split out Git/Command.hs

Git/Command.hs

@@ -0,0 +1,82 @@
+{- running git commands
+ -
+ - Copyright 2010, 2011 Joey Hess <joey@kitenet.net>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+module Git.Command where
+
+import qualified Data.ByteString.Lazy.Char8 as L
+
+import Common
+import Git
+import Git.Types
+
+{- Constructs a git command line operating on the specified repo. -}
+gitCommandLine :: [CommandParam] -> Repo -> [CommandParam]
+gitCommandLine params repo@(Repo { location = Dir _ } ) =
+	-- force use of specified repo via --git-dir and --work-tree
+	[ Param ("--git-dir=" ++ gitDir repo)
+	, Param ("--work-tree=" ++ workTree repo)
+	] ++ params
+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 $
+	runBool subcommand params repo
+		>>! error $ "git " ++ 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 L.ByteString
+pipeRead params repo = assertLocal repo $ do
+	(_, h) <- hPipeFrom "git" $ toCommand $ gitCommandLine params repo
+	hSetBinaryMode h True
+	L.hGetContents h
+
+{- Runs a git subcommand, feeding it input.
+ - You should call either getProcessStatus or forceSuccess on the PipeHandle. -}
+pipeWrite :: [CommandParam] -> L.ByteString -> Repo -> IO PipeHandle
+pipeWrite params s repo = assertLocal repo $ do
+	(p, h) <- hPipeTo "git" (toCommand $ gitCommandLine params repo)
+	L.hPut h s
+	hClose h
+	return p
+
+{- Runs a git subcommand, feeding it input, and returning its output.
+ - You should call either getProcessStatus or forceSuccess on the PipeHandle. -}
+pipeWriteRead :: [CommandParam] -> L.ByteString -> Repo -> IO (PipeHandle, L.ByteString)
+pipeWriteRead params s repo = assertLocal repo $ do
+	(p, from, to) <- hPipeBoth "git" (toCommand $ gitCommandLine params repo)
+	hSetBinaryMode from True
+	L.hPut to s
+	hClose to
+	c <- L.hGetContents from
+	return (p, c)
+
+{- 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 = map L.unpack <$> pipeNullSplitB params repo
+
+{- For when Strings are not needed. -}
+pipeNullSplitB ::[CommandParam] -> Repo -> IO [L.ByteString]
+pipeNullSplitB params repo = filter (not . L.null) . L.split '\0' <$>
+	pipeRead params repo
+
+{- Reaps any zombie git processes. -}
+reap :: IO ()
+reap = do
+	-- throws an exception when there are no child processes
+	r <- catchDefaultIO (getAnyProcessStatus False True) Nothing
+	maybe (return ()) (const reap) r