Mirrors the rust exec-helpers Change-Id: I96f211d6545e228b8ae0c1dce4e60e6f6867690c Reviewed-on: https://cl.tvl.fyi/c/depot/+/6117 Tested-by: BuildkiteCI Reviewed-by: Profpatsch <mail@profpatsch.de>
		
			
				
	
	
		
			25 lines
		
	
	
	
		
			910 B
		
	
	
	
		
			Haskell
		
	
	
	
	
	
			
		
		
	
	
			25 lines
		
	
	
	
		
			910 B
		
	
	
	
		
			Haskell
		
	
	
	
	
	
{-# LANGUAGE LambdaCase #-}
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{-# LANGUAGE OverloadedStrings #-}
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{-# LANGUAGE QuasiQuotes #-}
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module ArglibNetencode where
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import qualified Data.Attoparsec.ByteString as Atto
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import Data.Maybe (fromMaybe)
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import ExecHelpers
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import MyPrelude
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import Netencode
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import qualified System.Environment as Env
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import qualified System.Posix.Env.ByteString as ByteEnv
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arglibNetencode :: CurrentProgramName -> Maybe Text -> IO T
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arglibNetencode progName mEnvvar = do
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  let envvar = mEnvvar & fromMaybe "ARGLIB_NETENCODE" & textToBytesUtf8
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  ByteEnv.getEnv envvar >>= \case
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    Nothing -> dieUserError progName [fmt|could not read args, envvar {envvar} not set|]
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    Just bytes ->
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      case Atto.parseOnly (Netencode.netencodeParser <* Atto.endOfInput) bytes of
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        Left err -> dieEnvironmentProblem progName [fmt|arglib parsing error: {err}|]
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        Right t -> do
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          ByteEnv.unsetEnv envvar
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          pure t
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