git-annex/UUID.hs
2010-10-15 20:20:16 -04:00

133 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.
-
-}
module UUID (
UUID,
getUUID,
prepUUID,
genUUID,
reposByUUID,
prettyPrintUUIDs,
describeUUID
) where
import Control.Monad.State
import Maybe
import List
import System.Cmd.Utils
import System.IO
import qualified Data.Map as M
import qualified GitRepo as Git
import Types
import Locations
import qualified Annex
type UUID = 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 r g
let u = uncached r
if (c /= u && u /= "")
then do
updatecache g r u
return u
else return c
where
uncached r = Git.configGet r "annex.uuid" ""
cached r g = Git.configGet g (cachekey r) ""
updatecache g r u = do
if (g /= r)
then setConfig (cachekey r) u
else return ()
cachekey r = "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
if ("" == u)
then do
uuid <- liftIO $ genUUID
setConfig configkey uuid
else return ()
{- Changes a git config setting in both internal state and .git/config -}
setConfig :: String -> String -> Annex ()
setConfig key value = do
g <- Annex.gitRepo
liftIO $ Git.run g ["config", key, value]
-- re-read git config and update the repo's state
g' <- liftIO $ Git.configRead g
Annex.gitRepoChange g'
return ()
{- 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 -> " "++(prettify m u)++"\n") uuids
where
prettify m u =
if (0 < (length $ 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
log <- uuidLog
liftIO $ writeFile log $ serialize m'
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
log <- uuidLog
s <- liftIO $ catch (readFile log) (\error -> return "")
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 ("", "")
{- Filename of uuid.log. -}
uuidLog :: Annex String
uuidLog = do
g <- Annex.gitRepo
return $ (gitStateDir g) ++ "uuid.log"