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{- git-union-merge library
-
- Copyright 2011 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module GitUnionMerge (
merge,
stage,
commit
) where
import System.Cmd.Utils
import Data.List
import Data.Maybe
import Data.String.Utils
import qualified GitRepo as Git
import Utility
{- Performs a union merge. Should be run with a temporary index file
- configured by Git.useIndex.
-
- Use indexpopulated only if the index file already contains exactly the
- contents of aref.
-}
merge :: Git.Repo -> String -> String -> String -> Bool -> IO ()
merge g aref bref newref indexpopulated = do
stage g aref bref indexpopulated
commit g "union merge" newref [aref, bref]
{- Stages the content of both refs into the index. -}
stage :: Git.Repo -> String -> String -> Bool -> IO ()
stage g aref bref indexpopulated = do
-- Get the contents of aref, as a starting point, unless
-- the index is already populated with it.
ls <- if indexpopulated
then return []
else fromgit ["ls-tree", "-z", "-r", "--full-tree", aref]
-- Identify files that are different between aref and bref, and
-- inject merged versions into git.
diff <- fromgit
["diff-tree", "--raw", "-z", "-r", "--no-renames", "-l0", aref, bref]
ls' <- mapM mergefile (pairs diff)
-- Populate the index file. Later lines override earlier ones.
togit ["update-index", "-z", "--index-info"]
(join "\0" $ ls++catMaybes ls')
where
fromgit l = Git.pipeNullSplit g (map Param l)
togit l content = Git.pipeWrite g (map Param l) content
>>= forceSuccess
pairs [] = []
pairs (_:[]) = error "parse error"
pairs (a:b:rest) = (a,b):pairs rest
nullsha = take Git.shaSize $ repeat '0'
ls_tree_line sha file = "100644 blob " ++ sha ++ "\t" ++ file
unionmerge = unlines . nub . lines
mergefile (info, file) = do
let [_colonamode, _bmode, asha, bsha, _status] = words info
if bsha == nullsha
then return Nothing -- already staged from aref
else mergefile' file asha bsha
mergefile' file asha bsha = do
let shas = filter (/= nullsha) [asha, bsha]
content <- Git.pipeRead g $ map Param ("show":shas)
sha <- Git.hashObject g $ unionmerge content
return $ Just $ ls_tree_line sha file
{- Commits the index into the specified branch. If refs are specified,
- commits a merge. -}
commit :: Git.Repo -> String -> String -> [String] -> IO ()
commit g message newref mergedrefs = do
tree <- Git.getSha "write-tree" $ ignorehandle $
pipeFrom "git" ["write-tree"]
sha <- Git.getSha "commit-tree" $ ignorehandle $
pipeBoth "git" (["commit-tree", tree] ++ ps) message
Git.run g "update-ref" [Param newref, Param sha]
where
ignorehandle a = return . snd =<< a
ps = concatMap (\r -> ["-p", r]) mergedrefs
|
