bca3fd65b9
Fix Key directory hash calculation code to behave as it did before version 3.20120227 when a key contains non-ascii. The hash directories for a given Key are based on its md5sum. Prior to ghc 7.4, Keys contained raw, undecoded bytes, so the md5sum was taken of each byte in turn. With the ghc 7.4 filename encoding change, keys contains decoded unicode characters (possibly with surrigates for undecodable bytes). This changes the result of the md5sum, since the md5sum used is pure haskell and supports unicode. And that won't do, as git-annex will start looking in a different hash directory for the content of a key. The surrigates are particularly bad, since that's essentially a ghc implementation detail, so could change again at any time. Also, changing the locale changes how the bytes are decoded, which can also change the md5sum. Symptoms would include things like: * git annex fsck would complain that no copies existed of a file, despite its symlink pointing to the content that was locally present * git annex fix would change the symlink to use the wrong hash directory. Only WORM backend is likely to have been affected, since only it tends to include much filename data (SHA1E could in theory also be affected). I have not tried to support the hash directories used by git-annex versions 3.20120227 to 3.20120308, so things added with those versions with WORM will require manual fixups. Sorry for the inconvenience!
43 lines
1.6 KiB
Haskell
43 lines
1.6 KiB
Haskell
{- GHC File system encoding handling.
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-
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- Copyright 2012 Joey Hess <joey@kitenet.net>
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-
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- Licensed under the GNU GPL version 3 or higher.
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-}
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module Utility.FileSystemEncoding where
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import qualified GHC.Foreign as GHC
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import qualified GHC.IO.Encoding as Encoding
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import Foreign.C
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import System.IO
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import System.IO.Unsafe
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{- Sets a Handle to use the filesystem encoding. This causes data
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- written or read from it to be encoded/decoded the same
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- as ghc 7.4 does to filenames etc. This special encoding
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- allows "arbitrary undecodable bytes to be round-tripped through it". -}
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fileEncoding :: Handle -> IO ()
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fileEncoding h = hSetEncoding h =<< Encoding.getFileSystemEncoding
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{- Marshal a Haskell FilePath into a NUL terminated C string using temporary
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- storage. The FilePath is encoded using the filesystem encoding,
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- reversing the decoding that should have been done when the FilePath
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- was obtained. -}
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withFilePath :: FilePath -> (CString -> IO a) -> IO a
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withFilePath fp f = Encoding.getFileSystemEncoding
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>>= \enc -> GHC.withCString enc fp f
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{- Encodes a FilePath into a String of encoded bytes, applying the
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- filesystem encoding.
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-
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- This use of unsafePerformIO is belived to be safe; GHC's interface
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- only allows doing this conversion with CStrings, and the CString buffer
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- is allocated, used, and deallocated within the call, with no side
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- effects.
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-}
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{-# NOINLINE encodeFilePath #-}
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encodeFilePath :: FilePath -> String
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encodeFilePath fp = unsafePerformIO $ do
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enc <- Encoding.getFileSystemEncoding
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GHC.withCString enc fp $ GHC.peekCString Encoding.char8
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