71 lines
1.8 KiB
Haskell
71 lines
1.8 KiB
Haskell
{- git cat-file interface
|
|
-
|
|
- Copyright 2011 Joey Hess <joey@kitenet.net>
|
|
-
|
|
- Licensed under the GNU GPL version 3 or higher.
|
|
-}
|
|
|
|
module Git.CatFile (
|
|
CatFileHandle,
|
|
catFileStart,
|
|
catFileStop,
|
|
catFile,
|
|
catObject
|
|
) where
|
|
|
|
import System.IO
|
|
import qualified Data.ByteString.Char8 as S
|
|
import qualified Data.ByteString.Lazy.Char8 as L
|
|
|
|
import Common
|
|
import Git
|
|
import Git.Sha
|
|
import Git.Command
|
|
import qualified Utility.CoProcess as CoProcess
|
|
|
|
type CatFileHandle = CoProcess.CoProcessHandle
|
|
|
|
catFileStart :: Repo -> IO CatFileHandle
|
|
catFileStart = CoProcess.start "git" . toCommand . gitCommandLine
|
|
[ Param "cat-file"
|
|
, Param "--batch"
|
|
]
|
|
|
|
catFileStop :: CatFileHandle -> IO ()
|
|
catFileStop = CoProcess.stop
|
|
|
|
{- Reads a file from a specified branch. -}
|
|
catFile :: CatFileHandle -> Branch -> FilePath -> IO L.ByteString
|
|
catFile h branch file = catObject h $ Ref $ show branch ++ ":" ++ file
|
|
|
|
{- Uses a running git cat-file read the content of an object.
|
|
- Objects that do not exist will have "" returned. -}
|
|
catObject :: CatFileHandle -> Ref -> IO L.ByteString
|
|
catObject h object = CoProcess.query h send receive
|
|
where
|
|
send to = hPutStrLn to $ show object
|
|
receive from = do
|
|
header <- hGetLine from
|
|
case words header of
|
|
[sha, objtype, size]
|
|
| length sha == shaSize &&
|
|
validobjtype objtype ->
|
|
case reads size of
|
|
[(bytes, "")] -> readcontent bytes from
|
|
_ -> dne
|
|
| otherwise -> dne
|
|
_
|
|
| header == show object ++ " missing" -> dne
|
|
| otherwise -> error $ "unknown response from git cat-file " ++ header
|
|
readcontent bytes from = do
|
|
content <- S.hGet from bytes
|
|
c <- hGetChar from
|
|
when (c /= '\n') $
|
|
error "missing newline from git cat-file"
|
|
return $ L.fromChunks [content]
|
|
dne = return L.empty
|
|
validobjtype t
|
|
| t == "blob" = True
|
|
| t == "commit" = True
|
|
| t == "tree" = True
|
|
| otherwise = False
|