Add rosidl_runtime_rs::ActionImpl::create_feedback_message()

Adds a trait method to create a feedback message given the goal ID and
the user-facing feedback message type. Depending on how many times we do
this, it may end up valuable to define a GoalUuid type in
rosidl_runtime_rs itself. We wouldn't be able to utilize the
`RCL_ACTION_UUID_SIZE` constant imported from `rcl_action`, but this is
pretty much guaranteed to be 16 forever.

Defining this method signature also required inverting the super-trait
relationship between Action and ActionImpl. Now ActionImpl is the
sub-trait as this gives it access to all of Action's associated types.
Action doesn't need to care about anything from ActionImpl (hopefully).

Author: nwn

rclrs/src/action/server.rs

@@ -83,7 +83,7 @@ where
 
 impl<T> ActionServer<T>
 where
-    T: rosidl_runtime_rs::Action,
+    T: rosidl_runtime_rs::Action + rosidl_runtime_rs::ActionImpl,
 {
     /// Creates a new action server.
     pub(crate) fn new(
@@ -95,7 +95,7 @@ where
         accepted_callback: impl Fn(ServerGoalHandle<T>) + 'static + Send + Sync,
     ) -> Result<Self, RclrsError>
     where
-        T: rosidl_runtime_rs::Action,
+        T: rosidl_runtime_rs::Action + rosidl_runtime_rs::ActionImpl,
     {
         // SAFETY: Getting a zero-initialized value is always safe.
         let mut rcl_action_server = unsafe { rcl_action_get_zero_initialized_server() };
@@ -335,7 +335,7 @@ where
 
 impl<T> ActionServerBase for ActionServer<T>
 where
-    T: rosidl_runtime_rs::Action,
+    T: rosidl_runtime_rs::Action + rosidl_runtime_rs::ActionImpl,
 {
     fn handle(&self) -> &ActionServerHandle {
         &self.handle

rclrs/src/node.rs

@@ -244,7 +244,7 @@ impl Node {
         handle_accepted: AcceptedCallback,
     ) -> Result<Arc<ActionServer<ActionT>>, RclrsError>
     where
-        ActionT: rosidl_runtime_rs::Action,
+        ActionT: rosidl_runtime_rs::Action + rosidl_runtime_rs::ActionImpl,
         GoalCallback: Fn(GoalUuid, <ActionT as rosidl_runtime_rs::Action>::Goal) -> GoalResponse + 'static + Send + Sync,
         CancelCallback: Fn(ServerGoalHandle<ActionT>) -> CancelResponse + 'static + Send + Sync,
         AcceptedCallback: Fn(ServerGoalHandle<ActionT>) + 'static + Send + Sync,

rosidl_runtime_rs/src/traits.rs

@@ -163,7 +163,7 @@ pub trait Service: 'static {
 /// Trait for actions.
 ///
 /// User code never needs to call this trait's method, much less implement this trait.
-pub trait Action: 'static + ActionImpl {
+pub trait Action: 'static {
     /// The goal message associated with this action.
     type Goal: Message;
 
@@ -180,7 +180,7 @@ pub trait Action: 'static + ActionImpl {
 /// Trait for action implementation details.
 ///
 /// User code never needs to implement this trait, nor use its associated types.
-pub trait ActionImpl: 'static {
+pub trait ActionImpl: 'static + Action {
     /// The goal_status message associated with this action.
     type GoalStatusMessage: Message;
 
@@ -201,4 +201,7 @@ pub trait ActionImpl: 'static {
 
     /// Sets the `accepted` field of a goal response.
     fn set_goal_response_accepted(response: &mut <<Self::SendGoalService as Service>::Response as Message>::RmwMsg, accepted: bool);
+
+    /// Create a feedback message with the given goal ID and contents.
+    fn create_feedback_message(goal_id: &[u8; 16], feedback: &<<Self as Action>::Feedback as Message>::RmwMsg) -> <Self::FeedbackMessage as Message>::RmwMsg;
 }