git-annex/Database/Fsck.hs
2015-02-22 16:57:19 -04:00

106 lines
2.8 KiB
Haskell

{- Sqlite database used for incremental fsck.
-
- Copyright 2015 Joey Hess <id@joeyh.name>
-:
- Licensed under the GNU GPL version 3 or higher.
-}
{-# LANGUAGE QuasiQuotes, TypeFamilies, TemplateHaskell #-}
{-# LANGUAGE OverloadedStrings, GADTs, FlexibleContexts #-}
{-# LANGUAGE MultiParamTypeClasses, GeneralizedNewtypeDeriving #-}
{-# LANGUAGE RankNTypes #-}
module Database.Fsck (
FsckHandle,
newPass,
openDb,
closeDb,
addDb,
inDb,
FsckedId,
) where
import Database.Types
import qualified Database.Handle as H
import Locations
import Utility.PosixFiles
import Utility.Exception
import Annex
import Types.Key
import Types.UUID
import Annex.Perms
import Annex.LockFile
import Database.Persist.TH
import Database.Esqueleto hiding (Key)
import Control.Monad
import Control.Monad.IfElse
import Control.Monad.IO.Class (liftIO)
import System.Directory
import System.FilePath
import Data.Maybe
import Control.Applicative
data FsckHandle = FsckHandle H.DbHandle UUID
{- Each key stored in the database has already been fscked as part
- of the latest incremental fsck pass. -}
share [mkPersist sqlSettings, mkMigrate "migrateFsck"] [persistLowerCase|
Fscked
key SKey
UniqueKey key
|]
{- The database is removed when starting a new incremental fsck pass.
-
- This may fail, if other fsck processes are currently running using the
- database. Removing the database in that situation would lead to crashes
- or undefined behavior.
-}
newPass :: UUID -> Annex Bool
newPass u = isJust <$> tryExclusiveLock (gitAnnexFsckDbLock u) go
where
go = liftIO . void . tryIO . removeDirectoryRecursive
=<< fromRepo (gitAnnexFsckDbDir u)
{- Opens the database, creating it atomically if it doesn't exist yet. -}
openDb :: UUID -> Annex FsckHandle
openDb u = do
dbdir <- fromRepo (gitAnnexFsckDbDir u)
let db = dbdir </> "db"
unlessM (liftIO $ doesFileExist db) $ do
let tmpdbdir = dbdir ++ ".tmp"
let tmpdb = tmpdbdir </> "db"
liftIO $ do
createDirectoryIfMissing True tmpdbdir
H.initDb tmpdb $ void $
runMigrationSilent migrateFsck
setAnnexDirPerm tmpdbdir
setAnnexFilePerm tmpdb
liftIO $ do
void $ tryIO $ removeDirectoryRecursive dbdir
rename tmpdbdir dbdir
lockFileShared =<< fromRepo (gitAnnexFsckDbLock u)
h <- liftIO $ H.openDb db "fscked"
return $ FsckHandle h u
closeDb :: FsckHandle -> Annex ()
closeDb (FsckHandle h u) = do
liftIO $ H.closeDb h
unlockFile =<< fromRepo (gitAnnexFsckDbLock u)
addDb :: FsckHandle -> Key -> IO ()
addDb (FsckHandle h _) k = H.queueDb h 1000 $
void $ insertUnique $ Fscked sk
where
sk = toSKey k
inDb :: FsckHandle -> Key -> IO Bool
inDb (FsckHandle h _) = H.queryDb h . inDb' . toSKey
inDb' :: SKey -> SqlPersistM Bool
inDb' sk = do
r <- select $ from $ \r -> do
where_ (r ^. FsckedKey ==. val sk)
return (r ^. FsckedKey)
return $ not $ null r