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