ar-timestamp-wiper (empty) → 0.1.0

raw patch · 4 files changed

+115/−0 lines, 4 filesdep +basedep +bytestringsetup-changed

Dependencies added: base, bytestring

Files

• ArTimestampWiper.hs +55/−0
• Main.hs +13/−0
• Setup.hs +2/−0
• ar-timestamp-wiper.cabal +45/−0

@@ -0,0 +1,55 @@+{-# LANGUAGE OverloadedStrings #-}++module ArTimestampWiper where++import           Control.Applicative+import           Control.Monad+import qualified Data.ByteString as BS+import qualified Data.ByteString.Char8 as BS8+import           Data.Char+import           System.IO+++-- | Removes the time stamps of all files in the .a file.+arFileWipeTimeStamps :: FilePath -> IO ()+arFileWipeTimeStamps path = withBinaryFile path ReadWriteMode $ \h -> do++  -- We iterate through the archive stepping from one file header to the next,+  -- setting the time stamp field to zero.+  -- The size field tells us where the next header is.+  -- See: http://en.wikipedia.org/wiki/Ar_%28Unix%29.++  archiveSize <- hFileSize h++  let go entryOffset | entryOffset == archiveSize = return () -- done, at end+                     | entryOffset >  archiveSize = die "Archive truncated"+                     -- Headers are aligned to even bytes+                     | odd entryOffset            = go (entryOffset + 1)+                     | otherwise = do++        -- Sanity check+        magic <- goto 58 >> BS.hGet h 2+        when (magic /= "\x60\x0a") $ die "Bad ar magic"++        -- Get size (to find following file)+        size <- goto 48 >> parseSize . BS8.unpack <$> BS.hGet h 10++        -- Wipe time stamp+        goto 16 >> BS.hPut h "0           " -- 12 chars++        -- Seek to next file at header + file size+        go (entryOffset + 60 + size)++        where+          goto pos = hSeek h AbsoluteSeek (entryOffset + pos)++          parseSize x = case reads x of+            [(s, r)] | all isSpace r -> s+            _                        -> die "Malformed header"++          die msg = error $ "arFileWipeTimeStamps: " ++ path ++ ": "+                            ++ msg ++ " at offset " ++ show entryOffset++  go 8 -- 8 == size of global header, before first file header++

@@ -0,0 +1,13 @@+module Main where++import           System.Environment (getArgs)++import           ArTimestampWiper++main :: IO ()+main = do+  args <- getArgs+  case args of+    [file] -> arFileWipeTimeStamps file+    _      -> error "Usage: ar-timestamp-wiper [file.a]"+

@@ -0,0 +1,2 @@+import Distribution.Simple+main = defaultMain

@@ -0,0 +1,45 @@+name:          ar-timestamp-wiper+version:       0.1.0+license:       MIT+copyright:     2013 Niklas Hambüchen <mail@nh2.me>+author:        Niklas Hambüchen <mail@nh2.me>+maintainer:    Niklas Hambüchen <mail@nh2.me>+category:      Application+build-type:    Simple+stability:     experimental+tested-with:   GHC==7.6.3+cabal-version: >= 1.10+homepage:      https://github.com/nh2/ar-timestamp-wiper+bug-reports:   https://github.com/nh2/ar-timestamp-wiper/issues+synopsis:      Wipes time stamps from .a files (like ar -D)+description:+  This application takes an archive (.a) file as created by the Unix ar tool,+  and sets all time stamps in it to zero.+  .+  These time stamps make ar generate different output for same input every time,+  which is problematic if you want to know if the contents actually changed+  as compared to the last time you created the archive (e.g. in build tools+  to avoid unnecessary linking).+  .+  Recent versions of GNU binutils and BSD ar af the -D flag for deterministic+  mode that creates the archive with all time stamps set to zero.+  However, these versions of ar are not wide spread yet, and this tool+  can help with that.++source-repository head+  type:      git+  location:  git://github.com/nh2/ar-timestamp-wiper.git+++library+  default-language: Haskell2010+  exposed-modules:  ArTimestampWiper+  build-depends:    base < 5, bytestring >= 0.9+  ghc-options:      -Wall+++executable ar-timestamp-wiper+  default-language: Haskell2010+  main-is:          Main.hs+  build-depends:    base < 5, bytestring >= 0.9+  ghc-options:      -Wall