blob: c5ee22c8952f4b70966b0dc88a88ac2a00740a35 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
|
{- Transactional sets
-
- Copyright 2012, 2013 Joey Hess <joey@kitenet.net>
-}
module Utility.TSet where
import Common
import Control.Concurrent.STM
type TSet = TChan
newTSet :: STM (TSet a)
newTSet = newTChan
{- Gets the contents of the TSet. Blocks until at least one item is
- present. -}
getTSet :: TSet a -> STM [a]
getTSet tset = do
c <- readTChan tset
l <- readTSet tset
return $ c:l
{- Gets anything currently in the TSet, without blocking. -}
readTSet :: TSet a -> STM [a]
readTSet tset = go []
where
go l = do
v <- tryReadTChan tset
case v of
Nothing -> return l
Just c -> go (c:l)
{- Puts items into a TSet. -}
putTSet :: TSet a -> [a] -> STM ()
putTSet tset vs = mapM_ (writeTChan tset) vs
{- Put a single item into a TSet. -}
putTSet1 :: TSet a -> a -> STM ()
putTSet1 tset v = void $ writeTChan tset v
|
