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-- | Interval-based implementation of preview polling, for the platforms which
-- are not supported by inotify.
--
module Hakyll.Web.Preview.Poll
( previewPoll
) where
import Control.Applicative ((<$>))
import Control.Concurrent (threadDelay)
import Control.Monad (when)
import System.Time (getClockTime)
import Data.Set (Set)
import qualified Data.Set as S
import System.Directory (getModificationTime)
import Hakyll.Core.Configuration
import Hakyll.Core.Identifier
import Hakyll.Core.Resource
-- | A preview thread that periodically recompiles the site.
--
previewPoll :: HakyllConfiguration -- ^ Configuration
-> Set Resource -- ^ Resources to watch
-> IO () -- ^ Action called when something changes
-> IO () -- ^ Can block forever
previewPoll _ resources callback = do
let files = map (toFilePath . unResource) $ S.toList resources
time <- getClockTime
loop files time
where
delay = 1000000
loop files time = do
threadDelay delay
modified <- any (time <) <$> mapM getModificationTime files
when modified callback
loop files =<< getClockTime
|
