git-annex/Git/Ref.hs
2011-12-30 18:36:40 -04:00

65 lines
1.9 KiB
Haskell

{- git ref stuff
-
- Copyright 2011 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Git.Ref where
import qualified Data.ByteString.Lazy.Char8 as L
import Common
import Git
import Git.Command
{- Converts a fully qualified git ref into a user-visible string. -}
describe :: Ref -> String
describe = show . base
{- Often git refs are fully qualified (eg: refs/heads/master).
- Converts such a fully qualified ref into a base ref (eg: master). -}
base :: Ref -> Ref
base = Ref . remove "refs/heads/" . remove "refs/remotes/" . show
where
remove prefix s
| prefix `isPrefixOf` s = drop (length prefix) s
| otherwise = s
{- Given a directory such as "refs/remotes/origin", and a ref such as
- refs/heads/master, yields a version of that ref under the directory,
- such as refs/remotes/origin/master. -}
under :: String -> Ref -> Ref
under dir r = Ref $ dir </> show (base r)
{- Checks if a ref exists. -}
exists :: Ref -> Repo -> IO Bool
exists ref = runBool "show-ref"
[Param "--verify", Param "-q", Param $ show ref]
{- Get the sha of a fully qualified git ref, if it exists. -}
sha :: Branch -> Repo -> IO (Maybe Sha)
sha branch repo = process . L.unpack <$> showref repo
where
showref = pipeRead [Param "show-ref",
Param "--hash", -- get the hash
Param $ show branch]
process [] = Nothing
process s = Just $ Ref $ firstLine s
{- List of (refs, branches) matching a given ref spec. -}
matching :: Ref -> Repo -> IO [(Ref, Branch)]
matching ref repo = do
r <- pipeRead [Param "show-ref", Param $ show ref] repo
return $ map (gen . L.unpack) (L.lines r)
where
gen l = let (r, b) = separate (== ' ') l in
(Ref r, Ref b)
{- List of (refs, branches) matching a given ref spec.
- Duplicate refs are filtered out. -}
matchingUniq :: Ref -> Repo -> IO [(Ref, Branch)]
matchingUniq ref repo = nubBy uniqref <$> matching ref repo
where
uniqref (a, _) (b, _) = a == b