git-annex/Command/ReKey.hs

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{- git-annex command
-
- Copyright 2012-2016 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
module Command.ReKey where
import Command
import qualified Annex
import Annex.Content
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import Annex.Ingest
import Annex.Link
import Annex.Perms
import Annex.ReplaceFile
import Logs.Location
import Git.FilePath
import qualified Database.Keys
import Annex.InodeSentinal
import Utility.InodeCache
import qualified Utility.RawFilePath as R
cmd :: Command
cmd = command "rekey" SectionPlumbing
"change keys used for files"
(paramRepeating $ paramPair paramPath paramKey)
(seek <$$> optParser)
data ReKeyOptions = ReKeyOptions
{ reKeyThese :: CmdParams
, batchOption :: BatchMode
}
optParser :: CmdParamsDesc -> Parser ReKeyOptions
optParser desc = ReKeyOptions
<$> cmdParams desc
<*> parseBatchOption
-- Split on the last space, since a FilePath can contain whitespace,
-- but a Key very rarely does.
batchParser :: String -> Annex (Either String (RawFilePath, Key))
batchParser s = case separate (== ' ') (reverse s) of
(rk, rf)
| null rk || null rf -> return $ Left "Expected: \"file key\""
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| otherwise -> case deserializeKey (reverse rk) of
Nothing -> return $ Left "bad key"
Just k -> do
let f = reverse rf
f' <- liftIO $ relPathCwdToFile f
return $ Right (toRawFilePath f', k)
seek :: ReKeyOptions -> CommandSeek
seek o = case batchOption o of
Batch fmt -> batchInput fmt batchParser
(batchCommandAction . uncurry start)
NoBatch -> withPairs
(\(si, p) -> commandAction (start si (parsekey p)))
(reKeyThese o)
where
parsekey (file, skey) =
(toRawFilePath file, fromMaybe (giveup "bad key") (deserializeKey skey))
start :: SeekInput -> (RawFilePath, Key) -> CommandStart
start si (file, newkey) = ifAnnexed file go stop
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where
go oldkey
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| oldkey == newkey = stop
| otherwise = starting "rekey" ai si $
make CommandStart return a StartMessage The goal is to be able to run CommandStart in the main thread when -J is used, rather than unncessarily passing it off to a worker thread, which incurs overhead that is signficant when the CommandStart is going to quickly decide to stop. To do that, the message it displays needs to be displayed in the worker thread, after the CommandStart has run. Also, the change will mean that CommandStart will no longer necessarily run with the same Annex state as CommandPerform. While its docs already said it should avoid modifying Annex state, I audited all the CommandStart code as part of the conversion. (Note that CommandSeek already sometimes runs with a different Annex state, and that has not been a source of any problems, so I am not too worried that this change will lead to breakage going forward.) The only modification of Annex state I found was it calling allowMessages in some Commands that default to noMessages. Dealt with that by adding a startCustomOutput and a startingUsualMessages. This lets a command start with noMessages and then select the output it wants for each CommandStart. One bit of breakage: onlyActionOn has been removed from commands that used it. The plan is that, since a StartMessage contains an ActionItem, when a Key can be extracted from that, the parallel job runner can run onlyActionOn' automatically. Then commands won't need to worry about this detail. Future work. Otherwise, this was a fairly straightforward process of making each CommandStart compile again. Hopefully other behavior changes were mostly avoided. In a few cases, a command had a CommandStart that called a CommandPerform that then called showStart multiple times. I have collapsed those down to a single start action. The main command to perhaps suffer from it is Command.Direct, which used to show a start for each file, and no longer does. Another minor behavior change is that some commands used showStart before, but had an associated file and a Key available, so were changed to ShowStart with an ActionItemAssociatedFile. That will not change the normal output or behavior, but --json output will now include the key. This should not break it for anyone using a real json parser.
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perform file oldkey newkey
ai = ActionItemWorkTreeFile file
perform :: RawFilePath -> Key -> Key -> CommandPerform
perform file oldkey newkey = do
ifM (inAnnex oldkey)
( unlessM (linkKey file oldkey newkey) $
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giveup "failed creating link from old to new key"
, unlessM (Annex.getState Annex.force) $
giveup $ fromRawFilePath file ++ " is not available (use --force to override)"
)
next $ cleanup file oldkey newkey
{- Make a hard link to the old key content (when supported),
- to avoid wasting disk space. -}
linkKey :: RawFilePath -> Key -> Key -> Annex Bool
linkKey file oldkey newkey = ifM (isJust <$> isAnnexLink file)
{- If the object file is already hardlinked to elsewhere, a hard
- link won't be made by getViaTmpFromDisk, but a copy instead.
- This avoids hard linking to content linked to an
- unlocked file, which would leave the new key unlocked
- and vulnerable to corruption. -}
( getViaTmpFromDisk RetrievalAllKeysSecure DefaultVerify newkey $ \tmp -> unVerified $ do
oldobj <- fromRawFilePath <$> calcRepo (gitAnnexLocation oldkey)
isJust <$> linkOrCopy' (return True) newkey oldobj tmp Nothing
, do
{- The file being rekeyed is itself an unlocked file; if
- it's hard linked to the old key, that link must be broken. -}
oldobj <- fromRawFilePath <$> calcRepo (gitAnnexLocation oldkey)
v <- tryNonAsync $ do
st <- liftIO $ R.getFileStatus file
when (linkCount st > 1) $ do
freezeContent oldobj
replaceWorkTreeFile (fromRawFilePath file) $ \tmp -> do
unlessM (checkedCopyFile oldkey oldobj tmp Nothing) $
error "can't lock old key"
thawContent tmp
ic <- withTSDelta (liftIO . genInodeCache file)
case v of
Left e -> do
warning (show e)
return False
Right () -> do
r <- linkToAnnex newkey (fromRawFilePath file) ic
return $ case r of
LinkAnnexFailed -> False
LinkAnnexOk -> True
LinkAnnexNoop -> True
)
cleanup :: RawFilePath -> Key -> Key -> CommandCleanup
cleanup file oldkey newkey = do
ifM (isJust <$> isAnnexLink file)
( do
-- Update symlink to use the new key.
liftIO $ removeFile (fromRawFilePath file)
addLink (CheckGitIgnore False) (fromRawFilePath file) newkey Nothing
, do
mode <- liftIO $ catchMaybeIO $ fileMode <$> R.getFileStatus file
liftIO $ whenM (isJust <$> isPointerFile file) $
writePointerFile file newkey mode
stagePointerFile file mode =<< hashPointerFile newkey
Database.Keys.removeAssociatedFile oldkey
=<< inRepo (toTopFilePath file)
)
whenM (inAnnex newkey) $
logStatus newkey InfoPresent
return True