FinalizerPtr,
newForeignPtr_,
mallocForeignPtr,
+ mallocPlainForeignPtr,
mallocForeignPtrBytes,
+ mallocPlainForeignPtrBytes,
addForeignPtrFinalizer,
touchForeignPtr,
unsafeForeignPtrToPtr,
import Control.Monad ( sequence_ )
import Foreign.Storable
-import Numeric ( showHex )
import GHC.Show
-import GHC.Num
-import GHC.List ( null, replicate, length )
+import GHC.List ( null )
import GHC.Base
import GHC.IOBase
import GHC.STRef ( STRef(..) )
-import GHC.Ptr ( Ptr(..), FunPtr, castFunPtrToPtr )
+import GHC.Ptr ( Ptr(..), FunPtr )
import GHC.Err
-- |The type 'ForeignPtr' represents references to objects that are
-- object, because that ensures that whatever the finalizer is
-- attached to is kept alive.
-data ForeignPtrContents
+data ForeignPtrContents
= PlainForeignPtr !(IORef [IO ()])
- | MallocPtr (MutableByteArray# RealWorld) !(IORef [IO ()])
+ | MallocPtr (MutableByteArray# RealWorld) !(IORef [IO ()])
+ | PlainPtr (MutableByteArray# RealWorld)
instance Eq (ForeignPtr a) where
p == q = unsafeForeignPtrToPtr p == unsafeForeignPtrToPtr q
instance Show (ForeignPtr a) where
showsPrec p f = showsPrec p (unsafeForeignPtrToPtr f)
-#include "MachDeps.h"
-
-#if (WORD_SIZE_IN_BITS == 32 || WORD_SIZE_IN_BITS == 64)
-instance Show (Ptr a) where
- showsPrec p (Ptr a) rs = pad_out (showHex (word2Integer(int2Word#(addr2Int# a))) "") rs
- where
- -- want 0s prefixed to pad it out to a fixed length.
- pad_out ls rs =
- '0':'x':(replicate (2*SIZEOF_HSPTR - length ls) '0') ++ ls ++ rs
- -- word2Integer :: Word# -> Integer (stolen from Word.lhs)
- word2Integer w = case word2Integer# w of
- (# s, d #) -> J# s d
-
-instance Show (FunPtr a) where
- showsPrec p = showsPrec p . castFunPtrToPtr
-#endif
-- |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
(MallocPtr mbarr# r) #)
}
+-- | Allocate some memory and return a 'ForeignPtr' to it. The memory
+-- will be released automatically when the 'ForeignPtr' is discarded.
+--
+-- GHC notes: 'mallocPlainForeignPtr' has a heavily optimised
+-- implementation in GHC. It uses pinned memory in the garbage
+-- collected heap, as for mallocForeignPtr. Unlike mallocForeignPtr, a
+-- ForeignPtr created with mallocPlainForeignPtr carries no finalizers.
+-- It is not possible to add a finalizer to a ForeignPtr created with
+-- mallocPlainForeignPtr. This is useful for ForeignPtrs that will live
+-- only inside Haskell (such as those created for packed strings).
+-- Attempts to add a finalizer to a ForeignPtr created this way, or to
+-- finalize such a pointer, will throw an exception.
+--
+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# #) ->
+ (# s, ForeignPtr (byteArrayContents# (unsafeCoerce# mbarr#))
+ (PlainPtr mbarr#) #)
+ }
+ where (I# size) = sizeOf 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 (I# size) = IO $ \s ->
+ case newPinnedByteArray# size s of { (# s, mbarr# #) ->
+ (# s, ForeignPtr (byteArrayContents# (unsafeCoerce# mbarr#))
+ (PlainPtr mbarr#) #)
+ }
+
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
(# s1, w #) -> (# s1, () #)
else return ()
+addForeignPtrConcFinalizer_ _ _ =
+ error "GHC.ForeignPtr: attempt to add a finalizer to plain pointer"
+
foreign import ccall "dynamic"
mkFinalizer :: FinalizerPtr a -> Ptr a -> IO ()
-- | Causes the finalizers associated with a foreign pointer to be run
-- immediately.
finalizeForeignPtr :: ForeignPtr a -> IO ()
+finalizeForeignPtr (ForeignPtr _ (PlainPtr _)) = return () -- no effect
finalizeForeignPtr (ForeignPtr _ foreignPtr) = do
finalizers <- readIORef refFinalizers
sequence_ finalizers
where
refFinalizers = case foreignPtr of
(PlainForeignPtr ref) -> ref
- (MallocPtr _ ref) -> ref
+ (MallocPtr _ ref) -> ref
+