Introduce ServiceWaitable/ClientWaitable/SubscriptionWaitable

rclrs/src/node.rs

@@ -10,7 +10,7 @@ pub use self::service::*;
 pub use self::subscription::*;
 
 use crate::rcl_bindings::*;
-use crate::{Context, ParameterOverrideMap, QoSProfile, RclrsError, ToResult, Waitable};
+use crate::{Context, ParameterOverrideMap, QoSProfile, RclrsError, ToResult};
 
 use std::cmp::PartialEq;
 use std::ffi::CStr;
@@ -72,9 +72,9 @@ unsafe impl Send for rcl_node_t {}
 pub struct Node {
     rcl_node_mtx: Arc<Mutex<rcl_node_t>>,
     pub(crate) rcl_context_mtx: Arc<Mutex<rcl_context_t>>,
-    pub(crate) clients: Vec<Weak<dyn Waitable>>,
-    pub(crate) services: Vec<Weak<dyn Waitable>>,
-    pub(crate) subscriptions: Vec<Weak<dyn Waitable>>,
+    pub(crate) clients: Vec<Weak<dyn ClientWaitable>>,
+    pub(crate) services: Vec<Weak<dyn ServiceWaitable>>,
+    pub(crate) subscriptions: Vec<Weak<dyn SubscriptionWaitable>>,
     _parameter_map: ParameterOverrideMap,
 }
 
@@ -193,7 +193,7 @@ impl Node {
     {
         let client = Arc::new(crate::node::client::Client::<T>::new(self, topic)?);
         self.clients
-            .push(Arc::downgrade(&client) as Weak<dyn Waitable>);
+            .push(Arc::downgrade(&client) as Weak<dyn ClientWaitable>);
         Ok(client)
     }
 
@@ -229,7 +229,7 @@ impl Node {
             self, topic, callback,
         )?);
         self.services
-            .push(Arc::downgrade(&service) as Weak<dyn Waitable>);
+            .push(Arc::downgrade(&service) as Weak<dyn ServiceWaitable>);
         Ok(service)
     }
 
@@ -249,23 +249,23 @@ impl Node {
     {
         let subscription = Arc::new(Subscription::<T>::new(self, topic, qos, callback)?);
         self.subscriptions
-            .push(Arc::downgrade(&subscription) as Weak<dyn Waitable>);
+            .push(Arc::downgrade(&subscription) as Weak<dyn SubscriptionWaitable>);
         Ok(subscription)
     }
 
     /// Returns the subscriptions that have not been dropped yet.
-    pub(crate) fn live_subscriptions(&self) -> Vec<Arc<dyn Waitable>> {
+    pub(crate) fn live_subscriptions(&self) -> Vec<Arc<dyn SubscriptionWaitable>> {
         self.subscriptions
             .iter()
             .filter_map(Weak::upgrade)
             .collect()
     }
 
-    pub(crate) fn live_clients(&self) -> Vec<Arc<dyn Waitable>> {
+    pub(crate) fn live_clients(&self) -> Vec<Arc<dyn ClientWaitable>> {
         self.clients.iter().filter_map(Weak::upgrade).collect()
     }
 
-    pub(crate) fn live_services(&self) -> Vec<Arc<dyn Waitable>> {
+    pub(crate) fn live_services(&self) -> Vec<Arc<dyn ServiceWaitable>> {
         self.services.iter().filter_map(Weak::upgrade).collect()
     }
 

rclrs/src/node/client.rs

@@ -85,6 +85,11 @@ where
     }
 }
 
+/// A marker trait to distinguish `Client` waitables from other [`Waitable`]s.
+pub(crate) trait ClientWaitable: Waitable {}
+
+impl<T> ClientWaitable for Client<T> where T: rosidl_runtime_rs::Service {}
+
 impl<T> Client<T>
 where
     T: rosidl_runtime_rs::Service,

rclrs/src/node/service.rs

@@ -89,6 +89,11 @@ where
     }
 }
 
+/// A marker trait to distinguish `Service` waitables from other [`Waitable`]s.
+pub(crate) trait ServiceWaitable: Waitable {}
+
+impl<T> ServiceWaitable for Service<T> where T: rosidl_runtime_rs::Service {}
+
 impl<T> Service<T>
 where
     T: rosidl_runtime_rs::Service,

rclrs/src/node/subscription.rs

@@ -85,6 +85,11 @@ where
     }
 }
 
+/// A marker trait to distinguish `Subscription` waitables from other [`Waitable`]s.
+pub(crate) trait SubscriptionWaitable: Waitable {}
+
+impl<T> SubscriptionWaitable for Subscription<T> where T: Message {}
+
 impl<T> Subscription<T>
 where
     T: Message,