git-annex/Git/Command.hs
2012-07-19 00:57:40 -04:00

70 lines
2.3 KiB
Haskell

{- running git commands
-
- Copyright 2010-2012 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Git.Command where
import System.Posix.Process (getAnyProcessStatus)
import Common
import Git
import Git.Types
{- Constructs a git command line operating on the specified repo. -}
gitCommandLine :: [CommandParam] -> Repo -> [CommandParam]
gitCommandLine params Repo { location = l@(Local _ _ ) } = setdir : settree ++ params
where
setdir = Param $ "--git-dir=" ++ gitdir l
settree = case worktree l of
Nothing -> []
Just t -> [Param $ "--work-tree=" ++ t]
gitCommandLine _ repo = assertLocal repo $ error "internal"
{- Runs git in the specified repo. -}
runBool :: String -> [CommandParam] -> Repo -> IO Bool
runBool subcommand params repo = assertLocal repo $
boolSystem "git" $ gitCommandLine (Param subcommand : params) repo
{- Runs git in the specified repo, throwing an error if it fails. -}
run :: String -> [CommandParam] -> Repo -> IO ()
run subcommand params repo = assertLocal repo $
unlessM (runBool subcommand params repo) $
error $ "git " ++ subcommand ++ " " ++ show params ++ " failed"
{- Runs a git subcommand and returns its output, lazily.
-
- Note that this leaves the git process running, and so zombies will
- result unless reap is called.
-}
pipeRead :: [CommandParam] -> Repo -> IO String
pipeRead params repo = assertLocal repo $
withHandle StdoutHandle createBackgroundProcess p $ \h -> do
fileEncoding h
hGetContents h
where
p = proc "git" $ toCommand $ gitCommandLine params repo
{- Runs a git subcommand, feeding it input, and returning its output,
- which is expected to be fairly small, since it's all read into memory
- strictly. -}
pipeWriteRead :: [CommandParam] -> String -> Repo -> IO String
pipeWriteRead params s repo = assertLocal repo $
writeReadProcess "git" (toCommand $ gitCommandLine params repo) s
{- Reads null terminated output of a git command (as enabled by the -z
- parameter), and splits it. -}
pipeNullSplit :: [CommandParam] -> Repo -> IO [String]
pipeNullSplit params repo =
filter (not . null) . split sep <$> pipeRead params repo
where
sep = "\0"
{- Reaps any zombie git processes. -}
reap :: IO ()
reap = do
-- throws an exception when there are no child processes
catchDefaultIO (getAnyProcessStatus False True) Nothing
>>= maybe noop (const reap)