git-annex/Assistant/Threads/TransferWatcher.hs
Joey Hess 1296cfb09a avoid possibly re-adding a removed transfer when updating its info
Doesn't fix the bug I thought it'd fix, but is clearly correct.
2012-08-28 14:19:11 -04:00

80 lines
2.4 KiB
Haskell

{- git-annex assistant transfer watching thread
-
- Copyright 2012 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Assistant.Threads.TransferWatcher where
import Assistant.Common
import Assistant.ThreadedMonad
import Assistant.DaemonStatus
import Logs.Transfer
import Utility.DirWatcher
import Utility.Types.DirWatcher
import qualified Remote
thisThread :: ThreadName
thisThread = "TransferWatcher"
{- This thread watches for changes to the gitAnnexTransferDir,
- and updates the DaemonStatus's map of ongoing transfers. -}
transferWatcherThread :: ThreadState -> DaemonStatusHandle -> IO ()
transferWatcherThread st dstatus = do
g <- runThreadState st $ fromRepo id
let dir = gitAnnexTransferDir g
createDirectoryIfMissing True dir
let hook a = Just $ runHandler st dstatus a
let hooks = mkWatchHooks
{ addHook = hook onAdd
, delHook = hook onDel
, errHook = hook onErr
}
void $ watchDir dir (const False) hooks id
debug thisThread ["watching for transfers"]
type Handler = ThreadState -> DaemonStatusHandle -> FilePath -> Maybe FileStatus -> IO ()
{- Runs an action handler.
-
- Exceptions are ignored, otherwise a whole thread could be crashed.
-}
runHandler :: ThreadState -> DaemonStatusHandle -> Handler -> FilePath -> Maybe FileStatus -> IO ()
runHandler st dstatus handler file filestatus = void $ do
either print (const noop) =<< tryIO go
where
go = handler st dstatus file filestatus
{- Called when there's an error with inotify. -}
onErr :: Handler
onErr _ _ msg _ = error msg
{- Called when a new transfer information file is written. -}
onAdd :: Handler
onAdd st dstatus file _ = case parseTransferFile file of
Nothing -> noop
Just t -> go t =<< runThreadState st (checkTransfer t)
where
go _ Nothing = noop -- transfer already finished
go t (Just info) = do
debug thisThread
[ "transfer starting:"
, show t
]
r <- headMaybe . filter (sameuuid t) . knownRemotes
<$> getDaemonStatus dstatus
alterTransferInfo dstatus t info
{ transferRemote = r }
sameuuid t r = Remote.uuid r == transferUUID t
{- Called when a transfer information file is removed. -}
onDel :: Handler
onDel _ dstatus file _ = case parseTransferFile file of
Nothing -> noop
Just t -> do
debug thisThread
[ "transfer finishing:"
, show t
]
void $ removeTransfer dstatus t