git-annex/Command/Lock.hs
Joey Hess 436f107715
make CommandStart return a StartMessage
The goal is to be able to run CommandStart in the main thread when -J is
used, rather than unncessarily passing it off to a worker thread, which
incurs overhead that is signficant when the CommandStart is going to
quickly decide to stop.

To do that, the message it displays needs to be displayed in the worker
thread, after the CommandStart has run.

Also, the change will mean that CommandStart will no longer necessarily
run with the same Annex state as CommandPerform. While its docs already
said it should avoid modifying Annex state, I audited all the
CommandStart code as part of the conversion. (Note that CommandSeek
already sometimes runs with a different Annex state, and that has not been
a source of any problems, so I am not too worried that this change will
lead to breakage going forward.)

The only modification of Annex state I found was it calling
allowMessages in some Commands that default to noMessages. Dealt with
that by adding a startCustomOutput and a startingUsualMessages.
This lets a command start with noMessages and then select the output it
wants for each CommandStart.

One bit of breakage: onlyActionOn has been removed from commands that used it.
The plan is that, since a StartMessage contains an ActionItem,
when a Key can be extracted from that, the parallel job runner can
run onlyActionOn' automatically. Then commands won't need to worry about
this detail. Future work.

Otherwise, this was a fairly straightforward process of making each
CommandStart compile again. Hopefully other behavior changes were mostly
avoided.

In a few cases, a command had a CommandStart that called a CommandPerform
that then called showStart multiple times. I have collapsed those
down to a single start action. The main command to perhaps suffer from it
is Command.Direct, which used to show a start for each file, and no
longer does.

Another minor behavior change is that some commands used showStart
before, but had an associated file and a Key available, so were changed
to ShowStart with an ActionItemAssociatedFile. That will not change the
normal output or behavior, but --json output will now include the key.
This should not break it for anyone using a real json parser.
2019-06-06 17:13:54 -04:00

119 lines
3.3 KiB
Haskell

{- git-annex command
-
- Copyright 2010,2015 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
module Command.Lock where
import Command
import qualified Annex.Queue
import qualified Annex
import Annex.Version
import Annex.Content
import Annex.Link
import Annex.InodeSentinal
import Annex.Perms
import Annex.ReplaceFile
import Utility.InodeCache
import qualified Database.Keys
import Annex.Ingest
import Logs.Location
import Git.FilePath
cmd :: Command
cmd = notDirect $ withGlobalOptions [jsonOptions, annexedMatchingOptions] $
command "lock" SectionCommon
"undo unlock command"
paramPaths (withParams seek)
seek :: CmdParams -> CommandSeek
seek ps = do
l <- workTreeItems ps
ifM versionSupportsUnlockedPointers
( withFilesInGit (commandAction . (whenAnnexed startNew)) l
, do
withFilesOldUnlocked (commandAction . startOld) l
withFilesOldUnlockedToBeCommitted (commandAction . startOld) l
)
startNew :: FilePath -> Key -> CommandStart
startNew file key = ifM (isJust <$> isAnnexLink file)
( stop
, starting "lock" (mkActionItem (key, file)) $
go =<< liftIO (isPointerFile file)
)
where
go (Just key')
| key' == key = cont
| otherwise = errorModified
go Nothing =
ifM (isUnmodified key file)
( cont
, ifM (Annex.getState Annex.force)
( cont
, errorModified
)
)
cont = performNew file key
performNew :: FilePath -> Key -> CommandPerform
performNew file key = do
lockdown =<< calcRepo (gitAnnexLocation key)
addLink file key
=<< withTSDelta (liftIO . genInodeCache file)
next $ cleanupNew file key
where
lockdown obj = do
ifM (isUnmodified key obj)
( breakhardlink obj
, repopulate obj
)
whenM (liftIO $ doesFileExist obj) $
freezeContent obj
-- It's ok if the file is hard linked to obj, but if some other
-- associated file is, we need to break that link to lock down obj.
breakhardlink obj = whenM (catchBoolIO $ (> 1) . linkCount <$> liftIO (getFileStatus obj)) $ do
mfc <- withTSDelta (liftIO . genInodeCache file)
unlessM (sameInodeCache obj (maybeToList mfc)) $ do
modifyContent obj $ replaceFile obj $ \tmp -> do
unlessM (checkedCopyFile key obj tmp Nothing) $
giveup "unable to lock file"
Database.Keys.storeInodeCaches key [obj]
-- Try to repopulate obj from an unmodified associated file.
repopulate obj = modifyContent obj $ do
g <- Annex.gitRepo
fs <- map (`fromTopFilePath` g)
<$> Database.Keys.getAssociatedFiles key
mfile <- firstM (isUnmodified key) fs
liftIO $ nukeFile obj
case mfile of
Just unmodified ->
unlessM (checkedCopyFile key unmodified obj Nothing)
lostcontent
Nothing -> lostcontent
lostcontent = logStatus key InfoMissing
cleanupNew :: FilePath -> Key -> CommandCleanup
cleanupNew file key = do
Database.Keys.removeAssociatedFile key =<< inRepo (toTopFilePath file)
return True
startOld :: FilePath -> CommandStart
startOld file = do
unlessM (Annex.getState Annex.force)
errorModified
starting "lock" (ActionItemWorkTreeFile file) $
performOld file
performOld :: FilePath -> CommandPerform
performOld file = do
Annex.Queue.addCommand "checkout" [Param "--"] [file]
next $ return True
errorModified :: a
errorModified = giveup "Locking this file would discard any changes you have made to it. Use 'git annex add' to stage your changes. (Or, use --force to override)"