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|
{- git-annex assistant change tracking
-
- Copyright 2012 Joey Hess <joey@kitenet.net>
-}
module Assistant.Changes where
import Common.Annex
import qualified Annex.Queue
import Control.Concurrent.STM
import Data.Time.Clock
data ChangeType = PendingAddChange | LinkChange | RmChange | RmDirChange
deriving (Show, Eq)
type ChangeChan = TChan Change
data Change = Change
{ changeTime :: UTCTime
, changeFile :: FilePath
, changeType :: ChangeType
}
deriving (Show)
runChangeChan :: STM a -> IO a
runChangeChan = atomically
newChangeChan :: IO ChangeChan
newChangeChan = atomically newTChan
{- Handlers call this when they made a change that needs to get committed. -}
madeChange :: FilePath -> ChangeType -> Annex (Maybe Change)
madeChange f t = do
-- Just in case the commit thread is not flushing the queue fast enough.
when (t /= PendingAddChange) $
Annex.Queue.flushWhenFull
liftIO $ Just <$> (Change <$> getCurrentTime <*> pure f <*> pure t)
noChange :: Annex (Maybe Change)
noChange = return Nothing
{- Gets all unhandled changes.
- Blocks until at least one change is made. -}
getChanges :: ChangeChan -> IO [Change]
getChanges chan = runChangeChan $ do
c <- readTChan chan
go [c]
where
go l = do
v <- tryReadTChan chan
case v of
Nothing -> return l
Just c -> go (c:l)
{- Puts unhandled changes back into the channel.
- Note: Original order is not preserved. -}
refillChanges :: ChangeChan -> [Change] -> IO ()
refillChanges chan cs = runChangeChan $ mapM_ (writeTChan chan) cs
|
