git-annex/Git/Construct.hs
2011-12-14 15:43:13 -04:00

215 lines
6.2 KiB
Haskell

{- Construction of Git Repo objects
-
- Copyright 2010,2011 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Git.Construct (
fromCwd,
fromAbsPath,
fromUrl,
fromUnknown,
localToUrl,
remoteNamed,
remoteNamedFromKey,
fromRemotes,
fromRemoteLocation,
repoAbsPath,
) where
import System.Posix.User
import qualified Data.Map as M hiding (map, split)
import Network.URI
import Common
import Git.Types
import Git
import qualified Git.Url as Url
{- Finds the current git repository, which may be in a parent directory. -}
fromCwd :: IO Repo
fromCwd = getCurrentDirectory >>= seekUp isRepoTop >>= maybe norepo makerepo
where
makerepo = return . newFrom . Dir
norepo = error "Not in a git repository."
{- Local Repo constructor, requires an absolute path to the repo be
- specified. -}
fromAbsPath :: FilePath -> IO Repo
fromAbsPath dir
| "/" `isPrefixOf` dir = do
-- Git always looks for "dir.git" in preference to
-- to "dir", even if dir ends in a "/".
let canondir = dropTrailingPathSeparator dir
let dir' = canondir ++ ".git"
e <- doesDirectoryExist dir'
if e
then ret dir'
else if "/.git" `isSuffixOf` canondir
then do
-- When dir == "foo/.git", git looks
-- for "foo/.git/.git", and failing
-- that, uses "foo" as the repository.
e' <- doesDirectoryExist $ dir </> ".git"
if e'
then ret dir
else ret $ takeDirectory canondir
else ret dir
| otherwise = error $ "internal error, " ++ dir ++ " is not absolute"
where
ret = return . newFrom . Dir
{- Remote Repo constructor. Throws exception on invalid url. -}
fromUrl :: String -> IO Repo
fromUrl url
| startswith "file://" url = fromAbsPath $ uriPath u
| otherwise = return $ newFrom $ Url u
where
u = fromMaybe bad $ parseURI url
bad = error $ "bad url " ++ url
{- Creates a repo that has an unknown location. -}
fromUnknown :: IO Repo
fromUnknown = return $ newFrom Unknown
{- Converts a local Repo into a remote repo, using the reference repo
- which is assumed to be on the same host. -}
localToUrl :: Repo -> Repo -> Repo
localToUrl reference r
| not $ repoIsUrl reference = error "internal error; reference repo not url"
| repoIsUrl r = r
| otherwise = r { location = Url $ fromJust $ parseURI absurl }
where
absurl =
Url.scheme reference ++ "//" ++
Url.authority reference ++
workTree r
{- Calculates a list of a repo's configured remotes, by parsing its config. -}
fromRemotes :: Repo -> IO [Repo]
fromRemotes repo = mapM construct remotepairs
where
filterconfig f = filter f $ M.toList $ config repo
filterkeys f = filterconfig (\(k,_) -> f k)
remotepairs = filterkeys isremote
isremote k = startswith "remote." k && endswith ".url" k
construct (k,v) = remoteNamedFromKey k $ fromRemoteLocation v repo
{- Sets the name of a remote when constructing the Repo to represent it. -}
remoteNamed :: String -> IO Repo -> IO Repo
remoteNamed n constructor = do
r <- constructor
return $ r { remoteName = Just n }
{- Sets the name of a remote based on the git config key, such as
"remote.foo.url". -}
remoteNamedFromKey :: String -> IO Repo -> IO Repo
remoteNamedFromKey k = remoteNamed basename
where
basename = join "." $ reverse $ drop 1 $
reverse $ drop 1 $ split "." k
{- Constructs a new Repo for one of a Repo's remotes using a given
- location (ie, an url). -}
fromRemoteLocation :: String -> Repo -> IO Repo
fromRemoteLocation s repo = gen $ calcloc s
where
filterconfig f = filter f $ M.toList $ config repo
gen v
| scpstyle v = fromUrl $ scptourl v
| isURI v = fromUrl v
| otherwise = fromRemotePath v repo
-- insteadof config can rewrite remote location
calcloc l
| null insteadofs = l
| otherwise = replacement ++ drop (length bestvalue) l
where
replacement = drop (length prefix) $
take (length bestkey - length suffix) bestkey
(bestkey, bestvalue) = maximumBy longestvalue insteadofs
longestvalue (_, a) (_, b) = compare b a
insteadofs = filterconfig $ \(k, v) ->
startswith prefix k &&
endswith suffix k &&
startswith v l
(prefix, suffix) = ("url." , ".insteadof")
-- git remotes can be written scp style -- [user@]host:dir
scpstyle v = ":" `isInfixOf` v && not ("//" `isInfixOf` v)
scptourl v = "ssh://" ++ host ++ slash dir
where
(host, dir) = separate (== ':') v
slash d | d == "" = "/~/" ++ d
| "/" `isPrefixOf` d = d
| "~" `isPrefixOf` d = '/':d
| otherwise = "/~/" ++ d
{- Constructs a Repo from the path specified in the git remotes of
- another Repo. -}
fromRemotePath :: FilePath -> Repo -> IO Repo
fromRemotePath dir repo = do
dir' <- expandTilde dir
fromAbsPath $ workTree repo </> dir'
{- Git remotes can have a directory that is specified relative
- to the user's home directory, or that contains tilde expansions.
- This converts such a directory to an absolute path.
- Note that it has to run on the system where the remote is.
-}
repoAbsPath :: FilePath -> IO FilePath
repoAbsPath d = do
d' <- expandTilde d
h <- myHomeDir
return $ h </> d'
expandTilde :: FilePath -> IO FilePath
expandTilde = expandt True
where
expandt _ [] = return ""
expandt _ ('/':cs) = do
v <- expandt True cs
return ('/':v)
expandt True ('~':'/':cs) = do
h <- myHomeDir
return $ h </> cs
expandt True ('~':cs) = do
let (name, rest) = findname "" cs
u <- getUserEntryForName name
return $ homeDirectory u </> rest
expandt _ (c:cs) = do
v <- expandt False cs
return (c:v)
findname n [] = (n, "")
findname n (c:cs)
| c == '/' = (n, cs)
| otherwise = findname (n++[c]) cs
seekUp :: (FilePath -> IO Bool) -> FilePath -> IO (Maybe FilePath)
seekUp want dir = do
ok <- want dir
if ok
then return $ Just dir
else case parentDir dir of
"" -> return Nothing
d -> seekUp want d
isRepoTop :: FilePath -> IO Bool
isRepoTop dir = do
r <- isRepo
b <- isBareRepo
return (r || b)
where
isRepo = gitSignature ".git" ".git/config"
isBareRepo = gitSignature "objects" "config"
gitSignature subdir file = liftM2 (&&)
(doesDirectoryExist (dir ++ "/" ++ subdir))
(doesFileExist (dir ++ "/" ++ file))
newFrom :: RepoLocation -> Repo
newFrom l =
Repo {
location = l,
config = M.empty,
remotes = [],
remoteName = Nothing
}