git-annex/Git/Index.hs
2014-11-10 15:38:31 -04:00

55 lines
1.4 KiB
Haskell

{- git index file stuff
-
- Copyright 2011 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Git.Index where
import Common
import Git
import Utility.Env
indexEnv :: String
indexEnv = "GIT_INDEX_FILE"
{- Forces git to use the specified index file.
-
- Returns an action that will reset back to the default
- index file.
-
- Warning: Not thread safe.
-}
override :: FilePath -> IO (IO ())
override index = do
res <- getEnv var
setEnv var index True
return $ reset res
where
var = "GIT_INDEX_FILE"
reset (Just v) = setEnv indexEnv v True
reset _ = unsetEnv var
indexFile :: Repo -> FilePath
indexFile r = localGitDir r </> "index"
{- Git locks the index by creating this file. -}
indexFileLock :: Repo -> FilePath
indexFileLock r = indexFile r ++ ".lock"
{- When the pre-commit hook is run, and git commit has been run with
- a file or files specified to commit, rather than committing the staged
- index, git provides the pre-commit hook with a "false index file".
-
- Changes made to this index will influence the commit, but won't
- affect the real index file.
-
- This detects when we're in this situation, using a heuristic, which
- might be broken by changes to git. Any use of this should have a test
- case to make sure it works.
-}
haveFalseIndex :: IO Bool
haveFalseIndex = maybe (False) check <$> getEnv indexEnv
where
check f = "next-index" `isPrefixOf` takeFileName f