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|
{- git fsck interface
-
- Copyright 2013 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Git.Fsck (
FsckResults,
MissingObjects,
findBroken,
foundBroken,
findMissing,
) where
import Common
import Git
import Git.Command
import Git.Sha
import Git.Objects
import Utility.Batch
import Utility.Hash
import qualified Data.Set as S
import qualified Data.ByteString.Lazy as L
type MissingObjects = S.Set Sha
{- If fsck succeeded, Just a set of missing objects it found.
- If it failed, Nothing. -}
type FsckResults = Maybe MissingObjects
{- Runs fsck to find some of the broken objects in the repository.
- May not find all broken objects, if fsck fails on bad data in some of
- the broken objects it does find.
-
- Strategy: Rather than parsing fsck's current specific output,
- look for anything in its output (both stdout and stderr) that appears
- to be a git sha. Not all such shas are of broken objects, so ask git
- to try to cat the object, and see if it fails.
-}
findBroken :: Bool -> Repo -> IO FsckResults
findBroken batchmode r = do
(output, fsckok) <- processTranscript command' (toCommand params') Nothing
let objs = findShas output
badobjs <- findMissing objs r
if S.null badobjs && not fsckok
then return Nothing
else return $ Just badobjs
where
(command, params) = ("git", fsckParams r)
(command', params')
| batchmode = toBatchCommand (command, params)
| otherwise = (command, params)
foundBroken :: FsckResults -> Bool
foundBroken Nothing = True
foundBroken (Just s) = not (S.null s)
{- Finds objects that are missing from the git repsitory, or are corrupt.
-
- This does not use git cat-file --batch, because catting a corrupt
- object can cause it to crash, or to report incorrect size information.a
-
- Note that git cat-file -p can succeed in printing out objects that
- are corrupt. Since its output may be a pretty-printed object, or may be
- a blob, it cannot be verified. So, this has false negatives.
-
- As a secondary check, if cat-file says the object is there, check if
- the loose object file is available, and if so, try taking its sha1
- ourselves. This will always work once all packs have been unpacked.
-}
findMissing :: [Sha] -> Repo -> IO MissingObjects
findMissing objs r = S.fromList <$> filterM (not <$$> present) objs
where
present o =
either (const $ return False) (const $ verifyLooseObject o r)
=<< tryIO (cat o)
cat o = runQuiet
[ Param "cat-file"
, Param "-p"
, Param (show o)
] r
verifyLooseObject :: Sha -> Repo -> IO Bool
verifyLooseObject s r = do
sha <- sha1 <$> L.readFile (looseObjectFile r s)
return $ show sha == show s
findShas :: String -> [Sha]
findShas = catMaybes . map extractSha . concat . map words . lines
fsckParams :: Repo -> [CommandParam]
fsckParams = gitCommandLine $
[ Param "fsck"
, Param "--no-dangling"
, Param "--no-reflogs"
]
|
