From d7d22ead2b2fd28208475e87e7dd8ed9859e1ac5 Mon Sep 17 00:00:00 2001
From: Anna Henningsen <anna@addaleax.net>
Date: Thu, 10 Aug 2017 16:56:04 +0200
Subject: [PATCH] src: add comments for cares library init refcount
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Ref: https://github.com/nodejs/node/pull/14738
PR-URL: https://github.com/nodejs/node/pull/14743
Reviewed-By: Timothy Gu <timothygu99@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Khaidi Chu <i@2333.moe>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
---
 src/cares_wrap.cc | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/cares_wrap.cc b/src/cares_wrap.cc
index 53a005444cc498..7869651a456c0a 100644
--- a/src/cares_wrap.cc
+++ b/src/cares_wrap.cc
@@ -489,6 +489,8 @@ void ChannelWrap::Setup() {
 
   int r;
   if (!library_inited_) {
+    // Multiple calls to ares_library_init() increase a reference counter,
+    // so this is a no-op except for the first call to it.
     r = ares_library_init(ARES_LIB_INIT_ALL);
     if (r != ARES_SUCCESS)
       return env()->ThrowError(ToErrorCodeString(r));
@@ -516,8 +518,10 @@ void ChannelWrap::Setup() {
 
 
 ChannelWrap::~ChannelWrap() {
-  if (library_inited_)
+  if (library_inited_) {
+    // This decreases the reference counter increased by ares_library_init().
     ares_library_cleanup();
+  }
 
   ares_destroy(channel_);
   CleanupTimer();