git-annex/Git/Construct.hs
2012-12-13 00:45:27 -04:00

253 lines
7.2 KiB
Haskell

{- Construction of Git Repo objects
-
- Copyright 2010-2012 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Git.Construct (
fromCwd,
fromAbsPath,
fromPath,
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
import Utility.UserInfo
{- Finds the git repository used for the cwd, which may be in a parent
- directory. -}
fromCwd :: IO Repo
fromCwd = getCurrentDirectory >>= seekUp checkForRepo
where
norepo = error "Not in a git repository."
seekUp check dir = do
r <- check dir
case r of
Nothing -> case parentDir dir of
"" -> norepo
d -> seekUp check d
Just loc -> newFrom loc
{- Local Repo constructor, accepts a relative or absolute path. -}
fromPath :: FilePath -> IO Repo
fromPath dir = fromAbsPath =<< absPath dir
{- Local Repo constructor, requires an absolute path to the repo be
- specified. -}
fromAbsPath :: FilePath -> IO Repo
fromAbsPath dir
| "/" `isPrefixOf` dir =
ifM (doesDirectoryExist dir') ( ret dir' , hunt )
| otherwise =
error $ "internal error, " ++ dir ++ " is not absolute"
where
ret = newFrom . LocalUnknown
{- Git always looks for "dir.git" in preference to
- to "dir", even if dir ends in a "/". -}
canondir = dropTrailingPathSeparator dir
dir' = canondir ++ ".git"
{- When dir == "foo/.git", git looks for "foo/.git/.git",
- and failing that, uses "foo" as the repository. -}
hunt
| "/.git" `isSuffixOf` canondir =
ifM (doesDirectoryExist $ dir </> ".git")
( ret dir
, ret $ takeDirectory canondir
)
| otherwise = ret dir
{- Remote Repo constructor. Throws exception on invalid url.
-
- Git is somewhat forgiving about urls to repositories, allowing
- eg spaces that are not normally allowed unescaped in urls.
-}
fromUrl :: String -> IO Repo
fromUrl url
| not (isURI url) = fromUrlStrict $ escapeURIString isUnescapedInURI url
| otherwise = fromUrlStrict url
fromUrlStrict :: String -> IO Repo
fromUrlStrict url
| startswith "file://" url = fromAbsPath $ uriPath u
| otherwise = 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 = 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 = concat
[ Url.scheme reference
, "//"
, Url.authority reference
, repoPath 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
gen v
| scpstyle v = fromUrl $ scptourl v
| urlstyle 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
filterconfig f = filter f $
concatMap splitconfigs $ M.toList $ fullconfig repo
splitconfigs (k, vs) = map (\v -> (k, v)) vs
(prefix, suffix) = ("url." , ".insteadof")
urlstyle v = isURI v || ":" `isInfixOf` v && "//" `isInfixOf` v
-- git remotes can be written scp style -- [user@]host:dir
-- but foo::bar is a git-remote-helper location instead
scpstyle v = ":" `isInfixOf` v
&& not ("//" `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 $ repoPath 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
checkForRepo :: FilePath -> IO (Maybe RepoLocation)
checkForRepo dir =
check isRepo $
check gitDirFile $
check isBareRepo $
return Nothing
where
check test cont = maybe cont (return . Just) =<< test
checkdir c = ifM c
( return $ Just $ LocalUnknown dir
, return Nothing
)
isRepo = checkdir $ gitSignature $ ".git" </> "config"
isBareRepo = checkdir $ gitSignature "config"
<&&> doesDirectoryExist (dir </> "objects")
gitDirFile = do
c <- firstLine <$>
catchDefaultIO "" (readFile $ dir </> ".git")
return $ if gitdirprefix `isPrefixOf` c
then Just $ Local
{ gitdir = absPathFrom dir $
drop (length gitdirprefix) c
, worktree = Just dir
}
else Nothing
where
gitdirprefix = "gitdir: "
gitSignature file = doesFileExist $ dir </> file
newFrom :: RepoLocation -> IO Repo
newFrom l = return Repo
{ location = l
, config = M.empty
, fullconfig = M.empty
, remotes = []
, remoteName = Nothing
, gitEnv = Nothing
}