ar-extract.hs

{-# LANGUAGE RecordWildCards #-}

import qualified Data.ByteString as BS
import Data.Foldable
import Data.Functor
import Data.Maybe
import Data.Set (Set)
import qualified Data.Set as S
import GHC.SysTools.Ar
import System.Environment.Blank
import System.FilePath

freshFileName :: Set FilePath -> FilePath -> FilePath
freshFileName fs f =
  fromJust $
    find
      (not . (`S.member` fs))
      (f : [(b <.> show i) <.> e | i <- [1 :: Int ..]])
  where
    (b, e) = splitExtension f

main :: IO ()
main = do
  [ar_path] <- getArgs
  Archive objs <- loadAr ar_path
  void $
    foldlM
      ( \fs ArchiveEntry {..} -> do
          let f = freshFileName fs filename
          BS.writeFile f filedata
          pure $ f `S.insert` fs
      )
      S.empty
      objs