git-annex/Logs/UUID.hs
Joey Hess 6280af2901
generate more compact git-annex branch for imports
Especially from borg, where the content identifier logs
all end up being the same identical file!

But also, for other imports, the location tracking logs can,
in some cases, be identical files.

Bonus optimisation: Avoid looking up (and parsing when set)
GIT_ANNEX_VECTOR_CLOCK env var every time a log is written to.
Although the lookup does happen at startup even when no
log will be written now.
2020-12-23 15:25:16 -04:00

61 lines
1.7 KiB
Haskell

{- git-annex uuid log
-
- uuid.log stores a list of known uuids, and their descriptions.
-
- Copyright 2010-2019 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
module Logs.UUID (
uuidLog,
describeUUID,
uuidDescMap,
uuidDescMapLoad,
uuidDescMapRaw,
) where
import Types.UUID
import Annex.Common
import Annex.VectorClock
import qualified Annex
import qualified Annex.Branch
import Logs
import Logs.UUIDBased
import qualified Annex.UUID
import qualified Data.Map.Strict as M
import qualified Data.ByteString.Lazy as L
import qualified Data.Attoparsec.ByteString.Lazy as A
{- Records a description for a uuid in the log. -}
describeUUID :: UUID -> UUIDDesc -> Annex ()
describeUUID uuid desc = do
c <- currentVectorClock
Annex.Branch.change uuidLog $
buildLogOld buildUUIDDesc . changeLog c uuid desc . parseUUIDLog
{- The map is cached for speed. -}
uuidDescMap :: Annex UUIDDescMap
uuidDescMap = maybe uuidDescMapLoad return =<< Annex.getState Annex.uuiddescmap
{- Read the uuidLog into a map, and cache it for later use.
-
- If the current repository has not been described, it is still included
- in the map with an empty description. -}
uuidDescMapLoad :: Annex UUIDDescMap
uuidDescMapLoad = do
m <- uuidDescMapRaw
u <- Annex.UUID.getUUID
let m' = M.insertWith preferold u mempty m
Annex.changeState $ \s -> s { Annex.uuiddescmap = Just m' }
return m'
where
preferold = flip const
{- Read the uuidLog into a map. Includes only actually set descriptions. -}
uuidDescMapRaw :: Annex UUIDDescMap
uuidDescMapRaw = simpleMap . parseUUIDLog <$> Annex.Branch.get uuidLog
parseUUIDLog :: L.ByteString -> Log UUIDDesc
parseUUIDLog = parseLogOld (UUIDDesc <$> A.takeByteString)