git-annex/Core.hs
2010-10-14 03:40:26 -04:00

87 lines
2.5 KiB
Haskell

{- git-annex core functions -}
module Core where
import System.IO
import System.Directory
import Control.Monad.State (liftIO)
import Control.Exception
import CmdLine
import Types
import BackendList
import Locations
import UUID
import qualified GitRepo as Git
import qualified Annex
{- Create and returns an Annex state object.
- Examines and prepares the git repo.
-}
start :: IO AnnexState
start = do
g <- Git.repoFromCwd
let s = Annex.new g
(_,s') <- Annex.run s (prep g)
return s'
where
prep g = do
-- setup git and read its config; update state
g' <- liftIO $ Git.configRead g
Annex.gitRepoChange g'
liftIO $ gitSetup g'
Annex.backendsChange $ parseBackendList $
Git.configGet g' "annex.backends" ""
prepUUID
{- Processes each param in the list by dispatching the handler function
- for the user-selection operation mode. 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 -> Mode -> [String] -> IO ()
tryRun state mode params = tryRun' state mode 0 0 params
tryRun' state mode errnum oknum [] = do
if (errnum > 0)
then error $ (show errnum) ++ " failed ; " ++ show (oknum) ++ " ok"
else return ()
tryRun' state mode errnum oknum (f:fs) = do
result <- try
(Annex.run state (dispatch mode f))::IO (Either SomeException ((), AnnexState))
case (result) of
Left err -> do
showErr err
tryRun' state mode (errnum + 1) oknum fs
Right (_,state') -> tryRun' state' mode errnum (oknum + 1) fs
{- Exception pretty-printing. -}
showErr e = do
hPutStrLn stderr $ "git-annex: " ++ (show e)
return ()
{- Sets up a git repo for git-annex. May be called repeatedly. -}
gitSetup :: Git.Repo -> IO ()
gitSetup repo = do
-- configure git to use union merge driver on state files
exists <- doesFileExist attributes
if (not exists)
then do
writeFile attributes $ attrLine ++ "\n"
commit
else do
content <- readFile attributes
if (all (/= attrLine) (lines content))
then do
appendFile attributes $ attrLine ++ "\n"
commit
else return ()
where
attrLine = stateLoc ++ "/*.log merge=union"
attributes = Git.attributes repo
commit = do
Git.run repo ["add", attributes]
Git.run repo ["commit", "-m", "git-annex setup",
attributes]