git-annex/LocationLog.hs
2011-10-05 16:02:51 -04:00

58 lines
1.5 KiB
Haskell

{- git-annex location log
-
- git-annex keeps track of which repositories have the contents of annexed
- files.
-
- Repositories record their UUID and the date when they --get or --drop
- a value.
-
- Copyright 2010-2011 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module LocationLog (
LogStatus(..),
logChange,
readLog,
keyLocations,
loggedKeys,
logFile,
logFileKey
) where
import Common.Annex
import qualified Git
import qualified Annex.Branch
import UUID
import PresenceLog
{- Log a change in the presence of a key's value in a repository. -}
logChange :: Git.Repo -> Key -> UUID -> LogStatus -> Annex ()
logChange repo key u s
| null u = error $
"unknown UUID for " ++ Git.repoDescribe repo ++
" (have you run git annex init there?)"
| otherwise = addLog (logFile key) =<< logNow s u
{- Returns a list of repository UUIDs that, according to the log, have
- the value of a key. -}
keyLocations :: Key -> Annex [UUID]
keyLocations = currentLog . logFile
{- Finds all keys that have location log information.
- (There may be duplicate keys in the list.) -}
loggedKeys :: Annex [Key]
loggedKeys = mapMaybe (logFileKey . takeFileName) <$> Annex.Branch.files
{- The filename of the log file for a given key. -}
logFile :: Key -> String
logFile key = hashDirLower key ++ keyFile key ++ ".log"
{- Converts a log filename into a key. -}
logFileKey :: FilePath -> Maybe Key
logFileKey file
| end == ".log" = fileKey beginning
| otherwise = Nothing
where
(beginning, end) = splitAt (length file - 4) file