git-annex/Logs/Location.hs
Joey Hess ed79596b75 noop
2012-04-21 23:32:33 -04:00

68 lines
1.9 KiB
Haskell

{-# LANGUAGE BangPatterns #-}
{- 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 Logs.Location (
LogStatus(..),
logChange,
loggedLocations,
loggedKeys,
loggedKeysFor,
logFile,
logFileKey
) where
import Common.Annex
import qualified Annex.Branch
import Logs.Presence
{- Log a change in the presence of a key's value in a repository. -}
logChange :: Key -> UUID -> LogStatus -> Annex ()
logChange key (UUID u) s = addLog (logFile key) =<< logNow s u
logChange _ NoUUID _ = noop
{- Returns a list of repository UUIDs that, according to the log, have
- the value of a key.
-}
loggedLocations :: Key -> Annex [UUID]
loggedLocations key = map toUUID <$> (currentLog . logFile) key
{- Finds all keys that have location log information.
- (There may be duplicate keys in the list.) -}
loggedKeys :: Annex [Key]
loggedKeys = mapMaybe (logFileKey . takeFileName) <$> Annex.Branch.files
{- Finds all keys that have location log information indicating
- they are present for the specified repository. -}
loggedKeysFor :: UUID -> Annex [Key]
loggedKeysFor u = filterM isthere =<< loggedKeys
where
{- This should run strictly to avoid the filterM
- building many thunks containing keyLocations data. -}
isthere k = do
us <- loggedLocations k
let !there = u `elem` us
return there
{- 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
| ext == ".log" = fileKey base
| otherwise = Nothing
where
(base, ext) = splitAt (length file - 4) file