1{- git index file stuff
2 -
3 - Copyright 2011-2018 Joey Hess <id@joeyh.name>
4 -
5 - Licensed under the GNU AGPL version 3 or higher.
6 -}
7
8{-# LANGUAGE OverloadedStrings #-}
9
10module Git.Index where
11
12import Common
13import Git
14import Utility.Env
15import Utility.Env.Set
16
17import qualified System.FilePath.ByteString as P
18
19indexEnv :: String
20indexEnv = "GIT_INDEX_FILE"
21
22{- Gets value to set GIT_INDEX_FILE to. Input should be absolute path,
23 - or relative to the CWD.
24 -
25 - When relative, GIT_INDEX_FILE is interpreted by git as being
26 - relative to the top of the work tree of the git repository,
27 - not to the CWD. Worse, other environment variables (GIT_WORK_TREE)
28 - or git options (--work-tree) or configuration (core.worktree)
29 - can change what the relative path is interpreted relative to.
30 -
31 - So, an absolute path is the only safe option for this to return.
32 -}
33indexEnvVal :: RawFilePath -> IO String
34indexEnvVal p = fromRawFilePath <$> absPath p
35
36{- Forces git to use the specified index file.
37 -
38 - Returns an action that will reset back to the default
39 - index file.
40 -
41 - Warning: Not thread safe.
42 -}
43override :: RawFilePath -> Repo -> IO (IO ())
44override index _r = do
45	res <- getEnv var
46	val <- indexEnvVal index
47	setEnv var val True
48	return $ reset res
49  where
50	var = "GIT_INDEX_FILE"
51	reset (Just v) = setEnv indexEnv v True
52	reset _ = unsetEnv var
53
54{- The normal index file. Does not check GIT_INDEX_FILE. -}
55indexFile :: Repo -> RawFilePath
56indexFile r = localGitDir r P.</> "index"
57
58{- The index file git will currently use, checking GIT_INDEX_FILE. -}
59currentIndexFile :: Repo -> IO RawFilePath
60currentIndexFile r = maybe (indexFile r) toRawFilePath <$> getEnv indexEnv
61
62{- Git locks the index by creating this file. -}
63indexFileLock :: RawFilePath -> RawFilePath
64indexFileLock f = f <> ".lock"
65