Fixed formatting, reduced the scope of the unsafe call to `trigger_ev…

…ent`, added satefy notice to the unsafe call

bgpsim/src/interactive.rs

@@ -65,21 +65,25 @@ where
     /// be set by `self.set_msg_limit`).
     fn simulate(&mut self) -> Result<(), NetworkError>;
 
-    /// Similarly to the [`Network::simulate`] function, this function will execute all events in the 
-    /// queue. This function provides a hook in the form of a closure that is called before and after 
+    /// Similarly to the [`Network::simulate`] function, this function will execute all events in the
+    /// queue. This function provides a hook in the form of a closure that is called before and after
     /// each event is processed.
-    /// 
-    /// The closure always provides immutable access to both the network and the currently processed 
-    /// event. Furthermore, it enables the user to determine whether it was called before or after 
+    ///
+    /// The closure always provides immutable access to both the network and the currently processed
+    /// event. Furthermore, it enables the user to determine whether it was called before or after
     /// the event was processed based on the value of the third argument.
-    /// 
+    ///
     /// If the closure is called *before* the event is processed, the third argument will be `None`.
     /// If the closure is called *after* the event is processed, the third argument will contain a
     /// `Some((StepUpdate, Vec<Event>))` tuple, where the second element contains a list of events
     /// that were generated by the event that was just processed.
     fn simulate_hooked(
         net: &mut Network<P, Q, Ospf>,
-        f: impl FnMut(&Network<P, Q, Ospf>, &Event<P, Q::Priority>, Option<&(StepUpdate<P>, Vec<Event<P, Q::Priority>>)>) -> (),
+        f: impl FnMut(
+            &Network<P, Q, Ospf>,
+            &Event<P, Q::Priority>,
+            Option<&(StepUpdate<P>, Vec<Event<P, Q::Priority>>)>,
+        ) -> (),
     ) -> Result<(), NetworkError>;
 
     /// Trigger the timeout event on any router. The router is picked randomly if the feature `rand`
@@ -228,44 +232,48 @@ impl<P: Prefix, Q: EventQueue<P>, Ospf: OspfImpl> InteractiveNetwork<P, Q, Ospf>
     }
 
     fn simulate_hooked(
-            net: &mut Network<P, Q, Ospf>,
-            mut f: impl FnMut(&Network<P, Q, Ospf>, &Event<P, Q::Priority>, Option<&(StepUpdate<P>, Vec<Event<P, Q::Priority>>)>) -> (),
-        ) -> Result<(), NetworkError> 
-    {
-            'timeout: loop {
-                // While there are events in the queue
-                while let Some(event) = net.queue_mut().pop() {
-                    let event_clone = event.clone();
-
-                    unsafe {
-                        // Straddle the trigger_event function with the pre- and post-event hooks
-                        f(net, &event_clone, None);
-                        let result = net.trigger_event(event)?;
-                        f(net, &event_clone, Some(&result));
-
-                        net.enqueue_events(result.1);
-                    }
+        net: &mut Network<P, Q, Ospf>,
+        mut f: impl FnMut(
+            &Network<P, Q, Ospf>,
+            &Event<P, Q::Priority>,
+            Option<&(StepUpdate<P>, Vec<Event<P, Q::Priority>>)>,
+        ) -> (),
+    ) -> Result<(), NetworkError> {
+        'timeout: loop {
+            // While there are events in the queue
+            while let Some(event) = net.queue_mut().pop() {
+                let event_clone = event.clone();
 
-                    if matches!(event_clone, Event::Ospf { .. }) {
-                        // OSPF event received! Check the BGP session state
-                        net.refresh_bgp_sessions()?;
-                    }
-                }
+                // Straddle the trigger_event function with the pre- and post-event hooks
+                f(net, &event_clone, None);
+                // Safety: This is safe because we are allowing the network to eventually 
+                // converge by exhausing all events in the queue. The extracted events are
+                // all immutable and won't be modified.
+                let result = unsafe { net.trigger_event(event)? };
+                f(net, &event_clone, Some(&result));
 
-                // trigger the next timeout event if it exists.
-                let trigger_router = net.trigger_timeout()?;
+                net.enqueue_events(result.1);
 
-                // if no timeout was triggered, break out of the loop. We are converged!
-                if trigger_router.is_none() {
-                    break 'timeout;
+                if matches!(event_clone, Event::Ospf { .. }) {
+                    // OSPF event received! Check the BGP session state
+                    net.refresh_bgp_sessions()?;
                 }
             }
 
-            // remove unreachable OSPF LSAs
-            net.internal_routers_mut()
-                .for_each(|r| r.ospf.remove_unreachable_lsas());
+            // trigger the next timeout event if it exists.
+            let trigger_router = net.trigger_timeout()?;
+
+            // if no timeout was triggered, break out of the loop. We are converged!
+            if trigger_router.is_none() {
+                break 'timeout;
+            }
+        }
+
+        // remove unreachable OSPF LSAs
+        net.internal_routers_mut()
+            .for_each(|r| r.ospf.remove_unreachable_lsas());
 
-            Ok(())
+        Ok(())
     }
 
     fn trigger_timeout(&mut self) -> Result<Option<RouterId>, NetworkError> {