git-annex/Assistant/TransferQueue.hs
Joey Hess 62876502c5 wait on child transfer processes, and invalidate cache
There's still a bug; if the child updates its transfer info file,
then the data from it will superscede the TransferInfo, losing the
info that we should wait on this child.
2012-07-06 16:44:13 -06:00

75 lines
2.3 KiB
Haskell

{- git-annex assistant pending transfer queue
-
- Copyright 2012 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Assistant.TransferQueue where
import Common.Annex
import Assistant.DaemonStatus
import Logs.Transfer
import Types.Remote
import qualified Remote
import Control.Concurrent.STM
type TransferQueue = TChan (Transfer, TransferInfo)
newTransferQueue :: IO TransferQueue
newTransferQueue = atomically newTChan
stubInfo :: AssociatedFile -> TransferInfo
stubInfo f = TransferInfo
{ startedTime = Nothing
, transferPid = Nothing
, transferRemote = Nothing
, bytesComplete = Nothing
, associatedFile = f
, shouldWait = False
}
{- Adds pending transfers to the end of the queue for some of the known
- remotes. -}
queueTransfers :: TransferQueue -> DaemonStatusHandle -> Key -> AssociatedFile -> Direction -> Annex ()
queueTransfers q daemonstatus k f direction =
mapM_ (\r -> queue r $ gentransfer r)
=<< sufficientremotes . knownRemotes
<$> getDaemonStatus daemonstatus
where
sufficientremotes l
-- Queue downloads from all remotes, with the
-- cheapest ones first. More expensive ones will
-- only be tried if downloading from a cheap one
-- fails.
-- TODO: avoid downloading from remotes that don't
-- have the key.
| direction == Download = l
-- TODO: Determine a smaller set of remotes that
-- can be uploaded to, in order to ensure all
-- remotes can access the content. Currently,
-- send to every remote we can.
| otherwise = l
gentransfer r = Transfer
{ transferDirection = direction
, transferKey = k
, transferUUID = Remote.uuid r
}
queue r t = liftIO $ void $ atomically $ do
let info = (stubInfo f) { transferRemote = Just r }
writeTChan q (t, info)
{- Adds a pending transfer to the end of the queue. -}
queueTransfer :: TransferQueue -> AssociatedFile -> Transfer -> IO ()
queueTransfer q f t = void $ atomically $
writeTChan q (t, stubInfo f)
{- Adds a pending transfer to the start of the queue, to be processed next. -}
queueNextTransfer :: TransferQueue -> AssociatedFile -> Transfer -> IO ()
queueNextTransfer q f t = void $ atomically $
unGetTChan q (t, stubInfo f)
{- Blocks until a pending transfer is available in the queue. -}
getNextTransfer :: TransferQueue -> IO (Transfer, TransferInfo)
getNextTransfer = atomically . readTChan