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{- A pool of "git-annex transferkeys" processes available for use
-
- Copyright 2013 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Assistant.Types.TransferrerPool where
import Common.Annex
import Utility.NotificationBroadcaster
import Assistant.Types.DaemonStatus
import Control.Concurrent.STM hiding (check)
{- This TMVar is never left empty. -}
type TransferrerPool = TMVar (MkCheckTransferrer, [TransferrerPoolItem])
type CheckTransferrer = IO Bool
type MkCheckTransferrer = IO (IO Bool)
{- Each item in the pool may have a transferrer running, and has an
- IO action that can be used to check if it's still ok to use the
- transferrer. -}
data TransferrerPoolItem = TransferrerPoolItem (Maybe Transferrer) CheckTransferrer
data Transferrer = Transferrer
{ transferrerRead :: Handle
, transferrerWrite :: Handle
, transferrerHandle :: ProcessHandle
}
newTransferrerPool :: MkCheckTransferrer -> IO TransferrerPool
newTransferrerPool c = newTMVarIO (c, [])
popTransferrerPool :: TransferrerPool -> STM (Maybe TransferrerPoolItem, Int)
popTransferrerPool p = do
(c, l) <- takeTMVar p
case l of
[] -> do
putTMVar p (c, [])
return (Nothing, 0)
(i:is) -> do
putTMVar p (c, is)
return $ (Just i, length is)
pushTransferrerPool :: TransferrerPool -> TransferrerPoolItem -> STM ()
pushTransferrerPool p i = do
(c, l) <- takeTMVar p
let l' = i:l
putTMVar p (c, l')
{- Note that making a CheckTransferrer may allocate resources,
- such as a NotificationHandle, so it's important that the returned
- TransferrerPoolItem is pushed into the pool, and not left to be
- garbage collected. -}
mkTransferrerPoolItem :: TransferrerPool -> Transferrer -> IO TransferrerPoolItem
mkTransferrerPoolItem p t = do
mkcheck <- atomically $ fst <$> readTMVar p
check <- mkcheck
return $ TransferrerPoolItem (Just t) check
checkNetworkConnections :: DaemonStatusHandle -> MkCheckTransferrer
checkNetworkConnections dstatushandle = do
dstatus <- atomically $ readTMVar dstatushandle
h <- newNotificationHandle False (networkConnectedNotifier dstatus)
return $ not <$> checkNotification h
|
