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|
{- git-annex transfers
-
- Copyright 2012-2014 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
{-# LANGUAGE CPP, FlexibleInstances #-}
module Annex.Transfer (
module X,
noObserver,
upload,
download,
runTransfer,
alwaysRunTransfer,
noRetry,
forwardRetry,
) where
import Common.Annex
import Logs.Transfer as X
import Annex.Notification as X
import Annex.Perms
import Utility.Metered
import Annex.LockPool
import Types.Remote (Verification(..))
import Control.Concurrent
type TransferObserver = Bool -> Transfer -> TransferInfo -> Annex ()
class Observable a where
observeBool :: a -> Bool
observeFailure :: a
instance Observable Bool where
observeBool = id
observeFailure = False
instance Observable (Bool, Verification) where
observeBool = fst
observeFailure = (False, UnVerified)
noObserver :: TransferObserver
noObserver _ _ _ = noop
upload :: Observable v => UUID -> Key -> AssociatedFile -> RetryDecider -> TransferObserver -> (MeterUpdate -> Annex v) -> NotifyWitness -> Annex v
upload u key f d o a _witness = runTransfer (Transfer Upload u key) f d o a
download :: Observable v => UUID -> Key -> AssociatedFile -> RetryDecider -> TransferObserver -> (MeterUpdate -> Annex v) -> NotifyWitness -> Annex v
download u key f d o a _witness = runTransfer (Transfer Download u key) f d o a
{- Runs a transfer action. Creates and locks the lock file while the
- action is running, and stores info in the transfer information
- file.
-
- If the transfer action returns False, the transfer info is
- left in the failedTransferDir.
-
- If the transfer is already in progress, returns False.
-
- An upload can be run from a read-only filesystem, and in this case
- no transfer information or lock file is used.
-}
runTransfer :: Observable v => Transfer -> Maybe FilePath -> RetryDecider -> TransferObserver -> (MeterUpdate -> Annex v) -> Annex v
runTransfer = runTransfer' False
{- Like runTransfer, but ignores any existing transfer lock file for the
- transfer, allowing re-running a transfer that is already in progress.
-
- Note that this may result in confusing progress meter display in the
- webapp, if multiple processes are writing to the transfer info file. -}
alwaysRunTransfer :: Observable v => Transfer -> Maybe FilePath -> RetryDecider -> TransferObserver -> (MeterUpdate -> Annex v) -> Annex v
alwaysRunTransfer = runTransfer' True
runTransfer' :: Observable v => Bool -> Transfer -> Maybe FilePath -> RetryDecider -> TransferObserver -> (MeterUpdate -> Annex v) -> Annex v
runTransfer' ignorelock t file shouldretry transferobserver transferaction = do
info <- liftIO $ startTransferInfo file
(meter, tfile, metervar) <- mkProgressUpdater t info
mode <- annexFileMode
(lck, inprogress) <- prep tfile mode info
if inprogress && not ignorelock
then do
showNote "transfer already in progress, or unable to take transfer lock"
return observeFailure
else do
v <- retry info metervar $ transferaction meter
liftIO $ cleanup tfile lck
transferobserver (observeBool v) t info
return v
where
#ifndef mingw32_HOST_OS
prep tfile mode info = do
let lck = transferLockFile tfile
r <- tryLockExclusive (Just mode) lck
case r of
Nothing -> return (Nothing, True)
Just lockhandle -> ifM (checkSaneLock lck lockhandle)
( do
void $ liftIO $ tryIO $
writeTransferInfoFile info tfile
return (Just lockhandle, False)
, return (Nothing, True)
)
#else
prep tfile _mode info = liftIO $ do
let lck = transferLockFile tfile
v <- catchMaybeIO $ lockExclusive lck
case v of
Nothing -> return (Nothing, False)
Just Nothing -> return (Nothing, True)
Just (Just lockhandle) -> do
void $ liftIO $ tryIO $
writeTransferInfoFile info tfile
return (Just lockhandle, False)
#endif
cleanup _ Nothing = noop
cleanup tfile (Just lockhandle) = do
let lck = transferLockFile tfile
void $ tryIO $ removeFile tfile
#ifndef mingw32_HOST_OS
void $ tryIO $ removeFile lck
dropLock lockhandle
#else
{- Windows cannot delete the lockfile until the lock
- is closed. So it's possible to race with another
- process that takes the lock before it's removed,
- so ignore failure to remove.
-}
dropLock lockhandle
void $ tryIO $ removeFile lck
#endif
retry oldinfo metervar run = do
v <- tryNonAsync run
case v of
Right b -> return b
Left e -> do
warning (show e)
b <- getbytescomplete metervar
let newinfo = oldinfo { bytesComplete = Just b }
if shouldretry oldinfo newinfo
then retry newinfo metervar run
else return observeFailure
getbytescomplete metervar
| transferDirection t == Upload =
liftIO $ readMVar metervar
| otherwise = do
f <- fromRepo $ gitAnnexTmpObjectLocation (transferKey t)
liftIO $ catchDefaultIO 0 $ getFileSize f
type RetryDecider = TransferInfo -> TransferInfo -> Bool
noRetry :: RetryDecider
noRetry _ _ = False
{- Retries a transfer when it fails, as long as the failed transfer managed
- to send some data. -}
forwardRetry :: RetryDecider
forwardRetry old new = bytesComplete old < bytesComplete new
|
