git-annex/Annex/Magic.hs
2019-05-03 10:58:34 -04:00

59 lines
1.3 KiB
Haskell

{- Interface to libmagic
-
- Copyright 2019 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
{-# LANGUAGE CPP #-}
module Annex.Magic (
Magic,
MimeType,
MimeEncoding,
initMagicMime,
getMagicMimeType,
getMagicMimeEncoding,
) where
import Types.Mime
#ifdef WITH_MAGICMIME
import Magic
import Utility.Env
import Common
#else
type Magic = ()
#endif
initMagicMime :: IO (Maybe Magic)
#ifdef WITH_MAGICMIME
initMagicMime = catchMaybeIO $ do
m <- magicOpen [MagicMime]
liftIO $ getEnv "GIT_ANNEX_DIR" >>= \case
Nothing -> magicLoadDefault m
Just d -> magicLoad m
(d </> "magic" </> "magic.mgc")
return m
#else
initMagicMime = return Nothing
#endif
getMagicMime :: Magic -> FilePath -> IO (Maybe (MimeType, MimeEncoding))
#ifdef WITH_MAGICMIME
getMagicMime m f = Just . parse <$> magicFile m f
where
parse s =
let (mimetype, rest) = separate (== ';') s
in case rest of
(' ':'c':'h':'a':'r':'s':'e':'t':'=':mimeencoding) ->
(mimetype, mimeencoding)
_ -> (mimetype, "")
#else
getMagicMime _ _ = return Nothing
#endif
getMagicMimeType :: Magic -> FilePath -> IO (Maybe MimeType)
getMagicMimeType m f = fmap fst <$> getMagicMime m f
getMagicMimeEncoding :: Magic -> FilePath -> IO (Maybe MimeEncoding)
getMagicMimeEncoding m f = fmap snd <$> getMagicMime m f