git-annex/Command/Unused.hs
2010-11-15 18:04:19 -04:00

80 lines
2.1 KiB
Haskell

{- git-annex command
-
- Copyright 2010 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Command.Unused where
import Control.Monad.State (liftIO)
import qualified Data.Map as M
import Command
import Types
import Core
import Messages
import Locations
import qualified Annex
seek :: [SubCmdSeek]
seek = [withNothing start]
{- Finds unused content in the annex. -}
start :: SubCmdStartNothing
start = do
showStart "unused" ""
return $ Just perform
perform :: SubCmdPerform
perform = do
ok <- checkUnused
if ok
then return $ Just $ return True
else return Nothing
checkUnused :: Annex Bool
checkUnused = do
showNote "checking for unused data..."
unused <- unusedKeys
if (null unused)
then return True
else do
let list = number 1 unused
g <- Annex.gitRepo
liftIO $ writeFile (annexUnusedLog g) $ unlines $
map (\(n, k) -> show n ++ " " ++ show k) list
showLongNote $ w list
return False
where
w u = unlines $
["Some annexed data is no longer pointed to by any files in the repository:",
" NUMBER KEY"]
++ (map (\(n, k) -> " " ++ (pad 6 $ show n) ++ " " ++ show k) u) ++
["(To see where data was previously used, try: git log --stat -S'KEY')",
"(To remove unwanted data: git-annex dropunused NUMBER)"]
pad n s = s ++ replicate (n - length s) ' '
number :: Integer -> [a] -> [(Integer, a)]
number _ [] = []
number n (x:xs) = (n, x):(number (n+1) xs)
{- 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