-- |
-- Module      : Streamly.Internal.BaseCompat
-- License     : BSD3
-- Maintainer  : streamly@composewell.com
-- Stability   : experimental
-- Portability : GHC
--
-- Compatibility functions for "base" package.
--
module Streamly.Internal.BaseCompat
    (
      (#.)
    , errorWithoutStackTrace
    , fromLeft
    , fromRight
    , unsafeWithForeignPtr
    , oneShot
    )
where

import Data.Coerce (Coercible, coerce)
#if MIN_VERSION_base(4,10,0)
import Data.Either (fromRight, fromLeft)
import qualified GHC.Exts as GHCExt
#endif
import GHC.ForeignPtr (ForeignPtr(..))
import GHC.Ptr (Ptr(..))
#if MIN_VERSION_base(4,15,0)
import qualified GHC.ForeignPtr as GHCForeignPtr
#else
import Foreign.ForeignPtr (withForeignPtr)
#endif

{-# INLINE (#.) #-}
(#.) :: Coercible b c => (b -> c) -> (a -> b) -> (a -> c)
(#.) _f = coerce

#if !(MIN_VERSION_base(4,9,0))
{-# NOINLINE errorWithoutStackTrace #-}
errorWithoutStackTrace :: String -> a
errorWithoutStackTrace = error
#endif

#if !(MIN_VERSION_base(4,10,0))
fromLeft :: a -> Either a b -> a
fromLeft _ (Left a) = a
fromLeft a _        = a

fromRight :: b -> Either a b -> b
fromRight _ (Right b) = b
fromRight b _         = b
#endif

unsafeWithForeignPtr :: ForeignPtr a -> (Ptr a -> IO b) -> IO b
#if MIN_VERSION_base(4,15,0)
unsafeWithForeignPtr = GHCForeignPtr.unsafeWithForeignPtr
#else
unsafeWithForeignPtr = withForeignPtr
#endif

oneShot :: (a -> b) -> a -> b
#if MIN_VERSION_base(4,10,0)
oneShot = GHCExt.oneShot
#else
oneShot = id
#endif