git-annex/Assistant/Pushes.hs
Joey Hess ae8a3ab31e added push notifier thread, currently a no-op
Hooked up everything that needs to notify on pushes. Note that
syncNewRemote does not notify. This is probably ok, and I'd need to thread
more state through to make it do so.

This is only set up to support a single push notification method; I didn't
use a NotificationBroadcaster. Partly because I don't yet know what info
about pushes needs to be communicated, so my data types are only
preliminary.
2012-10-24 13:38:28 -04:00

59 lines
1.8 KiB
Haskell

{- git-annex assistant push tracking
-
- Copyright 2012 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Assistant.Pushes where
import Common.Annex
import Control.Concurrent.STM
import Control.Concurrent.MSampleVar
import Data.Time.Clock
import qualified Data.Map as M
{- Track the most recent push failure for each remote. -}
type PushMap = M.Map Remote UTCTime
type FailedPushMap = TMVar PushMap
{- Used to notify about successful pushes. -}
newtype PushNotifier = PushNotifier (MSampleVar ())
{- The TMVar starts empty, and is left empty when there are no
- failed pushes. This way we can block until there are some failed pushes.
-}
newFailedPushMap :: IO FailedPushMap
newFailedPushMap = atomically newEmptyTMVar
{- Blocks until there are failed pushes.
- Returns Remotes whose pushes failed a given time duration or more ago.
- (This may be an empty list.) -}
getFailedPushesBefore :: FailedPushMap -> NominalDiffTime -> IO [Remote]
getFailedPushesBefore v duration = do
m <- atomically $ readTMVar v
now <- getCurrentTime
return $ M.keys $ M.filter (not . toorecent now) m
where
toorecent now time = now `diffUTCTime` time < duration
{- Modifies the map. -}
changeFailedPushMap :: FailedPushMap -> (PushMap -> PushMap) -> IO ()
changeFailedPushMap v a = atomically $
store . a . fromMaybe M.empty =<< tryTakeTMVar v
where
{- tryTakeTMVar empties the TMVar; refill it only if
- the modified map is not itself empty -}
store m
| m == M.empty = noop
| otherwise = putTMVar v $! m
newPushNotifier :: IO PushNotifier
newPushNotifier = PushNotifier <$> newEmptySV
notifyPush :: PushNotifier -> IO ()
notifyPush (PushNotifier sv) = writeSV sv ()
waitPush :: PushNotifier -> IO ()
waitPush (PushNotifier sv) = readSV sv