76 lines
		
	
	
	
		
			2.4 KiB
			
		
	
	
	
		
			Haskell
		
	
	
	
	
	
			
		
		
	
	
			76 lines
		
	
	
	
		
			2.4 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 Annex.Common
 | 
						|
import Types.Command
 | 
						|
import CmdLine.Action
 | 
						|
import CmdLine.GitAnnex.Options
 | 
						|
import Options.Applicative
 | 
						|
 | 
						|
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 Right (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 -> Either String a) -> (a -> Annex ()) -> Annex ()
 | 
						|
batchInput parser a = go =<< batchLines
 | 
						|
  where
 | 
						|
	go [] = return ()
 | 
						|
	go (l:rest) = do
 | 
						|
		either parseerr a (parser l)
 | 
						|
		go rest
 | 
						|
	parseerr s = giveup $ "Batch input parse failure: " ++ s
 | 
						|
 | 
						|
batchLines :: Annex [String]
 | 
						|
batchLines = liftIO $ lines <$> getContents
 | 
						|
 | 
						|
-- Runs a CommandStart in batch mode.
 | 
						|
--
 | 
						|
-- The batch mode user expects to read a line of output, and it's up to the
 | 
						|
-- CommandStart to generate that output as it succeeds or fails to do its
 | 
						|
-- job. However, if it stops without doing anything, it won't generate
 | 
						|
-- any output, so in that case, batchBadInput is used to provide the caller
 | 
						|
-- with an empty line.
 | 
						|
batchCommandAction :: CommandStart -> Annex ()
 | 
						|
batchCommandAction a = maybe (batchBadInput Batch) (const noop)
 | 
						|
	=<< callCommandAction' a
 | 
						|
 | 
						|
-- Reads lines of batch input and passes the filepaths to a CommandStart
 | 
						|
-- to handle them.
 | 
						|
batchFiles :: (FilePath -> CommandStart) -> Annex ()
 | 
						|
batchFiles a = batchInput Right $ batchCommandAction . a
 |