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Add long path support wrt #39 
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3 files changed

+216
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‎file-io.cabal

+11-1
Original file line numberDiff line numberDiff line change
@@ -29,6 +29,11 @@ flag os-string
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default: False
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manual: False
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flag long-paths
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description: Enable a hack for ad-hoc long path support on Windows
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default: True
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manual: True
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library
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default-language: Haskell2010
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@@ -51,6 +56,9 @@ library
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else
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build-depends: filepath >= 1.4.100.0 && < 1.5.0.0
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if flag(long-paths)
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cpp-options: -DLONG_PATHS
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exposed-modules:
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System.File.OsPath
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System.File.OsPath.Internal
@@ -111,6 +119,8 @@ test-suite Properties
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main-is: Properties.hs
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type: exitcode-stdio-1.0
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default-language: Haskell2010
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build-depends: base >=4.13.0.0 && <5, bytestring, tasty, tasty-hunit, file-io, filepath, temporary
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build-depends: base >=4.13.0.0 && <5, bytestring, directory, tasty, tasty-hunit, file-io, filepath, temporary
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ghc-options: -Wall -threaded -rtsopts "-with-rtsopts=-N10"
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if flag(long-paths)
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cpp-options: -DLONG_PATHS
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‎tests/Properties.hs

+33-1
Original file line numberDiff line numberDiff line change
@@ -18,12 +18,21 @@ import GHC.IO.Exception (IOErrorType(..), IOException(..))
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import System.IO
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import System.IO.Temp
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import qualified Data.ByteString as BS
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#if defined(LONG_PATHS)
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import Control.Monad (when)
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import System.Directory.OsPath (createDirectory, makeAbsolute)
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import System.IO.Error (catchIOError)
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#endif
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main :: IO ()
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main = defaultMain $ testGroup "All"
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[ testGroup "System.File.OsPath"
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[ testCase "readFile . writeFile" writeFileReadFile
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[
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#if defined(LONG_PATHS)
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testCase "writeFile (very long path)" writeFileLongPath,
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#endif
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testCase "readFile . writeFile" writeFileReadFile
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, testCase "readFile . writeFile . writeFile" writeWriteFileReadFile
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, testCase "readFile . appendFile . writeFile" appendFileReadFile
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, testCase "iomode: ReadFile does not allow write" iomodeReadFile
@@ -56,6 +65,29 @@ main = defaultMain $ testGroup "All"
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]
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]
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#if defined(LONG_PATHS)
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writeFileLongPath :: Assertion
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writeFileLongPath = do
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withSystemTempDirectory "test" $ \baseDir' -> do
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baseDir <- OSP.encodeFS baseDir'
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let longName = mconcat (replicate 10 [osp|"its_very_long"|])
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let longDir = baseDir </> longName </> longName
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supportsLongPaths <- do
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-- create 2 dirs because 1 path segment by itself can't exceed MAX_PATH
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-- tests: [createDirectory]
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createDirectory =<< makeAbsolute longName
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createDirectory longDir
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return True
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`catchIOError` \ _ ->
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return False
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when supportsLongPaths $ do
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OSP.writeFile (longDir </> [osp|foo|]) "test"
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contents <- OSP.readFile (longDir </> [osp|foo|])
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"test" @=? contents
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#endif
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writeFileReadFile :: Assertion
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writeFileReadFile = do
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withSystemTempDirectory "test" $ \baseDir' -> do

‎windows/System/File/Platform.hsc

+172-6
Original file line numberDiff line numberDiff line change
@@ -12,7 +12,6 @@ import System.OsPath.Windows ( WindowsPath )
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import qualified System.OsPath.Windows as WS
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import Foreign.C.Types
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15-
import qualified System.OsString.Windows as WS hiding (decodeFS)
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import System.OsString.Windows ( encodeUtf, WindowsString )
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import qualified System.Win32 as Win32
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import qualified System.Win32.WindowsString.File as WS
@@ -43,18 +42,28 @@ import Text.Printf (printf)
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#if MIN_VERSION_filepath(1, 5, 0)
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import System.OsString.Encoding
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import "os-string" System.OsString.Internal.Types (WindowsString(..), WindowsChar(..))
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import qualified "os-string" System.OsString.Data.ByteString.Short as BC
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#else
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import Data.Coerce (coerce)
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import System.OsPath.Encoding
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import "filepath" System.OsString.Internal.Types (WindowsString(..), WindowsChar(..))
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import qualified "filepath" System.OsPath.Data.ByteString.Short.Word16 as BC
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#endif
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import System.IO.Error (modifyIOError, ioeSetFileName)
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import GHC.IO.Encoding.UTF16 (mkUTF16le)
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import GHC.IO.Encoding.Failure (CodingFailureMode(TransliterateCodingFailure))
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import Control.Exception (displayException, Exception)
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#if defined(LONG_PATHS)
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import System.IO.Error (ioeSetLocation, ioeGetLocation, catchIOError)
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import Data.Char (isAlpha, isAscii, toUpper)
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import qualified System.Win32.WindowsString.Info as WS
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#endif
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-- | Open a file and return the 'Handle'.
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openFile :: WindowsPath -> IOMode -> IO Handle
57-
openFile fp iomode = bracketOnError
64+
openFile fp' iomode = (`ioeSetWsPath` fp') `modifyIOError` do
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fp <- furnishPath fp'
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bracketOnError
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(WS.createFile
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fp
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accessMode
@@ -104,7 +113,9 @@ writeShareMode =
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-- | Open an existing file and return the 'Handle'.
106115
openExistingFile :: WindowsPath -> IOMode -> IO Handle
107-
openExistingFile fp iomode = bracketOnError
116+
openExistingFile fp' iomode = (`ioeSetWsPath` fp') `modifyIOError` do
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fp <- furnishPath fp'
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bracketOnError
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(WS.createFile
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fp
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accessMode
@@ -248,3 +259,158 @@ any_ = coerce BC.any
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249260
#endif
250261

262+
ioeSetWsPath :: IOError -> WindowsPath -> IOError
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ioeSetWsPath err =
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ioeSetFileName err .
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rightOrError .
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WS.decodeWith (mkUTF16le TransliterateCodingFailure)
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rightOrError :: Exception e => Either e a -> a
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rightOrError (Left e) = error (displayException e)
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rightOrError (Right a) = a
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-- inlined stuff from directory package
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furnishPath :: WindowsPath -> IO WindowsPath
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#if !defined(LONG_PATHS)
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furnishPath path = pure path
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#else
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furnishPath path = pure path
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furnishPath' :: WindowsPath -> IO WindowsPath
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furnishPath' path =
281+
(toExtendedLengthPath <$> rawPrependCurrentDirectory path)
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`catchIOError` \ _ ->
283+
pure path
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285+
toExtendedLengthPath :: WindowsPath -> WindowsPath
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toExtendedLengthPath path =
287+
if WS.isRelative path
288+
then simplifiedPath
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else
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case WS.toChar <$> simplifiedPath' of
291+
'\\' : '?' : '?' : '\\' : _ -> simplifiedPath
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'\\' : '\\' : '?' : '\\' : _ -> simplifiedPath
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'\\' : '\\' : '.' : '\\' : _ -> simplifiedPath
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'\\' : '\\' : _ ->
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ws "\\\\?\\UNC" <> WS.pack (drop 1 simplifiedPath')
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_ -> ws "\\\\?\\" <> simplifiedPath
297+
where simplifiedPath = simplifyWindows path
298+
simplifiedPath' = WS.unpack simplifiedPath
299+
300+
rawPrependCurrentDirectory :: WindowsPath -> IO WindowsPath
301+
rawPrependCurrentDirectory path
302+
| WS.isRelative path =
303+
((`ioeAddLocation` "prependCurrentDirectory") .
304+
(`ioeSetWsPath` path)) `modifyIOError` do
305+
getFullPathName path
306+
| otherwise = pure path
307+
308+
simplifyWindows :: WindowsPath -> WindowsPath
309+
simplifyWindows path
310+
| path == mempty = mempty
311+
| drive' == ws "\\\\?\\" = drive' <> subpath
312+
| otherwise = simplifiedPath
313+
where
314+
simplifiedPath = WS.joinDrive drive' subpath'
315+
(drive, subpath) = WS.splitDrive path
316+
drive' = upperDrive (normaliseTrailingSep (normalisePathSeps drive))
317+
subpath' = appendSep . avoidEmpty . prependSep . WS.joinPath .
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stripPardirs . expandDots . skipSeps .
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WS.splitDirectories $ subpath
320+
321+
upperDrive d = case WS.unpack d of
322+
c : k : s
323+
| isAlpha (WS.toChar c), WS.toChar k == ':', all WS.isPathSeparator s ->
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-- unsafeFromChar is safe here since all characters are ASCII.
325+
WS.pack (WS.unsafeFromChar (toUpper (WS.toChar c)) : WS.unsafeFromChar ':' : s)
326+
_ -> d
327+
skipSeps =
328+
(WS.pack <$>) .
329+
filter (not . (`elem` (pure <$> WS.pathSeparators))) .
330+
(WS.unpack <$>)
331+
stripPardirs | pathIsAbsolute || subpathIsAbsolute = dropWhile (== ws "..")
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| otherwise = id
333+
prependSep | subpathIsAbsolute = (WS.pack [WS.pathSeparator] <>)
334+
| otherwise = id
335+
avoidEmpty | not pathIsAbsolute
336+
, drive == mempty || hasTrailingPathSep -- prefer "C:" over "C:."
337+
= emptyToCurDir
338+
| otherwise = id
339+
appendSep p | hasTrailingPathSep, not (pathIsAbsolute && p == mempty)
340+
= WS.addTrailingPathSeparator p
341+
| otherwise = p
342+
pathIsAbsolute = not (WS.isRelative path)
343+
subpathIsAbsolute = any WS.isPathSeparator (take 1 (WS.unpack subpath))
344+
hasTrailingPathSep = WS.hasTrailingPathSeparator subpath
345+
346+
expandDots :: [WindowsPath] -> [WindowsPath]
347+
expandDots = reverse . go []
348+
where
349+
go ys' xs' =
350+
case xs' of
351+
[] -> ys'
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x : xs
353+
| x == ws "." -> go ys' xs
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| x == ws ".." ->
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case ys' of
356+
[] -> go (x : ys') xs
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y : ys
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| y == ws ".." -> go (x : ys') xs
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| otherwise -> go ys xs
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| otherwise -> go (x : ys') xs
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362+
-- | Remove redundant trailing slashes and pick the right kind of slash.
363+
normaliseTrailingSep :: WindowsPath -> WindowsPath
364+
normaliseTrailingSep path = do
365+
let path' = reverse (WS.unpack path)
366+
let (sep, path'') = span WS.isPathSeparator path'
367+
let addSep = if null sep then id else (WS.pathSeparator :)
368+
WS.pack (reverse (addSep path''))
369+
370+
normalisePathSeps :: WindowsPath -> WindowsPath
371+
normalisePathSeps p = WS.pack (normaliseChar <$> WS.unpack p)
372+
where normaliseChar c = if WS.isPathSeparator c then WS.pathSeparator else c
373+
374+
emptyToCurDir :: WindowsPath -> WindowsPath
375+
emptyToCurDir path
376+
| path == mempty = ws "."
377+
| otherwise = path
378+
379+
ws :: String -> WindowsString
380+
ws = rightOrError . WS.encodeUtf
381+
382+
getFullPathName :: WindowsPath -> IO WindowsPath
383+
getFullPathName path =
384+
fromExtendedLengthPath <$> WS.getFullPathName (toExtendedLengthPath path)
385+
386+
ioeAddLocation :: IOError -> String -> IOError
387+
ioeAddLocation e loc = do
388+
ioeSetLocation e newLoc
389+
where
390+
newLoc = loc <> if null oldLoc then "" else ":" <> oldLoc
391+
oldLoc = ioeGetLocation e
392+
393+
fromExtendedLengthPath :: WindowsPath -> WindowsPath
394+
fromExtendedLengthPath ePath =
395+
case WS.unpack ePath of
396+
c1 : c2 : c3 : c4 : path
397+
| (WS.toChar <$> [c1, c2, c3, c4]) == "\\\\?\\" ->
398+
case path of
399+
c5 : c6 : c7 : subpath@(c8 : _)
400+
| (WS.toChar <$> [c5, c6, c7, c8]) == "UNC\\" ->
401+
WS.pack (c8 : subpath)
402+
drive : col : subpath
403+
-- if the path is not "regular", then the prefix is necessary
404+
-- to ensure the path is interpreted literally
405+
| WS.toChar col == ':', isDriveChar drive, isPathRegular subpath ->
406+
WS.pack path
407+
_ -> ePath
408+
_ -> ePath
409+
where
410+
isDriveChar drive = isAlpha (WS.toChar drive) && isAscii (WS.toChar drive)
411+
isPathRegular path =
412+
not ('/' `elem` (WS.toChar <$> path) ||
413+
ws "." `elem` WS.splitDirectories (WS.pack path) ||
414+
ws ".." `elem` WS.splitDirectories (WS.pack path))
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#endif

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