git-annex/Command/Fix.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

110 lines
3.1 KiB
Haskell

{- git-annex command
-
- Copyright 2010-2015 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
{-# LANGUAGE CPP #-}
module Command.Fix where
import Command
import Config
import qualified Annex
import Annex.Version
import Annex.ReplaceFile
import Annex.Content
import Annex.Perms
import qualified Annex.Queue
import qualified Database.Keys
#if ! defined(mingw32_HOST_OS)
import Utility.Touch
import System.Posix.Files
#endif
cmd :: Command
cmd = notDirect $ noCommit $ withGlobalOptions [annexedMatchingOptions] $
command "fix" SectionMaintenance
"fix up links to annexed content"
paramPaths (withParams seek)
seek :: CmdParams -> CommandSeek
seek ps = unlessM crippledFileSystem $ do
fixwhat <- ifM versionSupportsUnlockedPointers
( return FixAll
, return FixSymlinks
)
withFilesInGit
(commandAction . (whenAnnexed $ start fixwhat))
=<< workTreeItems ps
data FixWhat = FixSymlinks | FixAll
start :: FixWhat -> FilePath -> Key -> CommandStart
start fixwhat file key = do
currlink <- liftIO $ catchMaybeIO $ readSymbolicLink file
wantlink <- calcRepo $ gitAnnexLink file key
case currlink of
Just l
| l /= wantlink -> fixby $ fixSymlink file wantlink
| otherwise -> stop
Nothing -> case fixwhat of
FixAll -> fixthin
FixSymlinks -> stop
where
fixby = starting "fix" (mkActionItem (key, file))
fixthin = do
obj <- calcRepo $ gitAnnexLocation key
stopUnless (isUnmodified key file <&&> isUnmodified key obj) $ do
thin <- annexThin <$> Annex.getGitConfig
fs <- liftIO $ catchMaybeIO $ getFileStatus file
os <- liftIO $ catchMaybeIO $ getFileStatus obj
case (linkCount <$> fs, linkCount <$> os, thin) of
(Just 1, Just 1, True) ->
fixby $ makeHardLink file key
(Just n, Just n', False) | n > 1 && n == n' ->
fixby $ breakHardLink file key obj
_ -> stop
breakHardLink :: FilePath -> Key -> FilePath -> CommandPerform
breakHardLink file key obj = do
replaceFile file $ \tmp -> do
mode <- liftIO $ catchMaybeIO $ fileMode <$> getFileStatus file
unlessM (checkedCopyFile key obj tmp mode) $
error "unable to break hard link"
thawContent tmp
modifyContent obj $ freezeContent obj
Database.Keys.storeInodeCaches key [file]
next $ return True
makeHardLink :: FilePath -> Key -> CommandPerform
makeHardLink file key = do
replaceFile file $ \tmp -> do
mode <- liftIO $ catchMaybeIO $ fileMode <$> getFileStatus file
linkFromAnnex key tmp mode >>= \case
LinkAnnexFailed -> error "unable to make hard link"
_ -> noop
next $ return True
fixSymlink :: FilePath -> FilePath -> CommandPerform
fixSymlink file link = do
liftIO $ do
#if ! defined(mingw32_HOST_OS)
-- preserve mtime of symlink
mtime <- catchMaybeIO $ modificationTimeHiRes
<$> getSymbolicLinkStatus file
#endif
createDirectoryIfMissing True (parentDir file)
removeFile file
createSymbolicLink link file
#if ! defined(mingw32_HOST_OS)
maybe noop (\t -> touch file t False) mtime
#endif
next $ cleanupSymlink file
cleanupSymlink :: FilePath -> CommandCleanup
cleanupSymlink file = do
Annex.Queue.addCommand "add" [Param "--force", Param "--"] [file]
return True