src: do not persist timer handle in cares_wrap

Instead of relying on garbage collection to close the timer handle, manage its state more explicitly. PR-URL: #21093Fixes: #18190 Refs: #18307 Reviewed-By: Jeremiah Senkpiel <[email protected]> Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: Ben Noordhuis <[email protected]> Reviewed-By: Joyee Cheung <[email protected]> Reviewed-By: Colin Ihrig <[email protected]>

Author: apapirovski

src/cares_wrap.cc

@@ -151,7 +151,8 @@ class ChannelWrap : public AsyncWrap{
 
 voidSetup();
 voidEnsureServers();
-voidCleanupTimer();
+voidStartTimer();
+voidCloseTimer();
 
 voidModifyActivityQueryCount(int count);
 
@@ -313,13 +314,7 @@ void ares_sockstate_cb(void* data,
 if (read || write){
 if (!task){
 /* New socket */
-
-/* If this is the first socket then start the timer. */
-uv_timer_t* timer_handle = channel->timer_handle();
-if (!uv_is_active(reinterpret_cast<uv_handle_t*>(timer_handle))){
-CHECK(channel->task_list()->empty());
-uv_timer_start(timer_handle, ChannelWrap::AresTimeout, 1000, 1000);
- }
+ channel->StartTimer();
 
  task = ares_task_create(channel, sock);
 if (task == nullptr){
@@ -349,7 +344,7 @@ void ares_sockstate_cb(void* data,
  channel->env()->CloseHandle(&task->poll_watcher, ares_poll_close_cb);
 
 if (channel->task_list()->empty()){
-uv_timer_stop(channel->timer_handle());
+ channel->CloseTimer();
  }
  }
 }
@@ -490,15 +485,26 @@ void ChannelWrap::Setup(){
  }
 
  library_inited_ = true;
+}
 
-/* Initialize the timeout timer. The timer won't be started until the */
-/* first socket is opened. */
-CleanupTimer();
- timer_handle_ = newuv_timer_t();
- timer_handle_->data = static_cast<void*>(this);
-uv_timer_init(env()->event_loop(), timer_handle_);
+voidChannelWrap::StartTimer(){
+if (timer_handle_ == nullptr){
+ timer_handle_ = newuv_timer_t();
+ timer_handle_->data = static_cast<void*>(this);
+uv_timer_init(env()->event_loop(), timer_handle_);
+ } elseif (uv_is_active(reinterpret_cast<uv_handle_t*>(timer_handle_))){
+return;
+ }
+uv_timer_start(timer_handle_, AresTimeout, 1000, 1000);
 }
 
+voidChannelWrap::CloseTimer(){
+if (timer_handle_ == nullptr)
+return;
+
+env()->CloseHandle(timer_handle_, [](uv_timer_t* handle){delete handle});
+ timer_handle_ = nullptr;
+}
 
 ChannelWrap::~ChannelWrap(){
 if (library_inited_){
@@ -508,17 +514,10 @@ ChannelWrap::~ChannelWrap(){
  }
 
 ares_destroy(channel_);
-CleanupTimer();
+CloseTimer();
 }
 
 
-voidChannelWrap::CleanupTimer(){
-if (timer_handle_ == nullptr) return;
-
-env()->CloseHandle(timer_handle_, [](uv_timer_t* handle){delete handle});
- timer_handle_ = nullptr;
-}
-
 voidChannelWrap::ModifyActivityQueryCount(int count){
  active_query_count_ += count;
 if (active_query_count_ < 0) active_query_count_ = 0;
@@ -566,6 +565,7 @@ void ChannelWrap::EnsureServers(){
 /* destroy channel and reset channel */
 ares_destroy(channel_);
 
+CloseTimer();
 Setup();
 }