git-annex/Database/Keys.hs
Joey Hess ce73a96e4e
use InodeCache when dropping a key to see if a pointer file can be safely reset
The Keys database can hold multiple inode caches for a given key. One for
the annex object, and one for each pointer file, which may not be hard
linked to it.

Inode caches for a key are recorded when its content is added to the annex,
but only if it has known pointer files. This is to avoid the overhead of
maintaining the database when not needed.

When the smudge filter outputs a file's content, the inode cache is not
updated, because git's smudge interface doesn't let us write the file. So,
dropping will fall back to doing an expensive verification then. Ideally,
git's interface would be improved, and then the inode cache could be
updated then too.
2015-12-09 17:54:54 -04:00

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{- Sqlite database of information about Keys
-
- 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.Keys (
DbHandle,
openDb,
closeDb,
shutdown,
addAssociatedFile,
getAssociatedFiles,
removeAssociatedFile,
storeInodeCaches,
addInodeCaches,
getInodeCaches,
removeInodeCaches,
AssociatedId,
ContentId,
) where
import Database.Types
import Database.Keys.Types
import qualified Database.Handle as H
import Locations
import Common hiding (delete)
import Annex
import Types.Key
import Annex.Perms
import Annex.LockFile
import Messages
import Utility.InodeCache
import Annex.InodeSentinal
import Database.Persist.TH
import Database.Esqueleto hiding (Key)
share [mkPersist sqlSettings, mkMigrate "migrateKeysDb"] [persistLowerCase|
Associated
key SKey
file FilePath
KeyFileIndex key file
Content
key SKey
cache SInodeCache
KeyCacheIndex key cache
|]
{- Opens the database, creating it if it doesn't exist yet. -}
openDb :: Annex DbHandle
openDb = withExclusiveLock gitAnnexKeysDbLock $ do
dbdir <- fromRepo gitAnnexKeysDb
let db = dbdir </> "db"
unlessM (liftIO $ doesFileExist db) $ do
liftIO $ do
createDirectoryIfMissing True dbdir
H.initDb db $ void $
runMigrationSilent migrateKeysDb
setAnnexDirPerm dbdir
setAnnexFilePerm db
h <- liftIO $ H.openDb db "content"
-- work around https://github.com/yesodweb/persistent/issues/474
liftIO setConsoleEncoding
return $ DbHandle h
closeDb :: DbHandle -> IO ()
closeDb (DbHandle h) = H.closeDb h
withDbHandle :: (H.DbHandle -> IO a) -> Annex a
withDbHandle a = do
(DbHandle h) <- dbHandle
liftIO $ a h
dbHandle :: Annex DbHandle
dbHandle = maybe startup return =<< Annex.getState Annex.keysdbhandle
where
startup = do
h <- openDb
Annex.changeState $ \s -> s { Annex.keysdbhandle = Just h }
return h
shutdown :: Annex ()
shutdown = maybe noop go =<< Annex.getState Annex.keysdbhandle
where
go h = do
Annex.changeState $ \s -> s { Annex.keysdbhandle = Nothing }
liftIO $ closeDb h
addAssociatedFile :: Key -> FilePath -> Annex ()
addAssociatedFile k f = withDbHandle $ \h -> H.queueDb h (\_ _ -> pure True) $ do
-- If the same file was associated with a different key before,
-- remove that.
delete $ from $ \r -> do
where_ (r ^. AssociatedFile ==. val f &&. r ^. AssociatedKey ==. val sk)
void $ insertUnique $ Associated sk f
where
sk = toSKey k
{- Note that the files returned were once associated with the key, but
- some of them may not be any longer. -}
getAssociatedFiles :: Key -> Annex [FilePath]
getAssociatedFiles k = withDbHandle $ \h -> H.queryDb h $
getAssociatedFiles' $ toSKey k
getAssociatedFiles' :: SKey -> SqlPersistM [FilePath]
getAssociatedFiles' sk = do
l <- select $ from $ \r -> do
where_ (r ^. AssociatedKey ==. val sk)
return (r ^. AssociatedFile)
return $ map unValue l
removeAssociatedFile :: Key -> FilePath -> Annex ()
removeAssociatedFile k f = withDbHandle $ \h -> H.queueDb h (\_ _ -> pure True) $
delete $ from $ \r -> do
where_ (r ^. AssociatedKey ==. val sk &&. r ^. AssociatedFile ==. val f)
where
sk = toSKey k
{- Stats the files, and stores their InodeCaches. -}
storeInodeCaches :: Key -> [FilePath] -> Annex ()
storeInodeCaches k fs = withTSDelta $ \d ->
addInodeCaches k . catMaybes =<< liftIO (mapM (`genInodeCache` d) fs)
addInodeCaches :: Key -> [InodeCache] -> Annex ()
addInodeCaches k is = withDbHandle $ \h -> H.queueDb h (\_ _ -> pure True) $
forM_ is $ \i -> insertUnique $ Content (toSKey k) (toSInodeCache i)
{- A key may have multiple InodeCaches; one for the annex object, and one
- for each pointer file that is a copy of it. -}
getInodeCaches :: Key -> Annex [InodeCache]
getInodeCaches k = withDbHandle $ \h -> H.queryDb h $ do
l <- select $ from $ \r -> do
where_ (r ^. ContentKey ==. val sk)
return (r ^. ContentCache)
return $ map (fromSInodeCache. unValue) l
where
sk = toSKey k
removeInodeCaches :: Key -> Annex ()
removeInodeCaches k = withDbHandle $ \h -> H.queueDb h (\_ _ -> pure True) $
delete $ from $ \r -> do
where_ (r ^. ContentKey ==. val sk)
where
sk = toSKey k