From af0b1e6b0770561c2f4c08ee72e9323e0459db60 Mon Sep 17 00:00:00 2001
From: Brian Gerkey <gerkey@osrfoundation.org>
Date: Mon, 6 Jun 2016 16:20:51 -0700
Subject: [PATCH] Add mutex to protect vectors of pointers in callbackgroup

---
 rclcpp/include/rclcpp/callback_group.hpp | 3 +++
 rclcpp/src/rclcpp/callback_group.cpp     | 8 ++++++++
 2 files changed, 11 insertions(+)

diff --git a/rclcpp/include/rclcpp/callback_group.hpp b/rclcpp/include/rclcpp/callback_group.hpp
index 47ea417..af90476 100644
--- a/rclcpp/include/rclcpp/callback_group.hpp
+++ b/rclcpp/include/rclcpp/callback_group.hpp
@@ -16,6 +16,7 @@
 #define RCLCPP__CALLBACK_GROUP_HPP_
 
 #include <atomic>
+#include <mutex>
 #include <string>
 #include <vector>
 
@@ -97,6 +98,8 @@ private:
   add_client(const rclcpp::client::ClientBase::SharedPtr client_ptr);
 
   CallbackGroupType type_;
+  // Mutex to protect the subsequent vectors of pointers.
+  mutable std::mutex mutex_;
   std::vector<rclcpp::subscription::SubscriptionBase::WeakPtr> subscription_ptrs_;
   std::vector<rclcpp::timer::TimerBase::WeakPtr> timer_ptrs_;
   std::vector<rclcpp::service::ServiceBase::SharedPtr> service_ptrs_;
diff --git a/rclcpp/src/rclcpp/callback_group.cpp b/rclcpp/src/rclcpp/callback_group.cpp
index 6d728a6..40168e5 100644
--- a/rclcpp/src/rclcpp/callback_group.cpp
+++ b/rclcpp/src/rclcpp/callback_group.cpp
@@ -26,24 +26,28 @@ CallbackGroup::CallbackGroup(CallbackGroupType group_type)
 const std::vector<rclcpp::subscription::SubscriptionBase::WeakPtr> &
 CallbackGroup::get_subscription_ptrs() const
 {
+  std::lock_guard<std::mutex> lock(mutex_);
   return subscription_ptrs_;
 }
 
 const std::vector<rclcpp::timer::TimerBase::WeakPtr> &
 CallbackGroup::get_timer_ptrs() const
 {
+  std::lock_guard<std::mutex> lock(mutex_);
   return timer_ptrs_;
 }
 
 const std::vector<rclcpp::service::ServiceBase::SharedPtr> &
 CallbackGroup::get_service_ptrs() const
 {
+  std::lock_guard<std::mutex> lock(mutex_);
   return service_ptrs_;
 }
 
 const std::vector<rclcpp::client::ClientBase::WeakPtr> &
 CallbackGroup::get_client_ptrs() const
 {
+  std::lock_guard<std::mutex> lock(mutex_);
   return client_ptrs_;
 }
 
@@ -63,23 +67,27 @@ void
 CallbackGroup::add_subscription(
   const rclcpp::subscription::SubscriptionBase::SharedPtr subscription_ptr)
 {
+  std::lock_guard<std::mutex> lock(mutex_);
   subscription_ptrs_.push_back(subscription_ptr);
 }
 
 void
 CallbackGroup::add_timer(const rclcpp::timer::TimerBase::SharedPtr timer_ptr)
 {
+  std::lock_guard<std::mutex> lock(mutex_);
   timer_ptrs_.push_back(timer_ptr);
 }
 
 void
 CallbackGroup::add_service(const rclcpp::service::ServiceBase::SharedPtr service_ptr)
 {
+  std::lock_guard<std::mutex> lock(mutex_);
   service_ptrs_.push_back(service_ptr);
 }
 
 void
 CallbackGroup::add_client(const rclcpp::client::ClientBase::SharedPtr client_ptr)
 {
+  std::lock_guard<std::mutex> lock(mutex_);
   client_ptrs_.push_back(client_ptr);
 }