git-annex/Command/Fsck.hs
2010-11-08 15:15:21 -04:00

65 lines
1.6 KiB
Haskell

{- git-annex command
-
- Copyright 2010 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Command.Fsck where
import qualified Data.Map as M
import Command
import Types
import Core
import Messages
{- Checks the whole annex for problems. -}
start :: SubCmdStart
start = do
showStart "fsck" ""
return $ Just perform
perform :: SubCmdPerform
perform = do
ok <- checkUnused
if (ok)
then return $ Just $ return True
else do
showLongNote "Possible problems detected."
return Nothing
checkUnused :: Annex Bool
checkUnused = do
showNote "checking for unused data..."
unused <- unusedKeys
if (null unused)
then return True
else do
showLongNote $ w unused
return False
where
w u = unlines $ [
"Some annexed data is no longer pointed to by any files in the repository.",
"If this data is no longer needed, it can be removed using git-annex dropkey:"
] ++ map (\k -> " " ++ show k) u
{- Finds keys whose content is present, but that do not seem to be used
- by any files in the git repo. -}
unusedKeys :: Annex [Key]
unusedKeys = do
present <- getKeysPresent
referenced <- getKeysReferenced
-- Constructing a single map, of the set that tends to be smaller,
-- appears more efficient in both memory and CPU than constructing
-- and taking the M.difference of two maps.
let present_m = existsMap present
let unused_m = remove referenced present_m
return $ M.keys unused_m
where
remove [] m = m
remove (x:xs) m = remove xs $ M.delete x m
existsMap :: Ord k => [k] -> M.Map k Int
existsMap l = M.fromList $ map (\k -> (k, 1)) l