git-annex/Logs/Presence/Pure.hs
Joey Hess eba68572dc
Split lines in the git-annex branch on \r as well as \n, to deal with \r\n terminated lines written by some versions of git-annex on Windows.
This fixes strange displays in some cases, including whereis showing
many duplicate locations, and showing more total copies than actually
exist.

It's unknown if that lead to data loss when eg, dropping. At the moment,
it seems unlikely it could, since the UUID with \r's appended is not the
same as a UUID without, and so no remote matches it.

It's also unknown if \r's can leak in on windows, perhaps when merging the
git-annex branch.
2016-05-27 11:45:13 -04:00

106 lines
2.9 KiB
Haskell

{- git-annex presence log, pure operations
-
- Copyright 2010-2013 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Logs.Presence.Pure where
import Data.Time.Clock.POSIX
import qualified Data.Map as M
import Annex.Common
import Logs.TimeStamp
import Logs.Line
import Utility.QuickCheck
data LogLine = LogLine {
date :: POSIXTime,
status :: LogStatus,
info :: String
} deriving (Eq, Show)
data LogStatus = InfoPresent | InfoMissing | InfoDead
deriving (Eq, Show, Bounded, Enum)
{- Parses a log file. Unparseable lines are ignored. -}
parseLog :: String -> [LogLine]
parseLog = mapMaybe parseline . splitLines
where
parseline l = LogLine
<$> parsePOSIXTime d
<*> parseStatus s
<*> pure rest
where
(d, pastd) = separate (== ' ') l
(s, rest) = separate (== ' ') pastd
parseStatus :: String -> Maybe LogStatus
parseStatus "1" = Just InfoPresent
parseStatus "0" = Just InfoMissing
parseStatus "X" = Just InfoDead
parseStatus _ = Nothing
{- Generates a log file. -}
showLog :: [LogLine] -> String
showLog = unlines . map genline
where
genline (LogLine d s i) = unwords [show d, genstatus s, i]
genstatus InfoPresent = "1"
genstatus InfoMissing = "0"
genstatus InfoDead = "X"
{- Given a log, returns only the info that is are still in effect. -}
getLog :: String -> [String]
getLog = map info . filterPresent . parseLog
{- Returns the info from LogLines that are in effect. -}
filterPresent :: [LogLine] -> [LogLine]
filterPresent = filter (\l -> InfoPresent == status l) . compactLog
{- Compacts a set of logs, returning a subset that contains the current
- status. -}
compactLog :: [LogLine] -> [LogLine]
compactLog = mapLog . logMap
type LogMap = M.Map String LogLine
mapLog :: LogMap -> [LogLine]
mapLog = M.elems
logMap :: [LogLine] -> LogMap
logMap = foldr insertNewerLogLine M.empty
insertBetter :: (LogLine -> Bool) -> LogLine -> LogMap -> Maybe LogMap
insertBetter betterthan l m
| better = Just (M.insert i l m)
| otherwise = Nothing
where
better = maybe True betterthan (M.lookup i m)
i = info l
{- Inserts a log into a map of logs, if the log has newer
- information than the other logs in the map for the same info. -}
insertNewerLogLine :: LogLine -> LogMap -> LogMap
insertNewerLogLine l m = fromMaybe m $ insertBetter newer l m
where
newer l' = date l' <= date l
{- Inserts the log unless there's already one in the map with
- the same status for its info, in which case there's no need to
- change anything, to avoid log churn. -}
insertNewStatus :: LogLine -> LogMap -> Maybe LogMap
insertNewStatus l m = insertBetter diffstatus l m
where
diffstatus l' = status l' /= status l
instance Arbitrary LogLine where
arbitrary = LogLine
<$> arbitrary
<*> elements [minBound..maxBound]
<*> arbitrary `suchThat` ('\n' `notElem`)
prop_parse_show_log :: [LogLine] -> Bool
prop_parse_show_log l = parseLog (showLog l) == l