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{-# LANGUAGE Trustworthy #-} {-# LANGUAGE NoImplicitPrelude #-} {-# LANGUAGE CPP #-}

-- | -- Module : GHC.IO.SubSystem -- Copyright : (c) The University of Glasgow, 2017 -- License : see libraries/base/LICENSE

-- Maintainer : libraries@haskell.org -- Stability : internal -- Portability : non-portable

-- The SubSystem control interface. These methods can be used to disambiguate -- between the two operations.

module GHC.IO.SubSystem ( withIoSubSystem, withIoSubSystem', whenIoSubSystem, ioSubSystem, IoSubSystem(..), conditional, (<!>), isWindowsNativeIO ) where

import GHC.Base import GHC.RTS.Flags

#if defined(mingw32_HOST_OS) import GHC.IO.Unsafe #endif

infixl 7 <!>

-- | Conditionally execute an action depending on the configured I/O subsystem. -- On POSIX systems always execute the first action. -- On windows execute the second action if WINIO as active, otherwise fall back to -- the first action. conditional :: a -> a -> a #if defined(mingw32_HOST_OS) conditional posix windows = case ioSubSystem of IoPOSIX -> posix IoNative -> windows #else conditional :: forall a. a -> a -> a conditional a posix a _ = a posix #endif

-- | Infix version of conditional. -- posix <!> windows == conditional posix windows (<!>) :: a -> a -> a <!> :: forall a. a -> a -> a (<!>) = a -> a -> a forall a. a -> a -> a conditional

isWindowsNativeIO :: Bool isWindowsNativeIO :: Bool isWindowsNativeIO = Bool False Bool -> Bool -> Bool forall a. a -> a -> a <!> Bool True

ioSubSystem :: IoSubSystem #if defined(mingw32_HOST_OS) {-# NOINLINE ioSubSystem #-} ioSubSystem = unsafeDupablePerformIO getIoManagerFlag #else ioSubSystem :: IoSubSystem ioSubSystem = IoSubSystem IoPOSIX #endif

withIoSubSystem :: (IoSubSystem -> IO a) -> IO a withIoSubSystem :: forall a. (IoSubSystem -> IO a) -> IO a withIoSubSystem IoSubSystem -> IO a f = IoSubSystem -> IO a f IoSubSystem ioSubSystem

withIoSubSystem' :: (IoSubSystem -> a) -> a withIoSubSystem' :: forall a. (IoSubSystem -> a) -> a withIoSubSystem' IoSubSystem -> a f = IoSubSystem -> a f IoSubSystem ioSubSystem

whenIoSubSystem :: IoSubSystem -> IO () -> IO () whenIoSubSystem :: IoSubSystem -> IO () -> IO () whenIoSubSystem IoSubSystem m IO () f = do let sub :: IoSubSystem sub = IoSubSystem ioSubSystem Bool -> IO () -> IO () forall (f :: * -> *). Applicative f => Bool -> f () -> f () when (IoSubSystem sub IoSubSystem -> IoSubSystem -> Bool forall a. Eq a => a -> a -> Bool == IoSubSystem m) IO () f