87 lines
2.8 KiB
Haskell
87 lines
2.8 KiB
Haskell
{- git-annex command
|
|
-
|
|
- Copyright 2011 Joey Hess <id@joeyh.name>
|
|
-
|
|
- 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.Backend (canUpgradeKey, fastMigrate)
|
|
import Types.KeySource
|
|
import Annex.Content
|
|
import qualified Command.ReKey
|
|
import qualified Command.Fsck
|
|
|
|
cmd :: [Command]
|
|
cmd = [notDirect $ withOptions annexedMatchingOptions $
|
|
command "migrate" paramPaths seek
|
|
SectionUtility "switch data to different backend"]
|
|
|
|
seek :: CommandSeek
|
|
seek = withFilesInGit $ whenAnnexed start
|
|
|
|
start :: FilePath -> Key -> CommandStart
|
|
start file key = do
|
|
v <- Backend.getBackend file key
|
|
case v of
|
|
Nothing -> stop
|
|
Just oldbackend -> do
|
|
exists <- inAnnex key
|
|
newbackend <- choosebackend =<< chooseBackend file
|
|
if (newbackend /= oldbackend || upgradableKey oldbackend key) && exists
|
|
then do
|
|
showStart "migrate" file
|
|
next $ perform file key oldbackend newbackend
|
|
else stop
|
|
where
|
|
choosebackend Nothing = Prelude.head <$> orderedList
|
|
choosebackend (Just backend) = return backend
|
|
|
|
{- Checks if a key is upgradable to a newer representation.
|
|
-
|
|
- Reasons for migration:
|
|
- - Ideally, all keys have file size metadata. Old keys may not.
|
|
- - Something has changed in the backend, such as a bug fix.
|
|
-}
|
|
upgradableKey :: Backend -> Key -> Bool
|
|
upgradableKey backend key = isNothing (Types.Key.keySize key) || backendupgradable
|
|
where
|
|
backendupgradable = maybe False (\a -> a key) (canUpgradeKey backend)
|
|
|
|
{- 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.
|
|
-
|
|
- To ensure that the data we have for the old key is valid, it's
|
|
- fscked here. First we generate the new key. This ensures that the
|
|
- data cannot get corrupted after the fsck but before the new key is
|
|
- generated.
|
|
-}
|
|
perform :: FilePath -> Key -> Backend -> Backend -> CommandPerform
|
|
perform file oldkey oldbackend newbackend = go =<< genkey
|
|
where
|
|
go Nothing = stop
|
|
go (Just (newkey, knowngoodcontent))
|
|
| knowngoodcontent = finish newkey
|
|
| otherwise = stopUnless checkcontent $ finish newkey
|
|
checkcontent = Command.Fsck.checkBackend oldbackend oldkey $ Just file
|
|
finish newkey = stopUnless (Command.ReKey.linkKey oldkey newkey) $
|
|
next $ Command.ReKey.cleanup file oldkey newkey
|
|
genkey = case maybe Nothing (\fm -> fm oldkey newbackend (Just file)) (fastMigrate oldbackend) of
|
|
Just newkey -> return $ Just (newkey, True)
|
|
Nothing -> do
|
|
content <- calcRepo $ gitAnnexLocation oldkey
|
|
let source = KeySource
|
|
{ keyFilename = file
|
|
, contentLocation = content
|
|
, inodeCache = Nothing
|
|
}
|
|
v <- genKey source (Just newbackend)
|
|
return $ case v of
|
|
Just (newkey, _) -> Just (newkey, False)
|
|
_ -> Nothing
|