X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=Foreign%2FForeignPtr.hs;h=160bf3c99948c3424a629abbb2f0d768db7bc622;hb=b66a730b881d05c34c0dfe2da052b5fa01429244;hp=1941d8f0e68baca7e611bcf1f7bfad446265e865;hpb=02f6aa28c32351f5699271f4447849fd328ac677;p=haskell-directory.git

diff --git a/Foreign/ForeignPtr.hs b/Foreign/ForeignPtr.hs
index 1941d8f..160bf3c 100644
--- a/Foreign/ForeignPtr.hs
+++ b/Foreign/ForeignPtr.hs
@@ -1,4 +1,4 @@
-{-# OPTIONS -fno-implicit-prelude #-}
+{-# OPTIONS_GHC -fno-implicit-prelude #-}
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Foreign.ForeignPtr
@@ -19,38 +19,55 @@ module Foreign.ForeignPtr
         ( 
 	-- * Finalised data pointers
 	  ForeignPtr
+	, FinalizerPtr
+#if defined(__HUGS__) || defined(__GLASGOW_HASKELL__)
+	, FinalizerEnvPtr
+#endif
+	-- ** Basic operations
         , newForeignPtr
+        , newForeignPtr_
         , addForeignPtrFinalizer
+#if defined(__HUGS__) || defined(__GLASGOW_HASKELL__)
+	, newForeignPtrEnv
+	, addForeignPtrFinalizerEnv
+#endif
 	, withForeignPtr
-	, foreignPtrToPtr
+
+#ifdef __GLASGOW_HASKELL__
+	, finalizeForeignPtr
+#endif
+
+	-- ** Low-level operations
+	, unsafeForeignPtrToPtr
 	, touchForeignPtr
 	, castForeignPtr
 
-#ifndef __NHC__
+	-- ** Allocating managed memory
 	, mallocForeignPtr
 	, mallocForeignPtrBytes
 	, mallocForeignPtrArray
 	, mallocForeignPtrArray0
-#endif
         ) 
 	where
 
+import Foreign.Ptr
+
 #ifdef __NHC__
 import NHC.FFI
   ( ForeignPtr
+  , FinalizerPtr
   , newForeignPtr
+  , newForeignPtr_
   , addForeignPtrFinalizer
   , withForeignPtr
-  , foreignPtrToPtr
+  , unsafeForeignPtrToPtr
   , touchForeignPtr
   , castForeignPtr
+  , Storable(sizeOf)
+  , malloc, mallocBytes, finalizerFree
   )
 #endif
 
-#ifdef __GLASGOW_HASKELL__
-import GHC.ForeignPtr
-#endif
-
 #ifdef __HUGS__
 import Hugs.ForeignPtr
 #endif
@@ -64,15 +81,119 @@ import GHC.Base
 import GHC.IOBase
 import GHC.Num
 import GHC.Err		( undefined )
+import GHC.ForeignPtr
 #endif
 
+#if !defined(__NHC__) && !defined(__GLASGOW_HASKELL__)
+import Foreign.Marshal.Alloc	( malloc, mallocBytes, finalizerFree )
+
+instance Eq (ForeignPtr a) where 
+    p == q  =  unsafeForeignPtrToPtr p == unsafeForeignPtrToPtr q
+
+instance Ord (ForeignPtr a) where 
+    compare p q  =  compare (unsafeForeignPtrToPtr p) (unsafeForeignPtrToPtr q)
+
+instance Show (ForeignPtr a) where
+    showsPrec p f = showsPrec p (unsafeForeignPtrToPtr f)
+#endif
+
+
 #ifndef __NHC__
+newForeignPtr :: FinalizerPtr a -> Ptr a -> IO (ForeignPtr a)
+-- ^Turns a plain memory reference into a foreign pointer, and
+-- associates a finaliser with the reference.  The finaliser will be executed
+-- after the last reference to the foreign object is dropped.  Note that there
+-- is no guarantee on how soon the finaliser is executed after the last
+-- reference was dropped; this depends on the details of the Haskell storage
+-- manager. The only guarantee is that the finaliser runs before the program
+-- terminates.
+newForeignPtr finalizer p
+  = do fObj <- newForeignPtr_ p
+       addForeignPtrFinalizer finalizer fObj
+       return fObj
+
+withForeignPtr :: ForeignPtr a -> (Ptr a -> IO b) -> IO b
+-- ^This is a way to look at the pointer living inside a
+-- foreign object.  This function takes a function which is
+-- applied to that pointer. The resulting 'IO' action is then
+-- executed. The foreign object is kept alive at least during
+-- the whole action, even if it is not used directly
+-- inside. Note that it is not safe to return the pointer from
+-- the action and use it after the action completes. All uses
+-- of the pointer should be inside the
+-- 'withForeignPtr' bracket.  The reason for
+-- this unsafeness is the same as for
+-- 'unsafeForeignPtrToPtr' below: the finalizer
+-- may run earlier than expected, because the compiler can only
+-- track usage of the 'ForeignPtr' object, not
+-- a 'Ptr' object made from it.
+--
+-- This function is normally used for marshalling data to
+-- or from the object pointed to by the
+-- 'ForeignPtr', using the operations from the
+-- 'Storable' class.
+withForeignPtr fo io
+  = do r <- io (unsafeForeignPtrToPtr fo)
+       touchForeignPtr fo
+       return r
+#endif /* ! __NHC__ */
+
+#if defined(__HUGS__) || defined(__GLASGOW_HASKELL__)
+-- | This variant of 'newForeignPtr' adds a finalizer that expects an
+-- environment in addition to the finalized pointer.  The environment
+-- that will be passed to the finalizer is fixed by the second argument to
+-- 'newForeignPtrEnv'.
+newForeignPtrEnv ::
+    FinalizerEnvPtr env a -> Ptr env -> Ptr a -> IO (ForeignPtr a)
+newForeignPtrEnv finalizer env p
+  = do fObj <- newForeignPtr_ p
+       addForeignPtrFinalizerEnv finalizer env fObj
+       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
+  r <- malloc
+  newForeignPtr finalizerFree r
+
+mallocForeignPtrBytes :: Int -> IO (ForeignPtr a)
+mallocForeignPtrBytes n = do
+  r <- mallocBytes n
+  newForeignPtr finalizerFree r
+#endif /* !__GLASGOW_HASKELL__ */
+
+-- | This function is similar to 'Foreign.Marshal.Array.mallocArray',
+-- but yields a memory area that has a finalizer attached that releases
+-- the memory area.  As with 'mallocForeignPtr', it is not guaranteed that
+-- the block of memory was allocated by 'Foreign.Marshal.Alloc.malloc'.
 mallocForeignPtrArray :: Storable a => Int -> IO (ForeignPtr a)
 mallocForeignPtrArray  = doMalloc undefined
   where
-    doMalloc            :: Storable a => a -> Int -> IO (ForeignPtr a)
+    doMalloc            :: Storable b => b -> Int -> IO (ForeignPtr b)
     doMalloc dummy size  = mallocForeignPtrBytes (size * sizeOf dummy)
 
+-- | This function is similar to 'Foreign.Marshal.Array.mallocArray0',
+-- but yields a memory area that has a finalizer attached that releases
+-- the memory area.  As with 'mallocForeignPtr', it is not guaranteed that
+-- the block of memory was allocated by 'Foreign.Marshal.Alloc.malloc'.
 mallocForeignPtrArray0      :: Storable a => Int -> IO (ForeignPtr a)
 mallocForeignPtrArray0 size  = mallocForeignPtrArray (size + 1)
-#endif