0831e18372
Wrote nice pure transition calculator, and ugly code to stage its results into the git-annex branch. Also had to split up several Log modules that Annex.Branch needed to use, but that themselves used Annex.Branch. The transition calculator is limited to looking at and changing one file at a time. While this made the implementation relatively easy, it precludes transitions that do stuff like deleting old url log files for keys that are being removed because they are no longer present anywhere.
87 lines
2.8 KiB
Haskell
87 lines
2.8 KiB
Haskell
{- git-annex transitions log
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-
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- This is used to record transitions that have been performed on the
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- git-annex branch, and when the transition was first started.
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-
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- We can quickly detect when the local branch has already had an transition
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- done that is listed in the remote branch by checking that the local
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- branch contains the same transition, with the same or newer start time.
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-
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- Copyright 2013 Joey Hess <joey@kitenet.net>
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-
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- Licensed under the GNU GPL version 3 or higher.
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-}
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module Logs.Transitions where
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import Data.Time.Clock.POSIX
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import Data.Time
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import System.Locale
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import qualified Data.Set as S
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import Common.Annex
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transitionsLog :: FilePath
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transitionsLog = "transitions.log"
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data Transition
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= ForgetGitHistory
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| ForgetDeadRemotes
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deriving (Show, Ord, Eq, Read)
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data TransitionLine = TransitionLine
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{ transitionStarted :: POSIXTime
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, transition :: Transition
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} deriving (Show, Ord, Eq)
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type Transitions = S.Set TransitionLine
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describeTransition :: Transition -> String
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describeTransition ForgetGitHistory = "forget git history"
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describeTransition ForgetDeadRemotes = "forget dead remotes"
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noTransitions :: Transitions
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noTransitions = S.empty
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addTransition :: POSIXTime -> Transition -> Transitions -> Transitions
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addTransition ts t = S.insert $ TransitionLine ts t
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showTransitions :: Transitions -> String
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showTransitions = unlines . map showTransitionLine . S.elems
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{- If the log contains new transitions we don't support, returns Nothing. -}
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parseTransitions :: String -> Maybe Transitions
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parseTransitions = check . map parseTransitionLine . lines
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where
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check l
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| all isJust l = Just $ S.fromList $ catMaybes l
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| otherwise = Nothing
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parseTransitionsStrictly :: String -> String -> Transitions
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parseTransitionsStrictly source = fromMaybe badsource . parseTransitions
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where
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badsource = error $ "unknown transitions listed in " ++ source ++ "; upgrade git-annex!"
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showTransitionLine :: TransitionLine -> String
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showTransitionLine (TransitionLine ts t) = unwords [show t, show ts]
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parseTransitionLine :: String -> Maybe TransitionLine
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parseTransitionLine s = TransitionLine <$> pdate ds <*> readish ts
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where
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ws = words s
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ts = Prelude.head ws
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ds = unwords $ Prelude.tail ws
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pdate = parseTime defaultTimeLocale "%s%Qs" >=*> utcTimeToPOSIXSeconds
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combineTransitions :: [Transitions] -> Transitions
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combineTransitions = S.unions
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transitionList :: Transitions -> [Transition]
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transitionList = map transition . S.elems
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{- Typically ran with Annex.Branch.change, but we can't import Annex.Branch
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- here since it depends on this module. -}
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recordTransitions :: (FilePath -> (String -> String) -> Annex ()) -> Transitions -> Annex ()
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recordTransitions changer t = do
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changer transitionsLog $
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showTransitions . S.union t . parseTransitionsStrictly "local"
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