Start adding a Future ReturnToken

src/api/machine.rs

@@ -141,9 +141,10 @@ impl write::give_back::Server for GiveBack {
         _results: write::give_back::RetResults)
     -> Promise<(), Error>
     {
+        println!("I'm doing my part!");
         if let Some(chan) = self.0.take() {
-            chan.send(())
-                .expect("Other end of GiveBack token was dropped?!");
+            // Err here just means machine was taken from us
+            let _ = chan.send(());
         }
 
         Promise::ok(())

src/machine.rs

@@ -12,7 +12,9 @@ use std::fs;
 
 use serde::{Serialize, Deserialize};
 
+use futures::Stream;
 use futures::future::BoxFuture;
+use futures::channel::{mpsc, oneshot};
 
 use futures_signals::signal::Signal;
 use futures_signals::signal::SignalExt;
@@ -99,7 +101,8 @@ impl Machine {
             } else {
                 if new_state == MachineState::free() {
                     let mut guard = this.inner.try_lock().unwrap();
-                    return guard.do_state_change(new_state);
+                    guard.do_state_change(new_state);
+                    return Ok(ReturnToken(self.inner.clone()));
                 }
             }
 
@@ -123,6 +126,7 @@ impl Deref for Machine {
     }
 }
 
+
 #[derive(Debug)]
 /// Internal machine representation
 ///
@@ -142,7 +146,6 @@ pub struct Inner {
     /// case of an actor it should then make sure that the real world matches up with the set state
     state: Mutable<MachineState>,
     reset: Option<MachineState>,
-    rx: Option<futures::channel::oneshot::Receiver<()>>,
 }
 
 impl Inner {
@@ -156,7 +159,6 @@ impl Inner {
             desc: desc,
             state: Mutable::new(state),
             reset: None,
-            rx: None,
         }
     }
 
@@ -172,14 +174,9 @@ impl Inner {
         Box::pin(self.state.signal_cloned().dedupe_cloned())
     }
 
-    pub fn do_state_change(&mut self, new_state: MachineState) -> Result<ReturnToken> {
-            let (tx, rx) = futures::channel::oneshot::channel();
+    pub fn do_state_change(&mut self, new_state: MachineState) {
             let old_state = self.state.replace(new_state);
             self.reset.replace(old_state);
-            // Also this drops the old receiver, which will signal to the initiator that the
-            // machine has been taken off their hands.
-            self.rx.replace(rx);
-            return Ok(tx);
     }
 
     pub fn read_state(&self) -> ReadOnlyMutable<MachineState> {
@@ -197,28 +194,24 @@ impl Inner {
     }
 }
 
-pub type ReturnToken = futures::channel::oneshot::Sender<()>;
+//pub type ReturnToken = futures::channel::oneshot::Sender<()>;
+pub struct ReturnToken {
+    inner: Arc<Mutex<Inner>>,
+}
 
-impl Future for Inner {
-    type Output = MachineState;
+impl ReturnToken {
+    pub fn new(inner: Arc<Mutex<Inner>>) -> Self {
+        Self { inner }
+    }
+}
+
+impl Future for ReturnToken {
+    type Output = ();
 
     fn poll(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
-        let this = &mut *self;
-        // TODO Return this on exit
-        if false {
-            return Poll::Ready(self.state.get_cloned());
-        }
+        let mut this = &mut *self;
 
-        // Check if the return token was sent/dropped
-        if let Some(mut rx) = this.rx.take() {
-            match Future::poll(Pin::new(&mut rx), cx) {
-                // Regardless if we were canceled or properly returned, reset.
-                Poll::Ready(_) => self.reset_state(),
-                Poll::Pending => { this.rx.replace(rx); },
-            }
-        }
-
-        Poll::Pending
+        this.0
     }
 }
 
@@ -255,6 +248,8 @@ pub fn load(config: &crate::config::Config, access: Arc<access::AccessControl>)
             // TODO: Read state from the state db
             (v.name.clone(), Machine::construct(k, v, MachineState::new(), access.clone()))
         });
+
+
     Ok(HashMap::from_iter(it))
 }