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|
{- git-annex assistant git merge thread
-
- Copyright 2012 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Assistant.Threads.Merger where
import Common.Annex
import Assistant.ThreadedMonad
import Utility.DirWatcher
import Utility.Types.DirWatcher
import qualified Git
import qualified Git.Command
import qualified Git.Merge
import qualified Git.Branch
import qualified Command.Sync
import qualified Remote
{- This thread watches for changes to .git/refs/heads/synced/*,
- which indicate incoming pushes. It merges those pushes into the
- currently checked out branch. -}
mergeThread :: ThreadState -> IO ()
mergeThread st = do
g <- runThreadState st $ fromRepo id
let dir = Git.localGitDir g </> "refs" </> "heads" </> "synced"
createDirectoryIfMissing True dir
let hook a = Just $ runHandler st g a
let hooks = mkWatchHooks
{ addHook = hook onAdd
, errHook = hook onErr
}
watchDir dir (const False) hooks id
where
type Handler = ThreadState -> Git.Repo -> FilePath -> Maybe FileStatus -> IO ()
{- Runs an action handler.
-
- Exceptions are ignored, otherwise a whole thread could be crashed.
-}
runHandler :: ThreadState -> Git.Repo -> Handler -> FilePath -> Maybe FileStatus -> IO ()
runHandler st g handler file filestatus = void $ do
either print (const noop) =<< tryIO go
where
go = handler st g file filestatus
{- Called when there's an error with inotify. -}
onErr :: Handler
onErr _ _ msg _ = error msg
{- Called when a new branch ref is written.
-
- This relies on git's atomic method of updating branch ref files,
- which is to first write the new file to .lock, and then rename it
- over the old file. So, ignore .lock files, and the rename ensures
- the watcher sees a new file being added on each update.
-
- At startup, synthetic add events fire, causing this to run, but that's
- ok; it ensures that any changes pushed since the last time the assistant
- ran are merged in.
-}
onAdd :: Handler
onAdd st g file _
| ".lock" `isSuffixOf` file = noop
| otherwise = do
let changedbranch = Git.Ref $
"refs" </> "heads" </> takeFileName file
current <- Git.Branch.current g
when (Just changedbranch == current) $
void $ mergeBranch st changedbranch g
mergeBranch :: ThreadState -> Git.Ref -> Git.Repo -> IO Bool
mergeBranch st branch repo = do
ok <- Git.Merge.mergeNonInteractive (Command.Sync.syncBranch branch) repo
if ok
then return ok
else runThreadState st Command.Sync.resolveMerge
{- Manually pull from remotes and merge their branches. Called by the pusher
- when a push fails, which can happen due to a remote not having pushed
- changes to us. That could be because it doesn't have us as a remote, or
- because the assistant is not running there, or other reasons. -}
manualPull :: Git.Ref -> [Remote] -> Annex ()
manualPull currentbranch remotes = forM_ remotes $ \r -> do
void $ inRepo $ Git.Command.runBool "fetch" [Param $ Remote.name r]
Command.Sync.mergeRemote r currentbranch
|
