git-annex/Logs/Group.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

98 lines
2.9 KiB
Haskell

{- git-annex group log
-
- Copyright 2012, 2019 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Logs.Group (
groupLog,
groupChange,
groupSet,
lookupGroups,
groupMap,
groupMapLoad,
getStandardGroup,
inUnwantedGroup
) where
import qualified Data.Map as M
import qualified Data.Set as S
import qualified Data.Attoparsec.ByteString as A
import qualified Data.Attoparsec.ByteString.Char8 as A8
import Data.ByteString.Builder
import Annex.Common
import Logs
import qualified Annex.Branch
import qualified Annex
import Logs.UUIDBased
import Types.Group
import Types.StandardGroups
{- Returns the groups of a given repo UUID. -}
lookupGroups :: UUID -> Annex (S.Set Group)
lookupGroups u = (fromMaybe S.empty . M.lookup u) . groupsByUUID <$> groupMap
{- Applies a set modifier to change the groups for a uuid in the groupLog. -}
groupChange :: UUID -> (S.Set Group -> S.Set Group) -> Annex ()
groupChange uuid@(UUID _) modifier = do
curr <- lookupGroups uuid
c <- liftIO currentVectorClock
Annex.Branch.change groupLog $
buildLog buildGroup . changeLog c uuid (modifier curr) . parseLog parseGroup
-- The changed group invalidates the preferred content cache.
Annex.changeState $ \s -> s
{ Annex.groupmap = Nothing
, Annex.preferredcontentmap = Nothing
}
groupChange NoUUID _ = error "unknown UUID; cannot modify"
buildGroup :: S.Set Group -> Builder
buildGroup = go . S.toList
where
go [] = mempty
go (g:gs) = bld g <> mconcat [ charUtf8 ' ' <> bld g' | g' <- gs ]
bld (Group g) = byteString g
parseGroup :: A.Parser (S.Set Group)
parseGroup = S.fromList <$> go []
where
go l = (A.endOfInput *> pure l)
<|> ((getgroup <* A8.char ' ') >>= go . (:l))
<|> ((:l) <$> getgroup)
-- allow extra writespace before or after a group name
<|> (A8.char ' ' >>= const (go l))
getgroup = Group <$> A8.takeWhile1 (/= ' ')
groupSet :: UUID -> S.Set Group -> Annex ()
groupSet u g = groupChange u (const g)
{- The map is cached for speed. -}
groupMap :: Annex GroupMap
groupMap = maybe groupMapLoad return =<< Annex.getState Annex.groupmap
{- Loads the map, updating the cache. -}
groupMapLoad :: Annex GroupMap
groupMapLoad = do
m <- makeGroupMap . simpleMap . parseLog parseGroup <$> Annex.Branch.get groupLog
Annex.changeState $ \s -> s { Annex.groupmap = Just m }
return m
makeGroupMap :: M.Map UUID (S.Set Group) -> GroupMap
makeGroupMap byuuid = GroupMap byuuid bygroup
where
bygroup = M.fromListWith S.union $
concatMap explode $ M.toList byuuid
explode (u, s) = map (\g -> (g, S.singleton u)) (S.toList s)
{- If a repository is in exactly one standard group, returns it. -}
getStandardGroup :: S.Set Group -> Maybe StandardGroup
getStandardGroup s = case mapMaybe toStandardGroup $ S.toList s of
[g] -> Just g
_ -> Nothing
inUnwantedGroup :: UUID -> Annex Bool
inUnwantedGroup u = elem UnwantedGroup
. mapMaybe toStandardGroup . S.toList <$> lookupGroups u