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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.CatFile
import Utility.Batch
import qualified Data.Set as S
import System.Process (std_err, std_out)
import Control.Concurrent
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.
-
- Some forms of corruption will crash fsck in ways that does not let it
- output the sha of the broken object. In such a case, Nothing will be
- returned. In this case, to find broken objects, re-run with tryharder
- set to True. This makes fsck run in verbose mode, so it prints out
- shas before checking them. We assume that the last sha is the one that
- it crashed on, and it may have crashed following from eg, a commit to a
- tree to a subtree. So, run git show on the sha, and examin the stderr
- to find an actual bad sha.
-}
findBroken :: Bool -> Bool -> Repo -> IO FsckResults
findBroken batchmode tryharder r = do
(output, fsckok) <- processTranscript command' (toCommand params') Nothing
let objs = findShas output
if fsckok || not tryharder
then do
badobjs <- findMissing objs r
if S.null badobjs && not fsckok
then return Nothing
else return $ Just badobjs
else case lastMaybe objs of
Nothing -> return Nothing
Just o -> do
p@(_, _, _, pid) <- createProcess $
( proc "git" $ toCommand $ gitCommandLine [ Param "show", Param $ show o ] r )
{ std_err = CreatePipe
, std_out = CreatePipe
}
void $ forkIO $ void $ hGetContents (stdoutHandle p)
objs' <- findShas <$>
hGetContentsStrict (stderrHandle p)
badobjs <- findMissing objs' r
ifM (checkSuccessProcess pid)
( if S.null badobjs
then return Nothing
else return $ Just badobjs
, return $ Just $ S.singleton o
)
where
(command, params) = ("git", fsckParams tryharder 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.
-
- Note that catting a corrupt object will cause cat-file to crash;
- this is detected and it's restarted.
-}
findMissing :: [Sha] -> Repo -> IO MissingObjects
findMissing objs r = go objs [] =<< start
where
start = catFileStart' False r
go [] c h = do
void $ tryIO $ catFileStop h
return $ S.fromList c
go (o:os) c h = do
v <- tryIO $ isNothing <$> catObjectDetails h o
case v of
Left _ -> do
void $ tryIO $ catFileStop h
go os (o:c) =<< start
Right True -> go os (o:c) h
Right False -> go os c h
findShas :: String -> [Sha]
findShas = catMaybes . map extractSha . concat . map words . lines
fsckParams :: Bool -> Repo -> [CommandParam]
fsckParams verbose = gitCommandLine $
[ Param "fsck"
, Param "--no-dangling"
, Param "--no-reflogs"
] ++ if verbose then [ Param "--verbose" ] else []
|
