rekey: New plumbing level command, can be used to change the keys used for files en masse.

Command/ReKey.hs

@@ -0,0 +1,46 @@
+{- git-annex command
+ -
+ - Copyright 2012 Joey Hess <joey@kitenet.net>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+module Command.ReKey where
+
+import Common.Annex
+import Command
+import qualified Annex
+import Types.Key
+import Annex.Content
+import qualified Command.Migrate
+
+def :: [Command]
+def = [command "rekey"
+	(paramOptional $ paramRepeating $ paramPair paramPath paramKey)
+	seek "change keys used for files"]
+
+seek :: [CommandSeek]
+seek = [withPairs start]
+
+start :: (FilePath, String) -> CommandStart
+start (file, keyname) = ifAnnexed file go stop
+	where
+		newkey = fromMaybe (error "bad key") $ readKey keyname
+		go (oldkey, _)
+			| oldkey == newkey = stop
+			| otherwise = do
+				showStart "rekey" file
+				next $ perform file oldkey newkey
+
+perform :: FilePath -> Key -> Key -> CommandPerform
+perform file oldkey newkey = do
+	present <- inAnnex oldkey
+	_ <- if present
+		then do
+			src <- inRepo $ gitAnnexLocation oldkey
+			Command.Migrate.linkKey src newkey
+		else do
+			unlessM (Annex.getState Annex.force) $
+				error $ file ++ " is not available (use --force to override)"
+			return True
+	next $ Command.Migrate.cleanup file oldkey newkey