Return Arc from the create_node function to match other create_X functions (#294)

* Fine-grained locks. Made create_subscription, create_service, create_client not take a mutable self

* Return an Arc from rclrs::create_node to match other create_X functions

* Update spin* to take an Arc

* Fix clippy warning

Author: esteve

rclrs/message_demo/src/message_demo.rs

@@ -1,5 +1,6 @@
 use std::convert::TryInto;
 use std::env;
+use std::sync::Arc;
 
 use anyhow::{Error, Result};
 use rosidl_runtime_rs::{seq, BoundedSequence, Message, Sequence};
@@ -132,7 +133,7 @@ fn demonstrate_pubsub() -> Result<(), Error> {
     println!("================== Interoperability demo ==================");
     // Demonstrate interoperability between idiomatic and RMW-native message types
     let context = rclrs::Context::new(env::args())?;
-    let mut node = rclrs::create_node(&context, "message_demo")?;
+    let node = rclrs::create_node(&context, "message_demo")?;
 
     let idiomatic_publisher = node.create_publisher::<rclrs_example_msgs::msg::VariousTypes>(
         "topic",
@@ -159,10 +160,10 @@ fn demonstrate_pubsub() -> Result<(), Error> {
         )?;
     println!("Sending idiomatic message.");
     idiomatic_publisher.publish(rclrs_example_msgs::msg::VariousTypes::default())?;
-    rclrs::spin_once(&node, None)?;
+    rclrs::spin_once(Arc::clone(&node), None)?;
     println!("Sending RMW-native message.");
     direct_publisher.publish(rclrs_example_msgs::msg::rmw::VariousTypes::default())?;
-    rclrs::spin_once(&node, None)?;
+    rclrs::spin_once(Arc::clone(&node), None)?;
 
     Ok(())
 }

rclrs/minimal_client_service/src/minimal_client.rs

@@ -5,7 +5,7 @@ use anyhow::{Error, Result};
 fn main() -> Result<(), Error> {
     let context = rclrs::Context::new(env::args())?;
 
-    let mut node = rclrs::create_node(&context, "minimal_client")?;
+    let node = rclrs::create_node(&context, "minimal_client")?;
 
     let client = node.create_client::<example_interfaces::srv::AddTwoInts>("add_two_ints")?;
 
@@ -28,5 +28,5 @@ fn main() -> Result<(), Error> {
     std::thread::sleep(std::time::Duration::from_millis(500));
 
     println!("Waiting for response");
-    rclrs::spin(&node).map_err(|err| err.into())
+    rclrs::spin(node).map_err(|err| err.into())
 }

rclrs/minimal_client_service/src/minimal_client_async.rs

@@ -6,7 +6,7 @@ use anyhow::{Error, Result};
 async fn main() -> Result<(), Error> {
     let context = rclrs::Context::new(env::args())?;
 
-    let mut node = rclrs::create_node(&context, "minimal_client")?;
+    let node = rclrs::create_node(&context, "minimal_client")?;
 
     let client = node.create_client::<example_interfaces::srv::AddTwoInts>("add_two_ints")?;
 
@@ -20,7 +20,7 @@ async fn main() -> Result<(), Error> {
 
     println!("Waiting for response");
 
-    let rclrs_spin = tokio::task::spawn_blocking(move || rclrs::spin(&node));
+    let rclrs_spin = tokio::task::spawn_blocking(move || rclrs::spin(node));
 
     let response = future.await?;
     println!(

rclrs/minimal_client_service/src/minimal_service.rs

@@ -15,11 +15,11 @@ fn handle_service(
 fn main() -> Result<(), Error> {
     let context = rclrs::Context::new(env::args())?;
 
-    let mut node = rclrs::create_node(&context, "minimal_service")?;
+    let node = rclrs::create_node(&context, "minimal_service")?;
 
     let _server = node
         .create_service::<example_interfaces::srv::AddTwoInts, _>("add_two_ints", handle_service)?;
 
     println!("Starting server");
-    rclrs::spin(&node).map_err(|err| err.into())
+    rclrs::spin(node).map_err(|err| err.into())
 }

rclrs/minimal_pub_sub/src/minimal_subscriber.rs

@@ -5,7 +5,7 @@ use anyhow::{Error, Result};
 fn main() -> Result<(), Error> {
     let context = rclrs::Context::new(env::args())?;
 
-    let mut node = rclrs::create_node(&context, "minimal_subscriber")?;
+    let node = rclrs::create_node(&context, "minimal_subscriber")?;
 
     let mut num_messages: usize = 0;
 
@@ -19,5 +19,5 @@ fn main() -> Result<(), Error> {
         },
     )?;
 
-    rclrs::spin(&node).map_err(|err| err.into())
+    rclrs::spin(node).map_err(|err| err.into())
 }

rclrs/minimal_pub_sub/src/zero_copy_subscriber.rs

@@ -5,7 +5,7 @@ use anyhow::{Error, Result};
 fn main() -> Result<(), Error> {
     let context = rclrs::Context::new(env::args())?;
 
-    let mut node = rclrs::create_node(&context, "minimal_subscriber")?;
+    let node = rclrs::create_node(&context, "minimal_subscriber")?;
 
     let mut num_messages: usize = 0;
 
@@ -19,5 +19,5 @@ fn main() -> Result<(), Error> {
         },
     )?;
 
-    rclrs::spin(&node).map_err(|err| err.into())
+    rclrs::spin(node).map_err(|err| err.into())
 }