git-annex/Git/Construct.hs
Joey Hess e7134ca1eb
avoid partial functions in Git.Url
After the last commit, it was able to throw errors just due to an
unparseable url. This avoids needing to worry about that, as long
as the call site has already checked that it has a parseable url.
2021-01-18 15:07:23 -04:00

277 lines
8 KiB
Haskell

{- Construction of Git Repo objects
-
- Copyright 2010-2021 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE CPP #-}
module Git.Construct (
fromCwd,
fromAbsPath,
fromPath,
fromUrl,
fromUnknown,
localToUrl,
remoteNamed,
remoteNamedFromKey,
fromRemotes,
fromRemoteLocation,
repoAbsPath,
checkForRepo,
newFrom,
adjustGitDirFile,
) where
#ifndef mingw32_HOST_OS
import System.Posix.User
#endif
import qualified Data.Map as M
import Network.URI
import Common
import Git.Types
import Git
import Git.Remote
import Git.FilePath
import qualified Git.Url as Url
import Utility.UserInfo
import qualified Data.ByteString as B
import qualified System.FilePath.ByteString as P
{- Finds the git repository used for the cwd, which may be in a parent
- directory. -}
fromCwd :: IO (Maybe Repo)
fromCwd = getCurrentDirectory >>= seekUp
where
seekUp dir = do
r <- checkForRepo dir
case r of
Nothing -> case upFrom (toRawFilePath dir) of
Nothing -> return Nothing
Just d -> seekUp (fromRawFilePath d)
Just loc -> pure $ Just $ newFrom loc
{- Local Repo constructor, accepts a relative or absolute path. -}
fromPath :: RawFilePath -> IO Repo
fromPath dir = fromAbsPath =<< absPath dir
{- Local Repo constructor, requires an absolute path to the repo be
- specified. -}
fromAbsPath :: RawFilePath -> IO Repo
fromAbsPath dir
| absoluteGitPath dir = hunt
| otherwise =
error $ "internal error, " ++ show dir ++ " is not absolute"
where
ret = pure . newFrom . LocalUnknown
canondir = P.dropTrailingPathSeparator dir
{- When dir == "foo/.git", git looks for "foo/.git/.git",
- and failing that, uses "foo" as the repository. -}
hunt
| (P.pathSeparator `B.cons` ".git") `B.isSuffixOf` canondir =
ifM (doesDirectoryExist $ fromRawFilePath dir </> ".git")
( ret dir
, ret (P.takeDirectory canondir)
)
| otherwise = ifM (doesDirectoryExist (fromRawFilePath dir))
( checkGitDirFile dir >>= maybe (ret dir) (pure . newFrom)
-- git falls back to dir.git when dir doesn't
-- exist, as long as dir didn't end with a
-- path separator
, if dir == canondir
then ret (dir <> ".git")
else ret dir
)
{- Construct a Repo for a remote's url.
-
- Git is somewhat forgiving about urls to repositories, allowing
- eg spaces that are not normally allowed unescaped in urls. Such
- characters get escaped.
-
- This will always succeed, even if the url cannot be parsed
- or is invalid, because git can also function despite remotes having
- such urls, only failing if such a remote is used.
-}
fromUrl :: String -> IO Repo
fromUrl url
| not (isURI url) = fromUrl' $ escapeURIString isUnescapedInURI url
| otherwise = fromUrl' url
fromUrl' :: String -> IO Repo
fromUrl' url
| "file://" `isPrefixOf` url = case parseURI url of
Just u -> fromAbsPath $ toRawFilePath $ unEscapeString $ uriPath u
Nothing -> pure $ newFrom $ UnparseableUrl url
| otherwise = case parseURI url of
Just u -> pure $ newFrom $ Url u
Nothing -> pure $ newFrom $ UnparseableUrl url
{- Creates a repo that has an unknown location. -}
fromUnknown :: 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 = case (Url.authority reference, Url.scheme reference) of
(Just auth, Just s) ->
let absurl = concat
[ s
, "//"
, auth
, fromRawFilePath (repoPath r)
]
in r { location = Url $ fromJust $ parseURI absurl }
_ -> 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 isRemoteKey
construct (k,v) = remoteNamedFromKey k $
fromRemoteLocation (fromConfigValue 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 :: ConfigKey -> IO Repo -> IO Repo
remoteNamedFromKey = remoteNamed . remoteKeyToRemoteName
{- 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 $ parseRemoteLocation s repo
where
gen (RemotePath p) = fromRemotePath p repo
gen (RemoteUrl u) = fromUrl u
{- 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
fromPath $ repoPath repo P.</> toRawFilePath 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 :: RawFilePath -> IO RawFilePath
repoAbsPath d = do
d' <- expandTilde (fromRawFilePath d)
h <- myHomeDir
return $ toRawFilePath $ h </> d'
expandTilde :: FilePath -> IO FilePath
#ifdef mingw32_HOST_OS
expandTilde = return
#else
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 "~" = myHomeDir
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
#endif
{- Checks if a git repository exists in a directory. Does not find
- git repositories in parent directories. -}
checkForRepo :: FilePath -> IO (Maybe RepoLocation)
checkForRepo dir =
check isRepo $
check (checkGitDirFile (toRawFilePath dir)) $
check isBareRepo $
return Nothing
where
check test cont = maybe cont (return . Just) =<< test
checkdir c = ifM c
( return $ Just $ LocalUnknown $ toRawFilePath dir
, return Nothing
)
isRepo = checkdir $
gitSignature (".git" </> "config")
<||>
-- A git-worktree lacks .git/config, but has .git/commondir.
-- (Normally the .git is a file, not a symlink, but it can
-- be converted to a symlink and git will still work;
-- this handles that case.)
gitSignature (".git" </> "gitdir")
isBareRepo = checkdir $ gitSignature "config"
<&&> doesDirectoryExist (dir </> "objects")
gitSignature file = doesFileExist $ dir </> file
-- Check for a .git file.
checkGitDirFile :: RawFilePath -> IO (Maybe RepoLocation)
checkGitDirFile dir = adjustGitDirFile' $ Local
{ gitdir = dir P.</> ".git"
, worktree = Just dir
}
-- git-submodule, git-worktree, and --separate-git-dir
-- make .git be a file pointing to the real git directory.
-- Detect that, and return a RepoLocation with gitdir pointing
-- to the real git directory.
adjustGitDirFile :: RepoLocation -> IO RepoLocation
adjustGitDirFile loc = fromMaybe loc <$> adjustGitDirFile' loc
adjustGitDirFile' :: RepoLocation -> IO (Maybe RepoLocation)
adjustGitDirFile' loc = do
let gd = gitdir loc
c <- firstLine <$> catchDefaultIO "" (readFile (fromRawFilePath gd))
if gitdirprefix `isPrefixOf` c
then do
top <- fromRawFilePath . P.takeDirectory <$> absPath gd
return $ Just $ loc
{ gitdir = absPathFrom
(toRawFilePath top)
(toRawFilePath
(drop (length gitdirprefix) c))
}
else return Nothing
where
gitdirprefix = "gitdir: "
newFrom :: RepoLocation -> Repo
newFrom l = Repo
{ location = l
, config = M.empty
, fullconfig = M.empty
, remoteName = Nothing
, gitEnv = Nothing
, gitEnvOverridesGitDir = False
, gitGlobalOpts = []
}