git-annex/UUID.hs

132 lines
3.2 KiB
Haskell

{- git-annex uuids
-
- Each git repository used by git-annex has an annex.uuid setting that
- uniquely identifies that repository.
-
- Copyright 2010 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module UUID (
UUID,
getUUID,
prepUUID,
genUUID,
reposByUUID,
prettyPrintUUIDs,
describeUUID,
uuidLog
) where
import Control.Monad.State
import Maybe
import List
import System.Cmd.Utils
import System.IO
import System.Directory
import qualified Data.Map as M
import System.Posix.Process
import qualified GitRepo as Git
import Types
import Locations
import qualified Annex
import Utility
type UUID = String
configkey :: String
configkey="annex.uuid"
{- Generates a UUID. There is a library for this, but it's not packaged,
- so use the command line tool. -}
genUUID :: IO UUID
genUUID = liftIO $ pOpen ReadFromPipe "uuid" ["-m"] $ \h -> hGetLine h
{- Looks up a repo's UUID. May return "" if none is known.
-
- UUIDs of remotes are cached in git config, using keys named
- remote.<name>.annex-uuid
-
- -}
getUUID :: Git.Repo -> Annex UUID
getUUID r = do
g <- Annex.gitRepo
let c = cached g
let u = uncached
if (c /= u && u /= "")
then do
updatecache g u
return u
else return c
where
uncached = Git.configGet r "annex.uuid" ""
cached g = Git.configGet g cachekey ""
updatecache g u = when (g /= r) $ Annex.setConfig cachekey u
cachekey = "remote." ++ (Git.repoRemoteName r) ++ ".annex-uuid"
{- Make sure that the repo has an annex.uuid setting. -}
prepUUID :: Annex ()
prepUUID = do
g <- Annex.gitRepo
u <- getUUID g
when ("" == u) $ do
uuid <- liftIO $ genUUID
Annex.setConfig configkey uuid
{- Filters a list of repos to ones that have listed UUIDs. -}
reposByUUID :: [Git.Repo] -> [UUID] -> Annex [Git.Repo]
reposByUUID repos uuids = do
filterM match repos
where
match r = do
u <- getUUID r
return $ isJust $ elemIndex u uuids
{- Pretty-prints a list of UUIDs -}
prettyPrintUUIDs :: [UUID] -> Annex String
prettyPrintUUIDs uuids = do
m <- uuidMap
return $ unwords $ map (\u -> "\t"++(prettify m u)++"\n") uuids
where
prettify m u =
if (not $ null $ findlog m u)
then u ++ " -- " ++ (findlog m u)
else u
findlog m u = M.findWithDefault "" u m
{- Records a description for a uuid in the uuidLog. -}
describeUUID :: UUID -> String -> Annex ()
describeUUID uuid desc = do
m <- uuidMap
let m' = M.insert uuid desc m
logfile <- uuidLog
pid <- liftIO $ getProcessID
let tmplogfile = logfile ++ ".tmp" ++ show pid
liftIO $ createDirectoryIfMissing True (parentDir logfile)
liftIO $ writeFile tmplogfile $ serialize m'
liftIO $ renameFile tmplogfile logfile
where
serialize m = unlines $ map (\(u, d) -> u++" "++d) $ M.toList m
{- Read and parse the uuidLog into a Map -}
uuidMap :: Annex (M.Map UUID String)
uuidMap = do
logfile <- uuidLog
s <- liftIO $ catch (readFile logfile) ignoreerror
return $ M.fromList $ map (\l -> pair l) $ lines s
where
pair l =
if (1 < (length $ words l))
then ((words l) !! 0, unwords $ drop 1 $ words l)
else ("", "")
ignoreerror _ = return ""
{- Filename of uuid.log. -}
uuidLog :: Annex String
uuidLog = do
g <- Annex.gitRepo
return $ (gitStateDir g) ++ "uuid.log"