git-annex/Git/Index.hs
Joey Hess 40ecf58d4b
update licenses from GPL to AGPL
This does not change the overall license of the git-annex program, which
was already AGPL due to a number of sources files being AGPL already.

Legally speaking, I'm adding a new license under which these files are
now available; I already released their current contents under the GPL
license. Now they're dual licensed GPL and AGPL. However, I intend
for all my future changes to these files to only be released under the
AGPL license, and I won't be tracking the dual licensing status, so I'm
simply changing the license statement to say it's AGPL.

(In some cases, others wrote parts of the code of a file and released it
under the GPL; but in all cases I have contributed a significant portion
of the code in each file and it's that code that is getting the AGPL
license; the GPL license of other contributors allows combining with
AGPL code.)
2019-03-13 15:48:14 -04:00

76 lines
2.3 KiB
Haskell

{- git index file stuff
-
- Copyright 2011-2018 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
module Git.Index where
import Common
import Git
import Utility.Env
import Utility.Env.Set
indexEnv :: String
indexEnv = "GIT_INDEX_FILE"
{- Gets value to set GIT_INDEX_FILE to. Input should be absolute path,
- or relative to the CWD.
-
- When relative, GIT_INDEX_FILE is interpreted by git as being
- relative to the top of the work tree of the git repository,
- not to the CWD. Worse, other environment variables (GIT_WORK_TREE)
- or git options (--work-tree) or configuration (core.worktree)
- can change what the relative path is interpreted relative to.
-
- So, an absolute path is the only safe option for this to return.
-}
indexEnvVal :: FilePath -> IO String
indexEnvVal = absPath
{- 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 -> Repo -> IO (IO ())
override index _r = do
res <- getEnv var
val <- indexEnvVal index
setEnv var val True
return $ reset res
where
var = "GIT_INDEX_FILE"
reset (Just v) = setEnv indexEnv v True
reset _ = unsetEnv var
{- The normal index file. Does not check GIT_INDEX_FILE. -}
indexFile :: Repo -> FilePath
indexFile r = localGitDir r </> "index"
{- The index file git will currently use, checking GIT_INDEX_FILE. -}
currentIndexFile :: Repo -> IO FilePath
currentIndexFile r = fromMaybe (indexFile r) <$> getEnv indexEnv
{- Git locks the index by creating this file. -}
indexFileLock :: FilePath -> FilePath
indexFileLock f = f ++ ".lock"
{- When the pre-commit hook is run, and git commit has been run with
- a file or files specified to commit, rather than committing the staged
- index, git provides the pre-commit hook with a "false index file".
-
- Changes made to this index will influence the commit, but won't
- affect the real index file.
-
- This detects when we're in this situation, using a heuristic, which
- might be broken by changes to git. Any use of this should have a test
- case to make sure it works.
-}
haveFalseIndex :: IO Bool
haveFalseIndex = maybe (False) check <$> getEnv indexEnv
where
check f = "next-index" `isPrefixOf` takeFileName f