git-annex/Git/HashObject.hs
Joey Hess a6bebe3c0f
make hashFile support paths with newlines
git hash-object --stdin-paths is a newline protocol so it cannot
support them. It would help to not use absPath, when the problem
is that the repository itself is in a path with a newline. But,
there's a reason it used absPath, which is that
git hash-object --stdin-paths actually chdirs to the top of the
repository on startup! That is not documented, and I think is a bug
in git.

I considered making the path relative to the top of the repo, but
then what if this is a git bug and gets fixed? git-annex would break
horribly.

So instead, keep the absPath, but when the path contains a newline,
fall back to running git hash-object once per file, which avoids
the problem with newlines and --stdin-paths. It will be slower,
but this is an edge case. (Similar slow code paths are already used
elsewhere when dealing with filenames with newlines and other parts
of git that use line-based protocols.)

Sponsored-by: Dartmouth College's Datalad project
2023-03-13 13:43:40 -04:00

98 lines
3.2 KiB
Haskell

{- git hash-object interface
-
- Copyright 2011-2023 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
{-# LANGUAGE CPP #-}
module Git.HashObject where
import Common
import Git
import Git.Sha
import Git.Command
import Git.Types
import qualified Utility.CoProcess as CoProcess
import Utility.Tmp
import qualified Data.ByteString as S
import qualified Data.ByteString.Char8 as S8
import qualified Data.ByteString.Lazy as L
import Data.ByteString.Builder
import Data.Char
data HashObjectHandle = HashObjectHandle CoProcess.CoProcessHandle Repo [CommandParam]
hashObjectStart :: Bool -> Repo -> IO HashObjectHandle
hashObjectStart writeobject repo = do
h <- gitCoProcessStart True (ps ++ [Param "--stdin-paths"]) repo
return (HashObjectHandle h repo ps)
where
ps = catMaybes
[ Just (Param "hash-object")
, if writeobject then Just (Param "-w") else Nothing
, Just (Param "--no-filters")
]
hashObjectStop :: HashObjectHandle -> IO ()
hashObjectStop (HashObjectHandle h _ _) = CoProcess.stop h
{- Injects a file into git, returning the Sha of the object. -}
hashFile :: HashObjectHandle -> RawFilePath -> IO Sha
hashFile hdl@(HashObjectHandle h _ _) file = do
-- git hash-object chdirs to the top of the repository on
-- start, so if the filename is relative, it will
-- not work. This seems likely to be a git bug.
-- So, make the filename absolute, which will work now
-- and also if git's behavior later changes.
file' <- absPath file
if newline `S.elem` file'
then hashFile' hdl file
else CoProcess.query h (send file') receive
where
send file' to = S8.hPutStrLn to file'
receive from = getSha "hash-object" $ S8.hGetLine from
newline = fromIntegral (ord '\n')
{- Runs git hash-object once per call, rather than using a running
- one, so is slower. But, is able to handle newlines in the filepath,
- which --stdin-paths cannot. -}
hashFile' :: HashObjectHandle -> RawFilePath -> IO Sha
hashFile' (HashObjectHandle _ repo ps) file = getSha "hash-object" $
pipeReadStrict (ps ++ [File (fromRawFilePath file)]) repo
class HashableBlob t where
hashableBlobToHandle :: Handle -> t -> IO ()
instance HashableBlob L.ByteString where
hashableBlobToHandle = L.hPut
instance HashableBlob S.ByteString where
hashableBlobToHandle = S.hPut
instance HashableBlob Builder where
hashableBlobToHandle = hPutBuilder
{- Injects a blob into git. Unfortunately, the current git-hash-object
- interface does not allow batch hashing without using temp files. -}
hashBlob :: HashableBlob b => HashObjectHandle -> b -> IO Sha
hashBlob h b = withTmpFile "hash" $ \tmp tmph -> do
hashableBlobToHandle tmph b
hClose tmph
hashFile h (toRawFilePath tmp)
{- Injects some content into git, returning its Sha.
-
- Avoids using a tmp file, but runs a new hash-object command each
- time called. -}
hashObject :: ObjectType -> String -> Repo -> IO Sha
hashObject objtype content = hashObject' objtype (flip hPutStr content)
hashObject' :: ObjectType -> (Handle -> IO ()) -> Repo -> IO Sha
hashObject' objtype writer repo = getSha subcmd $
pipeWriteRead (map Param params) (Just writer) repo
where
subcmd = "hash-object"
params = [subcmd, "-t", decodeBS (fmtObjectType objtype), "-w", "--stdin", "--no-filters"]