git-annex/Git/Ref.hs
Joey Hess 4bf7940d6b
fileRef: make paths relative and simplified
Fix behavior of several commands, including reinject, addurl, and rmurl
when given an absolute path to an unlocked file, or a relative path that
leaves and re-enters the repository.

To avoid slowing down all the cases where the paths are already ok
with an unncessary call to getCurrentDirectory, put in an optimisation
in relPathCwdToFile. That will probably also speed up other parts of
git-annex by some small amount, but I have not benchmarked.

Note that I did not convert branchFileRef, because it seems likely that
it will be used with a file that is not provided by the user, so is already
in a sane format. This is certainly true for the way git-annex uses it,
though maybe arguable to the extent Git.Ref is a reusable library.
2021-05-07 13:25:59 -04:00

213 lines
6.2 KiB
Haskell

{- git ref stuff
-
- Copyright 2011-2020 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
{-# LANGUAGE OverloadedStrings #-}
module Git.Ref where
import Common
import Git
import Git.Command
import Git.Sha
import Git.Types
import Git.FilePath
import Data.Char (chr, ord)
import qualified Data.ByteString as S
import qualified Data.ByteString.Char8 as S8
headRef :: Ref
headRef = Ref "HEAD"
headFile :: Repo -> FilePath
headFile r = fromRawFilePath (localGitDir r) </> "HEAD"
setHeadRef :: Ref -> Repo -> IO ()
setHeadRef ref r = S.writeFile (headFile r) ("ref: " <> fromRef' ref)
{- Converts a fully qualified git ref into a user-visible string. -}
describe :: Ref -> String
describe = fromRef . base
{- Often git refs are fully qualified
- (eg refs/heads/master or refs/remotes/origin/master).
- Converts such a fully qualified ref into a base ref
- (eg: master or origin/master). -}
base :: Ref -> Ref
base = removeBase "refs/heads/" . removeBase "refs/remotes/"
{- Removes a directory such as "refs/heads/master" from a
- fully qualified ref. Any ref not starting with it is left as-is. -}
removeBase :: String -> Ref -> Ref
removeBase dir r
| prefix `isPrefixOf` rs = Ref $ encodeBS $ drop (length prefix) rs
| otherwise = r
where
rs = fromRef r
prefix = case end dir of
['/'] -> dir
_ -> dir ++ "/"
{- Given a directory such as "refs/remotes/origin", and a ref such as
- refs/heads/master, yields a version of that ref under the directory,
- such as refs/remotes/origin/master. -}
underBase :: String -> Ref -> Ref
underBase dir r = Ref $ encodeBS dir <> "/" <> fromRef' (base r)
{- Convert a branch such as "master" into a fully qualified ref. -}
branchRef :: Branch -> Ref
branchRef = underBase "refs/heads"
{- A Ref that can be used to refer to a file in the repository, as staged
- in the index.
-}
fileRef :: RawFilePath -> IO Ref
fileRef f = do
-- The filename could be absolute, or contain eg "../repo/file",
-- neither of which work in a ref, so convert it to a minimal
-- relative path.
f' <- relPathCwdToFile f
-- Prefixing the file with ./ makes this work even when in a
-- subdirectory of a repo. Eg, ./foo in directory bar refers
-- to bar/foo, not to foo in the top of the repository.
return $ Ref $ ":./" <> toInternalGitPath f'
{- A Ref that can be used to refer to a file in a particular branch. -}
branchFileRef :: Branch -> RawFilePath -> Ref
branchFileRef branch f = Ref $ fromRef' branch <> ":" <> toInternalGitPath f
{- Converts a Ref to refer to the content of the Ref on a given date. -}
dateRef :: Ref -> RefDate -> Ref
dateRef r (RefDate d) = Ref $ fromRef' r <> "@" <> encodeBS' d
{- A Ref that can be used to refer to a file in the repository as it
- appears in a given Ref. -}
fileFromRef :: Ref -> RawFilePath -> IO Ref
fileFromRef r f = do
(Ref fr) <- fileRef f
return (Ref (fromRef' r <> fr))
{- Checks if a ref exists. Note that it must be fully qualified,
- eg refs/heads/master rather than master. -}
exists :: Ref -> Repo -> IO Bool
exists ref = runBool
[ Param "show-ref"
, Param "--verify"
, Param "-q"
, Param $ fromRef ref
]
{- The file used to record a ref. (Git also stores some refs in a
- packed-refs file.) -}
file :: Ref -> Repo -> FilePath
file ref repo = fromRawFilePath (localGitDir repo) </> fromRef ref
{- Checks if HEAD exists. It generally will, except for in a repository
- that was just created. -}
headExists :: Repo -> IO Bool
headExists repo = do
ls <- S.split nl <$> pipeReadStrict [Param "show-ref", Param "--head"] repo
return $ any (" HEAD" `S.isSuffixOf`) ls
where
nl = fromIntegral (ord '\n')
{- Get the sha of a fully qualified git ref, if it exists. -}
sha :: Branch -> Repo -> IO (Maybe Sha)
sha branch repo = process <$> showref repo
where
showref = pipeReadStrict
[ Param "show-ref"
, Param "--hash" -- get the hash
, Param $ fromRef branch
]
process s
| S.null s = Nothing
| otherwise = Just $ Ref $ firstLine' s
headSha :: Repo -> IO (Maybe Sha)
headSha = sha headRef
{- List of (shas, branches) matching a given ref or refs. -}
matching :: [Ref] -> Repo -> IO [(Sha, Branch)]
matching = matching' []
{- Includes HEAD in the output, if asked for it. -}
matchingWithHEAD :: [Ref] -> Repo -> IO [(Sha, Branch)]
matchingWithHEAD = matching' [Param "--head"]
matching' :: [CommandParam] -> [Ref] -> Repo -> IO [(Sha, Branch)]
matching' ps rs repo = map gen . S8.lines <$>
pipeReadStrict (Param "show-ref" : ps ++ rps) repo
where
gen l = let (r, b) = separate' (== fromIntegral (ord ' ')) l
in (Ref r, Ref b)
rps = map (Param . fromRef) rs
{- List of (shas, branches) matching a given ref.
- Duplicate shas are filtered out. -}
matchingUniq :: [Ref] -> Repo -> IO [(Sha, Branch)]
matchingUniq refs repo = nubBy uniqref <$> matching refs repo
where
uniqref (a, _) (b, _) = a == b
{- List of all refs. -}
list :: Repo -> IO [(Sha, Ref)]
list = matching' [] []
{- Deletes a ref. This can delete refs that are not branches,
- which git branch --delete refuses to delete. -}
delete :: Sha -> Ref -> Repo -> IO ()
delete oldvalue ref = run
[ Param "update-ref"
, Param "-d"
, Param $ fromRef ref
, Param $ fromRef oldvalue
]
{- Gets the sha of the tree a ref uses.
-
- The ref may be something like a branch name, and it could contain
- ":subdir" if a subtree is wanted. -}
tree :: Ref -> Repo -> IO (Maybe Sha)
tree (Ref ref) = extractSha <$$> pipeReadStrict
[ Param "rev-parse"
, Param "--verify"
, Param "--quiet"
, Param (decodeBS' ref')
]
where
ref' = if ":" `S.isInfixOf` ref
then ref
-- de-reference commit objects to the tree
else ref <> ":"
{- Checks if a String is a legal git ref name.
-
- The rules for this are complex; see git-check-ref-format(1) -}
legal :: Bool -> String -> Bool
legal allowonelevel s = all (== False) illegal
where
illegal =
[ any ("." `isPrefixOf`) pathbits
, any (".lock" `isSuffixOf`) pathbits
, not allowonelevel && length pathbits < 2
, contains ".."
, any (\c -> contains [c]) illegalchars
, begins "/"
, ends "/"
, contains "//"
, ends "."
, contains "@{"
, null s
]
contains v = v `isInfixOf` s
ends v = v `isSuffixOf` s
begins v = v `isPrefixOf` s
pathbits = splitc '/' s
illegalchars = " ~^:?*[\\" ++ controlchars
controlchars = chr 0o177 : [chr 0 .. chr (0o40-1)]