git-annex/Command/Smudge.hs
Joey Hess 0860731760
reorder associated file db update
There's a potential race where the smudge filter is run at the same time an
object is being downloaded. If the download finished after the inAnnex
check, and before the keys db was updated, the associated file would not
get updated with the downloaded content.

I'm not sure this closes the race; it may only narrow the window. Problem
is, the keys database needs to communicate between two different processes.
In the case of the assistant, the transferkeys command is the other
process, and it closes the db handle after getting the file. So, it should
re-open the database and so see the update that the smudge filter has
written to it. But, what if the smudge filter takes a while to update the
database?
2016-05-16 14:55:05 -04:00

102 lines
2.8 KiB
Haskell

{- git-annex command
-
- Copyright 2015 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Command.Smudge where
import Command
import qualified Annex
import Annex.Content
import Annex.Link
import Annex.FileMatcher
import Annex.Ingest
import Logs.Location
import qualified Database.Keys
import Git.FilePath
import qualified Data.ByteString.Lazy as B
cmd :: Command
cmd = noCommit $ noMessages $
command "smudge" SectionPlumbing
"git smudge filter"
paramFile (seek <$$> optParser)
data SmudgeOptions = SmudgeOptions
{ smudgeFile :: FilePath
, cleanOption :: Bool
}
optParser :: CmdParamsDesc -> Parser SmudgeOptions
optParser desc = SmudgeOptions
<$> argument str ( metavar desc )
<*> switch ( long "clean" <> help "clean filter" )
seek :: SmudgeOptions -> CommandSeek
seek o = commandAction $
(if cleanOption o then clean else smudge) (smudgeFile o)
-- Smudge filter is fed git file content, and if it's a pointer to an
-- available annex object, should output its content.
smudge :: FilePath -> CommandStart
smudge file = do
b <- liftIO $ B.hGetContents stdin
case parseLinkOrPointer b of
Nothing -> liftIO $ B.putStr b
Just k -> do
Database.Keys.addAssociatedFile k =<< inRepo (toTopFilePath file)
-- A previous unlocked checkout of the file may have
-- led to the annex object getting modified;
-- don't provide such modified content as it
-- will be confusing. inAnnex will detect such
-- modifications.
ifM (inAnnex k)
( do
content <- calcRepo (gitAnnexLocation k)
whenM (annexThin <$> Annex.getGitConfig) $
warning $ "Not able to honor annex.thin when git is checking out " ++ file ++ " (run git annex fix to re-thin files)"
liftIO $ B.putStr . fromMaybe b
=<< catchMaybeIO (B.readFile content)
, liftIO $ B.putStr b
)
stop
-- Clean filter is fed file content on stdin, decides if a file
-- should be stored in the annex, and outputs a pointer to its
-- injested content.
clean :: FilePath -> CommandStart
clean file = do
b <- liftIO $ B.hGetContents stdin
if isJust (parseLinkOrPointer b)
then liftIO $ B.hPut stdout b
else ifM (shouldAnnex file)
( do
-- Even though we ingest the actual file,
-- and not stdin, we need to consume all
-- stdin, or git will get annoyed.
B.length b `seq` return ()
liftIO . emitPointer
=<< go =<< ingest =<< lockDown cfg file
, liftIO $ B.hPut stdout b
)
stop
where
go (Just k, _) = do
logStatus k InfoPresent
return k
go _ = error "could not add file to the annex"
cfg = LockDownConfig
{ lockingFile = False
, hardlinkFileTmp = False
}
shouldAnnex :: FilePath -> Annex Bool
shouldAnnex file = do
matcher <- largeFilesMatcher
checkFileMatcher matcher file
emitPointer :: Key -> IO ()
emitPointer = putStr . formatPointer