From 3288bdd2c5d2923c79af355a70ab69d99d59bacd Mon Sep 17 00:00:00 2001
From: Barry Xu <43591679+Barry-Xu-2018@users.noreply.github.com>
Date: Tue, 3 Dec 2019 05:38:41 +0800
Subject: [PATCH] Use weak_ptr to store context in GraphListener (#906)

* Use weak_ptr to store context in graph listener

Signed-off-by: Barry Xu <Barry.Xu@sony.com>
---
 rclcpp/include/rclcpp/graph_listener.hpp |  2 +-
 rclcpp/src/rclcpp/graph_listener.cpp     | 22 ++++++++++++++++++----
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/rclcpp/include/rclcpp/graph_listener.hpp b/rclcpp/include/rclcpp/graph_listener.hpp
index ca4f05c..901ba46 100644
--- a/rclcpp/include/rclcpp/graph_listener.hpp
+++ b/rclcpp/include/rclcpp/graph_listener.hpp
@@ -165,7 +165,7 @@ private:
   void
   __shutdown(bool);
 
-  rclcpp::Context::SharedPtr parent_context_;
+  rclcpp::Context::WeakPtr parent_context_;
 
   std::thread listener_thread_;
   bool is_started_;
diff --git a/rclcpp/src/rclcpp/graph_listener.cpp b/rclcpp/src/rclcpp/graph_listener.cpp
index b097564..2936932 100644
--- a/rclcpp/src/rclcpp/graph_listener.cpp
+++ b/rclcpp/src/rclcpp/graph_listener.cpp
@@ -80,7 +80,7 @@ GraphListener::start_if_not_started()
       0,  // number_of_clients
       0,  // number_of_services
       0,  // number_of_events
-      this->parent_context_->get_rcl_context().get(),
+      interrupt_guard_condition_context_.get(),
       rcl_get_default_allocator());
     if (RCL_RET_OK != ret) {
       throw_from_rcl_error(ret, "failed to initialize wait set");
@@ -355,10 +355,24 @@ GraphListener::__shutdown(bool should_throw)
       throw_from_rcl_error(ret, "failed to finalize interrupt guard condition");
     }
     if (shutdown_guard_condition_) {
-      if (should_throw) {
-        parent_context_->release_interrupt_guard_condition(&wait_set_);
+      auto parent_context_ptr = parent_context_.lock();
+      if (parent_context_ptr) {
+        if (should_throw) {
+          parent_context_ptr->release_interrupt_guard_condition(&wait_set_);
+        } else {
+          parent_context_ptr->release_interrupt_guard_condition(&wait_set_, std::nothrow);
+        }
       } else {
-        parent_context_->release_interrupt_guard_condition(&wait_set_, std::nothrow);
+        ret = rcl_guard_condition_fini(shutdown_guard_condition_);
+        if (RCL_RET_OK != ret) {
+          if (should_throw) {
+            throw_from_rcl_error(ret, "failed to finalize shutdown guard condition");
+          } else {
+            RCLCPP_ERROR(
+              rclcpp::get_logger("rclcpp"),
+              "failed to finalize shutdown guard condition");
+          }
+        }
       }
       shutdown_guard_condition_ = nullptr;
     }