dont panic in accept loop

actix-server/src/accept.rs

@@ -65,7 +65,7 @@ impl AcceptLoop {
         let poll = self.poll.take().unwrap();
         let waker = self.waker.clone();
 
-        Accept::start(poll, waker, socks, srv, handles);
+        Accept::start(poll, waker, socks, srv, handles).expect("accept failed to start");
     }
 }
 
@@ -155,10 +155,13 @@ impl Accept {
         socks: Vec<(usize, MioListener)>,
         srv: ServerHandle,
         handles: Vec<WorkerHandleAccept>,
-    ) {
+    ) -> io::Result<()> {
         // Accept runs in its own thread and might spawn additional futures to current system
         let sys = System::try_current();
 
+        let (mut accept, mut sockets) =
+            Accept::new_with_sockets(poll, waker, socks, handles, srv)?;
+
         thread::Builder::new()
             .name("actix-server accept loop".to_owned())
             .spawn(move || {
@@ -167,12 +170,11 @@ impl Accept {
                     System::set_current(sys);
                 }
 
-                let (mut accept, mut sockets) =
-                    Accept::new_with_sockets(poll, waker, socks, handles, srv);
-
                 accept.poll_with(&mut sockets);
             })
             .unwrap();
+
+        Ok(())
     }
 
     fn new_with_sockets(
@@ -181,22 +183,21 @@ impl Accept {
         socks: Vec<(usize, MioListener)>,
         handles: Vec<WorkerHandleAccept>,
         srv: ServerHandle,
-    ) -> (Accept, Vec<ServerSocketInfo>) {
+    ) -> io::Result<(Accept, Box<[ServerSocketInfo]>)> {
         let sockets = socks
             .into_iter()
             .map(|(token, mut lst)| {
                 // Start listening for incoming connections
                 poll.registry()
-                    .register(&mut lst, MioToken(token), Interest::READABLE)
-                    .unwrap_or_else(|e| panic!("Can not register io: {}", e));
+                    .register(&mut lst, MioToken(token), Interest::READABLE)?;
 
-                ServerSocketInfo {
+                Ok(ServerSocketInfo {
                     token,
                     lst,
                     timeout: None,
-                }
+                })
             })
-            .collect();
+            .collect::<io::Result<_>>()?;
 
         let mut avail = Availability::default();
 
@@ -213,7 +214,7 @@ impl Accept {
             paused: false,
         };
 
-        (accept, sockets)
+        Ok((accept, sockets))
     }
 
     fn poll_with(&mut self, sockets: &mut [ServerSocketInfo]) {

actix-server/src/availability.rs

@@ -0,0 +1,121 @@
+use crate::worker::WorkerHandleAccept;
+
+/// Array of u128 with every bit as marker for a worker handle's availability.
+#[derive(Debug, Default)]
+pub(crate) struct Availability([u128; 4]);
+
+impl Availability {
+    /// Check if any worker handle is available
+    #[inline(always)]
+    pub(crate) fn available(&self) -> bool {
+        self.0.iter().any(|a| *a != 0)
+    }
+
+    /// Check if worker handle is available by index
+    #[inline(always)]
+    pub(crate) fn get_available(&self, idx: usize) -> bool {
+        let (offset, idx) = Self::offset(idx);
+
+        self.0[offset] & (1 << idx as u128) != 0
+    }
+
+    /// Set worker handle available state by index.
+    pub(crate) fn set_available(&mut self, idx: usize, avail: bool) {
+        let (offset, idx) = Self::offset(idx);
+
+        let off = 1 << idx as u128;
+        if avail {
+            self.0[offset] |= off;
+        } else {
+            self.0[offset] &= !off
+        }
+    }
+
+    /// Set all worker handle to available state.
+    /// This would result in a re-check on all workers' availability.
+    pub(crate) fn set_available_all(&mut self, handles: &[WorkerHandleAccept]) {
+        handles.iter().for_each(|handle| {
+            self.set_available(handle.idx(), true);
+        })
+    }
+
+    /// Get offset and adjusted index of given worker handle index.
+    pub(crate) fn offset(idx: usize) -> (usize, usize) {
+        if idx < 128 {
+            (0, idx)
+        } else if idx < 128 * 2 {
+            (1, idx - 128)
+        } else if idx < 128 * 3 {
+            (2, idx - 128 * 2)
+        } else if idx < 128 * 4 {
+            (3, idx - 128 * 3)
+        } else {
+            panic!("Max WorkerHandle count is 512")
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn single(aval: &mut Availability, idx: usize) {
+        aval.set_available(idx, true);
+        assert!(aval.available());
+
+        aval.set_available(idx, true);
+
+        aval.set_available(idx, false);
+        assert!(!aval.available());
+
+        aval.set_available(idx, false);
+        assert!(!aval.available());
+    }
+
+    fn multi(aval: &mut Availability, mut idx: Vec<usize>) {
+        idx.iter().for_each(|idx| aval.set_available(*idx, true));
+
+        assert!(aval.available());
+
+        while let Some(idx) = idx.pop() {
+            assert!(aval.available());
+            aval.set_available(idx, false);
+        }
+
+        assert!(!aval.available());
+    }
+
+    #[test]
+    fn availability() {
+        let mut aval = Availability::default();
+
+        single(&mut aval, 1);
+        single(&mut aval, 128);
+        single(&mut aval, 256);
+        single(&mut aval, 511);
+
+        let idx = (0..511).filter(|i| i % 3 == 0 && i % 5 == 0).collect();
+
+        multi(&mut aval, idx);
+
+        multi(&mut aval, (0..511).collect())
+    }
+
+    #[test]
+    #[should_panic]
+    fn overflow() {
+        let mut aval = Availability::default();
+        single(&mut aval, 512);
+    }
+
+    #[test]
+    fn pin_point() {
+        let mut aval = Availability::default();
+
+        aval.set_available(438, true);
+
+        aval.set_available(479, true);
+
+        assert_eq!(aval.0[3], 1 << (438 - 384) | 1 << (479 - 384));
+    }
+}