From aafb224147555c59d5abd277cc45f76668ac7046 Mon Sep 17 00:00:00 2001
From: Anna Henningsen <anna@addaleax.net>
Date: Wed, 15 Jan 2020 20:20:06 +0100
Subject: [PATCH] src: exclude C++ SetImmediate() from count

There is no real reason to manage a count manually, given that
checking whether there are C++ callbacks is a single pointer
comparison.

This makes it easier to add other kinds of native C++ callbacks
that are managed in a similar way.

Backport-PR-URL: https://github.com/nodejs/node/pull/32301
PR-URL: https://github.com/nodejs/node/pull/31386
Refs: https://github.com/openjs-foundation/summit/pull/240
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
---
 src/env-inl.h |  9 ---------
 src/env.cc    | 12 ++++--------
 src/env.h     |  2 --
 3 files changed, 4 insertions(+), 19 deletions(-)

diff --git a/src/env-inl.h b/src/env-inl.h
index 5ad84e8222a52f..0de92c25cb7997 100644
--- a/src/env-inl.h
+++ b/src/env-inl.h
@@ -242,14 +242,6 @@ inline bool ImmediateInfo::has_outstanding() const {
   return fields_[kHasOutstanding] == 1;
 }
 
-inline void ImmediateInfo::count_inc(uint32_t increment) {
-  fields_[kCount] += increment;
-}
-
-inline void ImmediateInfo::count_dec(uint32_t decrement) {
-  fields_[kCount] -= decrement;
-}
-
 inline void ImmediateInfo::ref_count_inc(uint32_t increment) {
   fields_[kRefCount] += increment;
 }
@@ -771,7 +763,6 @@ void Environment::CreateImmediate(Fn&& cb, bool ref) {
   auto callback = std::make_unique<NativeImmediateCallbackImpl<Fn>>(
       std::move(cb), ref);
   native_immediates_.Push(std::move(callback));
-  immediate_info()->count_inc(1);
 }
 
 template <typename Fn>
diff --git a/src/env.cc b/src/env.cc
index 61832920347c6b..ea0f2a4004a2c6 100644
--- a/src/env.cc
+++ b/src/env.cc
@@ -664,7 +664,6 @@ void Environment::RunAndClearNativeImmediates(bool only_refed) {
   TraceEventScope trace_scope(TRACING_CATEGORY_NODE1(environment),
                               "RunAndClearNativeImmediates", this);
   size_t ref_count = 0;
-  size_t count = 0;
 
   NativeImmediateQueue queue;
   queue.ConcatMove(std::move(native_immediates_));
@@ -673,7 +672,6 @@ void Environment::RunAndClearNativeImmediates(bool only_refed) {
     TryCatchScope try_catch(this);
     DebugSealHandleScope seal_handle_scope(isolate());
     while (std::unique_ptr<NativeImmediateCallback> head = queue.Shift()) {
-      count++;
       if (head->is_refed())
         ref_count++;
 
@@ -691,9 +689,10 @@ void Environment::RunAndClearNativeImmediates(bool only_refed) {
   };
   while (queue.size() > 0 && drain_list()) {}
 
-  DCHECK_GE(immediate_info()->count(), count);
-  immediate_info()->count_dec(count);
   immediate_info()->ref_count_dec(ref_count);
+
+  if (immediate_info()->ref_count() == 0)
+    ToggleImmediateRef(false);
 }
 
 
@@ -779,15 +778,12 @@ void Environment::CheckImmediate(uv_check_t* handle) {
   TraceEventScope trace_scope(TRACING_CATEGORY_NODE1(environment),
                               "CheckImmediate", env);
 
-  if (env->immediate_info()->count() == 0)
-    return;
-
   HandleScope scope(env->isolate());
   Context::Scope context_scope(env->context());
 
   env->RunAndClearNativeImmediates();
 
-  if (!env->can_call_into_js())
+  if (env->immediate_info()->count() == 0 || !env->can_call_into_js())
     return;
 
   do {
diff --git a/src/env.h b/src/env.h
index ce4668b5839968..86a8f43858f5e2 100644
--- a/src/env.h
+++ b/src/env.h
@@ -734,8 +734,6 @@ class ImmediateInfo : public MemoryRetainer {
   inline uint32_t count() const;
   inline uint32_t ref_count() const;
   inline bool has_outstanding() const;
-  inline void count_inc(uint32_t increment);
-  inline void count_dec(uint32_t decrement);
   inline void ref_count_inc(uint32_t increment);
   inline void ref_count_dec(uint32_t decrement);