git-annex/Database/Types.hs
Joey Hess cf260d9a15
Fix storing of filenames of v6 unlocked files when the filename is not representable in the current locale.
This is a mostly backwards compatable change. I broke backwards
compatability in the case where a filename starts with double-quote.
That seems likely to be very rare, and v6 unlocked files are a new feature
anyway, and fsck needs to fix missing associated file mappings anyway. So,
I decided that is good enough.

The encoding used is to just show the String when it contains a problem
character. While that adds some overhead to addAssociatedFile and
removeAssociatedFile, those are not called very often. This approach has
minimal decode overhead, because most filenames won't be encoded that way,
and it only has to look for the leading double-quote to skip the expensive
read. So, getAssociatedFiles remains fast.

I did consider using ByteString instead, but getting a FilePath converted
with all chars intact, even surrigates, is difficult, and it looks like
instance PersistField ByteString uses Text, which I don't trust for problem
encoded data. It would probably be slower too, and it would make the
database less easy to inspect manually.
2016-02-14 16:37:25 -04:00

95 lines
2.3 KiB
Haskell

{- types for SQL databases
-
- Copyright 2015-2016 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
{-# LANGUAGE TemplateHaskell #-}
module Database.Types where
import Database.Persist.TH
import Data.Maybe
import Data.Char
import Utility.PartialPrelude
import Types.Key
import Utility.InodeCache
-- A serialized Key
newtype SKey = SKey String
deriving (Show, Read)
toSKey :: Key -> SKey
toSKey = SKey . key2file
fromSKey :: SKey -> Key
fromSKey (SKey s) = fromMaybe (error $ "bad serialied Key " ++ s) (file2key s)
derivePersistField "SKey"
-- A Key index. More efficient than SKey, but its Read instance does not
-- work when it's used in any kind of complex data structure.
newtype IKey = IKey String
instance Read IKey where
readsPrec _ s = [(IKey s, "")]
instance Show IKey where
show (IKey s) = s
toIKey :: Key -> IKey
toIKey = IKey . key2file
fromIKey :: IKey -> Key
fromIKey (IKey s) = fromMaybe (error $ "bad serialied Key " ++ s) (file2key s)
derivePersistField "IKey"
-- A serialized InodeCache
newtype SInodeCache = I String
deriving (Show, Read)
toSInodeCache :: InodeCache -> SInodeCache
toSInodeCache = I . showInodeCache
fromSInodeCache :: SInodeCache -> InodeCache
fromSInodeCache (I s) = fromMaybe (error $ "bad serialized InodeCache " ++ s) (readInodeCache s)
derivePersistField "SInodeCache"
-- A serialized FilePath.
--
-- Not all unicode characters round-trip through sqlite. In particular,
-- surrigate code points do not. So, escape the FilePath. But, only when
-- it contains such characters.
newtype SFilePath = SFilePath String
-- Note that Read instance does not work when used in any kind of complex
-- data structure.
instance Read SFilePath where
readsPrec _ s = [(SFilePath s, "")]
instance Show SFilePath where
show (SFilePath s) = s
toSFilePath :: FilePath -> SFilePath
toSFilePath s@('"':_) = SFilePath (show s)
toSFilePath s
| any needsescape s = SFilePath (show s)
| otherwise = SFilePath s
where
needsescape c = case generalCategory c of
Surrogate -> True
PrivateUse -> True
NotAssigned -> True
_ -> False
fromSFilePath :: SFilePath -> FilePath
fromSFilePath (SFilePath s@('"':_)) =
fromMaybe (error "bad serialized SFilePath " ++ s) (readish s)
fromSFilePath (SFilePath s) = s
derivePersistField "SFilePath"