git-annex/Assistant/Threads/TransferWatcher.hs
Joey Hess cf47bb3f50 run file transfers in threads, not processes
This should fix OSX/BSD issues with not noticing transfer information
files with kqueue. Now that threads are used, the thread can manage the
transfer slot allocation and deallocation by itself; much cleaner.
2012-07-18 19:15:34 -04:00

66 lines
2.1 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 Common.Annex
import Assistant.ThreadedMonad
import Assistant.DaemonStatus
import Logs.Transfer
import Utility.DirWatcher
import Utility.Types.DirWatcher
import Data.Map as M
{- 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
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 -> runThreadState st $ go t =<< checkTransfer t
where
go _ Nothing = noop -- transfer already finished
go t (Just info) = adjustTransfers dstatus $
M.insertWith' merge t info
-- preseve transferTid, which is not written to disk
merge new old = new { transferTid = transferTid old }
{- Called when a transfer information file is removed. -}
onDel :: Handler
onDel st dstatus file _ = case parseTransferFile file of
Nothing -> noop
Just t -> void $ runThreadState st $ removeTransfer dstatus t