git-annex/Command/TransferKeys.hs
Joey Hess 2fd63f3cfa port transferkeys to windows; make stopping in progress transfers work too (probably)
transferkeys had used special FDs for communication, but that would be
quite annoying to do in Windows.

Instead, use stdin and stdout. But, to avoid commands like rsync stomping
on them and messing up the communications channel, they're duplicated to a
different handle; stdin is replaced with a null handle, and stdout is
replaced with a copy of stderr. This should all work in windows too.

Stopping in progress transfers may work on windows.. if the types unify
anyway. ;) May need some more porting.
2013-12-10 23:19:18 -04:00

139 lines
3.7 KiB
Haskell

{- git-annex command, used internally by assistant
-
- Copyright 2012, 2013 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
{-# LANGUAGE TypeSynonymInstances, FlexibleInstances #-}
module Command.TransferKeys where
import Common.Annex
import Command
import Annex.Content
import Logs.Location
import Logs.Transfer
import qualified Remote
import Types.Key
import GHC.IO.Handle
data TransferRequest = TransferRequest Direction Remote Key AssociatedFile
def :: [Command]
def = [command "transferkeys" paramNothing seek
SectionPlumbing "transfers keys"]
seek :: [CommandSeek]
seek = [withNothing start]
start :: CommandStart
start = withHandles $ \(readh, writeh) -> do
runRequests readh writeh runner
stop
where
runner (TransferRequest direction remote key file)
| direction == Upload =
upload (Remote.uuid remote) key file forwardRetry $ \p -> do
ok <- Remote.storeKey remote key file p
when ok $
Remote.logStatus remote key InfoPresent
return ok
| otherwise = download (Remote.uuid remote) key file forwardRetry $ \p ->
getViaTmp key $ \t -> Remote.retrieveKeyFile remote key file t p
{- stdin and stdout are connected with the caller, to be used for
- communication with it. But doing a transfer might involve something
- that tries to read from stdin, or write to stdout. To avoid that, close
- stdin, and duplicate stderr to stdout. Return two new handles
- that are duplicates of the original (stdin, stdout). -}
withHandles :: ((Handle, Handle) -> Annex a) -> Annex a
withHandles a = do
readh <- liftIO $ hDuplicate stdin
writeh <- liftIO $ hDuplicate stdout
liftIO $ do
nullh <- openFile devNull ReadMode
nullh `hDuplicateTo` stdin
stderr `hDuplicateTo` stdout
a (readh, writeh)
runRequests
:: Handle
-> Handle
-> (TransferRequest -> Annex Bool)
-> Annex ()
runRequests readh writeh a = do
liftIO $ do
hSetBuffering readh NoBuffering
fileEncoding readh
fileEncoding writeh
go =<< readrequests
where
go (d:u:k:f:rest) = do
case (deserialize d, deserialize u, deserialize k, deserialize f) of
(Just direction, Just uuid, Just key, Just file) -> do
mremote <- Remote.remoteFromUUID uuid
case mremote of
Nothing -> sendresult False
Just remote -> sendresult =<< a
(TransferRequest direction remote key file)
_ -> sendresult False
go rest
go [] = noop
go [""] = noop
go v = error $ "transferkeys protocol error: " ++ show v
readrequests = liftIO $ split fieldSep <$> hGetContents readh
sendresult b = liftIO $ do
hPutStrLn writeh $ serialize b
hFlush writeh
sendRequest :: Transfer -> AssociatedFile -> Handle -> IO ()
sendRequest t f h = do
hPutStr h $ intercalate fieldSep
[ serialize (transferDirection t)
, serialize (transferUUID t)
, serialize (transferKey t)
, serialize f
, "" -- adds a trailing null
]
hFlush h
readResponse :: Handle -> IO Bool
readResponse h = fromMaybe False . deserialize <$> hGetLine h
fieldSep :: String
fieldSep = "\0"
class Serialized a where
serialize :: a -> String
deserialize :: String -> Maybe a
instance Serialized Bool where
serialize True = "1"
serialize False = "0"
deserialize "1" = Just True
deserialize "0" = Just False
deserialize _ = Nothing
instance Serialized Direction where
serialize Upload = "u"
serialize Download = "d"
deserialize "u" = Just Upload
deserialize "d" = Just Download
deserialize _ = Nothing
instance Serialized AssociatedFile where
serialize (Just f) = f
serialize Nothing = ""
deserialize "" = Just Nothing
deserialize f = Just $ Just f
instance Serialized UUID where
serialize = fromUUID
deserialize = Just . toUUID
instance Serialized Key where
serialize = key2file
deserialize = file2key