55 lines
1.6 KiB
Haskell
55 lines
1.6 KiB
Haskell
{- Some git commands output encoded filenames, in a rather annoyingly complex
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- C-style encoding.
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-
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- Copyright 2010, 2011 Joey Hess <id@joeyh.name>
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-
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- Licensed under the GNU AGPL version 3 or higher.
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-}
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module Git.Filename where
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import Common
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import Utility.Format (decode_c, encode_c)
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import Data.Char
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import Data.Word
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import qualified Data.ByteString as S
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-- encoded filenames will be inside double quotes
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decode :: S.ByteString -> RawFilePath
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decode b = case S.uncons b of
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Nothing -> b
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Just (h, t)
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| h /= q -> b
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| otherwise -> case S.unsnoc t of
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Nothing -> b
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Just (i, l)
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| l /= q -> b
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| otherwise ->
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encodeBS $ decode_c $ decodeBS i
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where
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q :: Word8
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q = fromIntegral (ord '"')
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{- Should not need to use this, except for testing decode. -}
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encode :: RawFilePath -> S.ByteString
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encode s = encodeBS $ "\"" ++ encode_c (decodeBS s) ++ "\""
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prop_encode_decode_roundtrip :: FilePath -> Bool
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prop_encode_decode_roundtrip s = s' ==
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fromRawFilePath (decode (encode (toRawFilePath s')))
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where
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s' = nonul (nohigh s)
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-- Encoding and then decoding roundtrips only when
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-- the string does not contain high unicode, because eg,
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-- both "\12345" and "\227\128\185" are encoded to
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-- "\343\200\271".
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--
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-- This property papers over the problem, by only
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-- testing chars < 256.
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nohigh = filter (\c -> ord c < 256)
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-- A String can contain a NUL, but toRawFilePath
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-- truncates on the NUL, which is generally fine
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-- because unix filenames cannot contain NUL.
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-- So the encoding only roundtrips when there is no nul.
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nonul = filter (/= '\NUL')
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