1052eeface
http://git-annex.branchable.com/bugs/Unicode_file_names_ignored_on_Windows/ Not a complete fix yet.
132 lines
4.2 KiB
Haskell
132 lines
4.2 KiB
Haskell
{- GHC File system encoding handling.
|
|
-
|
|
- Copyright 2012-2014 Joey Hess <joey@kitenet.net>
|
|
-
|
|
- Licensed under the GNU GPL version 3 or higher.
|
|
-}
|
|
|
|
{-# LANGUAGE CPP #-}
|
|
|
|
module Utility.FileSystemEncoding (
|
|
fileEncoding,
|
|
withFilePath,
|
|
md5FilePath,
|
|
decodeBS,
|
|
decodeW8,
|
|
encodeW8,
|
|
truncateFilePath,
|
|
) where
|
|
|
|
import qualified GHC.Foreign as GHC
|
|
import qualified GHC.IO.Encoding as Encoding
|
|
import Foreign.C
|
|
import System.IO
|
|
import System.IO.Unsafe
|
|
import qualified Data.Hash.MD5 as MD5
|
|
import Data.Word
|
|
import Data.Bits.Utils
|
|
import qualified Data.ByteString.Lazy as L
|
|
#ifdef mingw32_HOST_OS
|
|
import qualified Data.ByteString.Lazy.UTF8 as L8
|
|
#endif
|
|
|
|
{- Sets a Handle to use the filesystem encoding. This causes data
|
|
- written or read from it to be encoded/decoded the same
|
|
- as ghc 7.4 does to filenames etc. This special encoding
|
|
- allows "arbitrary undecodable bytes to be round-tripped through it".
|
|
-}
|
|
fileEncoding :: Handle -> IO ()
|
|
#ifndef mingw32_HOST_OS
|
|
fileEncoding h = hSetEncoding h =<< Encoding.getFileSystemEncoding
|
|
#else
|
|
{- The file system encoding does not work well on Windows,
|
|
- and Windows only has utf FilePaths anyway. -}
|
|
fileEncoding h = hSetEncoding h Encoding.utf8
|
|
#endif
|
|
|
|
{- Marshal a Haskell FilePath into a NUL terminated C string using temporary
|
|
- storage. The FilePath is encoded using the filesystem encoding,
|
|
- reversing the decoding that should have been done when the FilePath
|
|
- was obtained. -}
|
|
withFilePath :: FilePath -> (CString -> IO a) -> IO a
|
|
withFilePath fp f = Encoding.getFileSystemEncoding
|
|
>>= \enc -> GHC.withCString enc fp f
|
|
|
|
{- Encodes a FilePath into a String, applying the filesystem encoding.
|
|
-
|
|
- There are very few things it makes sense to do with such an encoded
|
|
- string. It's not a legal filename; it should not be displayed.
|
|
- So this function is not exported, but instead used by the few functions
|
|
- that can usefully consume it.
|
|
-
|
|
- This use of unsafePerformIO is belived to be safe; GHC's interface
|
|
- only allows doing this conversion with CStrings, and the CString buffer
|
|
- is allocated, used, and deallocated within the call, with no side
|
|
- effects.
|
|
-}
|
|
{-# NOINLINE _encodeFilePath #-}
|
|
_encodeFilePath :: FilePath -> String
|
|
_encodeFilePath fp = unsafePerformIO $ do
|
|
enc <- Encoding.getFileSystemEncoding
|
|
GHC.withCString enc fp $ GHC.peekCString Encoding.char8
|
|
|
|
{- Encodes a FilePath into a Md5.Str, applying the filesystem encoding. -}
|
|
md5FilePath :: FilePath -> MD5.Str
|
|
md5FilePath = MD5.Str . _encodeFilePath
|
|
|
|
{- Decodes a ByteString into a FilePath, applying the filesystem encoding. -}
|
|
decodeBS :: L.ByteString -> FilePath
|
|
#ifndef mingw32_HOST_OS
|
|
decodeBS = encodeW8 . L.unpack
|
|
#else
|
|
{- On Windows, we assume that the ByteString is utf-8, since Windows
|
|
- only uses unicode for filenames. -}
|
|
decodeBS = L8.toString
|
|
#endif
|
|
|
|
{- Converts a [Word8] to a FilePath, encoding using the filesystem encoding.
|
|
-
|
|
- w82c produces a String, which may contain Chars that are invalid
|
|
- unicode. From there, this is really a simple matter of applying the
|
|
- file system encoding, only complicated by GHC's interface to doing so.
|
|
-}
|
|
{-# NOINLINE encodeW8 #-}
|
|
encodeW8 :: [Word8] -> FilePath
|
|
encodeW8 w8 = unsafePerformIO $ do
|
|
enc <- Encoding.getFileSystemEncoding
|
|
GHC.withCString Encoding.char8 (w82s w8) $ GHC.peekCString enc
|
|
|
|
{- Useful when you want the actual number of bytes that will be used to
|
|
- represent the FilePath on disk. -}
|
|
decodeW8 :: FilePath -> [Word8]
|
|
decodeW8 = s2w8 . _encodeFilePath
|
|
|
|
{- Truncates a FilePath to the given number of bytes (or less),
|
|
- as represented on disk.
|
|
-
|
|
- Avoids returning an invalid part of a unicode byte sequence, at the
|
|
- cost of efficiency when running on a large FilePath.
|
|
-}
|
|
truncateFilePath :: Int -> FilePath -> FilePath
|
|
#ifndef mingw32_HOST_OS
|
|
truncateFilePath n = go . reverse
|
|
where
|
|
go f =
|
|
let bytes = decodeW8 f
|
|
in if length bytes <= n
|
|
then reverse f
|
|
else go (drop 1 f)
|
|
#else
|
|
{- On Windows, count the number of bytes used by each utf8 character. -}
|
|
truncateFilePath n = reverse . go [] n . L8.fromString
|
|
where
|
|
go coll cnt bs
|
|
| cnt <= 0 = coll
|
|
| otherwise = case L8.decode bs of
|
|
Just (c, x) | c /= L8.replacement_char ->
|
|
let x' = fromIntegral x
|
|
in if cnt - x' < 0
|
|
then coll
|
|
else go (c:coll) (cnt - x') (L8.drop 1 bs)
|
|
_ -> coll
|
|
#endif
|