git-annex/Annex/CatFile.hs
Joey Hess 9290095fc2 improve type signatures with a Ref newtype
In git, a Ref can be a Sha, or a Branch, or a Tag. I added type aliases for
those. Note that this does not prevent mixing up of eg, refs and branches
at the type level. Since git really doesn't care, except rare cases like
git update-ref, or git tag -d, that seems ok for now.

There's also a tree-ish, but let's just use Ref for it. A given Sha or Ref
may or may not be a tree-ish, depending on the object type, so there seems
no point in trying to represent it at the type level.
2011-11-16 02:41:46 -04:00

31 lines
798 B
Haskell

{- git cat-file interface, with handle automatically stored in the Annex monad
-
- Copyright 2011 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Annex.CatFile (
catFile,
catFileHandle
) where
import qualified Data.ByteString.Lazy.Char8 as L
import Common.Annex
import qualified Git
import qualified Git.CatFile
import qualified Annex
catFile :: Git.Branch -> FilePath -> Annex L.ByteString
catFile branch file = do
h <- catFileHandle
liftIO $ Git.CatFile.catFile h branch file
catFileHandle :: Annex Git.CatFile.CatFileHandle
catFileHandle = maybe startup return =<< Annex.getState Annex.catfilehandle
where
startup = do
h <- inRepo Git.CatFile.catFileStart
Annex.changeState $ \s -> s { Annex.catfilehandle = Just h }
return h