67 lines
1.5 KiB
Haskell
67 lines
1.5 KiB
Haskell
{- thread scheduling
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-
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- Copyright 2012-2024 Joey Hess <id@joeyh.name>
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-
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- License: BSD-2-clause
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-}
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{-# LANGUAGE CPP #-}
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module Utility.ThreadScheduler (
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Seconds(..),
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Microseconds,
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runEvery,
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threadDelaySeconds,
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waitForTermination,
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oneSecond,
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unboundDelay,
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) where
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import Control.Monad
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import qualified Control.Concurrent.Thread.Delay as Unbounded
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#ifndef mingw32_HOST_OS
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import Control.Concurrent
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import Control.Monad.IfElse
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import System.Posix.IO
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#endif
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#ifndef mingw32_HOST_OS
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import System.Posix.Signals
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import System.Posix.Terminal
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#endif
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newtype Seconds = Seconds { fromSeconds :: Int }
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deriving (Eq, Ord, Show)
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type Microseconds = Integer
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{- Runs an action repeatedly forever, sleeping at least the specified number
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- of seconds in between. -}
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runEvery :: Seconds -> IO a -> IO a
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runEvery n a = forever $ do
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threadDelaySeconds n
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a
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threadDelaySeconds :: Seconds -> IO ()
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threadDelaySeconds (Seconds n) = unboundDelay (fromIntegral n * oneSecond)
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{- Like threadDelay, but not bounded by an Int. -}
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unboundDelay :: Microseconds -> IO ()
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unboundDelay = Unbounded.delay
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{- Pauses the main thread, letting children run until program termination. -}
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waitForTermination :: IO ()
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waitForTermination = do
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#ifdef mingw32_HOST_OS
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forever $ threadDelaySeconds (Seconds 6000)
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#else
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lock <- newEmptyMVar
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let check sig = void $
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installHandler sig (CatchOnce $ putMVar lock ()) Nothing
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check softwareTermination
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whenM (queryTerminal stdInput) $
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check keyboardSignal
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takeMVar lock
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#endif
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oneSecond :: Microseconds
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oneSecond = 1000000
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