git-annex/Logs/Transitions.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

87 lines
2.7 KiB
Haskell

{- git-annex transitions log
-
- This is used to record transitions that have been performed on the
- git-annex branch, and when the transition was first started.
-
- We can quickly detect when the local branch has already had an transition
- done that is listed in the remote branch by checking that the local
- branch contains the same transition, with the same or newer start time.
-
- Copyright 2013 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Logs.Transitions where
import Data.Time.Clock.POSIX
import qualified Data.Set as S
import Annex.Common
import Logs.TimeStamp
import Logs.Line
transitionsLog :: FilePath
transitionsLog = "transitions.log"
data Transition
= ForgetGitHistory
| ForgetDeadRemotes
deriving (Show, Ord, Eq, Read)
data TransitionLine = TransitionLine
{ transitionStarted :: POSIXTime
, transition :: Transition
} deriving (Show, Ord, Eq)
type Transitions = S.Set TransitionLine
describeTransition :: Transition -> String
describeTransition ForgetGitHistory = "forget git history"
describeTransition ForgetDeadRemotes = "forget dead remotes"
noTransitions :: Transitions
noTransitions = S.empty
addTransition :: POSIXTime -> Transition -> Transitions -> Transitions
addTransition ts t = S.insert $ TransitionLine ts t
showTransitions :: Transitions -> String
showTransitions = unlines . map showTransitionLine . S.elems
{- If the log contains new transitions we don't support, returns Nothing. -}
parseTransitions :: String -> Maybe Transitions
parseTransitions = check . map parseTransitionLine . splitLines
where
check l
| all isJust l = Just $ S.fromList $ catMaybes l
| otherwise = Nothing
parseTransitionsStrictly :: String -> String -> Transitions
parseTransitionsStrictly source = fromMaybe badsource . parseTransitions
where
badsource = error $ "unknown transitions listed in " ++ source ++ "; upgrade git-annex!"
showTransitionLine :: TransitionLine -> String
showTransitionLine (TransitionLine ts t) = unwords [show t, show ts]
parseTransitionLine :: String -> Maybe TransitionLine
parseTransitionLine s = TransitionLine
<$> parsePOSIXTime ds
<*> readish ts
where
ws = words s
ts = Prelude.head ws
ds = unwords $ Prelude.tail ws
combineTransitions :: [Transitions] -> Transitions
combineTransitions = S.unions
transitionList :: Transitions -> [Transition]
transitionList = nub . map transition . S.elems
{- Typically ran with Annex.Branch.change, but we can't import Annex.Branch
- here since it depends on this module. -}
recordTransitions :: (FilePath -> (String -> String) -> Annex ()) -> Transitions -> Annex ()
recordTransitions changer t = changer transitionsLog $
showTransitions . S.union t . parseTransitionsStrictly "local"