module Control.Eff.Concurrent.Process.SingleThreadedScheduler
( scheduleM
, schedulePure
, scheduleIO
, scheduleMonadIOEff
, scheduleIOWithLogging
, defaultMainSingleThreaded
, singleThreadedIoScheduler
)
where
import Control.Concurrent ( yield )
import Control.DeepSeq
import Control.Eff
import Control.Eff.Lift
import Control.Eff.Extend
import Control.Eff.Concurrent.Process
import Control.Eff.Log
import Control.Lens hiding ( (|>)
, Empty
)
import Control.Monad ( void
, when
)
import Control.Monad.IO.Class
import qualified Data.Sequence as Seq
import Data.Sequence ( Seq(..) )
import qualified Data.Map.Strict as Map
import qualified Data.Set as Set
import GHC.Stack
import Data.Kind ( )
import Data.Dynamic
import Data.Foldable
import Data.Monoid
import qualified Control.Monad.State.Strict as State
data STS r m = STS
{ _nextPid :: !ProcessId
, _nextRef :: !Int
, _msgQs :: !(Map.Map ProcessId (Seq Dynamic))
, _monitors :: !(Set.Set (MonitorReference, ProcessId))
, _processLinks :: !(Set.Set (ProcessId, ProcessId))
, _runEff :: (forall a . Eff r a -> m a)
, _yieldEff :: m ()
}
initStsMainProcess :: (forall a . Eff r a -> m a) -> m () -> STS r m
initStsMainProcess = STS 1 0 (Map.singleton 0 Seq.empty) Set.empty Set.empty
makeLenses ''STS
instance Show (STS r m) where
showsPrec d sts = showParen
(d >= 10)
( showString "STS "
. showString "nextRef: "
. shows (_nextRef sts)
. showString " msgQs: "
. appEndo
(foldMap
(\(pid, msgs) -> Endo (showString " " . shows pid . showString ": ")
<> foldMap (\m -> Endo (shows (dynTypeRep m))) (toList msgs)
)
(sts ^.. msgQs . itraversed . withIndex )
)
)
dropMsgQ :: ProcessId -> STS r m -> STS r m
dropMsgQ pid = msgQs . at pid .~ Nothing
getProcessState :: ProcessId -> STS r m -> Maybe ProcessState
getProcessState pid sts = toPS <$> sts ^. msgQs . at pid
where
toPS Empty = ProcessIdle
toPS (_ :<| _) = ProcessBusy
incRef :: STS r m -> (Int, STS r m)
incRef sts = (sts ^. nextRef, sts & nextRef %~ (+ 1))
enqueueMsg :: ProcessId -> Dynamic -> STS r m -> STS r m
enqueueMsg toPid msg = msgQs . at toPid . _Just %~ (:|> msg)
newProcessQ :: Maybe ProcessId -> STS r m -> (ProcessId, STS r m)
newProcessQ parentLink sts =
( sts ^. nextPid
, let stsQ =
sts & nextPid %~ (+ 1) & msgQs . at (sts ^. nextPid) ?~ Seq.empty
in case parentLink of
Nothing -> stsQ
Just pid ->
let (Nothing, stsQL) = addLink pid (sts ^. nextPid) stsQ in stsQL
)
flushMsgs :: ProcessId -> STS m r -> ([Dynamic], STS m r)
flushMsgs pid = State.runState $ do
msgs <- msgQs . at pid . _Just <<.= Empty
return (toList msgs)
receiveMsg
:: ProcessId -> MessageSelector a -> STS m r -> Maybe (Maybe (a, STS m r))
receiveMsg pid messageSelector sts = case sts ^. msgQs . at pid of
Nothing -> Nothing
Just msgQ -> Just $ case partitionMessages msgQ Empty of
Nothing -> Nothing
Just (result, otherMessages) ->
Just (result, sts & msgQs . at pid . _Just .~ otherMessages)
where
partitionMessages Empty _acc = Nothing
partitionMessages (m :<| msgRest) acc = maybe
(partitionMessages msgRest (acc :|> m))
(\res -> Just (res, acc Seq.>< msgRest))
(runMessageSelector messageSelector m)
addMonitoring
:: ProcessId -> ProcessId -> STS m r -> (MonitorReference, STS m r)
addMonitoring owner target = State.runState $ do
mi <- State.state incRef
let mref = MonitorReference mi target
when (target /= owner) $ do
pt <- use msgQs
if Map.member target pt
then monitors %= Set.insert (mref, owner)
else
let pdown =
(ProcessDown mref (SomeExitReason (ProcessNotRunning target)))
in State.modify' (enqueueMsg owner (toDyn pdown))
return mref
removeMonitoring :: MonitorReference -> STS m r -> STS m r
removeMonitoring mref = monitors %~ Set.filter (\(ref, _) -> ref /= mref)
triggerAndRemoveMonitor :: ProcessId -> SomeExitReason -> STS m r -> STS m r
triggerAndRemoveMonitor downPid reason = State.execState $ do
monRefs <- use monitors
traverse_ go monRefs
where
go (mr, owner) = when
(monitoredProcess mr == downPid)
(let pdown = ProcessDown mr reason
in State.modify' (enqueueMsg owner (toDyn pdown) . removeMonitoring mr)
)
addLink :: ProcessId -> ProcessId -> STS m r -> (Maybe InterruptReason, STS m r)
addLink fromPid toPid = State.runState $ do
hasToPid <- use (msgQs . to (Map.member toPid))
if hasToPid
then do
let (a, b) =
if fromPid <= toPid then (fromPid, toPid) else (toPid, fromPid)
processLinks %= Set.insert (a, b)
return Nothing
else return (Just (LinkedProcessCrashed toPid))
removeLinksTo :: ProcessId -> STS m r -> ([ProcessId], STS m r)
removeLinksTo pid sts = flip State.runState sts $ do
pl <- use processLinks
let aPids = pl ^.. folded . filtered (\(_, b) -> b == pid) . _1
let bPids = pl ^.. folded . filtered (\(a, _) -> a == pid) . _2
processLinks %= Set.filter (\(a, b) -> a /= pid && b /= pid)
return (aPids ++ bPids)
kontinue :: STS r m -> (ResumeProcess a -> Eff r a1) -> a -> m a1
kontinue sts k x = (sts ^. runEff) (k (ResumeWith x))
diskontinue :: STS r m -> (ResumeProcess v -> Eff r a) -> InterruptReason -> m a
diskontinue sts k e = (sts ^. runEff) (k (Interrupted e))
schedulePure
:: Eff (InterruptableProcess '[Logs LogMessage]) a
-> Either (ExitReason 'NoRecovery) a
schedulePure e = run (scheduleM ignoreLogs (return ()) e)
scheduleIO
:: MonadIO m
=> (forall b . Eff r b -> Eff '[Lift m] b)
-> Eff (InterruptableProcess r) a
-> m (Either (ExitReason 'NoRecovery) a)
scheduleIO r = scheduleM (runLift . r) (liftIO yield)
scheduleMonadIOEff
:: MonadIO (Eff r)
=> Eff (InterruptableProcess r) a
-> Eff r (Either (ExitReason 'NoRecovery) a)
scheduleMonadIOEff =
scheduleM id (liftIO yield)
scheduleIOWithLogging
:: (NFData l)
=> LogWriter l IO
-> Eff (InterruptableProcess '[Logs l, LogWriterReader l IO, Lift IO]) a
-> IO (Either (ExitReason 'NoRecovery) a)
scheduleIOWithLogging h = scheduleIO (writeLogs h)
scheduleM
:: forall m r a
. Monad m
=> (forall b . Eff r b -> m b)
-> m ()
-> Eff (InterruptableProcess r) a
-> m (Either (ExitReason 'NoRecovery) a)
scheduleM r y e = do
c <- runAsCoroutinePure r (provideInterruptsShutdown e)
handleProcess (initStsMainProcess r y) (Seq.singleton (c, 0))
data OnYield r a where
OnFlushMessages :: (ResumeProcess [Dynamic] -> Eff r (OnYield r a))
-> OnYield r a
OnYield :: (ResumeProcess () -> Eff r (OnYield r a))
-> OnYield r a
OnSelf :: (ResumeProcess ProcessId -> Eff r (OnYield r a))
-> OnYield r a
OnSpawn :: Bool
-> Eff (Process r ': r) ()
-> (ResumeProcess ProcessId -> Eff r (OnYield r a))
-> OnYield r a
OnDone :: !a -> OnYield r a
OnShutdown :: ExitReason 'NoRecovery -> OnYield r a
OnInterrupt :: ExitReason 'Recoverable
-> (ResumeProcess b -> Eff r (OnYield r a))
-> OnYield r a
OnSend :: !ProcessId -> !Dynamic
-> (ResumeProcess () -> Eff r (OnYield r a))
-> OnYield r a
OnRecv :: MessageSelector b -> (ResumeProcess b -> Eff r (OnYield r a))
-> OnYield r a
OnGetProcessState
:: ProcessId
-> (ResumeProcess (Maybe ProcessState) -> Eff r (OnYield r a))
-> OnYield r a
OnSendShutdown :: !ProcessId -> ExitReason 'NoRecovery
-> (ResumeProcess () -> Eff r (OnYield r a)) -> OnYield r a
OnSendInterrupt :: !ProcessId -> ExitReason 'Recoverable
-> (ResumeProcess () -> Eff r (OnYield r a)) -> OnYield r a
OnMakeReference :: (ResumeProcess Int -> Eff r (OnYield r a)) -> OnYield r a
OnMonitor
:: ProcessId
-> (ResumeProcess MonitorReference -> Eff r (OnYield r a))
-> OnYield r a
OnDemonitor
:: MonitorReference
-> (ResumeProcess () -> Eff r (OnYield r a))
-> OnYield r a
OnLink
:: ProcessId
-> (ResumeProcess () -> Eff r (OnYield r a))
-> OnYield r a
OnUnlink
:: ProcessId
-> (ResumeProcess () -> Eff r (OnYield r a))
-> OnYield r a
instance Show (OnYield r a) where
show =
\case
OnFlushMessages _ -> "OnFlushMessages"
OnYield _ -> "OnYield"
OnSelf _ -> "OnSelf"
OnSpawn False _ _ -> "OnSpawn"
OnSpawn True _ _ -> "OnSpawn (link)"
OnDone _ -> "OnDone"
OnShutdown e -> "OnShutdown " ++ show e
OnInterrupt e _ -> "OnInterrupt "++ show e
OnSend toP _ _ -> "OnSend " ++ show toP
OnRecv _ _ -> "OnRecv"
OnGetProcessState p _ -> "OnGetProcessState " ++ show p
OnSendShutdown p e _ -> "OnSendShutdow " ++ show p ++ " " ++ show e
OnSendInterrupt p e _ -> "OnSendInterrupt " ++ show p ++ " " ++ show e
OnMakeReference _ -> "OnMakeReference"
OnMonitor p _ -> "OnMonitor " ++ show p
OnDemonitor p _ -> "OnDemonitor " ++ show p
OnLink p _ -> "OnLink " ++ show p
OnUnlink p _ -> "OnUnlink " ++ show p
runAsCoroutinePure
:: forall v r m
. Monad m
=> (forall a . Eff r a -> m a)
-> Eff (ConsProcess r) v
-> m (OnYield r v)
runAsCoroutinePure r = r . handle_relay (return . OnDone) cont
where
cont :: Process r x -> (x -> Eff r (OnYield r v)) -> Eff r (OnYield r v)
cont FlushMessages k = return (OnFlushMessages k)
cont YieldProcess k = return (OnYield k)
cont SelfPid k = return (OnSelf k)
cont (Spawn e ) k = return (OnSpawn False e k)
cont (SpawnLink e ) k = return (OnSpawn True e k)
cont (Shutdown !sr ) _k = return (OnShutdown sr)
cont (SendMessage !tp !msg ) k = return (OnSend tp msg k)
cont (ReceiveSelectedMessage f ) k = return (OnRecv f k)
cont (GetProcessState !tp) k = return (OnGetProcessState tp k)
cont (SendInterrupt !tp !er ) k = return (OnSendInterrupt tp er k)
cont (SendShutdown !pid !sr ) k = return (OnSendShutdown pid sr k)
cont MakeReference k = return (OnMakeReference k)
cont (Monitor !pid) k = return (OnMonitor pid k)
cont (Demonitor !ref) k = return (OnDemonitor ref k)
cont (Link !pid) k = return (OnLink pid k)
cont (Unlink !pid) k = return (OnUnlink pid k)
handleProcess
:: Monad m
=> STS r m
-> Seq (OnYield r finalResult, ProcessId)
-> m (Either (ExitReason 'NoRecovery) finalResult)
handleProcess _sts Empty =
return $ Left (NotRecovered (ProcessError "no main process"))
handleProcess sts allProcs@((!processState, !pid) :<| rest)
= let
handleExit res = if pid == 0
then return res
else do
let (downPids, stsNew) = removeLinksTo pid sts
linkedPids = filter (/= pid) downPids
reason = LinkedProcessCrashed pid
unlinkLoop [] ps = return ps
unlinkLoop (dPid : dPidRest) ps = do
ps' <- sendInterruptToOtherPid dPid reason ps
unlinkLoop dPidRest ps'
let allProcsWithoutPid = Seq.filter (\(_, p) -> p /= pid) rest
nextTargets <- unlinkLoop linkedPids allProcsWithoutPid
handleProcess
(dropMsgQ
pid
(triggerAndRemoveMonitor
pid
(either SomeExitReason (const (SomeExitReason ExitNormally)) res
)
stsNew
)
)
nextTargets
in
case processState of
OnDone r -> handleExit (Right r)
OnShutdown e -> handleExit (Left e)
OnInterrupt e k -> do
nextK <- diskontinue sts k e
handleProcess sts (rest :|> (nextK, pid))
OnSendInterrupt targetPid sr k -> doSendInterrupt targetPid sr k
OnSendShutdown targetPid sr k -> do
let allButTarget =
Seq.filter (\(_, e) -> e /= pid && e /= targetPid) allProcs
targets = Seq.filter (\(_, e) -> e == targetPid) allProcs
suicide = targetPid == pid
if suicide
then handleExit (Left sr)
else do
let deliverTheGoodNews (targetState, tPid) = do
nextTargetState <- case targetState of
OnSendInterrupt _ _ _tk -> return (OnShutdown sr)
OnSendShutdown _ _ _tk -> return (OnShutdown sr)
OnFlushMessages _tk -> return (OnShutdown sr)
OnYield _tk -> return (OnShutdown sr)
OnSelf _tk -> return (OnShutdown sr)
OnSend _ _ _tk -> return (OnShutdown sr)
OnRecv _ _tk -> return (OnShutdown sr)
OnSpawn _ _ _tk -> return (OnShutdown sr)
OnDone x -> return (OnDone x)
OnGetProcessState _ _tk -> return (OnShutdown sr)
OnShutdown sr' -> return (OnShutdown sr')
OnInterrupt _er _tk -> return (OnShutdown sr)
OnMakeReference _tk -> return (OnShutdown sr)
OnMonitor _ _tk -> return (OnShutdown sr)
OnDemonitor _ _tk -> return (OnShutdown sr)
OnLink _ _tk -> return (OnShutdown sr)
OnUnlink _ _tk -> return (OnShutdown sr)
return (nextTargetState, tPid)
nextTargets <- _runEff sts $ traverse deliverTheGoodNews targets
nextK <- kontinue sts k ()
handleProcess
sts
(allButTarget Seq.>< (nextTargets :|> (nextK, pid)))
OnSelf k -> do
nextK <- kontinue sts k pid
handleProcess sts (rest :|> (nextK, pid))
OnMakeReference k -> do
let (ref, stsNext) = incRef sts
nextK <- kontinue sts k ref
handleProcess stsNext (rest :|> (nextK, pid))
OnYield k -> do
sts ^. yieldEff
nextK <- kontinue sts k ()
handleProcess sts (rest :|> (nextK, pid))
OnSend toPid msg k -> do
nextK <- kontinue sts k ()
handleProcess (enqueueMsg toPid msg sts) (rest :|> (nextK, pid))
OnGetProcessState toPid k -> do
nextK <- kontinue sts k (getProcessState toPid sts)
handleProcess sts (rest :|> (nextK, pid))
OnSpawn link f k -> do
let (newPid, newSts) =
newProcessQ (if link then Just pid else Nothing) sts
fk <- runAsCoroutinePure (newSts ^. runEff) (f >> exitNormally SP)
nextK <- kontinue newSts k newPid
handleProcess newSts (rest :|> (fk, newPid) :|> (nextK, pid))
OnFlushMessages k -> do
let (msgs, newSts) = flushMsgs pid sts
nextK <- kontinue newSts k msgs
handleProcess newSts (rest :|> (nextK, pid))
recv@(OnRecv messageSelector k) ->
case receiveMsg pid messageSelector sts of
Nothing -> do
nextK <- diskontinue
sts
k
(ProcessError (show pid ++ " has no message queue"))
handleProcess sts (rest :|> (nextK, pid))
Just Nothing -> if Seq.length rest == 0
then do
nextK <- diskontinue
sts
k
(ProcessError (show pid ++ " deadlocked"))
handleProcess sts (rest :|> (nextK, pid))
else handleProcess sts (rest :|> (recv, pid))
Just (Just (result, newSts)) -> do
nextK <- kontinue newSts k result
handleProcess newSts (rest :|> (nextK, pid))
OnMonitor toPid k -> do
let (ref, stsNew) = addMonitoring pid toPid sts
nextK <- kontinue stsNew k ref
handleProcess stsNew (rest :|> (nextK, pid))
OnDemonitor monRef k -> do
let stsNew = removeMonitoring monRef sts
nextK <- kontinue stsNew k ()
handleProcess stsNew (rest :|> (nextK, pid))
OnLink toPid k -> do
let (downInterrupts, stsNew) = addLink pid toPid sts
nextK <- case downInterrupts of
Nothing -> kontinue stsNew k ()
Just i -> diskontinue stsNew k i
handleProcess stsNew (rest :|> (nextK, pid))
OnUnlink toPid k -> do
let (_, stsNew) = removeLinksTo toPid sts
nextK <- kontinue stsNew k ()
handleProcess stsNew (rest :|> (nextK, pid))
where
doSendInterrupt targetPid sr k = do
let suicide = targetPid == pid
if suicide
then do
nextK <- diskontinue sts k sr
handleProcess sts (rest :|> (nextK, pid))
else do
nextTargets <- sendInterruptToOtherPid targetPid sr rest
nextK <- kontinue sts k ()
handleProcess sts (nextTargets :|> (nextK, pid))
sendInterruptToOtherPid targetPid sr procs = do
let allButTarget = Seq.filter (\(_, e) -> e /= targetPid) procs
targets = Seq.filter (\(_, e) -> e == targetPid) procs
deliverTheGoodNews (targetState, tPid) = do
nextTargetState <- case targetState of
OnSendInterrupt _ _ tk -> tk (Interrupted sr)
OnSendShutdown _ _ tk -> tk (Interrupted sr)
OnFlushMessages tk -> tk (Interrupted sr)
OnYield tk -> tk (Interrupted sr)
OnSelf tk -> tk (Interrupted sr)
OnSend _ _ tk -> tk (Interrupted sr)
OnRecv _ tk -> tk (Interrupted sr)
OnSpawn _ _ tk -> tk (Interrupted sr)
OnDone x -> return (OnDone x)
OnGetProcessState _ tk -> tk (Interrupted sr)
OnShutdown sr' -> return (OnShutdown sr')
OnInterrupt er tk -> tk (Interrupted er)
OnMakeReference tk -> tk (Interrupted sr)
OnMonitor _ tk -> tk (Interrupted sr)
OnDemonitor _ tk -> tk (Interrupted sr)
OnLink _ tk -> tk (Interrupted sr)
OnUnlink _ tk -> tk (Interrupted sr)
return (nextTargetState, tPid)
nextTargets <- _runEff sts $ traverse deliverTheGoodNews targets
return (nextTargets Seq.>< allButTarget)
type LoggingAndIo =
'[ Logs LogMessage
, LogWriterReader LogMessage IO
, Lift IO
]
singleThreadedIoScheduler :: SchedulerProxy LoggingAndIo
singleThreadedIoScheduler = SchedulerProxy
defaultMainSingleThreaded
:: HasCallStack
=> Eff
( InterruptableProcess
'[Logs LogMessage, LogWriterReader LogMessage IO, Lift IO]
)
()
-> IO ()
defaultMainSingleThreaded =
void
. runLift
. writeLogs (multiMessageLogWriter ($ printLogMessage))
. scheduleMonadIOEff