blob: 89d7da2fec0243aaf29f3ad9881b99c983da1d7e (
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
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
|
{- thread scheduling
-
- Copyright 2012, 2013 Joey Hess <joey@kitenet.net>
- Copyright 2011 Bas van Dijk & Roel van Dijk
-
- Licensed under the GNU GPL version 3 or higher.
-}
{-# LANGUAGE CPP #-}
module Utility.ThreadScheduler where
import Common
import Control.Concurrent
import System.Posix.Signals
#ifndef __ANDROID__
import System.Posix.Terminal
#endif
newtype Seconds = Seconds { fromSeconds :: Int }
deriving (Eq, Ord, Show)
type Microseconds = Integer
{- Runs an action repeatedly forever, sleeping at least the specified number
- of seconds in between. -}
runEvery :: Seconds -> IO a -> IO a
runEvery n a = forever $ do
threadDelaySeconds n
a
threadDelaySeconds :: Seconds -> IO ()
threadDelaySeconds (Seconds n) = unboundDelay (fromIntegral n * oneSecond)
{- Like threadDelay, but not bounded by an Int.
-
- There is no guarantee that the thread will be rescheduled promptly when the
- delay has expired, but the thread will never continue to run earlier than
- specified.
-
- Taken from the unbounded-delay package to avoid a dependency for 4 lines
- of code.
-}
unboundDelay :: Microseconds -> IO ()
unboundDelay time = do
let maxWait = min time $ toInteger (maxBound :: Int)
threadDelay $ fromInteger maxWait
when (maxWait /= time) $ unboundDelay (time - maxWait)
{- Pauses the main thread, letting children run until program termination. -}
waitForTermination :: IO ()
waitForTermination = do
lock <- newEmptyMVar
check softwareTermination lock
#ifndef __ANDROID__
whenM (queryTerminal stdInput) $
check keyboardSignal lock
#endif
takeMVar lock
where
check sig lock = void $
installHandler sig (CatchOnce $ putMVar lock ()) Nothing
oneSecond :: Microseconds
oneSecond = 1000000
|
