git-annex/CmdLine/Batch.hs
2015-12-22 11:58:59 -04:00

54 lines
1.5 KiB
Haskell

{- git-annex batch commands
-
- Copyright 2015 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module CmdLine.Batch where
import Common.Annex
import Command
data BatchMode = Batch | NoBatch
parseBatchOption :: Parser BatchMode
parseBatchOption = flag NoBatch Batch
( long "batch"
<> help "enable batch mode"
)
-- A batchable command can run in batch mode, or not.
-- In batch mode, one line at a time is read, parsed, and a reply output to
-- stdout. In non batch mode, the command's parameters are parsed and
-- a reply output for each.
batchable :: (opts -> String -> Annex Bool) -> Parser opts -> CmdParamsDesc -> CommandParser
batchable handler parser paramdesc = batchseeker <$> batchparser
where
batchparser = (,,)
<$> parser
<*> parseBatchOption
<*> cmdParams paramdesc
batchseeker (opts, NoBatch, params) = mapM_ (go NoBatch opts) params
batchseeker (opts, Batch, _) = batchInput (go Batch opts)
go batchmode opts p =
unlessM (handler opts p) $
batchBadInput batchmode
-- bad input is indicated by an empty line in batch mode. In non batch
-- mode, exit on bad input.
batchBadInput :: BatchMode -> Annex ()
batchBadInput NoBatch = liftIO exitFailure
batchBadInput Batch = liftIO $ putStrLn ""
-- Reads lines of batch mode input and passes to the action to handle.
batchInput :: (String -> Annex ()) -> Annex ()
batchInput a = do
mp <- liftIO $ catchMaybeIO getLine
case mp of
Nothing -> return ()
Just p -> do
a p
batchInput a