git-annex/Git/Ref.hs
2015-01-21 12:50:09 -04:00

144 lines
4.4 KiB
Haskell

{- git ref stuff
-
- Copyright 2011-2013 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Git.Ref where
import Common
import Git
import Git.Command
import Git.Sha
import Git.Types
import Data.Char (chr)
headRef :: Ref
headRef = Ref "HEAD"
{- Converts a fully qualified git ref into a user-visible string. -}
describe :: Ref -> String
describe = fromRef . 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/" . fromRef
where
remove prefix s
| prefix `isPrefixOf` s = drop (length prefix) s
| otherwise = s
{- Given a directory and any ref, takes the basename of the ref and puts
- it under the directory. -}
under :: String -> Ref -> Ref
under dir r = Ref $ dir ++ "/" ++
(reverse $ takeWhile (/= '/') $ reverse $ fromRef r)
{- 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. -}
underBase :: String -> Ref -> Ref
underBase dir r = Ref $ dir ++ "/" ++ fromRef (base r)
{- A Ref that can be used to refer to a file in the repository, as staged
- in the index.
-
- Prefixing the file with ./ makes this work even if in a subdirectory
- of a repo.
-}
fileRef :: FilePath -> Ref
fileRef f = Ref $ ":./" ++ f
{- Converts a Ref to refer to the content of the Ref on a given date. -}
dateRef :: Ref -> RefDate -> Ref
dateRef (Ref r) (RefDate d) = Ref $ r ++ "@" ++ d
{- A Ref that can be used to refer to a file in the repository as it
- appears in a given Ref. -}
fileFromRef :: Ref -> FilePath -> Ref
fileFromRef (Ref r) f = let (Ref fr) = fileRef f in Ref (r ++ fr)
{- Checks if a ref exists. -}
exists :: Ref -> Repo -> IO Bool
exists ref = runBool
[Param "show-ref", Param "--verify", Param "-q", Param $ fromRef ref]
{- The file used to record a ref. (Git also stores some refs in a
- packed-refs file.) -}
file :: Ref -> Repo -> FilePath
file ref repo = localGitDir repo </> fromRef ref
{- Checks if HEAD exists. It generally will, except for in a repository
- that was just created. -}
headExists :: Repo -> IO Bool
headExists repo = do
ls <- lines <$> pipeReadStrict [Param "show-ref", Param "--head"] repo
return $ any (" HEAD" `isSuffixOf`) ls
{- Get the sha of a fully qualified git ref, if it exists. -}
sha :: Branch -> Repo -> IO (Maybe Sha)
sha branch repo = process <$> showref repo
where
showref = pipeReadStrict [Param "show-ref",
Param "--hash", -- get the hash
Param $ fromRef branch]
process [] = Nothing
process s = Just $ Ref $ firstLine s
{- List of (shas, branches) matching a given ref or refs. -}
matching :: [Ref] -> Repo -> IO [(Sha, Branch)]
matching refs repo = matching' (map fromRef refs) repo
{- Includes HEAD in the output, if asked for it. -}
matchingWithHEAD :: [Ref] -> Repo -> IO [(Sha, Branch)]
matchingWithHEAD refs repo = matching' ("--head" : map fromRef refs) repo
{- List of (shas, branches) matching a given ref or refs. -}
matching' :: [String] -> Repo -> IO [(Sha, Branch)]
matching' ps repo = map gen . lines <$>
pipeReadStrict (Param "show-ref" : map Param ps) repo
where
gen l = let (r, b) = separate (== ' ') l
in (Ref r, Ref b)
{- List of (shas, branches) matching a given ref spec.
- Duplicate shas are filtered out. -}
matchingUniq :: [Ref] -> Repo -> IO [(Sha, Branch)]
matchingUniq refs repo = nubBy uniqref <$> matching refs repo
where
uniqref (a, _) (b, _) = a == b
{- Gets the sha of the tree a ref uses. -}
tree :: Ref -> Repo -> IO (Maybe Sha)
tree ref = extractSha <$$> pipeReadStrict
[ Param "rev-parse", Param (fromRef ref ++ ":") ]
{- Checks if a String is a legal git ref name.
-
- The rules for this are complex; see git-check-ref-format(1) -}
legal :: Bool -> String -> Bool
legal allowonelevel s = all (== False) illegal
where
illegal =
[ any ("." `isPrefixOf`) pathbits
, any (".lock" `isSuffixOf`) pathbits
, not allowonelevel && length pathbits < 2
, contains ".."
, any (\c -> contains [c]) illegalchars
, begins "/"
, ends "/"
, contains "//"
, ends "."
, contains "@{"
, null s
]
contains v = v `isInfixOf` s
ends v = v `isSuffixOf` s
begins v = v `isPrefixOf` s
pathbits = split "/" s
illegalchars = " ~^:?*[\\" ++ controlchars
controlchars = chr 0o177 : [chr 0 .. chr (0o40-1)]