{-# LANGUAGE CPP #-}
{-# LANGUAGE MagicHash #-}
{-# LANGUAGE UnliftedFFITypes #-}
{-# OPTIONS_HADDOCK not-home #-}
module Effectful.Internal.Utils
  ( inlineBracket

    -- * Utils for 'ThreadId'
  , weakThreadId
  , eqThreadId

    -- * Utils for 'Any'
  , Any
  , toAny
  , fromAny

    -- * Strict 'IORef'
  , IORef'
  , newIORef'
  , readIORef'
  , writeIORef'

    -- * Strict 'MVar'
  , MVar'
  , toMVar'
  , newMVar'
  , readMVar'
  , modifyMVar'
  , modifyMVar_'

    -- * Unique
  , Unique
  , newUnique
  ) where

import Control.Concurrent.MVar
import Control.Exception
import Data.IORef
import Data.Primitive.ByteArray
import GHC.Conc.Sync (ThreadId(..))
import GHC.Exts (Addr#, Any, RealWorld, ThreadId#, unsafeCoerce#)
import Unsafe.Coerce (unsafeCoerce)

#if __GLASGOW_HASKELL__ >= 904
import Data.Word
#else
import Foreign.C.Types
#endif

-- | Version of bracket with an INLINE pragma to work around
-- https://gitlab.haskell.org/ghc/ghc/-/issues/22824.
inlineBracket :: IO a -> (a -> IO b) -> (a -> IO c) -> IO c
inlineBracket :: forall a b c. IO a -> (a -> IO b) -> (a -> IO c) -> IO c
inlineBracket IO a
before a -> IO b
after a -> IO c
action = forall b. ((forall a. IO a -> IO a) -> IO b) -> IO b
mask forall a b. (a -> b) -> a -> b
$ \forall a. IO a -> IO a
unmask -> do
  a
a <- IO a
before
  c
r <- forall a. IO a -> IO a
unmask (a -> IO c
action a
a) forall a b. IO a -> IO b -> IO a
`onException` a -> IO b
after a
a
  b
_ <- a -> IO b
after a
a
  forall (f :: Type -> Type) a. Applicative f => a -> f a
pure c
r
{-# INLINE inlineBracket #-}

----------------------------------------

-- | Get an id of a thread that doesn't prevent its garbage collection.
weakThreadId :: ThreadId -> Int
weakThreadId :: ThreadId -> Int
weakThreadId (ThreadId ThreadId#
t#) = forall a b. (Integral a, Num b) => a -> b
fromIntegral forall a b. (a -> b) -> a -> b
$ Addr# -> CLong
rts_getThreadId (ThreadId# -> Addr#
threadIdToAddr# ThreadId#
t#)

foreign import ccall unsafe "rts_getThreadId"
#if __GLASGOW_HASKELL__ >= 904
  -- https://gitlab.haskell.org/ghc/ghc/-/merge_requests/6163
  rts_getThreadId :: Addr# -> Word64
#elif __GLASGOW_HASKELL__ >= 900
  -- https://gitlab.haskell.org/ghc/ghc/-/merge_requests/1254
  rts_getThreadId :: Addr# -> CLong
#else
  rts_getThreadId :: Addr# -> CInt
#endif

-- Note: FFI imports take Addr# instead of ThreadId# because of
-- https://gitlab.haskell.org/ghc/ghc/-/issues/8281, which would prevent loading
-- effectful-core into GHCi.
--
-- Previous workaround was to use an internal library with just this module, but
-- this is not viable because of bugs in stack (sigh).
--
-- The coercion is fine because GHC represents ThreadId# as a pointer.
threadIdToAddr# :: ThreadId# -> Addr#
threadIdToAddr# :: ThreadId# -> Addr#
threadIdToAddr# = unsafeCoerce# :: forall a b. a -> b
unsafeCoerce#

----------------------------------------

#if __GLASGOW_HASKELL__ < 900

-- | 'Eq' instance for 'ThreadId' is broken in GHC < 9, see
-- https://gitlab.haskell.org/ghc/ghc/-/issues/16761 for more info.
eqThreadId :: ThreadId -> ThreadId -> Bool
eqThreadId (ThreadId t1#) (ThreadId t2#) =
  eq_thread (threadIdToAddr# t1#) (threadIdToAddr# t2#) == 1

foreign import ccall unsafe "effectful_eq_thread"
  eq_thread :: Addr# -> Addr# -> CLong

#else

eqThreadId :: ThreadId -> ThreadId -> Bool
eqThreadId :: ThreadId -> ThreadId -> Bool
eqThreadId = forall a. Eq a => a -> a -> Bool
(==)

#endif

----------------------------------------

toAny :: a -> Any
toAny :: forall a. a -> Any
toAny = forall a b. a -> b
unsafeCoerce

fromAny :: Any -> a
fromAny :: forall a. Any -> a
fromAny = forall a b. a -> b
unsafeCoerce

----------------------------------------

-- | A strict variant of 'IORef'.
newtype IORef' a = IORef' (IORef a)
  deriving IORef' a -> IORef' a -> Bool
forall a. IORef' a -> IORef' a -> Bool
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
/= :: IORef' a -> IORef' a -> Bool
$c/= :: forall a. IORef' a -> IORef' a -> Bool
== :: IORef' a -> IORef' a -> Bool
$c== :: forall a. IORef' a -> IORef' a -> Bool
Eq

newIORef' :: a -> IO (IORef' a)
newIORef' :: forall a. a -> IO (IORef' a)
newIORef' a
a = a
a seq :: forall a b. a -> b -> b
`seq` (forall a. IORef a -> IORef' a
IORef' forall (f :: Type -> Type) a b. Functor f => (a -> b) -> f a -> f b
<$> forall a. a -> IO (IORef a)
newIORef a
a)

readIORef' :: IORef' a -> IO a
readIORef' :: forall a. IORef' a -> IO a
readIORef' (IORef' IORef a
var) = forall a. IORef a -> IO a
readIORef IORef a
var

writeIORef' :: IORef' a -> a -> IO ()
writeIORef' :: forall a. IORef' a -> a -> IO ()
writeIORef' (IORef' IORef a
var) a
a = a
a seq :: forall a b. a -> b -> b
`seq` forall a. IORef a -> a -> IO ()
writeIORef IORef a
var a
a

----------------------------------------

-- | A strict variant of 'MVar'.
newtype MVar' a = MVar' (MVar a)
  deriving MVar' a -> MVar' a -> Bool
forall a. MVar' a -> MVar' a -> Bool
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
/= :: MVar' a -> MVar' a -> Bool
$c/= :: forall a. MVar' a -> MVar' a -> Bool
== :: MVar' a -> MVar' a -> Bool
$c== :: forall a. MVar' a -> MVar' a -> Bool
Eq

toMVar' :: MVar a -> IO (MVar' a)
toMVar' :: forall a. MVar a -> IO (MVar' a)
toMVar' MVar a
var = do
  let var' :: MVar' a
var' = forall a. MVar a -> MVar' a
MVar' MVar a
var
  forall a. MVar' a -> (a -> IO a) -> IO ()
modifyMVar_' MVar' a
var' forall (f :: Type -> Type) a. Applicative f => a -> f a
pure
  forall (f :: Type -> Type) a. Applicative f => a -> f a
pure MVar' a
var'

newMVar' :: a -> IO (MVar' a)
newMVar' :: forall a. a -> IO (MVar' a)
newMVar' a
a = a
a seq :: forall a b. a -> b -> b
`seq` (forall a. MVar a -> MVar' a
MVar' forall (f :: Type -> Type) a b. Functor f => (a -> b) -> f a -> f b
<$> forall a. a -> IO (MVar a)
newMVar a
a)

readMVar' :: MVar' a -> IO a
readMVar' :: forall a. MVar' a -> IO a
readMVar' (MVar' MVar a
var) = forall a. MVar a -> IO a
readMVar MVar a
var

modifyMVar' :: MVar' a -> (a -> IO (a, r)) -> IO r
modifyMVar' :: forall a r. MVar' a -> (a -> IO (a, r)) -> IO r
modifyMVar' (MVar' MVar a
var) a -> IO (a, r)
action = forall a b. MVar a -> (a -> IO (a, b)) -> IO b
modifyMVar MVar a
var forall a b. (a -> b) -> a -> b
$ \a
a0 -> do
  (a
a, r
r) <- a -> IO (a, r)
action a
a0
  a
a seq :: forall a b. a -> b -> b
`seq` forall (f :: Type -> Type) a. Applicative f => a -> f a
pure (a
a, r
r)

modifyMVar_' :: MVar' a -> (a -> IO a) -> IO ()
modifyMVar_' :: forall a. MVar' a -> (a -> IO a) -> IO ()
modifyMVar_' (MVar' MVar a
var) a -> IO a
action = forall a. MVar a -> (a -> IO a) -> IO ()
modifyMVar_ MVar a
var forall a b. (a -> b) -> a -> b
$ \a
a0 -> do
  a
a <- a -> IO a
action a
a0
  a
a seq :: forall a b. a -> b -> b
`seq` forall (f :: Type -> Type) a. Applicative f => a -> f a
pure a
a

----------------------------------------

-- | A unique with no possibility for CAS contention.
--
-- Credits for this go to Edward Kmett.
newtype Unique = Unique (MutableByteArray RealWorld)

instance Eq Unique where
  Unique MutableByteArray RealWorld
a == :: Unique -> Unique -> Bool
== Unique MutableByteArray RealWorld
b = forall s. MutableByteArray s -> MutableByteArray s -> Bool
sameMutableByteArray MutableByteArray RealWorld
a MutableByteArray RealWorld
b

newUnique :: IO Unique
newUnique :: IO Unique
newUnique = MutableByteArray RealWorld -> Unique
Unique forall (f :: Type -> Type) a b. Functor f => (a -> b) -> f a -> f b
<$> forall (m :: Type -> Type).
PrimMonad m =>
Int -> m (MutableByteArray (PrimState m))
newByteArray Int
0