git-annex/GitRepo.hs
2010-11-06 17:07:11 -04:00

438 lines
13 KiB
Haskell

{- git repository handling
-
- This is written to be completely independant of git-annex and should be
- suitable for other uses.
-
- Copyright 2010 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module GitRepo (
Repo,
repoFromCwd,
repoFromPath,
repoFromUrl,
repoIsUrl,
repoIsSsh,
repoDescribe,
workTree,
gitDir,
relative,
urlPath,
urlHost,
configGet,
configMap,
configRead,
configTrue,
gitCommandLine,
run,
pipeRead,
hPipeRead,
attributes,
remotes,
remotesAdd,
repoRemoteName,
inRepo,
notInRepo,
stagedFiles,
checkAttr,
decodeGitFile,
encodeGitFile,
prop_idempotent_deencode
) where
import Control.Monad (unless)
import System.Directory
import System.Posix.Directory
import System.Path
import System.Cmd.Utils
import IO (bracket_)
import Data.String.Utils
import System.IO
import qualified Data.Map as Map hiding (map, split)
import Network.URI
import Data.Maybe
import Data.Char
import Data.Word (Word8)
import Codec.Binary.UTF8.String (encode)
import Text.Printf
import Utility
{- There are two types of repositories; those on local disk and those
- accessed via an URL. -}
data RepoLocation = Dir FilePath | Url URI
deriving (Show, Eq)
data Repo = Repo {
location :: RepoLocation,
config :: Map.Map String String,
remotes :: [Repo],
-- remoteName holds the name used for this repo in remotes
remoteName :: Maybe String
} deriving (Show, Eq)
newFrom :: RepoLocation -> Repo
newFrom l =
Repo {
location = l,
config = Map.empty,
remotes = [],
remoteName = Nothing
}
{- Local Repo constructor. -}
repoFromPath :: FilePath -> Repo
repoFromPath dir = newFrom $ Dir dir
{- Remote Repo constructor. Throws exception on invalid url. -}
repoFromUrl :: String -> Repo
repoFromUrl url
| startswith "file://" url = repoFromPath $ uriPath u
| otherwise = newFrom $ Url u
where u = fromJust $ parseURI url
{- User-visible description of a git repo. -}
repoDescribe :: Repo -> String
repoDescribe Repo { remoteName = Just name } = name
repoDescribe Repo { location = Url url } = show url
repoDescribe Repo { location = Dir dir } = dir
{- 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 :: Repo -> String
repoRemoteName Repo { remoteName = Just name } = name
repoRemoteName _ = ""
{- Some code needs to vary between URL and normal repos,
- or bare and non-bare, these functions help with that. -}
repoIsUrl :: Repo -> Bool
repoIsUrl Repo { location = Url _ } = True
repoIsUrl _ = False
repoIsSsh :: Repo -> Bool
repoIsSsh Repo { location = Url url }
| uriScheme url == "ssh:" = True
| otherwise = False
repoIsSsh _ = False
assertLocal :: Repo -> a -> a
assertLocal repo action =
if (not $ repoIsUrl repo)
then action
else error $ "acting on URL git repo " ++ repoDescribe repo ++
" not supported"
assertUrl :: Repo -> a -> a
assertUrl repo action =
if (repoIsUrl repo)
then action
else error $ "acting on local git repo " ++ repoDescribe repo ++
" not supported"
assertSsh :: Repo -> a -> a
assertSsh repo action =
if (repoIsSsh repo)
then action
else error $ "unsupported url in repo " ++ repoDescribe repo
bare :: Repo -> Bool
bare repo = case Map.lookup "core.bare" $ config repo of
Just v -> configTrue v
Nothing -> error $ "it is not known if git repo " ++
repoDescribe repo ++
" is a bare repository; config not read"
{- Path to a repository's gitattributes file. -}
attributes :: Repo -> String
attributes repo
| bare repo = workTree repo ++ "/info/.gitattributes"
| otherwise = workTree repo ++ "/.gitattributes"
{- Path to a repository's .git directory, relative to its workTree. -}
gitDir :: Repo -> String
gitDir repo
| bare repo = ""
| otherwise = ".git"
{- Path to a repository's --work-tree, that is, its top.
-
- Note that for URL repositories, this is the path on the remote host. -}
workTree :: Repo -> FilePath
workTree r@(Repo { location = Url _ }) = urlPath r
workTree (Repo { location = Dir d }) = d
{- 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@(Repo { location = Dir d }) file = drop (length absrepo) absfile
where
-- normalize both repo and file, so that repo
-- will be substring of file
absrepo = case (absNormPath "/" d) of
Just f -> f ++ "/"
Nothing -> error $ "bad repo" ++ repoDescribe repo
absfile = case (secureAbsNormPath absrepo file) of
Just f -> f
Nothing -> error $ file ++ " is not located inside git repository " ++ absrepo
relative repo _ = assertLocal repo $ error "internal"
{- Hostname of an URL repo. (May include a username and/or port too.) -}
urlHost :: Repo -> String
urlHost Repo { location = Url u } = uriUserInfo a ++ uriRegName a ++ uriPort a
where a = fromJust $ uriAuthority u
urlHost repo = assertUrl repo $ error "internal"
{- Path of an URL repo. -}
urlPath :: Repo -> String
urlPath Repo { location = Url u } = uriPath u
urlPath repo = assertUrl repo $ error "internal"
{- Constructs a git command line operating on the specified repo. -}
gitCommandLine :: Repo -> [String] -> [String]
gitCommandLine repo@(Repo { location = Dir d} ) params =
-- force use of specified repo via --git-dir and --work-tree
["--git-dir="++d++"/"++(gitDir repo), "--work-tree="++d] ++ params
gitCommandLine repo _ = assertLocal repo $ error "internal"
{- Runs git in the specified repo, throwing an error if it fails. -}
run :: Repo -> [String] -> IO ()
run repo params = assertLocal repo $ do
ok <- boolSystem "git" (gitCommandLine repo params)
unless (ok) $ error $ "git " ++ show params ++ " failed"
{- Runs a git subcommand and returns its output. -}
pipeRead :: Repo -> [String] -> IO String
pipeRead repo params = assertLocal repo $ do
pOpen ReadFromPipe "git" (gitCommandLine repo params) $ \h -> do
hGetContentsStrict h
{- Like pipeRead, but does not read output strictly; recommended
- for git commands that produce a lot of output that will be processed
- lazily.
-
- ONLY AFTER the string has been read completely, You must call either
- getProcessStatus or forceSuccess on the PipeHandle. Zombies will result
- otherwise.-}
hPipeRead :: Repo -> [String] -> IO (PipeHandle, String)
hPipeRead repo params = assertLocal repo $ do
pipeFrom "git" (gitCommandLine repo params)
{- Passed a location, recursively scans for all files that
- are checked into git at that location. -}
inRepo :: Repo -> FilePath -> IO [FilePath]
inRepo repo l = pipeNullSplit repo
["ls-files", "--cached", "--exclude-standard", "-z", l]
{- Passed a location, recursively scans for all files that are not checked
- into git, and not gitignored. -}
notInRepo :: Repo -> FilePath -> IO [FilePath]
notInRepo repo l = pipeNullSplit repo
["ls-files", "--others", "--exclude-standard", "-z", l]
{- Passed a location, returns a list of the files, staged for
- commit, that are being added, moved, or changed (but not deleted). -}
stagedFiles :: Repo -> FilePath -> IO [FilePath]
stagedFiles repo l = pipeNullSplit repo
["diff", "--cached", "--name-only", "--diff-filter=ACMRT", "-z",
"HEAD", l]
{- Reads null terminated output of a git command (as enabled by the -z
- parameter), and splits it into a list of files. -}
pipeNullSplit :: Repo -> [String] -> IO [FilePath]
pipeNullSplit repo params = do
-- XXX handle is left open, this is ok for git-annex, but may need
-- to be cleaned up for other uses.
(_, fs0) <- hPipeRead repo params
return $ split0 fs0
where
split0 s = filter (not . null) $ split "\0" s
{- Runs git config and populates a repo with its config.
-
- For a ssh repository, a list of ssh options may optionally be specified. -}
configRead :: Repo -> Maybe [String] -> IO Repo
configRead repo@(Repo { location = Dir d }) _ = do
{- Cannot use pipeRead because it relies on the config having
been already read. Instead, chdir to the repo. -}
cwd <- getCurrentDirectory
bracket_ (changeWorkingDirectory d)
(\_ -> changeWorkingDirectory cwd) $
pOpen ReadFromPipe "git" ["config", "--list"] $
hConfigRead repo
configRead repo sshopts = assertSsh repo $ do
pOpen ReadFromPipe "ssh" params $ hConfigRead repo
where
params = case sshopts of
Nothing -> [urlHost repo, command]
Just l -> l ++ [urlHost repo, command]
command = "cd " ++ (shellEscape $ urlPath repo) ++
" && git config --list"
hConfigRead :: Repo -> Handle -> IO Repo
hConfigRead repo h = do
val <- hGetContentsStrict h
let r = repo { config = configParse val }
return r { remotes = configRemotes r }
{- Checks if a string fron git config is a true value. -}
configTrue :: String -> Bool
configTrue s = map toLower s == "true"
{- Calculates a list of a repo's configured remotes, by parsing its config. -}
configRemotes :: Repo -> [Repo]
configRemotes repo = map construct remotepairs
where
remotepairs = Map.toList $ filterremotes $ config repo
filterremotes = Map.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 | isURI v = repoFromUrl v
| otherwise = 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.Map String String
configMap repo = config repo
{- Looks up a gitattributes value for each file in a list. -}
checkAttr :: Repo -> String -> [FilePath] -> IO [(FilePath, String)]
checkAttr repo attr files = do
(_, s) <- pipeBoth "git" params files0
return $ map topair $ lines s
-- XXX handle is left open, this is ok for git-annex, but may need
-- to be cleaned up for other uses.
where
params = gitCommandLine repo ["check-attr", attr, "-z", "--stdin"]
files0 = join "\0" files
topair l = (file, value)
where
file = decodeGitFile $ join sep $ take end bits
value = bits !! end
end = length bits - 1
bits = split sep l
sep = ": " ++ attr ++ ": "
{- Some git commands output encoded filenames. Decode that (annoyingly
- complex) encoding. -}
decodeGitFile :: String -> FilePath
decodeGitFile [] = []
decodeGitFile f@(c:s)
-- encoded strings will be inside double quotes
| c == '"' = unescape ("", middle)
| otherwise = f
where
e = '\\'
middle = take (length s - 1) s
unescape (b, []) = b
-- look for escapes starting with '\'
unescape (b, v) = b ++ beginning ++ unescape (decode rest)
where
pair = span (/= e) v
beginning = fst pair
rest = snd pair
isescape x = x == e
-- \NNN is an octal encoded character
decode (x:n1:n2:n3:rest)
| isescape x && alloctal = (fromoctal, rest)
where
alloctal = isOctDigit n1 &&
isOctDigit n2 &&
isOctDigit n3
fromoctal = [chr $ readoctal (n1:n2:n3:[])]
readoctal o = read $ "0o" ++ o :: Int
-- \C is used for a few special characters
decode (x:nc:rest)
| isescape x = ([echar nc], rest)
where
echar 'a' = '\a'
echar 'b' = '\b'
echar 'f' = '\f'
echar 'n' = '\n'
echar 'r' = '\r'
echar 't' = '\t'
echar 'v' = '\v'
echar a = a
decode n = ("", n)
{- Should not need to use this, except for testing decodeGitFile. -}
encodeGitFile :: FilePath -> String
encodeGitFile s = (foldl (++) "\"" (map echar s)) ++ "\""
where
e c = "\\" ++ [c]
echar '\a' = e 'a'
echar '\b' = e 'b'
echar '\f' = e 'f'
echar '\n' = e 'n'
echar '\r' = e 'r'
echar '\t' = e 't'
echar '\v' = e 'v'
echar '\\' = e '\\'
echar '"' = e '"'
echar x
| ord x < 0x20 = e_num x -- low ascii
| ord x >= 256 = e_utf x
| ord x > 0x7E = e_num x -- high ascii
| otherwise = [x] -- printable ascii
where
showoctal i = "\\" ++ (printf "%03o" i)
e_num c = showoctal $ ord c
-- unicode character is decomposed to
-- Word8s and each is shown in octal
e_utf c = foldl (++) "" $ map showoctal $
(encode [c] :: [Word8])
{- for quickcheck -}
prop_idempotent_deencode :: String -> Bool
prop_idempotent_deencode s = s == (decodeGitFile $ encodeGitFile s)
{- 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 :: 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 = do
s <- (doesDirectoryExist (dir ++ "/" ++ subdir))
f <- (doesFileExist (dir ++ "/" ++ file))
return (s && f)