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| -rw-r--r-- | src/Hakyll/Web/Preview/Interval.hs | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/src/Hakyll/Web/Preview/Interval.hs b/src/Hakyll/Web/Preview/Interval.hs new file mode 100644 index 0000000..5ab90e5 --- /dev/null +++ b/src/Hakyll/Web/Preview/Interval.hs @@ -0,0 +1,36 @@ +-- | Interval-based implementation of preview polling, for the platforms which +-- are not supported by inotify. +-- +module Hakyll.Web.Preview.Interval + ( 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.ResourceProvider + +-- | 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 |