git-annex/Command/DiffDriver.hs
Joey Hess fa62c98910
simplify and speed up Utility.FileSystemEncoding
This eliminates the distinction between decodeBS and decodeBS', encodeBS
and encodeBS', etc. The old implementation truncated at NUL, and the
primed versions had to do extra work to avoid that problem. The new
implementation does not truncate at NUL, and is also a lot faster.
(Benchmarked at 2x faster for decodeBS and 3x for encodeBS; more for the
primed versions.)

Note that filepath-bytestring 1.4.2.1.8 contains the same optimisation,
and upgrading to it will speed up to/fromRawFilePath.

AFAIK, nothing relied on the old behavior of truncating at NUL. Some
code used the faster versions in places where I was sure there would not
be a NUL. So this change is unlikely to break anything.

Also, moved s2w8 and w82s out of the module, as they do not involve
filesystem encoding really.

Sponsored-by: Shae Erisson on Patreon
2021-08-11 12:13:31 -04:00

103 lines
2.7 KiB
Haskell

{- git-annex command
-
- Copyright 2014-2021 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
module Command.DiffDriver where
import Command
import Annex.Content
import Annex.Link
import Git.Types
cmd :: Command
cmd = dontCheck repoExists $
command "diffdriver" SectionPlumbing
"external git diff driver shim"
("-- cmd --") (withParams seek)
seek :: CmdParams -> CommandSeek
seek = withWords (commandAction . start)
start :: [String] -> CommandStart
start opts = do
let (req, differ) = parseReq opts
void $ liftIO . exitBool =<< liftIO . differ =<< fixupReq req
stop
data Req
= Req
{ rPath :: FilePath
, rOldFile :: FilePath
, rOldHex :: String
, rOldMode :: String
, rNewFile :: FilePath
, rNewHex :: String
, rNewMode ::String
}
| UnmergedReq
{ rPath :: FilePath
}
type Differ = Req -> IO Bool
serializeReq :: Req -> [CommandParam]
serializeReq req@(UnmergedReq {}) = [Param $ rPath req]
serializeReq req@(Req {}) = map Param
[ rPath req
, rOldFile req
, rOldHex req
, rOldMode req
, rNewFile req
, rNewHex req
, rNewMode req
]
parseReq :: [String] -> (Req, Differ)
parseReq opts = case separate (== "--") opts of
(c:ps, l) -> (mk l, externalDiffer c ps)
([],_) -> badopts
where
mk (path:old_file:old_hex:old_mode:new_file:new_hex:new_mode:[]) =
Req
{ rPath = path
, rOldFile = old_file
, rOldHex = old_hex
, rOldMode = old_mode
, rNewFile = new_file
, rNewHex = new_hex
, rNewMode = new_mode
}
mk (unmergedpath:[]) = UnmergedReq { rPath = unmergedpath }
mk _ = badopts
badopts = giveup $ "Unexpected input: " ++ unwords opts
{- Check if either file is a symlink to a git-annex object,
- which git-diff will leave as a normal file containing the link text.
-
- Also check if either file is a pointer file, as used for unlocked files.
-
- In either case, adjust the Req to instead point to the actual
- location of the annexed object (which may or may not be present).
-}
fixupReq :: Req -> Annex Req
fixupReq req@(UnmergedReq {}) = return req
fixupReq req@(Req {}) =
check rOldFile rOldMode (\r f -> r { rOldFile = f }) req
>>= check rNewFile rNewMode (\r f -> r { rNewFile = f })
where
check getfile getmode setfile r = case readTreeItemType (encodeBS (getmode r)) of
Just TreeSymlink -> do
v <- getAnnexLinkTarget' f False
maybe (return r) repoint (parseLinkTargetOrPointer =<< v)
_ -> maybe (return r) repoint =<< liftIO (isPointerFile f)
where
repoint k = withObjectLoc k $
pure . setfile r . fromRawFilePath
f = toRawFilePath (getfile r)
externalDiffer :: String -> [String] -> Differ
externalDiffer c ps = \req -> boolSystem c (map Param ps ++ serializeReq req )