git-annex/Command/Migrate.hs
Joey Hess e0fdfb2e70 maintain set of files pendingAdd
Kqueue needs to remember which files failed to be added due to being open,
and retry them. This commit gets the data in place for such a retry thread.

Broke KeySource out into its own file, and added Eq and Ord instances
so it can be stored in a Set.
2012-06-20 16:31:46 -04:00

53 lines
1.7 KiB
Haskell

{- git-annex command
-
- Copyright 2011 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Command.Migrate where
import Common.Annex
import Command
import Backend
import qualified Types.Key
import Types.KeySource
import Annex.Content
import qualified Command.ReKey
def :: [Command]
def = [command "migrate" paramPaths seek "switch data to different backend"]
seek :: [CommandSeek]
seek = [withFilesInGit $ whenAnnexed start]
start :: FilePath -> (Key, Backend) -> CommandStart
start file (key, oldbackend) = do
exists <- inAnnex key
newbackend <- choosebackend =<< chooseBackend file
if (newbackend /= oldbackend || upgradableKey key) && exists
then do
showStart "migrate" file
next $ perform file key newbackend
else stop
where
choosebackend Nothing = Prelude.head <$> orderedList
choosebackend (Just backend) = return backend
{- Checks if a key is upgradable to a newer representation. -}
{- Ideally, all keys have file size metadata. Old keys may not. -}
upgradableKey :: Key -> Bool
upgradableKey key = isNothing $ Types.Key.keySize key
{- Store the old backend's key in the new backend
- The old backend's key is not dropped from it, because there may
- be other files still pointing at that key. -}
perform :: FilePath -> Key -> Backend -> CommandPerform
perform file oldkey newbackend = maybe stop go =<< genkey
where
go newkey = stopUnless (Command.ReKey.linkKey oldkey newkey) $
next $ Command.ReKey.cleanup file oldkey newkey
genkey = do
content <- inRepo $ gitAnnexLocation oldkey
let source = KeySource { keyFilename = file, contentLocation = content }
liftM fst <$> genKey source (Just newbackend)