwrap or napi_delete_reference.
 //
 // When it is called from Unwrap or napi_delete_reference we only
-// want to do the delete if the finalizer has already run,
+// want to do the delete if the finalizer has already run or
+// cannot have been queued to run (ie the reference count is > 0),
 // otherwise we may crash when the finalizer does run.
-// If the finalizer has not already run delay the delete until
-// the finalizer runs by not doing the delete
+// If the finalizer may have been queued and has not already run
+//delay the delete until the finalizer runs by not doing the delete
 // and setting _delete_self to true so that the finalizer will
 // delete it when it runs.
 //
 // The second way this is called is from
 // the finalizer and _delete_self is set. In this case we
 // know we need to do the deletion so just do it.
 staticvoidDelete(Reference* reference){
-if ((reference->_delete_self) || (reference->_finalize_ran)){
+if ((reference->RefCount() != 0) ||
+ (reference->_delete_self) ||
+ (reference->_finalize_ran)){
 delete reference;
  } else{
-//reduce the reference count to 0 and defer until
-//finalizer runs
+//defer until finalizer runs as
+//it may alread be queued
  reference->_delete_self = true;
-while (reference->Unref() != 0){}
  }
  }