From f5d5a1db650290902fbec064df087d2a6c2738dd Mon Sep 17 00:00:00 2001 From: Ivan Tomac Date: Wed, 10 Dec 2008 15:05:10 +0000 Subject: [PATCH] FIX #1364: added support for C finalizers that run as soon as the value is no longer reachable. Patch amended by Simon Marlow: - mkWeakFinalizer# commoned up with mkWeakFinalizerEnv# --- Foreign/ForeignPtr.hs | 18 ---------- GHC/ForeignPtr.hs | 96 ++++++++++++++++++++++++++++++++++++------------- 2 files changed, 72 insertions(+), 42 deletions(-) diff --git a/Foreign/ForeignPtr.hs b/Foreign/ForeignPtr.hs index a240e9d..59fcf82 100644 --- a/Foreign/ForeignPtr.hs +++ b/Foreign/ForeignPtr.hs @@ -152,24 +152,6 @@ newForeignPtrEnv finalizer env p return fObj #endif /* __HUGS__ */ -#ifdef __GLASGOW_HASKELL__ -type FinalizerEnvPtr env a = FunPtr (Ptr env -> Ptr 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 :: - FinalizerEnvPtr env a -> Ptr env -> ForeignPtr a -> IO () -addForeignPtrFinalizerEnv finalizer env fptr = - addForeignPtrConcFinalizer fptr - (mkFinalizerEnv finalizer env (unsafeForeignPtrToPtr fptr)) - -foreign import ccall "dynamic" - mkFinalizerEnv :: FinalizerEnvPtr env a -> Ptr env -> Ptr a -> IO () -#endif - - #ifndef __GLASGOW_HASKELL__ mallocForeignPtr :: Storable a => IO (ForeignPtr a) mallocForeignPtr = do diff --git a/GHC/ForeignPtr.hs b/GHC/ForeignPtr.hs index e043e09..50fa58d 100644 --- a/GHC/ForeignPtr.hs +++ b/GHC/ForeignPtr.hs @@ -19,12 +19,14 @@ module GHC.ForeignPtr ( ForeignPtr(..), FinalizerPtr, + FinalizerEnvPtr, newForeignPtr_, mallocForeignPtr, mallocPlainForeignPtr, mallocForeignPtrBytes, mallocPlainForeignPtrBytes, - addForeignPtrFinalizer, + addForeignPtrFinalizer, + addForeignPtrFinalizerEnv, touchForeignPtr, unsafeForeignPtrToPtr, castForeignPtr, @@ -42,7 +44,7 @@ import GHC.List ( null ) import GHC.Base import GHC.IOBase import GHC.STRef ( STRef(..) ) -import GHC.Ptr ( Ptr(..), FunPtr ) +import GHC.Ptr ( Ptr(..), FunPtr(..) ) import GHC.Err #include "Typeable.h" @@ -76,9 +78,15 @@ data ForeignPtr a = ForeignPtr Addr# ForeignPtrContents 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 @@ -95,7 +103,8 @@ instance Show (ForeignPtr a) where -- 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) -- @@ -141,7 +150,7 @@ mallocForeignPtr :: Storable a => IO (ForeignPtr a) mallocForeignPtr = doMalloc undefined where doMalloc :: Storable b => b -> IO (ForeignPtr b) doMalloc a = do - r <- newIORef [] + r <- newIORef (NoFinalizers, []) IO $ \s -> case newPinnedByteArray# size s of { (# s', mbarr# #) -> (# s', ForeignPtr (byteArrayContents# (unsafeCoerce# mbarr#)) @@ -153,7 +162,7 @@ mallocForeignPtr = doMalloc undefined -- size of the memory required is given explicitly as a number of bytes. mallocForeignPtrBytes :: Int -> IO (ForeignPtr a) mallocForeignPtrBytes (I# size) = do - r <- newIORef [] + r <- newIORef (NoFinalizers, []) IO $ \s -> case newPinnedByteArray# size s of { (# s', mbarr# #) -> (# s', ForeignPtr (byteArrayContents# (unsafeCoerce# mbarr#)) @@ -198,9 +207,41 @@ addForeignPtrFinalizer :: FinalizerPtr a -> ForeignPtr a -> IO () -- ^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 @@ -222,18 +263,16 @@ addForeignPtrConcFinalizer (ForeignPtr _ c) finalizer = 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, () #) @@ -242,17 +281,26 @@ addForeignPtrConcFinalizer_ f@(MallocPtr fo r) finalizer = do 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 () @@ -312,9 +360,9 @@ castForeignPtr f = unsafeCoerce# f 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 -- 1.7.10.4