git-annex/Annex/Branch/Transitions.hs
Joey Hess 591e4b145f
convert old uuid-based log parsers to attoparsec
This preserves the workaround for the old bug that caused NoUUID items
to be stored in the log, prefixing log lines with " ". It's now handled
implicitly, by using takeWhile1 (/= ' ') to get the uuid.

There is a behavior change from the old parser, which split the value
into words and then recombined it. That meant that "foo  bar" and "foo\tbar"
came out as "foo bar". That behavior was not documented, and seems
surprising; it meant that after a git-annex describe here "foo  bar",
you wouldn't get that same string back out when git-annex displayed repo
descriptions.

Otoh, some other parsers relied on the old behavior, and the attoparsec
rewrites had to deal with the issue themselves...

For group.log, there are some edge cases around the user providing a
group name with a leading or trailing space. The old parser would ignore
such excess whitespace. The new parser does too, because the alternative
is to refuse to parse something like " group1  group2 " due to excess
whitespace, which would be even more confusing behavior.

The only git-annex branch log file that is not converted to attoparsec
and bytestring-builder now is transitions.log.
2019-01-10 16:34:20 -04:00

87 lines
3 KiB
Haskell

{- git-annex branch transitions
-
- Copyright 2013-2019 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Annex.Branch.Transitions (
FileTransition(..),
getTransitionCalculator
) where
import Common
import Logs
import Logs.Transitions
import qualified Logs.UUIDBased as UUIDBased
import qualified Logs.Presence.Pure as Presence
import qualified Logs.Chunk.Pure as Chunk
import qualified Logs.MetaData.Pure as MetaData
import Types.TrustLevel
import Types.UUID
import Types.MetaData
import qualified Data.Map as M
import qualified Data.Set as S
import qualified Data.ByteString.Lazy as L
import qualified Data.Attoparsec.ByteString.Lazy as A
import Data.ByteString.Builder
data FileTransition
= ChangeFile Builder
| RemoveFile
| PreserveFile
type TransitionCalculator = FilePath -> L.ByteString -> TrustMap -> FileTransition
getTransitionCalculator :: Transition -> Maybe TransitionCalculator
getTransitionCalculator ForgetGitHistory = Nothing
getTransitionCalculator ForgetDeadRemotes = Just dropDead
dropDead :: FilePath -> L.ByteString -> TrustMap -> FileTransition
dropDead f content trustmap = case getLogVariety f of
Just UUIDBasedLog
-- Don't remove the dead repo from the trust log,
-- because git remotes may still exist, and they need
-- to still know it's dead.
| f == trustLog -> PreserveFile
| otherwise -> ChangeFile $
UUIDBased.buildLog byteString $
dropDeadFromMapLog trustmap id $
UUIDBased.parseLog A.takeByteString content
Just NewUUIDBasedLog -> ChangeFile $
UUIDBased.buildLogNew byteString $
dropDeadFromMapLog trustmap id $
UUIDBased.parseLogNew A.takeByteString content
Just (ChunkLog _) -> ChangeFile $
Chunk.buildLog $ dropDeadFromMapLog trustmap fst $ Chunk.parseLog content
Just (PresenceLog _) ->
let newlog = Presence.compactLog $
dropDeadFromPresenceLog trustmap $ Presence.parseLog content
in if null newlog
then RemoveFile
else ChangeFile $ Presence.buildLog newlog
Just RemoteMetaDataLog ->
let newlog = dropDeadFromRemoteMetaDataLog trustmap $ MetaData.simplifyLog $ MetaData.parseLog content
in if S.null newlog
then RemoveFile
else ChangeFile $ MetaData.buildLog newlog
Just OtherLog -> PreserveFile
Nothing -> PreserveFile
dropDeadFromMapLog :: TrustMap -> (k -> UUID) -> M.Map k v -> M.Map k v
dropDeadFromMapLog trustmap getuuid =
M.filterWithKey $ \k _v -> notDead trustmap getuuid k
{- Presence logs can contain UUIDs or other values. Any line that matches
- a dead uuid is dropped; any other values are passed through. -}
dropDeadFromPresenceLog :: TrustMap -> [Presence.LogLine] -> [Presence.LogLine]
dropDeadFromPresenceLog trustmap =
filter $ notDead trustmap (toUUID . Presence.fromLogInfo . Presence.info)
dropDeadFromRemoteMetaDataLog :: TrustMap -> MetaData.Log MetaData -> MetaData.Log MetaData
dropDeadFromRemoteMetaDataLog trustmap =
MetaData.filterOutEmpty . MetaData.filterRemoteMetaData (notDead trustmap id)
notDead :: TrustMap -> (v -> UUID) -> v -> Bool
notDead trustmap a v = M.findWithDefault def (a v) trustmap /= DeadTrusted