git-annex/Command/Sync.hs
2012-06-27 18:09:11 -04:00

291 lines
8.6 KiB
Haskell

{- git-annex command
-
- Copyright 2011 Joey Hess <joey@kitenet.net>
- Copyright 2011 Joachim Breitner <mail@joachim-breitner.de>
-
- Licensed under the GNU GPL version 3 or higher.
-}
{-# LANGUAGE BangPatterns #-}
module Command.Sync where
import Common.Annex
import Command
import qualified Remote
import qualified Annex
import qualified Annex.Branch
import qualified Annex.Queue
import Annex.Content
import Annex.CatFile
import qualified Git.Command
import qualified Git.LsFiles as LsFiles
import qualified Git.Merge
import qualified Git.Branch
import qualified Git.Ref
import qualified Git
import Git.Types (BlobType(..))
import qualified Types.Remote
import qualified Remote.Git
import qualified Data.Map as M
import qualified Data.ByteString.Lazy as L
import Data.Hash.MD5
def :: [Command]
def = [command "sync" (paramOptional (paramRepeating paramRemote))
[seek] "synchronize local repository with remotes"]
-- syncing involves several operations, any of which can independently fail
seek :: CommandSeek
seek rs = do
branch <- currentBranch
remotes <- syncRemotes rs
return $ concat
[ [ commit ]
, [ mergeLocal branch ]
, [ pullRemote remote branch | remote <- remotes ]
, [ mergeAnnex ]
, [ pushLocal branch ]
, [ pushRemote remote branch | remote <- remotes ]
]
currentBranch :: Annex Git.Ref
currentBranch = do
!branch <- fromMaybe nobranch <$> inRepo Git.Branch.current
return branch
where
nobranch = error "no branch is checked out"
syncBranch :: Git.Ref -> Git.Ref
syncBranch = Git.Ref.under "refs/heads/synced/"
remoteBranch :: Remote -> Git.Ref -> Git.Ref
remoteBranch remote = Git.Ref.under $ "refs/remotes/" ++ Remote.name remote
syncRemotes :: [String] -> Annex [Remote]
syncRemotes rs = ifM (Annex.getState Annex.fast) ( nub <$> pickfast , wanted )
where
pickfast = (++) <$> listed <*> (good =<< fastest <$> available)
wanted
| null rs = good =<< concat . byspeed <$> available
| otherwise = listed
listed = do
l <- catMaybes <$> mapM (Remote.byName . Just) rs
let s = filter special l
unless (null s) $
error $ "cannot sync special remotes: " ++
unwords (map Types.Remote.name s)
return l
available = filter nonspecial <$> Remote.enabledRemoteList
good = filterM $ Remote.Git.repoAvail . Types.Remote.repo
nonspecial r = Types.Remote.remotetype r == Remote.Git.remote
special = not . nonspecial
fastest = fromMaybe [] . headMaybe . byspeed
byspeed = map snd . sort . M.toList . costmap
costmap = M.fromListWith (++) . map costpair
costpair r = (Types.Remote.cost r, [r])
commit :: CommandStart
commit = do
showStart "commit" ""
next $ next $ do
showOutput
Annex.Branch.commit "update"
-- Commit will fail when the tree is clean, so ignore failure.
_ <- inRepo $ Git.Command.runBool "commit"
[Param "-a", Param "-m", Param "git-annex automatic sync"]
return True
mergeLocal :: Git.Ref -> CommandStart
mergeLocal branch = go =<< needmerge
where
syncbranch = syncBranch branch
needmerge = do
unlessM (inRepo $ Git.Ref.exists syncbranch) $
inRepo $ updateBranch syncbranch
inRepo $ Git.Branch.changed branch syncbranch
go False = stop
go True = do
showStart "merge" $ Git.Ref.describe syncbranch
next $ next $ mergeFrom syncbranch
pushLocal :: Git.Ref -> CommandStart
pushLocal branch = do
inRepo $ updateBranch $ syncBranch branch
stop
updateBranch :: Git.Ref -> Git.Repo -> IO ()
updateBranch syncbranch g =
unlessM go $ error $ "failed to update " ++ show syncbranch
where
go = Git.Command.runBool "branch"
[ Param "-f"
, Param $ show $ Git.Ref.base syncbranch
] g
pullRemote :: Remote -> Git.Ref -> CommandStart
pullRemote remote branch = do
showStart "pull" (Remote.name remote)
next $ do
showOutput
stopUnless fetch $
next $ mergeRemote remote branch
where
fetch = inRepo $ Git.Command.runBool "fetch"
[Param $ Remote.name remote]
{- The remote probably has both a master and a synced/master branch.
- Which to merge from? Well, the master has whatever latest changes
- were committed, while the synced/master may have changes that some
- other remote synced to this remote. So, merge them both. -}
mergeRemote :: Remote -> Git.Ref -> CommandCleanup
mergeRemote remote branch = all id <$> (mapM merge =<< tomerge)
where
merge = mergeFrom . remoteBranch remote
tomerge = filterM (changed remote) [branch, syncBranch branch]
pushRemote :: Remote -> Git.Ref -> CommandStart
pushRemote remote branch = go =<< needpush
where
needpush = anyM (newer remote) [syncBranch branch, Annex.Branch.name]
go False = stop
go True = do
showStart "push" (Remote.name remote)
next $ next $ do
showOutput
inRepo $ pushBranch remote branch
pushBranch :: Remote -> Git.Ref -> Git.Repo -> IO Bool
pushBranch remote branch g =
Git.Command.runBool "push"
[ Param (Remote.name remote)
, Param (show Annex.Branch.name)
, Param refspec
] g
where
refspec = concat
[ show $ Git.Ref.base branch
, ":"
, show $ Git.Ref.base $ syncBranch branch
]
mergeAnnex :: CommandStart
mergeAnnex = do
Annex.Branch.forceUpdate
stop
mergeFrom :: Git.Ref -> Annex Bool
mergeFrom branch = do
showOutput
ok <- inRepo $ Git.Merge.mergeNonInteractive branch
if ok
then return ok
else resolveMerge
{- Resolves a conflicted merge. It's important that any conflicts be
- resolved in a way that itself avoids later merge conflicts, since
- multiple repositories may be doing this concurrently.
-
- Only annexed files are resolved; other files are left for the user to
- handle.
-
- This uses the Keys pointed to by the files to construct new
- filenames. So when both sides modified file foo,
- it will be deleted, and replaced with files foo.KEYA and foo.KEYB.
-
- On the other hand, when one side deleted foo, and the other modified it,
- it will be deleted, and the modified version stored as file
- foo.KEYA (or KEYB).
-}
resolveMerge :: Annex Bool
resolveMerge = do
top <- fromRepo Git.repoPath
merged <- all id <$> (mapM resolveMerge' =<< inRepo (LsFiles.unmerged [top]))
when merged $ do
Annex.Queue.flush
void $ inRepo $ Git.Command.runBool "commit"
[Param "-m", Param "git-annex automatic merge conflict fix"]
return merged
resolveMerge' :: LsFiles.Unmerged -> Annex Bool
resolveMerge' u
| issymlink LsFiles.valUs && issymlink LsFiles.valThem =
withKey LsFiles.valUs $ \keyUs ->
withKey LsFiles.valThem $ \keyThem -> go keyUs keyThem
| otherwise = return False
where
go keyUs keyThem
| keyUs == keyThem = do
makelink keyUs
return True
| otherwise = do
liftIO $ nukeFile file
Annex.Queue.addCommand "rm" [Params "--quiet -f --"] [file]
makelink keyUs
makelink keyThem
return True
file = LsFiles.unmergedFile u
issymlink select = any (select (LsFiles.unmergedBlobType u) ==)
[Just SymlinkBlob, Nothing]
makelink (Just key) = do
let dest = mergeFile file key
l <- calcGitLink dest key
liftIO $ do
nukeFile dest
createSymbolicLink l dest
Annex.Queue.addCommand "add" [Param "--force", Param "--"] [dest]
makelink _ = noop
withKey select a = do
let msha = select $ LsFiles.unmergedSha u
case msha of
Nothing -> a Nothing
Just sha -> do
key <- fileKey . takeFileName
. encodeW8 . L.unpack
<$> catObject sha
maybe (return False) (a . Just) key
{- The filename to use when resolving a conflicted merge of a file,
- that points to a key.
-
- Something derived from the key needs to be included in the filename,
- but rather than exposing the whole key to the user, a very weak hash
- is used. There is a very real, although still unlikely, chance of
- conflicts using this hash.
-
- In the event that there is a conflict with the filename generated
- for some other key, that conflict will itself be handled by the
- conflicted merge resolution code. That case is detected, and the full
- key is used in the filename.
-}
mergeFile :: FilePath -> Key -> FilePath
mergeFile file key
| doubleconflict = go $ show key
| otherwise = go $ shortHash $ show key
where
varmarker = ".variant-"
doubleconflict = varmarker `isSuffixOf` (dropExtension file)
go v = takeDirectory file
</> dropExtension (takeFileName file)
++ varmarker ++ v
++ takeExtension file
shortHash :: String -> String
shortHash = take 4 . md5s . encodeFilePath
changed :: Remote -> Git.Ref -> Annex Bool
changed remote b = do
let r = remoteBranch remote b
ifM (inRepo $ Git.Ref.exists r)
( inRepo $ Git.Branch.changed b r
, return False
)
newer :: Remote -> Git.Ref -> Annex Bool
newer remote b = do
let r = remoteBranch remote b
ifM (inRepo $ Git.Ref.exists r)
( inRepo $ Git.Branch.changed r b
, return True
)