src: add helper for before/after scope without JS calls

Add `AsyncScope` for cases where the async_hooks `before` and
`after` callbacks should be called, to track async context,
but no actual JS is called in between and we can therefore
skip things like draining the microtask or `nextTick` queues.

PR-URL: https://github.com/nodejs/node/pull/18936
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/src/async_wrap.h b/src/async_wrap.h
index b7aed5d789..608764bab5 100644
--- a/src/async_wrap.h
+++ b/src/async_wrap.h
@@ -169,6 +169,18 @@ class AsyncWrap : public BaseObject {
 
   static void WeakCallback(const v8::WeakCallbackInfo<DestroyParam> &info);
 
+  // This is a simplified version of InternalCallbackScope that only runs
+  // the `before` and `after` hooks. Only use it when not actually calling
+  // back into JS; otherwise, use InternalCallbackScope.
+  class AsyncScope {
+   public:
+    explicit inline AsyncScope(AsyncWrap* wrap);
+    ~AsyncScope();
+
+   private:
+    AsyncWrap* wrap_ = nullptr;
+  };
+
  private:
   friend class PromiseWrap;