rethought distributed fsck; instead add activity.log and expire command

This is much more space efficient!

Command/Expire.hs

@@ -0,0 +1,100 @@
+{- git-annex command
+ -
+ - Copyright 2015 Joey Hess <id@joeyh.name>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+module Command.Expire where
+
+import Common.Annex
+import Command
+import Logs.Activity
+import Logs.UUID
+import Logs.MapLog
+import Logs.Trust
+import Annex.UUID
+import qualified Remote
+import Utility.HumanTime
+
+import Data.Time.Clock.POSIX
+import qualified Data.Map as M
+
+cmd :: [Command]
+cmd = [withOptions [activityOption] $ command "expire" paramExpire seek
+	SectionMaintenance "expire inactive repositories"]
+
+paramExpire :: String
+paramExpire = (paramRepeating $ paramOptional paramRemote ++ ":" ++ paramTime)
+
+activityOption :: Option
+activityOption = fieldOption [] "activity" "Name" "specify activity"
+
+seek :: CommandSeek
+seek ps = do
+	expire <- parseExpire ps
+	wantact <- getOptionField activityOption (pure . parseActivity)
+	actlog <- lastActivities wantact
+	u <- getUUID
+	us <- filter (/= u) . M.keys <$> uuidMap
+	descs <- uuidMap
+	seekActions $ pure $ map (start expire actlog descs) us
+
+start :: Expire -> Log Activity -> M.Map UUID String -> UUID -> CommandStart
+start (Expire expire) actlog descs u =
+	case lastact of
+		Just ent | notexpired ent -> checktrust (== DeadTrusted) $ do
+			showStart "unexpire" desc
+			showNote =<< whenactive
+			trustSet u SemiTrusted
+		_ -> checktrust (/= DeadTrusted) $ do
+			showStart "expire" desc
+			showNote =<< whenactive
+			trustSet u DeadTrusted
+  where
+	lastact = changed <$> M.lookup u actlog
+	whenactive = case lastact of
+		Just (Date t) -> do
+			d <- liftIO $ durationSince $ posixSecondsToUTCTime t
+			return $ "last active: " ++ fromDuration d ++ " ago"
+		_  -> return "no activity"
+	desc = fromUUID u ++ " " ++ fromMaybe "" (M.lookup u descs)
+	notexpired ent = case ent of
+		Unknown -> False
+		Date t -> case lookupexpire of
+			Just (Just expiretime) -> t >= expiretime
+			_ -> True
+	lookupexpire = headMaybe $ catMaybes $
+		map (`M.lookup` expire) [Just u, Nothing]
+	checktrust want a = ifM (want <$> lookupTrust u)
+		( do
+			void a
+			next $ next $ return True
+		, stop
+		)
+
+data Expire = Expire (M.Map (Maybe UUID) (Maybe POSIXTime))
+
+parseExpire :: [String] -> Annex Expire
+parseExpire [] = error "Specify an expire time."
+parseExpire ps = do
+	now <- liftIO getPOSIXTime
+	Expire . M.fromList <$> mapM (parse now) ps
+  where
+	parse now s = case separate (== ':') s of
+		(t, []) -> return (Nothing, parsetime now t)
+		(n, t) -> do
+			r <- Remote.nameToUUID n
+			return (Just r, parsetime now t)
+	parsetime _ "never" = Nothing
+	parsetime now s = case parseDuration s of
+		Nothing -> error $ "bad expire time: " ++ s
+		Just d -> Just (now - durationToPOSIXTime d)
+
+parseActivity :: Maybe String -> Maybe Activity
+parseActivity Nothing = Nothing
+parseActivity (Just s) = case readish s of
+	Nothing -> error $ "Unknown activity. Choose from: " ++ 
+		unwords (map show [minBound..maxBound :: Activity])
+	Just v -> Just v
+