WIP: Add kindaUnlift to find out what happens where

Author: dpwiz

troupe/src/Troupe.hs

@@ -13,6 +13,7 @@ module Troupe
     spawn,
     spawnLink,
     spawnMonitor,
+    kindaUnlift,
 
     -- *** Spawning processes with options
     spawnWithOptions,
@@ -118,6 +119,7 @@ import Troupe.Process
     sendLazy,
     setProcessOption,
     spawnWithOptions,
+    kindaUnlift,
     unlink,
   )
 import Troupe.Types (Down (..), MonitorRef, ProcessId)

troupe/src/Troupe/Process.hs

@@ -33,6 +33,7 @@ module Troupe.Process
     exit,
     isProcessAlive,
     spawnWithOptions,
+    kindaUnlift,
     SpawnOptions (..),
     ThreadAffinity (..),
     WithMonitor (..),
@@ -46,7 +47,7 @@ module Troupe.Process
 where
 
 import Control.Applicative (Alternative, (<|>))
-import Control.Concurrent (throwTo)
+import Control.Concurrent (threadDelay, throwTo)
 import Control.Concurrent.Async
   ( async,
     asyncThreadId,
@@ -100,7 +101,7 @@ import Control.Exception.Safe
     uninterruptibleMask_,
     withException,
   )
-import Control.Monad (MonadPlus, forM, unless, when)
+import Control.Monad (MonadPlus, forever, forM, unless, when)
 import Control.Monad.Error.Class (MonadError)
 import Control.Monad.Fix (MonadFix)
 import Control.Monad.IO.Class (MonadIO, liftIO)
@@ -583,17 +584,7 @@ data ThreadAffinity
 -- 'Troupe.spawn', 'Troupe.spawnLink' and 'Troupe.spawnMonitor' are specialized
 -- versions of this function.
 spawnWithOptions :: (MonadProcess r m, MonadIO m) => SpawnOptions t -> Process r a -> m t
-spawnWithOptions !options process = do
-  let cb pid = do
-        when (spawnOptionsLink options) $
-          linkSTM pid
-        case spawnOptionsMonitor options of
-          WithoutMonitor -> pure pid
-          WithMonitor -> do
-            ref <- monitorSTM pid
-            pure (pid, ref)
-
-  spawnImpl (spawnOptionsAffinity options) cb process
+spawnWithOptions options = spawnImpl (spawnOptionsAffinity options) (mkCallback options)
 {-# SPECIALIZE spawnWithOptions :: SpawnOptions t -> Process r a -> Process r t #-}
 
 data SendOptions = SendOptions
@@ -719,22 +710,43 @@ after ::
 after = MatchAfter
 {-# INLINE after #-}
 
+kindaUnlift :: (MonadProcess r m, MonadIO io) => ((ThreadAffinity -> Process r a -> io ()) -> m b) -> m b
+kindaUnlift foreignSpawner = do
+  env <- getProcessEnv
+  foreignSpawner $ \affinity action -> do
+    _pid <- spawnImplWith env affinity pure action -- XXX: does it make sense to link/monitor a wrapped process?
+    -- TODO: spawnImplWith should have a blocking version
+    liftIO . forever $
+      threadDelay 10000000
+
+mkCallback :: SpawnOptions r -> ProcessId -> ReaderT (ProcessEnv a) STM r
+mkCallback !options pid = do
+  when (spawnOptionsLink options) $
+    linkSTM pid
+  case spawnOptionsMonitor options of
+    WithoutMonitor -> pure pid
+    WithMonitor -> do
+      ref <- monitorSTM pid
+      pure (pid, ref)
+
 spawnImpl :: (MonadProcess r m, MonadIO m) => ThreadAffinity -> (ProcessId -> ReaderT (ProcessEnv r) STM t) -> Process r a -> m t
 spawnImpl affinity cb process = do
   currentEnv <- getProcessEnv
+  spawnImplWith currentEnv affinity cb process
 
-  liftIO $ do
-    processContext <- newProcessContext (processEnvNodeContext currentEnv)
-    let processEnv = currentEnv {processEnvProcessContext = processContext}
+spawnImplWith :: MonadIO m => ProcessEnv r -> ThreadAffinity -> (ProcessId -> ReaderT (ProcessEnv r) STM t) -> Process r a -> m t
+spawnImplWith currentEnv affinity cb process = liftIO $ do
+  processContext <- newProcessContext (processEnvNodeContext currentEnv)
+  let processEnv = currentEnv {processEnvProcessContext = processContext}
 
-    m <- newEmptyTMVarIO
+  m <- newEmptyTMVarIO
 
-    bracketOnError
-      (run currentEnv processEnv m)
-      uninterruptibleCancel
-      (wrapup m)
+  bracketOnError
+    (run processEnv m)
+    uninterruptibleCancel
+    (wrapup m)
   where
-    run currentEnv processEnv m = mask_ $ async $ do
+    run processEnv m = mask_ $ async $ do
       c <- newEmptyTMVarIO
       let act restore = atomically (readTMVar c) >>= \() -> restore (runProcess process processEnv)