Merge pull request #128 from ros2/create_subscription_with_queue_size

add version of create_subscription which just takes queue size and not a qos profile

rclcpp/include/rclcpp/node.hpp

@@ -114,6 +114,31 @@ public:
   create_publisher(
     const std::string & topic_name, const rmw_qos_profile_t & qos_profile);
 
+  /// Create and return a Subscription.
+  /**
+   * \param[in] topic_name The topic to subscribe on.
+   * \param[in] qos_history_depth The depth of the subscription's incoming message queue.
+   * \param[in] callback The user-defined callback function.
+   * \param[in] group The callback group for this subscription. NULL for no callback group.
+   * \param[in] ignore_local_publications True to ignore local publications.
+   * \param[in] msg_mem_strat The message memory strategy to use for allocating messages.
+   * \return Shared pointer to the created subscription.
+   */
+  /* TODO(jacquelinekay):
+     Windows build breaks when static member function passed as default
+     argument to msg_mem_strat, nullptr is a workaround.
+   */
+  template<typename MessageT, typename CallbackT>
+  typename rclcpp::subscription::Subscription<MessageT>::SharedPtr
+  create_subscription(
+    const std::string & topic_name,
+    size_t qos_history_depth,
+    CallbackT callback,
+    rclcpp::callback_group::CallbackGroup::SharedPtr group = nullptr,
+    bool ignore_local_publications = false,
+    typename rclcpp::message_memory_strategy::MessageMemoryStrategy<MessageT>::SharedPtr
+    msg_mem_strat = nullptr);
+
   /// Create and return a Subscription.
   /**
    * \param[in] topic_name The topic to subscribe on.

rclcpp/include/rclcpp/node_impl.hpp

@@ -205,6 +205,30 @@ Node::group_in_node(callback_group::CallbackGroup::SharedPtr group)
   return group_belongs_to_this_node;
 }
 
+template<typename MessageT, typename CallbackT>
+typename rclcpp::subscription::Subscription<MessageT>::SharedPtr
+Node::create_subscription(
+  const std::string & topic_name,
+  size_t qos_history_depth,
+  CallbackT callback,
+  rclcpp::callback_group::CallbackGroup::SharedPtr group,
+  bool ignore_local_publications,
+  typename rclcpp::message_memory_strategy::MessageMemoryStrategy<MessageT>::SharedPtr
+  msg_mem_strat)
+{
+  rclcpp::subscription::AnySubscriptionCallback<MessageT> any_subscription_callback;
+  any_subscription_callback.set(callback);
+  rmw_qos_profile_t qos = rmw_qos_profile_default;
+  qos.depth = qos_history_depth;
+  return this->create_subscription_internal(
+    topic_name,
+    qos,
+    any_subscription_callback,
+    group,
+    ignore_local_publications,
+    msg_mem_strat);
+}
+
 template<typename MessageT, typename CallbackT>
 typename rclcpp::subscription::Subscription<MessageT>::SharedPtr
 Node::create_subscription(