git-annex/Assistant/Threads/TransferWatcher.hs
2013-11-24 00:26:20 -04:00

104 lines
3.1 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.DaemonStatus
import Assistant.TransferSlots
import Logs.Transfer
import Utility.DirWatcher
import Utility.DirWatcher.Types
import qualified Remote
import Control.Concurrent
import qualified Data.Map as M
{- This thread watches for changes to the gitAnnexTransferDir,
- and updates the DaemonStatus's map of ongoing transfers. -}
transferWatcherThread :: NamedThread
transferWatcherThread = namedThread "TransferWatcher" $ do
dir <- liftAnnex $ gitAnnexTransferDir <$> gitRepo
liftIO $ createDirectoryIfMissing True dir
let hook a = Just <$> asIO2 (runHandler a)
addhook <- hook onAdd
delhook <- hook onDel
modifyhook <- hook onModify
errhook <- hook onErr
let hooks = mkWatchHooks
{ addHook = addhook
, delHook = delhook
, modifyHook = modifyhook
, errHook = errhook
}
void $ liftIO $ watchDir dir (const False) hooks id
debug ["watching for transfers"]
type Handler = FilePath -> Assistant ()
{- Runs an action handler.
-
- Exceptions are ignored, otherwise a whole thread could be crashed.
-}
runHandler :: Handler -> FilePath -> Maybe FileStatus -> Assistant ()
runHandler handler file _filestatus =
either (liftIO . print) (const noop) =<< tryIO <~> handler file
{- Called when there's an error with inotify. -}
onErr :: Handler
onErr = error
{- Called when a new transfer information file is written. -}
onAdd :: Handler
onAdd file = case parseTransferFile file of
Nothing -> noop
Just t -> go t =<< liftAnnex (checkTransfer t)
where
go _ Nothing = noop -- transfer already finished
go t (Just info) = do
debug [ "transfer starting:", describeTransfer t info ]
r <- liftAnnex $ Remote.remoteFromUUID $ transferUUID t
updateTransferInfo t info { transferRemote = r }
{- Called when a transfer information file is updated.
-
- The only thing that should change in the transfer info is the
- bytesComplete, so that's the only thing updated in the DaemonStatus. -}
onModify :: Handler
onModify file = case parseTransferFile file of
Nothing -> noop
Just t -> go t =<< liftIO (readTransferInfoFile Nothing file)
where
go _ Nothing = noop
go t (Just newinfo) = alterTransferInfo t $
\i -> i { bytesComplete = bytesComplete newinfo }
{- This thread can only watch transfer sizes when the DirWatcher supports
- tracking modificatons to files. -}
watchesTransferSize :: Bool
watchesTransferSize = modifyTracked
{- Called when a transfer information file is removed. -}
onDel :: Handler
onDel file = case parseTransferFile file of
Nothing -> noop
Just t -> do
debug [ "transfer finishing:", show t]
minfo <- removeTransfer t
-- Run transfer hook.
m <- transferHook <$> getDaemonStatus
maybe noop (\hook -> void $ liftIO $ forkIO $ hook t)
(M.lookup (transferKey t) m)
finished <- asIO2 finishedTransfer
void $ liftIO $ forkIO $ do
{- XXX race workaround delay. The location
- log needs to be updated before finishedTransfer
- runs. -}
threadDelay 10000000 -- 10 seconds
finished t minfo