timers: allow Immediates to be unrefed

Refactor Immediates handling to allow for them to be unrefed, similar
to setTimeout, but without extra handles.

Document the new `immediate.ref()` and `immediate.unref()` methods.

Add SetImmediateUnref on the C++ side.

PR-URL: https://github.com/nodejs/node/pull/18139
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Franziska Hinkelmann <franziska.hinkelmann@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

1 files changed, 5 insertions, 13 deletions

diff --git a/src/node_perf.cc b/src/node_perf.cc
index 97d3a2d995..34e6a35000 100644
--- a/src/node_perf.cc
+++ b/src/node_perf.cc
@@ -182,9 +182,8 @@ void SetupPerformanceObservers(const FunctionCallbackInfo<Value>& args) {
 }
 
 // Creates a GC Performance Entry and passes it to observers
-void PerformanceGCCallback(uv_async_t* handle) {
-  GCPerformanceEntry* entry = static_cast<GCPerformanceEntry*>(handle->data);
-  Environment* env = entry->env();
+void PerformanceGCCallback(Environment* env, void* ptr) {
+  GCPerformanceEntry* entry = static_cast<GCPerformanceEntry*>(ptr);
   HandleScope scope(env->isolate());
   Local<Context> context = env->context();
 
@@ -201,10 +200,6 @@ void PerformanceGCCallback(uv_async_t* handle) {
   }
 
   delete entry;
-  auto closeCB = [](uv_handle_t* handle) {
-    delete reinterpret_cast<uv_async_t*>(handle);
-  };
-  uv_close(reinterpret_cast<uv_handle_t*>(handle), closeCB);
 }
 
 // Marks the start of a GC cycle
@@ -221,16 +216,13 @@ void MarkGarbageCollectionEnd(Isolate* isolate,
                               v8::GCCallbackFlags flags,
                               void* data) {
   Environment* env = static_cast<Environment*>(data);
-  uv_async_t* async = new uv_async_t();
-  if (uv_async_init(env->event_loop(), async, PerformanceGCCallback))
-    return delete async;
-  uv_unref(reinterpret_cast<uv_handle_t*>(async));
-  async->data =
+  GCPerformanceEntry* entry =
       new GCPerformanceEntry(env,
                              static_cast<PerformanceGCKind>(type),
                              performance_last_gc_start_mark_,
                              PERFORMANCE_NOW());
-  CHECK_EQ(0, uv_async_send(async));
+  env->SetUnrefImmediate(PerformanceGCCallback,
+                         entry);
 }