git-annex/Command/CheckPresentKey.hs
Joey Hess 0a4479b8ec
Avoid backtraces on expected failures when built with ghc 8; only use backtraces for unexpected errors.
ghc 8 added backtraces on uncaught errors. This is great, but git-annex was
using error in many places for a error message targeted at the user, in
some known problem case. A backtrace only confuses such a message, so omit it.

Notably, commands like git annex drop that failed due to eg, numcopies,
used to use error, so had a backtrace.

This commit was sponsored by Ethan Aubin.
2016-11-15 21:29:54 -04:00

78 lines
2.1 KiB
Haskell

{- git-annex command
-
- Copyright 2015-2016 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Command.CheckPresentKey where
import Command
import qualified Remote
cmd :: Command
cmd = noCommit $ noMessages $
command "checkpresentkey" SectionPlumbing
"check if key is present in remote"
(paramPair paramKey (paramOptional paramRemote))
(seek <$$> optParser)
data CheckPresentKeyOptions = CheckPresentKeyOptions
{ params :: CmdParams
, batchOption :: BatchMode
}
optParser :: CmdParamsDesc -> Parser CheckPresentKeyOptions
optParser desc = CheckPresentKeyOptions
<$> cmdParams desc
<*> parseBatchOption
seek :: CheckPresentKeyOptions -> CommandSeek
seek o = case batchOption o of
NoBatch -> case params o of
(ks:rn:[]) -> toRemote rn >>= (check ks . Just) >>= exitResult
(ks:[]) -> check ks Nothing >>= exitResult
_ -> wrongnumparams
Batch -> do
checker <- case params o of
(rn:[]) -> toRemote rn >>= \r -> return (flip check (Just r))
[] -> return (flip check Nothing)
_ -> wrongnumparams
batchInput Right $ checker >=> batchResult
where
wrongnumparams = giveup "Wrong number of parameters"
data Result = Present | NotPresent | CheckFailure String
check :: String -> Maybe Remote -> Annex Result
check ks mr = case mr of
Nothing -> go Nothing =<< Remote.keyPossibilities k
Just r -> go Nothing [r]
where
k = toKey ks
go Nothing [] = return NotPresent
go (Just e) [] = return $ CheckFailure e
go olderr (r:rs) = do
v <- Remote.hasKey r k
case v of
Right True -> return Present
Right False -> go olderr rs
Left e -> go (Just e) rs
exitResult :: Result -> Annex a
exitResult Present = liftIO exitSuccess
exitResult NotPresent = liftIO exitFailure
exitResult (CheckFailure msg) = liftIO $ do
hPutStrLn stderr msg
exitWith $ ExitFailure 100
batchResult :: Result -> Annex ()
batchResult Present = liftIO $ putStrLn "1"
batchResult _ = liftIO $ putStrLn "0"
toKey :: String -> Key
toKey = fromMaybe (giveup "Bad key") . file2key
toRemote :: String -> Annex Remote
toRemote rn = maybe (giveup "Unknown remote") return
=<< Remote.byNameWithUUID (Just rn)