git-annex/Logs/Difference.hs
Joey Hess 591e4b145f
convert old uuid-based log parsers to attoparsec
This preserves the workaround for the old bug that caused NoUUID items
to be stored in the log, prefixing log lines with " ". It's now handled
implicitly, by using takeWhile1 (/= ' ') to get the uuid.

There is a behavior change from the old parser, which split the value
into words and then recombined it. That meant that "foo  bar" and "foo\tbar"
came out as "foo bar". That behavior was not documented, and seems
surprising; it meant that after a git-annex describe here "foo  bar",
you wouldn't get that same string back out when git-annex displayed repo
descriptions.

Otoh, some other parsers relied on the old behavior, and the attoparsec
rewrites had to deal with the issue themselves...

For group.log, there are some edge cases around the user providing a
group name with a leading or trailing space. The old parser would ignore
such excess whitespace. The new parser does too, because the alternative
is to refuse to parse something like " group1  group2 " due to excess
whitespace, which would be even more confusing behavior.

The only git-annex branch log file that is not converted to attoparsec
and bytestring-builder now is transitions.log.
2019-01-10 16:34:20 -04:00

42 lines
1.3 KiB
Haskell

{- git-annex difference log
-
- Copyright 2015 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Logs.Difference (
recordDifferences,
recordedDifferences,
recordedDifferencesFor,
module Logs.Difference.Pure
) where
import qualified Data.Map as M
import qualified Data.Attoparsec.ByteString as A
import Data.ByteString.Builder
import Annex.Common
import Types.Difference
import qualified Annex.Branch
import Logs
import Logs.UUIDBased
import Logs.Difference.Pure
recordDifferences :: Differences -> UUID -> Annex ()
recordDifferences ds@(Differences {}) uuid = do
c <- liftIO currentVectorClock
Annex.Branch.change differenceLog $
buildLog byteString
. changeLog c uuid (encodeBS $ showDifferences ds)
. parseLog A.takeByteString
recordDifferences UnknownDifferences _ = return ()
-- Map of UUIDs that have Differences recorded.
-- If a new version of git-annex has added a Difference this version
-- doesn't know about, it will contain UnknownDifferences.
recordedDifferences :: Annex (M.Map UUID Differences)
recordedDifferences = parseDifferencesLog <$> Annex.Branch.get differenceLog
recordedDifferencesFor :: UUID -> Annex Differences
recordedDifferencesFor u = fromMaybe mempty . M.lookup u <$> recordedDifferences