src/Streamly/Internal/Control/ForkLifted.hs · streamly

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streamly/src/Streamly/Internal/Control/ForkLifted.hs

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1-- |

2-- Module : Streamly.Internal.Control.ForkLifted

4-- License : BSD-3-Clause

5-- Maintainer : streamly@composewell.com

6-- Stability : experimental

7-- Portability : GHC

9module Streamly.Internal.Control.ForkLifted

10 (

11 doFork

12 , fork

13 , forkManaged

14 )

15where

17import Control.Concurrent (ThreadId, forkIO)

18import Control.Exception (SomeException(..), catch, mask)

19import Data.Functor (void)

20import Streamly.Internal.Control.Concurrent (MonadRunInIO, RunInIO(..), withRunInIO, withRunInIONoRestore)

21import Streamly.Internal.Control.ForkIO (rawForkIO, forkManagedWith)

23-- | Fork a thread to run the given computation, installing the provided

24-- exception handler. Lifted to any monad with 'MonadRunInIO m'

25-- capability.

26--

27-- TODO: the RunInIO argument can be removed, we can directly pass the action

28-- as "mrun action" instead.

29{-# INLINE doFork #-}

30doFork :: MonadRunInIO m

31 => m ()

32 -> RunInIO m

33 -> (SomeException -> IO ())

34 -> m ThreadId

35doFork action (RunInIO mrun) exHandler =

36 withRunInIO $ \run ->

37 mask $ \restore -> do

38 tid <- rawForkIO $ catch (restore $ void $ mrun action)

39 exHandler

40 run (return tid)

42-- | 'fork' lifted to any monad with 'MonadBaseControl IO m' capability.

43--

44{-# INLINABLE fork #-}

45fork :: MonadRunInIO m => m () -> m ThreadId

46fork m = withRunInIONoRestore $ \run -> forkIO $ void $ run m

48-- | Fork a thread that is automatically killed as soon as the reference to the

49-- returned threadId is garbage collected.

50--

51{-# INLINABLE forkManaged #-}

52forkManaged :: MonadRunInIO m => m () -> m ThreadId

53forkManaged = forkManagedWith fork