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Use explicit language extensions & remove extension fields from base.cabal
[ghc-base.git]
/
Control
/
Concurrent
/
SampleVar.hs
diff --git
a/Control/Concurrent/SampleVar.hs
b/Control/Concurrent/SampleVar.hs
index
ad89a95
..
ca68a38
100644
(file)
--- a/
Control/Concurrent/SampleVar.hs
+++ b/
Control/Concurrent/SampleVar.hs
@@
-1,3
+1,5
@@
+{-# LANGUAGE CPP #-}
+
-----------------------------------------------------------------------------
-- |
-- Module : Control.Concurrent.SampleVar
-----------------------------------------------------------------------------
-- |
-- Module : Control.Concurrent.SampleVar
@@
-30,10
+32,14
@@
import Prelude
import Control.Concurrent.MVar
import Control.Concurrent.MVar
-import Control.Exception ( block )
+import Control.Exception ( mask_ )
import Data.Functor ( (<$>) )
import Data.Functor ( (<$>) )
+import Data.Typeable
+
+#include "Typeable.h"
+
-- |
-- Sample variables are slightly different from a normal 'MVar':
--
-- |
-- Sample variables are slightly different from a normal 'MVar':
--
@@
-58,6
+64,8
@@
newtype SampleVar a = SampleVar ( MVar ( Int -- 1 == full
)
deriving (Eq)
)
deriving (Eq)
+INSTANCE_TYPEABLE1(SampleVar,sampleVarTc,"SampleVar")
+
-- |Build a new, empty, 'SampleVar'
newEmptySampleVar :: IO (SampleVar a)
newEmptySampleVar = do
-- |Build a new, empty, 'SampleVar'
newEmptySampleVar :: IO (SampleVar a)
newEmptySampleVar = do
@@
-72,8
+80,8
@@
newSampleVar a = do
-- |If the SampleVar is full, leave it empty. Otherwise, do nothing.
emptySampleVar :: SampleVar a -> IO ()
-- |If the SampleVar is full, leave it empty. Otherwise, do nothing.
emptySampleVar :: SampleVar a -> IO ()
-emptySampleVar (SampleVar v) = block $ do
- s@(readers, var) <- block $ takeMVar v
+emptySampleVar (SampleVar v) = mask_ $ do
+ s@(readers, var) <- takeMVar v
if readers > 0 then do
_ <- takeMVar var
putMVar v (0,var)
if readers > 0 then do
_ <- takeMVar var
putMVar v (0,var)
@@
-82,7
+90,7
@@
emptySampleVar (SampleVar v) = block $ do
-- |Wait for a value to become available, then take it and return.
readSampleVar :: SampleVar a -> IO a
-- |Wait for a value to become available, then take it and return.
readSampleVar :: SampleVar a -> IO a
-readSampleVar (SampleVar svar) = block $ do
+readSampleVar (SampleVar svar) = mask_ $ do
--
-- filled => make empty and grab sample
-- not filled => try to grab value, empty when read val.
--
-- filled => make empty and grab sample
-- not filled => try to grab value, empty when read val.
@@
-95,7
+103,7
@@
readSampleVar (SampleVar svar) = block $ do
-- |Write a value into the 'SampleVar', overwriting any previous value that
-- was there.
writeSampleVar :: SampleVar a -> a -> IO ()
-- |Write a value into the 'SampleVar', overwriting any previous value that
-- was there.
writeSampleVar :: SampleVar a -> a -> IO ()
-writeSampleVar (SampleVar svar) v = block $ do
+writeSampleVar (SampleVar svar) v = mask_ $ do
--
-- filled => overwrite
-- not filled => fill, write val
--
-- filled => overwrite
-- not filled => fill, write val
@@
-120,5
+128,5
@@
writeSampleVar (SampleVar svar) v = block $ do
isEmptySampleVar :: SampleVar a -> IO Bool
isEmptySampleVar (SampleVar svar) = do
(readers, _) <- readMVar svar
isEmptySampleVar :: SampleVar a -> IO Bool
isEmptySampleVar (SampleVar svar) = do
(readers, _) <- readMVar svar
- return (readers == 0)
+ return (readers <= 0)