From d1dce8ede9de5a966b8c866c6fcd023ce16db84a Mon Sep 17 00:00:00 2001
From: Simon Renblad <srenblad@m-labs.hk>
Date: Fri, 6 Sep 2024 17:31:37 +0800
Subject: [PATCH] good progress on restart_idle

---
 src/runtime/src/comms.rs | 99 +++++++++++++++-------------------------
 1 file changed, 38 insertions(+), 61 deletions(-)

diff --git a/src/runtime/src/comms.rs b/src/runtime/src/comms.rs
index e8a00e0..67950e8 100644
--- a/src/runtime/src/comms.rs
+++ b/src/runtime/src/comms.rs
@@ -805,82 +805,59 @@ pub fn main(timer: GlobalTimer, cfg: Config) {
     let restart_idle = Rc::new(Semaphore::new(0, 1));
     mgmt::start(cfg.clone(), restart_idle.clone());
     
-    let semaphores = Rc::new(
-        (Semaphore::new(0, 1), 
-         Semaphore::new(1, 1),
-         Semaphore::new(1, 1),
-         Semaphore::new(1, 1)));
-    
-    // handle connects
+    let terminate = Rc::new(Semaphore::new(0, 1));
+    let connection = Rc::new(Semaphore::new(1, 1));
+    let finish = Rc::new(Semaphore::new(1, 1));
+    let start = Rc::new(Semaphore::new(1, 1)); // run idle kernel once without needing restart
+    // turn the above into a control obj
+    //
+    let stream_refcell = Rc::new(RefCell::new(None));
+
     task::spawn(async move {
         loop {
             clone_mult!(semaphores, control, up_destinations, aux_mutex, routing_table);
-            semaphores.0.async_wait().await;
-            semaphores.1.try_wait();
-            let _ = task_lock.async_lock().await;
-            select_biased! {
-                _ = (async {
-                    // run connection
-                    let mut stream = stream_opt.borrow_mut()?;
-                    let _ = handle_connection(&mut stream, control.clone(), &up_destinations, &aux_mutex, &routing_table, timer)
-                        .await
-                        .map_err(|e| warn!("connection terminated: {}", e));
-                }).fuse() => {
-                    semaphores.2.signal();
-                },
-                _ = semaphores.1.async_wait().fuse() => (),
-            }
-        }
-    });
-    
-    // handle idle
-    task::spawn(async move {
-        loop {
-            clone_mult!(semaphores, control, up_destinations, aux_mutex, routing_table);
-            semaphores.2.async_wait().await;
-            semaphores.3.try_wait();
-            let _ = task_lock.async_lock().await;
+            start.async_wait().await;
+            let stream_opt = stream_refcell.borrow_mut();
+            let _ = connection.try_wait();
+            let _ = finish.try_wait();
             select_biased! {
                 _ = (async {
+                    if let Some(&mut stream) = stream_opt {
+                        let _ = handle_connection(&mut stream, control.clone(), &up_destinations, &aux_mutex, &routing_table, timer)
+                            .await
+                            .map_err(|e| warn!("connection terminated: {}", e));
+                    }
+                    connection.signal();
                     if let Some(buffer) = cfg.read("idle_kernel").ok() {
                         load_and_run_idle_kernel(&buffer, &control, &up_destinations, &aux_mutex, &routing_table, timer).await;
                     }
-                }).fuse() => (),
-                _ = semaphores.3.async_wait().fuse() => (),
+                }).fuse() => (), // TODO: on clean exit with existing idle -> run again?
+                _ = terminate.async_wait().fuse() => (),
             }
+            if let Some(&stream) = stream_opt {
+                stream.flush().await();
+                stream.abort().await();
+            }
+            finish.signal();
         }
     });
 
     task::spawn(async move {
         loop {
-            select_biased! {
+            clone_mult!(semaphores, stream_refcell);
+            let stream_opt = select_biased! {
+                temp_s = (async {
+                       Some(Rc::new(TcpStream::accept(1381, 0x10_000, 0x10_000).await.unwrap()))
+                    }).fuse() => temp_s,
                 _ = (async {
-                        let temp_s = Some(TcpStream::accept(1381, 0x10_000, 0x10_000).await.unwrap()); // ALT: implement dummy
-                    // tcp stream that is empty (another reason the priv construct is annoying)
-                        if let Some(&stream) = stream_opt {
-                           let _ = stream.flush().await;
-                           let _ = stream.abort().await;
-                        }
-                        stream_opt.replace(temp_s);
-                    }).fuse() => {
-                        if semaphore.1.try_wait().is_none() {
-                            semaphore.1.signal(); // STOP KERNEL
-                        }
-                        if semaphore.3.try_wait().is_none() {
-                            semaphore.3.signal(); // STOP IDLE
-                        }
-                        // if the other stream exists -> flush it and replace with the new stream
-                        semaphore.0.signal(); // NEW KERNEL
-                    }
-                _ = (async {
-                        restart_idle.wait_async().await;
-                    }).fuse() => {
-                        if semaphore.3.try_wait().is_none() {
-                            semaphore.3.signal(); // STOP IDLE
-                            semaphore.2.signal(); // NEW IDLE
-                        }
-                    }
-            }
+                        restart_idle.async_wait().await;
+                        connection.async_wait().await;
+                    }).fuse() => None
+            };
+            terminate.signal();
+            finish.async_wait().await;
+            stream_refcell.replace(stream_opt);
+            start.signal();
         }
     });