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|
-- ----------------------------------------------------------------------------
--
-- (c) The University of Glasgow 2006
--
-- Fingerprints for recompilation checking and ABI versioning.
--
-- http://ghc.haskell.org/trac/ghc/wiki/Commentary/Compiler/RecompilationAvoidance
--
-- ----------------------------------------------------------------------------
module Fingerprint (
Fingerprint(..), fingerprint0,
readHexFingerprint,
fingerprintData,
fingerprintString,
-- Re-exported from GHC.Fingerprint for GHC >= 7.7, local otherwise
getFileHash
) where
#include "md5.h"
##include "HsVersions.h"
import Numeric ( readHex )
#if __GLASGOW_HASKELL__ < 707
-- Only needed for getFileHash below.
import Foreign
import Panic
import System.IO
import Control.Monad ( when )
#endif
import GHC.Fingerprint
-- useful for parsing the output of 'md5sum', should we want to do that.
readHexFingerprint :: String -> Fingerprint
readHexFingerprint s = Fingerprint w1 w2
where (s1,s2) = splitAt 16 s
[(w1,"")] = readHex s1
[(w2,"")] = readHex (take 16 s2)
#if __GLASGOW_HASKELL__ < 707
-- Only use this if we're smaller than GHC 7.7, otherwise
-- GHC.Fingerprint exports a better version of this function.
-- | Computes the hash of a given file.
-- It loads the full file into memory an does not work with files bigger than
-- MAXINT.
getFileHash :: FilePath -> IO Fingerprint
getFileHash path = withBinaryFile path ReadMode $ \h -> do
fileSize <- toIntFileSize `fmap` hFileSize h
allocaBytes fileSize $ \bufPtr -> do
n <- hGetBuf h bufPtr fileSize
when (n /= fileSize) readFailedError
fingerprintData bufPtr fileSize
where
toIntFileSize :: Integer -> Int
toIntFileSize size
| size > fromIntegral (maxBound :: Int) = throwGhcException $
Sorry $ "Fingerprint.getFileHash: Tried to calculate hash of file "
++ path ++ " with size > maxBound :: Int. This is not supported."
| otherwise = fromIntegral size
readFailedError = throwGhcException $
Panic $ "Fingerprint.getFileHash: hGetBuf failed on interface file"
#endif
|
