Make notifier infallible

examples/poll.rs

@@ -32,17 +32,16 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
 
     println!("Connected");
 
-    let handle = poller.notifier().map(|mut notify_token| {
-        std::thread::spawn(move || {
-            loop {
-                std::thread::sleep(std::time::Duration::from_secs(5));
-                match notify_token.notify() {
-                    Ok(c) => notify_token = c,
-                    Err(_) => break,
-                }
+    let mut notify_token = poller.notifier();
+    let handle = std::thread::spawn(move || {
+        loop {
+            std::thread::sleep(std::time::Duration::from_secs(5));
+            match notify_token.notify() {
+                Ok(c) => notify_token = c,
+                Err(_) => break,
             }
-            println!("broken");
-        })
+        }
+        println!("broken");
     });
 
     let stream_key = poller.register(Arc::clone(&stream), Readiness::read() | Readiness::hangup());
@@ -112,9 +111,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
 
     println!("Disconnected");
 
-    if let Some(handle) = handle {
-        handle.join().unwrap();
-    }
+    handle.join().unwrap();
 
     Ok(())
 }

src/lib.rs

@@ -12,7 +12,7 @@ pub struct Key(usize);
 pub struct PollManager {
     id: usize,
     notify: Notify,
-    notify_token: Option<NotifyToken>,
+    notify_token: NotifyToken,
     notify_key: Option<usize>,
     io: HashMap<usize, Managed>,
 }
@@ -44,8 +44,9 @@ pub struct Notify {
     registered: OwnedFd,
 }
 
+#[derive(Clone)]
 pub struct NotifyToken {
-    free: OwnedFd,
+    free: Arc<OwnedFd>,
 }
 
 pub fn notify_pair() -> rustix::io::Result<(Notify, NotifyToken)> {
@@ -56,7 +57,12 @@ pub fn notify_pair() -> rustix::io::Result<(Notify, NotifyToken)> {
         Protocol::from_raw(0),
     )?;
 
-    Ok((Notify { registered }, NotifyToken { free }))
+    Ok((
+        Notify { registered },
+        NotifyToken {
+            free: Arc::new(free),
+        },
+    ))
 }
 
 impl PartialEq<usize> for Key {
@@ -83,7 +89,7 @@ impl PollManager {
         Ok(Self {
             id: 0,
             notify,
-            notify_token: Some(notify_token),
+            notify_token,
             notify_key: None,
             io: HashMap::new(),
         })
@@ -114,8 +120,8 @@ impl PollManager {
         self.io.remove(&key.0);
     }
 
-    pub fn notifier(&mut self) -> Option<NotifyToken> {
-        self.notify_token.take()
+    pub fn notifier(&self) -> NotifyToken {
+        self.notify_token.clone()
     }
 
     pub fn poll(&mut self) -> rustix::io::Result<Vec<(usize, Readiness)>> {
@@ -297,7 +303,7 @@ impl<'a> Poller<'a> {
 
 impl NotifyToken {
     pub fn notify(self) -> rustix::io::Result<Self> {
-        if let Err(e) = rustix::io::write(&self.free, &[0]) {
+        if let Err(e) = rustix::io::write(&*self.free, &[0]) {
             if e == rustix::io::Error::AGAIN || e == rustix::io::Error::WOULDBLOCK {
                 return Ok(self);
             }