git-annex/GitRepo.hs
2010-10-09 23:35:05 -04:00

67 lines
1.8 KiB
Haskell

{- git repository handling -}
module GitRepo where
import Directory
import System.Directory
import System.Path
import Data.String.Utils
import Utility
{- Given a relative or absolute filename, calculates the name to use
- relative to a git repository directory (which must be absolute).
- This is the same form displayed and used by git. -}
gitRelative :: String -> String -> String
gitRelative repo file = drop (length absrepo) absfile
where
-- normalize both repo and file, so that repo
-- will be substring of file
absrepo = case (absNormPath "/" repo) of
Just f -> f ++ "/"
Nothing -> error $ "bad repo" ++ repo
absfile = case (secureAbsNormPath absrepo file) of
Just f -> f
Nothing -> error $ file ++ " is not located inside git repository " ++ absrepo
{- Returns the path to the current repository's .git directory.
- (For a bare repository, that is the root of the repository.) -}
gitDir :: IO String
gitDir = do
repo <- repoTop
bare <- isBareRepo repo
if (bare)
then return repo
else return $ repo ++ "/.git"
{- Finds the top of the current git repository, which may be in a parent
- directory. -}
repoTop :: IO String
repoTop = do
cwd <- getCurrentDirectory
top <- seekUp cwd isRepoTop
case top of
(Just dir) -> return dir
Nothing -> error "Not in a git repository."
seekUp :: String -> (String -> IO Bool) -> IO (Maybe String)
seekUp dir want = do
ok <- want dir
if ok
then return (Just dir)
else case (parentDir dir) of
"" -> return Nothing
d -> seekUp d want
isRepoTop dir = do
r <- isGitRepo dir
b <- isBareRepo dir
return (r || b)
isGitRepo dir = gitSignature dir ".git" ".git/config"
isBareRepo dir = gitSignature dir "objects" "config"
gitSignature dir subdir file = do
s <- (doesDirectoryExist (dir ++ "/" ++ subdir))
f <- (doesFileExist (dir ++ "/" ++ file))
return (s && f)