git-annex/git-union-merge.hs
Joey Hess 5f494154a3 add journaling to speed up changes to the git-annex branch
git is slow when the index file is large and has to be rewritten each time
a file is changed. To speed this up, added a journal where changes are
recorded before being fed into the index file and committed to the
git-annex branch. The entire journal can be fed into git with just 2
commands, and only one write of the index file.
2011-06-23 11:37:26 -04:00

49 lines
1.1 KiB
Haskell

{- git-union-merge program
-
- Copyright 2011 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
import System.Environment
import System.FilePath
import System.Directory
import Control.Monad (when)
import qualified GitUnionMerge
import qualified GitRepo as Git
header :: String
header = "Usage: git-union-merge ref ref newref"
usage :: IO a
usage = error $ "bad parameters\n\n" ++ header
tmpIndex :: Git.Repo -> FilePath
tmpIndex g = Git.workTree g </> Git.gitDir g </> "index.git-union-merge"
setup :: Git.Repo -> IO ()
setup g = do
cleanup g -- idempotency
cleanup :: Git.Repo -> IO ()
cleanup g = do
e' <- doesFileExist (tmpIndex g)
when e' $ removeFile (tmpIndex g)
parseArgs :: IO [String]
parseArgs = do
args <- getArgs
if (length args /= 3)
then usage
else return args
main :: IO ()
main = do
[aref, bref, newref] <- parseArgs
g <- Git.configRead =<< Git.repoFromCwd
_ <- Git.useIndex (tmpIndex g)
setup g
GitUnionMerge.merge g [aref, bref]
GitUnionMerge.commit g "union merge" newref [aref, bref]
cleanup g