vicfg: New command, allows editing (or simply viewing) most of the repository configuration settings stored in the git-annex branch.

Incomplete; I need to finish parsing and saving. This will also be used
for editing transfer control expresssions.

Removed the group display from the status output, I didn't really
like that format, and vicfg can be used to see as well as edit rempository
group membership.

Command/Vicfg.hs

@@ -0,0 +1,115 @@
+{- git-annex command
+ -
+ - Copyright 2012 Joey Hess <joey@kitenet.net>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+module Command.Vicfg where
+
+import qualified Data.Map as M
+import qualified Data.Set as S
+import System.Environment (getEnv)
+import Data.Tuple (swap)
+
+import Common.Annex
+import Command
+import Annex.Perms
+import Types.TrustLevel
+import Types.Group
+import Logs.Trust
+import Logs.Group
+import Remote
+
+def :: [Command]
+def = [command "vicfg" paramNothing seek
+	"edit git-annex's configuration"]
+
+seek :: [CommandSeek]
+seek = [withNothing start]
+
+start :: CommandStart
+start = do
+	f <- fromRepo gitAnnexTmpCfgFile
+	createAnnexDirectory (parentDir f)
+	liftIO . writeFile f =<< genCfg <$> getCfg
+	vicfg f
+	stop
+
+vicfg :: FilePath -> Annex ()
+vicfg f = do
+	vi <- liftIO $ catchDefaultIO "vi" $ getEnv "EDITOR"
+	-- Allow EDITOR to be processed by the shell, so it can contain options.
+	unlessM (liftIO $ boolSystem "sh" [Param "-c", Param $ unwords [vi, f]]) $
+		error $ vi ++ " exited nonzero; aborting"
+	r <- parseCfg <$> liftIO (readFileStrict f)
+	liftIO $ nukeFile f
+	case r of
+		Left s -> do
+			liftIO $ writeFile f s
+			vicfg f
+		Right c -> setCfg c
+
+data Cfg = Cfg
+	{ cfgTrustMap :: TrustMap
+	, cfgGroupMap :: M.Map UUID (S.Set Group)
+	, cfgDescriptions :: M.Map UUID String
+	}
+
+getCfg :: Annex Cfg
+getCfg = Cfg
+	<$> trustMapRaw -- without local trust overrides
+	<*> (groupsByUUID <$> groupMap)
+	<*> uuidDescriptions
+
+setCfg :: Cfg -> Annex ()
+setCfg = error "TODO setCfg"
+
+genCfg :: Cfg -> String
+genCfg cfg = unlines $ concat
+	[intro, trustintro, trust, defaulttrust, groupsintro, groups, defaultgroups]
+	where
+		intro =
+			[ com "git-annex configuration"
+			, com ""
+			, com "Changes saved to this file will be recorded in the git-annex branch."
+			, com ""
+			, com "Lines in this file have the format:"
+			, com "  setting repo = value"
+			]
+		trustintro =
+			[ ""
+			, com "Repository trust configuration"
+			, com "(Valid trust levels: " ++
+			  unwords (map showTrustLevel [Trusted .. DeadTrusted]) ++
+			  ")"
+			]
+		trust = map (\(t, u) -> line "trust" u $ showTrustLevel t) $
+			sort $ map swap $ M.toList $ cfgTrustMap cfg
+		defaulttrust = map (\u -> pcom $ line "trust" u $ showTrustLevel SemiTrusted) $
+			missing cfgTrustMap
+		groupsintro = 
+			[ ""
+			, com "Repository groups"
+			, com "(Separate group names with spaces)"
+			]
+		groups = map (\(s, u) -> line "group" u $ unwords $ S.toList s) $
+			sort $ map swap $ M.toList $ cfgGroupMap cfg
+		defaultgroups = map (\u -> pcom $ line "group" u "") $
+			missing cfgGroupMap
+		line setting u value = unwords
+			[ setting
+			, showu u
+			, "=" 
+			, value
+			]
+		com s = "# " ++ s
+		pcom s = "#" ++ s
+		showu u = fromMaybe (fromUUID u) $
+			M.lookup u (cfgDescriptions cfg)
+		missing field = S.toList $ M.keysSet (cfgDescriptions cfg) `S.difference` M.keysSet (field cfg)
+
+{- If there's a parse error, returns a new version of the file,
+ - with the problem lines noted. -}
+parseCfg :: String -> Either String Cfg
+parseCfg = undefined