git-annex/GitRepo.hs
2010-10-14 02:36:41 -04:00

249 lines
7 KiB
Haskell

{- git repository handling
-
- This is written to be completely independant of git-annex and should be
- suitable for other uses.
-
-}
module GitRepo (
Repo,
repoFromCwd,
repoFromPath,
repoFromUrl,
repoIsLocal,
repoIsRemote,
repoDescribe,
workTree,
dir,
relative,
configGet,
configMap,
configRead,
run,
attributes,
remotes,
remotesAdd,
repoRemoteName
) where
import Directory
import System
import System.Directory
import System.Posix.Directory
import System.Path
import System.Cmd
import System.Cmd.Utils
import System.IO
import IO (bracket_)
import Data.String.Utils
import Data.Map as Map hiding (map, split)
import Network.URI
import Maybe
import Utility
{- A git repository can be on local disk or remote. Not to be confused
- with a git repo's configured remotes, some of which may be on local
- disk. -}
data Repo =
LocalRepo {
top :: FilePath,
config :: Map String String,
remotes :: [Repo],
-- remoteName holds the name used for this repo in remotes
remoteName :: Maybe String
} | RemoteRepo {
url :: String,
top :: FilePath,
config :: Map String String,
remotes :: [Repo],
remoteName :: Maybe String
} deriving (Show, Read, Eq)
{- Local Repo constructor. -}
repoFromPath :: FilePath -> Repo
repoFromPath dir =
LocalRepo {
top = dir,
config = Map.empty,
remotes = [],
remoteName = Nothing
}
{- Remote Repo constructor. Throws exception on invalid url. -}
repoFromUrl :: String -> Repo
repoFromUrl url =
RemoteRepo {
url = url,
top = path url,
config = Map.empty,
remotes = [],
remoteName = Nothing
}
where path url = uriPath $ fromJust $ parseURI url
{- User-visible description of a git repo. -}
repoDescribe repo =
if (isJust $ remoteName repo)
then fromJust $ remoteName repo
else if (repoIsLocal repo)
then top repo
else url repo
{- Constructs and returns an updated version of a repo with
- different remotes list. -}
remotesAdd :: Repo -> [Repo] -> Repo
remotesAdd repo rs = repo { remotes = rs }
{- Returns the name of the remote that corresponds to the repo, if
- it is a remote. Otherwise, "" -}
repoRemoteName r =
if (isJust $ remoteName r)
then fromJust $ remoteName r
else ""
{- Some code needs to vary between remote and local repos, or bare and
- non-bare, these functions help with that. -}
repoIsLocal repo = case (repo) of
LocalRepo {} -> True
RemoteRepo {} -> False
repoIsRemote repo = not $ repoIsLocal repo
assertlocal repo action =
if (repoIsLocal repo)
then action
else error $ "acting on remote git repo " ++ (repoDescribe repo) ++
" not supported"
bare :: Repo -> Bool
bare repo =
if (member b (config repo))
then ("true" == fromJust (Map.lookup b (config repo)))
else error $ "it is not known if git repo " ++ (repoDescribe repo) ++
" is a bare repository; config not read"
where
b = "core.bare"
{- Path to a repository's gitattributes file. -}
attributes :: Repo -> String
attributes repo = assertlocal repo $ do
if (bare repo)
then (top repo) ++ "/info/.gitattributes"
else (top repo) ++ "/.gitattributes"
{- Path to a repository's .git directory, relative to its topdir. -}
dir :: Repo -> String
dir repo = assertlocal repo $
if (bare repo)
then ""
else ".git"
{- Path to a repository's --work-tree. -}
workTree :: Repo -> FilePath
workTree repo = top repo
{- Given a relative or absolute filename in a repository, calculates the
- name to use to refer to the file relative to a git repository's top.
- This is the same form displayed and used by git. -}
relative :: Repo -> String -> String
relative repo file = drop (length absrepo) absfile
where
-- normalize both repo and file, so that repo
-- will be substring of file
absrepo = case (absNormPath "/" (top repo)) of
Just f -> f ++ "/"
Nothing -> error $ "bad repo" ++ (top repo)
absfile = case (secureAbsNormPath absrepo file) of
Just f -> f
Nothing -> error $ file ++ " is not located inside git repository " ++ absrepo
{- Constructs a git command line operating on the specified repo. -}
gitCommandLine :: Repo -> [String] -> [String]
gitCommandLine repo params = assertlocal repo $
-- force use of specified repo via --git-dir and --work-tree
["--git-dir="++(top repo)++"/"++(dir repo), "--work-tree="++(top repo)] ++ params
{- Runs git in the specified repo. -}
run :: Repo -> [String] -> IO ()
run repo params = assertlocal repo $ do
r <- rawSystem "git" (gitCommandLine repo params)
return ()
{- Runs a git subcommand and returns its output. -}
gitPipeRead :: Repo -> [String] -> IO String
gitPipeRead repo params = assertlocal repo $ do
pOpen ReadFromPipe "git" (gitCommandLine repo params) $ \h -> do
ret <- hGetContentsStrict h
return ret
{- Runs git config and populates a repo with its config. -}
configRead :: Repo -> IO Repo
configRead repo = assertlocal repo $ do
{- Cannot use gitPipeRead because it relies on the config having
been already read. Instead, chdir to the repo. -}
cwd <- getCurrentDirectory
bracket_ (changeWorkingDirectory (top repo))
(\_ -> changeWorkingDirectory cwd) $
pOpen ReadFromPipe "git" ["config", "--list"] $ \h -> do
val <- hGetContentsStrict h
let r = repo { config = configParse val }
return r { remotes = configRemotes r }
{- Calculates a list of a repo's configured remotes, by parsing its config. -}
configRemotes :: Repo -> [Repo]
configRemotes repo = map construct remotes
where
remotes = toList $ filter $ config repo
filter = filterWithKey (\k _ -> isremote k)
isremote k = (startswith "remote." k) && (endswith ".url" k)
remotename k = (split "." k) !! 1
construct (k,v) = (gen v) { remoteName = Just $ remotename k }
gen v = if (isURI v)
then repoFromUrl v
else repoFromPath v
{- Parses git config --list output into a config map. -}
configParse :: String -> Map.Map String String
configParse s = Map.fromList $ map pair $ lines s
where
pair l = (key l, val l)
key l = (keyval l) !! 0
val l = join sep $ drop 1 $ keyval l
keyval l = split sep l :: [String]
sep = "="
{- Returns a single git config setting, or a default value if not set. -}
configGet :: Repo -> String -> String -> String
configGet repo key defaultValue =
Map.findWithDefault defaultValue key (config repo)
{- Access to raw config Map -}
configMap :: Repo -> Map String String
configMap repo = config repo
{- Finds the current git repository, which may be in a parent directory. -}
repoFromCwd :: IO Repo
repoFromCwd = do
cwd <- getCurrentDirectory
top <- seekUp cwd isRepoTop
case top of
(Just dir) -> return $ repoFromPath 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 <- isRepo dir
b <- isBareRepo dir
return (r || b)
where
isRepo 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)