-{-# OPTIONS_GHC -XNoImplicitPrelude #-}
+{-# LANGUAGE CPP
+ , NoImplicitPrelude
+ , BangPatterns
+ , MagicHash
+ , UnboxedTuples
+ #-}
{-# OPTIONS_HADDOCK hide #-}
+
-----------------------------------------------------------------------------
-- |
-- Module : GHC.ForeignPtr
(
ForeignPtr(..),
FinalizerPtr,
+ FinalizerEnvPtr,
newForeignPtr_,
mallocForeignPtr,
mallocPlainForeignPtr,
mallocForeignPtrBytes,
mallocPlainForeignPtrBytes,
- addForeignPtrFinalizer,
+ addForeignPtrFinalizer,
+ addForeignPtrFinalizerEnv,
touchForeignPtr,
unsafeForeignPtrToPtr,
castForeignPtr,
import Control.Monad ( sequence_ )
import Foreign.Storable
+import Data.Typeable
import GHC.Show
import GHC.List ( null )
import GHC.Base
-import GHC.IOBase
+import GHC.IORef
import GHC.STRef ( STRef(..) )
-import GHC.Ptr ( Ptr(..), FunPtr )
+import GHC.Ptr ( Ptr(..), FunPtr(..) )
import GHC.Err
+#include "Typeable.h"
+
-- |The type 'ForeignPtr' represents references to objects that are
-- maintained in a foreign language, i.e., that are not part of the
-- data structures usually managed by the Haskell storage manager.
-- object, because that ensures that whatever the finalizer is
-- attached to is kept alive.
+INSTANCE_TYPEABLE1(ForeignPtr,foreignPtrTc,"ForeignPtr")
+
+data Finalizers
+ = NoFinalizers
+ | CFinalizers
+ | HaskellFinalizers
+ deriving Eq
+
data ForeignPtrContents
- = PlainForeignPtr !(IORef [IO ()])
- | MallocPtr (MutableByteArray# RealWorld) !(IORef [IO ()])
+ = PlainForeignPtr !(IORef (Finalizers, [IO ()]))
+ | MallocPtr (MutableByteArray# RealWorld) !(IORef (Finalizers, [IO ()]))
| PlainPtr (MutableByteArray# RealWorld)
instance Eq (ForeignPtr a) where
showsPrec p f = showsPrec p (unsafeForeignPtrToPtr f)
--- |A Finalizer is represented as a pointer to a foreign function that, at
+-- |A finalizer is represented as a pointer to a foreign function that, at
-- finalisation time, gets as an argument a plain pointer variant of the
-- foreign pointer that the finalizer is associated with.
--
-type FinalizerPtr a = FunPtr (Ptr a -> IO ())
+type FinalizerPtr a = FunPtr (Ptr a -> IO ())
+type FinalizerEnvPtr env a = FunPtr (Ptr env -> Ptr a -> IO ())
newConcForeignPtr :: Ptr a -> IO () -> IO (ForeignPtr a)
--
--
mallocForeignPtr = doMalloc undefined
where doMalloc :: Storable b => b -> IO (ForeignPtr b)
- doMalloc a = do
- r <- newIORef []
+ doMalloc a
+ | I# size < 0 = error "mallocForeignPtr: size must be >= 0"
+ | otherwise = do
+ r <- newIORef (NoFinalizers, [])
IO $ \s ->
- case newPinnedByteArray# size s of { (# s', mbarr# #) ->
+ case newAlignedPinnedByteArray# size align s of { (# s', mbarr# #) ->
(# s', ForeignPtr (byteArrayContents# (unsafeCoerce# mbarr#))
(MallocPtr mbarr# r) #)
}
- where (I# size) = sizeOf a
+ where !(I# size) = sizeOf a
+ !(I# align) = alignment a
-- | This function is similar to 'mallocForeignPtr', except that the
-- size of the memory required is given explicitly as a number of bytes.
mallocForeignPtrBytes :: Int -> IO (ForeignPtr a)
+mallocForeignPtrBytes size | size < 0 =
+ error "mallocForeignPtrBytes: size must be >= 0"
mallocForeignPtrBytes (I# size) = do
- r <- newIORef []
+ r <- newIORef (NoFinalizers, [])
IO $ \s ->
case newPinnedByteArray# size s of { (# s', mbarr# #) ->
(# s', ForeignPtr (byteArrayContents# (unsafeCoerce# mbarr#))
mallocPlainForeignPtr :: Storable a => IO (ForeignPtr a)
mallocPlainForeignPtr = doMalloc undefined
where doMalloc :: Storable b => b -> IO (ForeignPtr b)
- doMalloc a = IO $ \s ->
- case newPinnedByteArray# size s of { (# s', mbarr# #) ->
+ doMalloc a
+ | I# size < 0 = error "mallocForeignPtr: size must be >= 0"
+ | otherwise = IO $ \s ->
+ case newAlignedPinnedByteArray# size align s of { (# s', mbarr# #) ->
(# s', ForeignPtr (byteArrayContents# (unsafeCoerce# mbarr#))
(PlainPtr mbarr#) #)
}
- where (I# size) = sizeOf a
+ where !(I# size) = sizeOf a
+ !(I# align) = alignment a
-- | This function is similar to 'mallocForeignPtrBytes', except that
-- the internally an optimised ForeignPtr representation with no
-- finalizer is used. Attempts to add a finalizer will cause an
-- exception to be thrown.
mallocPlainForeignPtrBytes :: Int -> IO (ForeignPtr a)
+mallocPlainForeignPtrBytes size | size < 0 =
+ error "mallocPlainForeignPtrBytes: size must be >= 0"
mallocPlainForeignPtrBytes (I# size) = IO $ \s ->
case newPinnedByteArray# size s of { (# s', mbarr# #) ->
(# s', ForeignPtr (byteArrayContents# (unsafeCoerce# mbarr#))
-- ^This function adds a finalizer to the given foreign object. The
-- finalizer will run /before/ all other finalizers for the same
-- object which have already been registered.
-addForeignPtrFinalizer finalizer fptr =
- addForeignPtrConcFinalizer fptr
- (mkFinalizer finalizer (unsafeForeignPtrToPtr fptr))
+addForeignPtrFinalizer (FunPtr fp) (ForeignPtr p c) = case c of
+ PlainForeignPtr r -> f r >> return ()
+ MallocPtr _ r -> f r >> return ()
+ _ -> error "GHC.ForeignPtr: attempt to add a finalizer to a plain pointer"
+ where
+ f r =
+ noMixing CFinalizers r $
+ IO $ \s ->
+ case r of { IORef (STRef r#) ->
+ case mkWeakForeignEnv# r# () fp p 0# nullAddr# s of { (# s1, w #) ->
+ (# s1, finalizeForeign w #) }}
+
+addForeignPtrFinalizerEnv ::
+ FinalizerEnvPtr env a -> Ptr env -> ForeignPtr a -> IO ()
+-- ^ Like 'addForeignPtrFinalizerEnv' but allows the finalizer to be
+-- passed an additional environment parameter to be passed to the
+-- finalizer. The environment passed to the finalizer is fixed by the
+-- second argument to 'addForeignPtrFinalizerEnv'
+addForeignPtrFinalizerEnv (FunPtr fp) (Ptr ep) (ForeignPtr p c) = case c of
+ PlainForeignPtr r -> f r >> return ()
+ MallocPtr _ r -> f r >> return ()
+ _ -> error "GHC.ForeignPtr: attempt to add a finalizer to a plain pointer"
+ where
+ f r =
+ noMixing CFinalizers r $
+ IO $ \s ->
+ case r of { IORef (STRef r#) ->
+ case mkWeakForeignEnv# r# () fp p 1# ep s of { (# s1, w #) ->
+ (# s1, finalizeForeign w #) }}
+
+finalizeForeign :: Weak# () -> IO ()
+finalizeForeign w = IO $ \s ->
+ case finalizeWeak# w s of
+ (# s1, 0#, _ #) -> (# s1, () #)
+ (# s1, _ , f #) -> f s1
addForeignPtrConcFinalizer :: ForeignPtr a -> IO () -> IO ()
-- ^This function adds a finalizer to the given @ForeignPtr@. The
addForeignPtrConcFinalizer_ :: ForeignPtrContents -> IO () -> IO ()
addForeignPtrConcFinalizer_ (PlainForeignPtr r) finalizer = do
- fs <- readIORef r
- writeIORef r (finalizer : fs)
- if (null fs)
+ noFinalizers <- noMixing HaskellFinalizers r (return finalizer)
+ if noFinalizers
then IO $ \s ->
case r of { IORef (STRef r#) ->
case mkWeak# r# () (foreignPtrFinalizer r) s of { (# s1, _ #) ->
(# s1, () #) }}
else return ()
-addForeignPtrConcFinalizer_ f@(MallocPtr fo r) finalizer = do
- fs <- readIORef r
- writeIORef r (finalizer : fs)
- if (null fs)
+addForeignPtrConcFinalizer_ f@(MallocPtr fo r) finalizer = do
+ noFinalizers <- noMixing HaskellFinalizers r (return finalizer)
+ if noFinalizers
then IO $ \s ->
case mkWeak# fo () (do foreignPtrFinalizer r; touch f) s of
(# s1, _ #) -> (# s1, () #)
addForeignPtrConcFinalizer_ _ _ =
error "GHC.ForeignPtr: attempt to add a finalizer to plain pointer"
-foreign import ccall "dynamic"
- mkFinalizer :: FinalizerPtr a -> Ptr a -> IO ()
+noMixing ::
+ Finalizers -> IORef (Finalizers, [IO ()]) -> IO (IO ()) -> IO Bool
+noMixing ftype0 r mkF = do
+ (ftype, fs) <- readIORef r
+ if ftype /= NoFinalizers && ftype /= ftype0
+ then error ("GHC.ForeignPtr: attempt to mix Haskell and C finalizers " ++
+ "in the same ForeignPtr")
+ else do
+ f <- mkF
+ writeIORef r (ftype0, f : fs)
+ return (null fs)
-foreignPtrFinalizer :: IORef [IO ()] -> IO ()
-foreignPtrFinalizer r = do fs <- readIORef r; sequence_ fs
+foreignPtrFinalizer :: IORef (Finalizers, [IO ()]) -> IO ()
+foreignPtrFinalizer r = do (_, fs) <- readIORef r; sequence_ fs
newForeignPtr_ :: Ptr a -> IO (ForeignPtr a)
-- ^Turns a plain memory reference into a foreign pointer that may be
-- associated with finalizers by using 'addForeignPtrFinalizer'.
newForeignPtr_ (Ptr obj) = do
- r <- newIORef []
+ r <- newIORef (NoFinalizers, [])
return (ForeignPtr obj (PlainForeignPtr r))
touchForeignPtr :: ForeignPtr a -> IO ()
-- To avoid subtle coding errors, hand written marshalling code
-- should preferably use 'Foreign.ForeignPtr.withForeignPtr' rather
-- than combinations of 'unsafeForeignPtrToPtr' and
--- 'touchForeignPtr'. However, the later routines
+-- 'touchForeignPtr'. However, the latter routines
-- are occasionally preferred in tool generated marshalling code.
unsafeForeignPtrToPtr (ForeignPtr fo _) = Ptr fo
finalizeForeignPtr :: ForeignPtr a -> IO ()
finalizeForeignPtr (ForeignPtr _ (PlainPtr _)) = return () -- no effect
finalizeForeignPtr (ForeignPtr _ foreignPtr) = do
- finalizers <- readIORef refFinalizers
+ (ftype, finalizers) <- readIORef refFinalizers
sequence_ finalizers
- writeIORef refFinalizers []
+ writeIORef refFinalizers (ftype, [])
where
refFinalizers = case foreignPtr of
(PlainForeignPtr ref) -> ref