42 lines
1.4 KiB
Haskell
42 lines
1.4 KiB
Haskell
{- This file is part of Vervis.
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-
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- Written in 2019 by fr33domlover <fr33domlover@riseup.net>.
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-
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- ♡ Copying is an act of love. Please copy, reuse and share.
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-
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- The author(s) have dedicated all copyright and related and neighboring
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- rights to this software to the public domain worldwide. This software is
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- distributed without any warranty.
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-
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- You should have received a copy of the CC0 Public Domain Dedication along
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- with this software. If not, see
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- <http://creativecommons.org/publicdomain/zero/1.0/>.
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-}
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module Control.Concurrent.Local
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( forkCheck
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, periodically
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)
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where
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import Control.Concurrent
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import Control.Monad
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import Control.Monad.IO.Class
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import Data.Functor (void)
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import Data.Time.Interval
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-- | Like 'forkIO', but if the new thread terminates with an exception,
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-- re-throw it in the current thread.
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forkCheck :: IO () -> IO ()
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forkCheck run = do
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tid <- myThreadId
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void $ forkFinally run $ either (throwTo tid) (const $ return ())
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periodically :: MonadIO m => TimeInterval -> m () -> m ()
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periodically interval action =
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let micros = microseconds interval
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in if 0 < micros && micros <= toInteger (maxBound :: Int)
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then
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let micros' = fromInteger micros
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in forever $ liftIO (threadDelay micros') >> action
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else error $ "periodically: interval out of range: " ++ show micros
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