{-# LANGUAGE CPP #-}
{-# OPTIONS_HADDOCK hide #-}
module System.Glib.FFI (
nullForeignPtr,
maybeNull,
newForeignPtr,
withForeignPtrs,
#if MIN_VERSION_base(4,4,0)
unsafePerformIO,
unsafeForeignPtrToPtr,
#endif
module Foreign,
module Foreign.C
) where
import Foreign.C
#if MIN_VERSION_base(4,4,0)
import Foreign hiding (unsafePerformIO, unsafeForeignPtrToPtr, newForeignPtr, free)
import System.IO.Unsafe (unsafePerformIO)
import Foreign.ForeignPtr.Unsafe (unsafeForeignPtrToPtr)
#else
import Foreign hiding (newForeignPtr, free)
#endif
import qualified Foreign.Concurrent
newForeignPtr :: Ptr a -> FinalizerPtr a -> IO (ForeignPtr a)
newForeignPtr p finalizer
= Foreign.Concurrent.newForeignPtr p (mkFinalizer finalizer p)
foreign import ccall "dynamic"
mkFinalizer :: FinalizerPtr a -> Ptr a -> IO ()
nullForeignPtr :: ForeignPtr a
nullForeignPtr = unsafePerformIO $ newForeignPtr_ nullPtr
withForeignPtrs :: [ForeignPtr a] -> ([Ptr a] -> IO b) -> IO b
withForeignPtrs fptrs body = do
result <- body (map unsafeForeignPtrToPtr fptrs)
mapM_ touchForeignPtr fptrs
return result
maybeNull :: (IO (Ptr a) -> IO a) -> IO (Ptr a) -> IO (Maybe a)
maybeNull marshal genPtr = do
ptr <- genPtr
if ptr == nullPtr
then return Nothing
else do result <- marshal (return ptr)
return (Just result)