git-annex/git-annex.hs
2010-10-14 21:10:59 -04:00

46 lines
1.3 KiB
Haskell

{- git-annex main program -}
import Control.Exception
import System.IO
import System.Environment
import qualified Annex
import Types
import Core
import Commands
import Annex
import qualified GitRepo as Git
main = do
args <- getArgs
(flags, actions) <- parseCmd args
gitrepo <- Git.repoFromCwd
state <- new gitrepo
tryRun state $ [startup flags] ++ actions ++ [shutdown]
{- Runs a list of Annex actions. Catches exceptions, not stopping
- if some error out, and propigates an overall error status at the end.
-
- This runs in the IO monad, not in the Annex monad. It seems that
- exceptions can only be caught in the IO monad, not in a stacked monad;
- or more likely I missed an easy way to do it. So, I have to laboriously
- thread AnnexState through this function.
-}
tryRun :: AnnexState -> [Annex ()] -> IO ()
tryRun state actions = tryRun' state 0 actions
tryRun' state errnum (a:as) = do
result <- try
(Annex.run state a)::IO (Either SomeException ((), AnnexState))
case (result) of
Left err -> do
showErr err
tryRun' state (errnum + 1) as
Right (_,state') -> tryRun' state' errnum as
tryRun' state errnum [] = do
if (errnum > 0)
then error $ (show errnum) ++ " failed"
else return ()
{- Exception pretty-printing. -}
showErr e = do
hPutStrLn stderr $ "git-annex: " ++ (show e)
return ()