[project @ 2001-11-23 16:20:08 by simonpj]

[ghc-hetmet.git] / ghc / lib / std / PrelConc.lhs

diff --git a/ghc/lib/std/PrelConc.lhs b/ghc/lib/std/PrelConc.lhs
index 74a1d7a..e011060 100644 (file)
--- a/ghc/lib/std/PrelConc.lhs
+++ b/ghc/lib/std/PrelConc.lhs
@@ -1,5 +1,7 @@
+% -----------------------------------------------------------------------------
+% $Id: PrelConc.lhs,v 1.25 2001/09/14 15:49:56 simonpj Exp $
 %
-% (c) The AQUA Project, Glasgow University, 1994-1996
+% (c) The University of Glasgow, 1994-2000
 %
 
 \section[PrelConc]{Module @PrelConc@}
@@ -15,9 +17,9 @@ module PrelConc
        -- Forking and suchlike
        , myThreadId    -- :: IO ThreadId
        , killThread    -- :: ThreadId -> IO ()
-       , raiseInThread -- :: ThreadId -> Exception -> IO ()
+       , throwTo       -- :: ThreadId -> Exception -> IO ()
        , par           -- :: a -> b -> b
-       , seq           -- :: a -> b -> b
+       , pseq          -- :: a -> b -> b
        , yield         -- :: IO ()
 
        -- Waiting
@@ -31,22 +33,21 @@ module PrelConc
        , newEmptyMVar  -- :: IO (MVar a)
        , takeMVar      -- :: MVar a -> IO a
        , putMVar       -- :: MVar a -> a -> IO ()
-       , readMVar      -- :: MVar a -> IO a
-       , swapMVar      -- :: MVar a -> a -> IO a
        , tryTakeMVar   -- :: MVar a -> IO (Maybe a)
+       , tryPutMVar    -- :: MVar a -> a -> IO Bool
        , isEmptyMVar   -- :: MVar a -> IO Bool
+       , addMVarFinalizer -- :: MVar a -> IO () -> IO ()
 
     ) where
 
 import PrelBase
 import PrelMaybe
-import PrelErr ( parError, seqError )
-import PrelST          ( liftST )
-import PrelIOBase      ( IO(..), MVar(..), unsafePerformIO )
+import PrelErr         ( parError, seqError )
+import PrelIOBase      ( IO(..), MVar(..) )
 import PrelBase                ( Int(..) )
 import PrelException    ( Exception(..), AsyncException(..) )
 
-infixr 0 `par`, `seq`
+infixr 0 `par`, `pseq`
 \end{code}
 
 %************************************************************************
@@ -67,8 +68,8 @@ killThread :: ThreadId -> IO ()
 killThread (ThreadId id) = IO $ \ s ->
    case (killThread# id (AsyncException ThreadKilled) s) of s1 -> (# s1, () #)
 
-raiseInThread :: ThreadId -> Exception -> IO ()
-raiseInThread (ThreadId id) ex = IO $ \ s ->
+throwTo :: ThreadId -> Exception -> IO ()
+throwTo (ThreadId id) ex = IO $ \ s ->
    case (killThread# id ex s) of s1 -> (# s1, () #)
 
 myThreadId :: IO ThreadId
@@ -79,7 +80,10 @@ yield :: IO ()
 yield = IO $ \s -> 
    case (yield# s) of s1 -> (# s1, () #)
 
--- "seq" is defined a bit wierdly (see below)
+--     Nota Bene: 'pseq' used to be 'seq'
+--                but 'seq' is now defined in PrelGHC
+--
+-- "pseq" is defined a bit weirdly (see below)
 --
 -- The reason for the strange "0# -> parError" case is that
 -- it fools the compiler into thinking that seq is non-strict in
@@ -90,9 +94,9 @@ yield = IO $ \s ->
 -- Just before converting from Core to STG there's a bit of magic
 -- that recognises the seq# and eliminates the duff case.
 
-{-# INLINE seq  #-}
-seq :: a -> b -> b
-seq  x y = case (seq#  x) of { 0# -> seqError; _ -> y }
+{-# INLINE pseq  #-}
+pseq :: a -> b -> b
+pseq  x y = case (seq#  x) of { 0# -> seqError; _ -> y }
 
 {-# INLINE par  #-}
 par :: a -> b -> b
@@ -129,24 +133,18 @@ putMVar (MVar mvar#) x = IO $ \ s# ->
     case putMVar# mvar# x s# of
         s2# -> (# s2#, () #)
 
+tryPutMVar  :: MVar a -> a -> IO Bool
+tryPutMVar (MVar mvar#) x = IO $ \ s# ->
+    case tryPutMVar# mvar# x s# of
+        (# s, 0# #) -> (# s, False #)
+        (# s, _  #) -> (# s, True #)
+
 newMVar :: a -> IO (MVar a)
 newMVar value =
     newEmptyMVar       >>= \ mvar ->
     putMVar mvar value >>
     return mvar
 
-readMVar :: MVar a -> IO a
-readMVar mvar =
-    takeMVar mvar      >>= \ value ->
-    putMVar mvar value >>
-    return value
-
-swapMVar :: MVar a -> a -> IO a
-swapMVar mvar new =
-    takeMVar mvar      >>= \ old ->
-    putMVar mvar new   >>
-    return old
-
 -- tryTakeMVar is a non-blocking takeMVar
 tryTakeMVar :: MVar a -> IO (Maybe a)
 tryTakeMVar (MVar m) = IO $ \ s ->
@@ -172,6 +170,11 @@ isEmptyMVar :: MVar a -> IO Bool
 isEmptyMVar (MVar mv#) = IO $ \ s# -> 
     case isEmptyMVar# mv# s# of
         (# s2#, flg #) -> (# s2#, not (flg ==# 0#) #)
+
+-- Like addForeignPtrFinalizer, but for MVars
+addMVarFinalizer :: MVar a -> IO () -> IO ()
+addMVarFinalizer (MVar m) finalizer = 
+  IO $ \s -> case mkWeak# m () finalizer s of { (# s1, w #) -> (# s1, () #) }
 \end{code}