git-annex/Git/CheckIgnore.hs
2015-01-21 12:50:09 -04:00

71 lines
1.9 KiB
Haskell

{- git check-ignore interface
-
- Copyright 2013 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Git.CheckIgnore (
CheckIgnoreHandle,
checkIgnoreStart,
checkIgnoreStop,
checkIgnored
) where
import Common
import Git
import Git.Command
import qualified Git.Version
import qualified Utility.CoProcess as CoProcess
import System.IO.Error
type CheckIgnoreHandle = CoProcess.CoProcessHandle
{- Starts git check-ignore running, and returns a handle.
-
- This relies on git check-ignore --non-matching -v outputting
- lines for both matching an non-matching files. Also relies on
- GIT_FLUSH behavior flushing the output buffer when git check-ignore
- is piping to us.
-
- The first version of git to support what we need is 1.8.4.
- Nothing is returned if an older git is installed.
-}
checkIgnoreStart :: Repo -> IO (Maybe CheckIgnoreHandle)
checkIgnoreStart repo = ifM supportedGitVersion
( Just <$> (CoProcess.rawMode =<< gitCoProcessStart True params repo)
, return Nothing
)
where
params =
[ Param "check-ignore"
, Params "-z --stdin --verbose --non-matching"
]
supportedGitVersion :: IO Bool
supportedGitVersion = do
v <- Git.Version.installed
return $ v >= Git.Version.normalize "1.8.4"
checkIgnoreStop :: CheckIgnoreHandle -> IO ()
checkIgnoreStop = CoProcess.stop
{- Returns True if a file is ignored. -}
checkIgnored :: CheckIgnoreHandle -> FilePath -> IO Bool
checkIgnored h file = CoProcess.query h send (receive "")
where
send to = do
hPutStr to $ file ++ "\0"
hFlush to
receive c from = do
s <- hGetSomeString from 1024
if null s
then eofError
else do
let v = c ++ s
maybe (receive v from) return (parse v)
parse s = case segment (== '\0') s of
(_source:_line:pattern:_pathname:_eol:[]) -> Just $ not $ null pattern
_ -> Nothing
eofError = ioError $ mkIOError userErrorType "git cat-file EOF" Nothing Nothing