Create node clock calls const (try 2) (#922)

* create node clock calls const

Signed-off-by: stevemacenski <stevenmacenski@gmail.com>

* two methods for get clock, one const

Signed-off-by: stevemacenski <stevenmacenski@gmail.com>

* changing APIs for NodeClock and NodeClockInterface

Signed-off-by: stevemacenski <stevenmacenski@gmail.com>

* changing RCLCPP_LIFECYCLE_PUBLIC from RCLCPP_PUBLIC for rclcpp lifecycle node get_clock const method

Signed-off-by: stevemacenski <stevenmacenski@gmail.com>

rclcpp/include/rclcpp/node.hpp

@@ -894,9 +894,13 @@ public:
   rclcpp::Clock::SharedPtr
   get_clock();
 
+  RCLCPP_PUBLIC
+  rclcpp::Clock::ConstSharedPtr
+  get_clock() const;
+
   RCLCPP_PUBLIC
   Time
-  now();
+  now() const;
 
   /// Return the Node's internal NodeBaseInterface implementation.
   RCLCPP_PUBLIC

rclcpp/include/rclcpp/node_interfaces/node_clock.hpp

@@ -54,6 +54,12 @@ public:
   rclcpp::Clock::SharedPtr
   get_clock() override;
 
+  /// Get a clock which will be kept up to date by the node.
+  RCLCPP_PUBLIC
+  virtual
+  rclcpp::Clock::ConstSharedPtr
+  get_clock() const;
+
 private:
   RCLCPP_DISABLE_COPY(NodeClock)
 

rclcpp/include/rclcpp/node_interfaces/node_clock_interface.hpp

@@ -40,6 +40,12 @@ public:
   virtual
   rclcpp::Clock::SharedPtr
   get_clock() = 0;
+
+  /// Get a const ROS clock which will be kept up to date by the node.
+  RCLCPP_PUBLIC
+  virtual
+  rclcpp::Clock::ConstSharedPtr
+  get_clock() const = 0;
 };
 
 }  // namespace node_interfaces

rclcpp/src/rclcpp/node.cpp

@@ -390,8 +390,14 @@ Node::get_clock()
   return node_clock_->get_clock();
 }
 
+rclcpp::Clock::ConstSharedPtr
+Node::get_clock() const
+{
+  return node_clock_->get_clock();
+}
+
 rclcpp::Time
-Node::now()
+Node::now() const
 {
   return node_clock_->get_clock()->now();
 }

rclcpp/src/rclcpp/node_interfaces/node_clock.cpp

@@ -36,8 +36,14 @@ NodeClock::NodeClock(
 NodeClock::~NodeClock()
 {}
 
-std::shared_ptr<rclcpp::Clock>
+rclcpp::Clock::SharedPtr
 NodeClock::get_clock()
 {
   return ros_clock_;
 }
+
+rclcpp::Clock::ConstSharedPtr
+NodeClock::get_clock() const
+{
+  return ros_clock_;
+}

rclcpp_lifecycle/include/rclcpp_lifecycle/lifecycle_node.hpp

@@ -465,9 +465,13 @@ public:
   rclcpp::Clock::SharedPtr
   get_clock();
 
+  RCLCPP_LIFECYCLE_PUBLIC
+  rclcpp::Clock::ConstSharedPtr
+  get_clock() const;
+
   RCLCPP_LIFECYCLE_PUBLIC
   rclcpp::Time
-  now();
+  now() const;
 
   /// Return the Node's internal NodeBaseInterface implementation.
   RCLCPP_LIFECYCLE_PUBLIC

rclcpp_lifecycle/src/lifecycle_node.cpp

@@ -316,8 +316,14 @@ LifecycleNode::get_clock()
   return node_clock_->get_clock();
 }
 
+rclcpp::Clock::ConstSharedPtr
+LifecycleNode::get_clock() const
+{
+  return node_clock_->get_clock();
+}
+
 rclcpp::Time
-LifecycleNode::now()
+LifecycleNode::now() const
 {
   return node_clock_->get_clock()->now();
 }