diff options
Diffstat (limited to 'libraries/base/GHC/ForeignPtr.hs')
| -rw-r--r-- | libraries/base/GHC/ForeignPtr.hs | 44 |
1 files changed, 39 insertions, 5 deletions
diff --git a/libraries/base/GHC/ForeignPtr.hs b/libraries/base/GHC/ForeignPtr.hs index 4706c20687..89eb29c627 100644 --- a/libraries/base/GHC/ForeignPtr.hs +++ b/libraries/base/GHC/ForeignPtr.hs @@ -2,6 +2,7 @@ {-# LANGUAGE MagicHash #-} {-# LANGUAGE NoImplicitPrelude #-} {-# LANGUAGE UnboxedTuples #-} +{-# LANGUAGE PatternSynonyms #-} {-# LANGUAGE Unsafe #-} {-# OPTIONS_HADDOCK not-home #-} @@ -24,7 +25,7 @@ module GHC.ForeignPtr ( -- * Types ForeignPtr(..), - ForeignPtrContents(..), + ForeignPtrContents(PlainForeignPtr, FinalPtr, MallocPtr, PlainPtr), Finalizers(..), FinalizerPtr, FinalizerEnvPtr, @@ -117,11 +118,11 @@ data Finalizers -- > Prohibited | PlainPtr | FinalPtr | -- > +------------+-----------------+ data ForeignPtrContents - = PlainForeignPtr !(IORef Finalizers) + = PlainForeignPtr_ !(IORef Finalizers) -- ^ The pointer refers to unmanaged memory that was allocated by -- a foreign function (typically using @malloc@). The finalizer -- frequently calls the C function @free@ or some variant of it. - | FinalPtr + | FinalPtr_ -- ^ The pointer refers to unmanaged memory that should not be freed when -- the 'ForeignPtr' becomes unreachable. Functions that add finalizers -- to a 'ForeignPtr' throw exceptions when the 'ForeignPtr' is backed by @@ -129,7 +130,7 @@ data ForeignPtrContents -- See Note [Why FinalPtr]. -- -- @since 4.15 - | MallocPtr (MutableByteArray# RealWorld) !(IORef Finalizers) + | MallocPtr_ (MutableByteArray# RealWorld) !(IORef Finalizers) -- ^ The pointer refers to a byte array. -- The 'MutableByteArray#' field means that the 'MutableByteArray#' is -- reachable (by GC) whenever the 'ForeignPtr' is reachable. When the @@ -154,7 +155,7 @@ data ForeignPtrContents -- > incrBad (ForeignPtr p (MallocPtr m _)) = do -- > f <- newIORef NoFinalizers -- > pure (ForeignPtr p (MallocPtr m f)) - | PlainPtr (MutableByteArray# RealWorld) + | PlainPtr_ (MutableByteArray# RealWorld) -- ^ The pointer refers to a byte array. Finalization is not -- supported. This optimizes @MallocPtr@ by avoiding the allocation -- of a @MutVar#@ when it is known that no one will add finalizers to @@ -162,6 +163,31 @@ data ForeignPtrContents -- throw exceptions when the 'ForeignPtr' is backed by 'PlainPtr'. -- The invariants that apply to 'MallocPtr' apply to 'PlainPtr' as well. +plainPtr :: MutableByteArray# RealWorld -> ForeignPtrContents +plainPtr = PlainPtr_ +{-# INLINE [1] plainPtr #-} + +mallocPtr :: MutableByteArray# RealWorld -> IORef Finalizers -> ForeignPtrContents +mallocPtr = MallocPtr_ +{-# INLINE [1] mallocPtr #-} + +finalPtr :: ForeignPtrContents +finalPtr = FinalPtr_ +{-# INLINE [1] finalPtr #-} + +plainForeignPtr :: IORef Finalizers -> ForeignPtrContents +plainForeignPtr = PlainForeignPtr_ +{-# INLINE [1] plainForeignPtr #-} + +pattern PlainPtr mba <- PlainPtr_ mba where + PlainPtr mba = plainPtr mba +pattern MallocPtr mba fin <- MallocPtr_ mba fin where + MallocPtr mba bin = mallocPtr mba bin +pattern FinalPtr <- FinalPtr_ where + FinalPtr = finalPtr +pattern PlainForeignPtr fin <- PlainForeignPtr_ fin where + PlainForeignPtr fin = plainForeignPtr fin + -- Note [Why FinalPtr] -- -- FinalPtr exists as an optimization for foreign pointers created @@ -528,6 +554,14 @@ withForeignPtr fo@(ForeignPtr _ r) f = IO $ \s -> case f (unsafeForeignPtrToPtr fo) of IO action# -> keepAlive# r s action# +{-# RULES "keepAlive#/PlainForeignPtr" forall s k ref . + keepAlive# (plainForeignPtr ref) s k = keepAlive# ref s k #-} +{-# RULES "keepAlive#/FinalPtr" forall s k . + keepAlive# finalPtr s k = k s #-} +{-# RULES "keepAlive#/MallocPtr" forall s k mba x . + keepAlive# (mallocPtr mba x) s k = keepAlive# mba s k #-} +{-# RULES "keepAlive#/PlainPtr" forall s k mba . + keepAlive# (plainPtr mba) s k = keepAlive# mba s k #-} touchForeignPtr :: ForeignPtr a -> IO () -- ^This function ensures that the foreign object in |