Planning: updated stop in reference line provider.

modules/planning/reference_line/reference_line_provider.cc

@@ -60,6 +60,13 @@ bool ReferenceLineProvider::Start() {
   return true;
 }
 
+void ReferenceLineProvider::Stop() {
+  is_stop_ = true;
+  if (thread_ && thread_->joinable()) {
+    thread_->join();
+  }
+}
+
 void ReferenceLineProvider::Generate() {
   while (!is_stop_) {
     const auto &curr_adc_position =

modules/planning/reference_line/reference_line_provider.h

@@ -57,7 +57,8 @@ class ReferenceLineProvider {
             const ReferenceLineSmootherConfig& smoother_config);
 
   bool Start();
-  void Stop() { is_stop_ = true; }
+
+  void Stop();
 
   std::vector<ReferenceLine> GetReferenceLines();