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|
{-# LANGUAGE Trustworthy #-}
{-# LANGUAGE NoImplicitPrelude
, BangPatterns
, ForeignFunctionInterface
, EmptyDataDecls
#-}
-- ----------------------------------------------------------------------------
--
-- (c) The University of Glasgow 2006
--
-- Fingerprints for recompilation checking and ABI versioning, and
-- implementing fast comparison of Typeable.
--
-- ----------------------------------------------------------------------------
module GHC.Fingerprint (
Fingerprint(..), fingerprint0,
fingerprintData,
fingerprintString,
fingerprintFingerprints,
getFileHash
) where
import GHC.IO
import GHC.Base
import GHC.Num
import GHC.List
import GHC.Real
import GHC.Show
import Foreign
import Foreign.C
import System.IO
import Control.Monad (when)
import GHC.Fingerprint.Type
-- for SIZEOF_STRUCT_MD5CONTEXT:
#include "HsBaseConfig.h"
-- XXX instance Storable Fingerprint
-- defined in Foreign.Storable to avoid orphan instance
fingerprint0 :: Fingerprint
fingerprint0 = Fingerprint 0 0
fingerprintFingerprints :: [Fingerprint] -> Fingerprint
fingerprintFingerprints fs = unsafeDupablePerformIO $
withArrayLen fs $ \len p -> do
fingerprintData (castPtr p) (len * sizeOf (head fs))
fingerprintData :: Ptr Word8 -> Int -> IO Fingerprint
fingerprintData buf len = do
allocaBytes SIZEOF_STRUCT_MD5CONTEXT $ \pctxt -> do
c_MD5Init pctxt
c_MD5Update pctxt buf (fromIntegral len)
allocaBytes 16 $ \pdigest -> do
c_MD5Final pdigest pctxt
peek (castPtr pdigest :: Ptr Fingerprint)
-- This is duplicated in compiler/utils/Fingerprint.hsc
fingerprintString :: String -> Fingerprint
fingerprintString str = unsafeDupablePerformIO $
withArrayLen word8s $ \len p ->
fingerprintData p len
where word8s = concatMap f str
f c = let w32 :: Word32
w32 = fromIntegral (ord c)
in [fromIntegral (w32 `shiftR` 24),
fromIntegral (w32 `shiftR` 16),
fromIntegral (w32 `shiftR` 8),
fromIntegral w32]
-- | Computes the hash of a given file.
-- This function loops over the handle, running in constant memory.
getFileHash :: FilePath -> IO Fingerprint
getFileHash path = withBinaryFile path ReadMode $ \h -> do
allocaBytes SIZEOF_STRUCT_MD5CONTEXT $ \pctxt -> do
c_MD5Init pctxt
processChunks h (\buf size -> c_MD5Update pctxt buf (fromIntegral size))
allocaBytes 16 $ \pdigest -> do
c_MD5Final pdigest pctxt
peek (castPtr pdigest :: Ptr Fingerprint)
where
_BUFSIZE = 4096
-- | Loop over _BUFSIZE sized chunks read from the handle,
-- passing the callback a block of bytes and its size.
processChunks :: Handle -> (Ptr Word8 -> Int -> IO ()) -> IO ()
processChunks h f = allocaBytes _BUFSIZE $ \arrPtr ->
let loop = do
count <- hGetBuf h arrPtr _BUFSIZE
eof <- hIsEOF h
when (count /= _BUFSIZE && not eof) $ error $
"GHC.Fingerprint.getFileHash: only read " ++ show count ++ " bytes"
f arrPtr count
when (not eof) loop
in loop
data MD5Context
foreign import ccall unsafe "__hsbase_MD5Init"
c_MD5Init :: Ptr MD5Context -> IO ()
foreign import ccall unsafe "__hsbase_MD5Update"
c_MD5Update :: Ptr MD5Context -> Ptr Word8 -> CInt -> IO ()
foreign import ccall unsafe "__hsbase_MD5Final"
c_MD5Final :: Ptr Word8 -> Ptr MD5Context -> IO ()
|
