feat(runtime): first steps towards adding timers, prng and get curren…

…t time

src/runtime-prototype/src/StuntDouble/ActorMap.hs

@@ -58,8 +58,9 @@ data ActorF x
   | On Promise (Resolution -> Free ActorF ()) (() -> x)
   | Get (State -> x)
   | Put State (() -> x)
-  -- XXX: Random?
-  -- XXX: GetTime?
+  | GetTime (UTCTime -> x)
+  | Random (Double -> x)
+  | SetTimer Time.NominalDiffTime (Promise -> x)
   -- XXX: Throw?
 deriving instance Functor ActorF
 
@@ -84,6 +85,15 @@ put s' = Free (Put s' return)
 modify :: (State -> State) -> Free ActorF ()
 modify f = put . f =<< get
 
+getTime :: Free ActorF UTCTime
+getTime = Free (GetTime return)
+
+random :: Free ActorF Double
+random = Free (Random return)
+
+setTimer :: Time.NominalDiffTime -> Free ActorF Promise
+setTimer ndt = Free (SetTimer ndt return)
+
 ------------------------------------------------------------------------
 
 newtype ActorMap = ActorMap (Map LocalRef (Message -> Actor, State))
@@ -110,6 +120,7 @@ data Action
   = SendAction LocalRef Message RemoteRef Promise
   | AsyncIOAction (IO IOResult) Promise
   | OnAction Promise (Resolution -> Free ActorF ()) LocalRef
+  | SetTimerAction Time.NominalDiffTime Promise
 
 -- XXX: what about exceptions? transactional in state, but also in actions?!
 actorMapTurn :: LocalRef -> Message -> ActorMap
@@ -144,6 +155,16 @@ actorMapTurn' p acc  lref (Free op)  am = case op of
     case am of
       ActorMap m ->
         actorMapTurn' p acc lref (k ()) (ActorMap (Map.adjust (\(a, _s) -> (a, s')) lref m))
+  GetTime k ->
+    -- XXX: Should time live in the actor map (so each actor can have a
+    -- different perception of what the time is), or should time live in the
+    -- event loop? The former can be useful for simulating time scews even
+    -- though all actors are run in the same event loop.
+    actorMapTurn' p acc lref (k (error "XXX: need current time here...")) am
+  Random k ->
+    error "XXX: need seed from `EventLoop`..."
+  SetTimer ndt k ->
+    actorMapTurn' (p + 1) (SetTimerAction ndt p : acc) lref (k p) am
 
 actorMapPeek :: LocalRef -> Message -> ActorMap -> (Message, ActorMap)
 actorMapPeek lref msg am =
@@ -230,9 +251,13 @@ data AsyncState = AsyncState
   { asyncStateAsyncIO       :: Map (Async IOResult) Promise
   , asyncStateContinuations :: Map Promise (Resolution -> Free ActorF (), LocalRef)
   , asyncStateAdminSend     :: Map Promise (TMVar Message)
-  , asyncStateTimeouts      :: Heap (Entry UTCTime Promise)
+  , asyncStateTimeouts      :: Heap (Entry UTCTime (TimeoutKind, Promise))
   }
 
+data TimeoutKind
+  = SendTimeout
+  | TimerTimeout
+
 emptyAsyncState :: AsyncState
 emptyAsyncState = AsyncState Map.empty Map.empty Map.empty Heap.empty
 
@@ -242,6 +267,7 @@ madePromises = foldMap go
     go (SendAction _from _msg _to (Promise i)) = Set.singleton i
     go (AsyncIOAction _io (Promise i)) = Set.singleton i
     go OnAction {} = Set.empty
+    go (SetTimerAction _ndt (Promise i)) = Set.singleton i
 
 act :: EventLoopName -> [Action] -> Time -> Transport IO -> AsyncState -> IO AsyncState
 act name as time transport s0 = foldM go s0 as
@@ -257,7 +283,7 @@ act name as time transport s0 = foldM go s0 as
       -- XXX: make it possible to specify when a send request should timeout.
       let timeoutAfter = Time.addUTCTime 60 t
       return s { asyncStateTimeouts =
-                   Heap.insert (Entry timeoutAfter p) (asyncStateTimeouts s) }
+                   Heap.insert (Entry timeoutAfter (SendTimeout, p)) (asyncStateTimeouts s) }
     go s (AsyncIOAction io p) = do
       -- XXX: Use `asyncOn` a different capability than main loop.
       a <- async io
@@ -269,10 +295,15 @@ act name as time transport s0 = foldM go s0 as
                       Map.insert p (k, lref) (asyncStateContinuations s) })
       | otherwise =
           error "act: impossible, `On` must be supplied with a promise that was just made."
+    go s (SetTimerAction ndt p) = do
+      t <- getCurrentTime time
+      let timeoutAfter = Time.addUTCTime ndt t
+      return s { asyncStateTimeouts =
+                   Heap.insert (Entry timeoutAfter (TimerTimeout, p)) (asyncStateTimeouts s) }
 
 data Reaction
   = Receive Promise Envelope
-  | SendTimeout (Free ActorF ()) LocalRef
+  | SendTimeoutReaction (Free ActorF ()) LocalRef
   | AsyncIOFinished Promise IOResult
   | AsyncIOFailed Promise SomeException
 
@@ -300,7 +331,7 @@ react (Receive p e) s =
               (AdminSendResponse returnVar (envelopeMessage e),
                 s { asyncStateAdminSend =
                       Map.delete p (asyncStateAdminSend s) })
-react (SendTimeout a lref) s = (ResumeContinuation a lref, s)
+react (SendTimeoutReaction a lref) s = (ResumeContinuation a lref, s)
 react (AsyncIOFinished p result) s =
   case Map.lookup p (asyncStateContinuations s) of
     Nothing ->
@@ -426,24 +457,27 @@ handleTimeouts ls = forever go
       now <- getCurrentTime (lsTime ls)
       als <- atomically (stateTVar (lsAsyncState ls) (findTimedout now))
       mapM_ (\(a, lref) ->
-               atomically (writeTBQueue (lsQueue ls) (Reaction (SendTimeout a lref))))
+               atomically (writeTBQueue (lsQueue ls) (Reaction (SendTimeoutReaction a lref))))
         als
 
 findTimedout :: UTCTime -> AsyncState
              -> ([(Free ActorF (), LocalRef)], AsyncState)
 findTimedout now s =
   let
     (timedout, heap') = Heap.span (\(Entry t _p) -> t <= now) (asyncStateTimeouts s)
-    ps = map Heap.payload (toList timedout)
-    cs = catMaybes (map (\p -> Map.lookup p (asyncStateContinuations s)) ps)
-    als = map ((\(c, lref) -> (c (Left (error "XXX: timeout")), lref))) cs
-    ks = foldr Map.delete (asyncStateContinuations s) ps
+    ts = map Heap.payload (toList timedout)
+    cs = catMaybes (map (\(tk, p) ->
+                           fmap (\c -> (tk, c)) (Map.lookup p (asyncStateContinuations s))) ts)
+    als = map ((\(tk, (c, lref)) -> case tk of
+                   -- XXX: Introduce `Timer` in `Resolution`.
+                   SendTimeout  -> (c (Left (error "XXX: timeout")), lref)
+                   TimerTimeout -> (c (Left (error "XXX: tick")), lref))) cs
+    ks = foldr Map.delete (asyncStateContinuations s) (map snd ts)
   in
     (als, s { asyncStateContinuations = ks
             , asyncStateTimeouts      = heap'
             })
 
-
 handleEvents :: EventLoop -> IO ()
 handleEvents ls = forever go
   where