66 lines
1.7 KiB
Haskell
66 lines
1.7 KiB
Haskell
{- 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
|