36 lines
841 B
Haskell
36 lines
841 B
Haskell
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{- locking between threads
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-
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- Copyright 2012 Joey Hess <joey@kitenet.net>
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-
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- Licensed under the GNU GPL version 3 or higher.
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-}
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module Utility.ThreadLock where
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import Common
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import System.Posix.Terminal
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import Control.Concurrent.MVar
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import System.Posix.Signals
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type Lock = MVar ()
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newLock :: IO Lock
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newLock = newMVar ()
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{- Runs an action with a lock held, so only one thread at a time can run it. -}
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withLock :: Lock -> IO a -> IO a
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withLock lock = withMVar lock . const
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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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lock <- newEmptyMVar
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check softwareTermination lock
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whenM (queryTerminal stdInput) $
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check keyboardSignal lock
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takeMVar lock
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where
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check sig lock = void $
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installHandler sig (CatchOnce $ putMVar lock ()) Nothing
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