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Add long path support wrt #39 
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‎file-io.cabal‎

Lines changed: 11 additions & 1 deletion
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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3237
library
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default-language: Haskell2010
3439

@@ -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
114-
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

Lines changed: 33 additions & 1 deletion
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"
26-
[ 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"
5665
]
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]
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68+
#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|foo|])
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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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5991
writeFileReadFile :: Assertion
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writeFileReadFile = do
6193
withSystemTempDirectory "test" $ \baseDir' -> do

‎windows/System/File/Platform.hsc‎

Lines changed: 167 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -52,9 +52,20 @@ import "filepath" System.OsString.Internal.Types (WindowsString(..), WindowsChar
5252
import qualified "filepath" System.OsPath.Data.ByteString.Short.Word16 as BC
5353
#endif
5454

55+
#if defined(LONG_PATHS)
56+
import Control.Exception (displayException, Exception)
57+
import System.IO.Error (ioeSetFileName, modifyIOError, ioeSetLocation, ioeGetLocation, catchIOError)
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import Data.Char (isAlpha, isAscii, toUpper)
59+
import GHC.IO.Encoding.Failure (CodingFailureMode(TransliterateCodingFailure))
60+
import GHC.IO.Encoding.UTF16 (mkUTF16le)
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import qualified System.Win32.WindowsString.Info as WS
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#endif
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5564
-- | Open a file and return the 'Handle'.
5665
openFile :: WindowsPath -> IOMode -> IO Handle
57-
openFile fp iomode = bracketOnError
66+
openFile fp' iomode = (`ioeSetWsPath` fp') `modifyIOError` $ do
67+
fp <- furnishPath fp'
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bracketOnError
5869
(WS.createFile
5970
fp
6071
accessMode
@@ -104,7 +115,9 @@ writeShareMode =
104115

105116
-- | Open an existing file and return the 'Handle'.
106117
openExistingFile :: WindowsPath -> IOMode -> IO Handle
107-
openExistingFile fp iomode = bracketOnError
118+
openExistingFile fp' iomode = (`ioeSetWsPath` fp') `modifyIOError` $ do
119+
fp <- furnishPath fp'
120+
bracketOnError
108121
(WS.createFile
109122
fp
110123
accessMode
@@ -248,3 +261,155 @@ any_ = coerce BC.any
248261

249262
#endif
250263

264+
-- inlined stuff from directory package
265+
furnishPath :: WindowsPath -> IO WindowsPath
266+
#if !defined(LONG_PATHS)
267+
furnishPath path = pure path
268+
#else
269+
furnishPath path =
270+
(toExtendedLengthPath <$> rawPrependCurrentDirectory path)
271+
`catchIOError` \ _ ->
272+
pure path
273+
274+
toExtendedLengthPath :: WindowsPath -> WindowsPath
275+
toExtendedLengthPath path =
276+
if WS.isRelative path
277+
then simplifiedPath
278+
else
279+
case WS.toChar <$> simplifiedPath' of
280+
'\\' : '?' : '?' : '\\' : _ -> simplifiedPath
281+
'\\' : '\\' : '?' : '\\' : _ -> simplifiedPath
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'\\' : '\\' : '.' : '\\' : _ -> simplifiedPath
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'\\' : '\\' : _ ->
284+
ws "\\\\?\\UNC" <> WS.pack (drop 1 simplifiedPath')
285+
_ -> ws "\\\\?\\" <> simplifiedPath
286+
where simplifiedPath = simplifyWindows path
287+
simplifiedPath' = WS.unpack simplifiedPath
288+
289+
rawPrependCurrentDirectory :: WindowsPath -> IO WindowsPath
290+
rawPrependCurrentDirectory path
291+
| WS.isRelative path =
292+
((`ioeAddLocation` "prependCurrentDirectory") .
293+
(`ioeSetWsPath` path)) `modifyIOError` do
294+
getFullPathName path
295+
| otherwise = pure path
296+
297+
simplifyWindows :: WindowsPath -> WindowsPath
298+
simplifyWindows path
299+
| path == mempty = mempty
300+
| drive' == ws "\\\\?\\" = drive' <> subpath
301+
| otherwise = simplifiedPath
302+
where
303+
simplifiedPath = WS.joinDrive drive' subpath'
304+
(drive, subpath) = WS.splitDrive path
305+
drive' = upperDrive (normaliseTrailingSep (normalisePathSeps drive))
306+
subpath' = appendSep . avoidEmpty . prependSep . WS.joinPath .
307+
stripPardirs . expandDots . skipSeps .
308+
WS.splitDirectories $ subpath
309+
310+
upperDrive d = case WS.unpack d of
311+
c : k : s
312+
| isAlpha (WS.toChar c), WS.toChar k == ':', all WS.isPathSeparator s ->
313+
-- unsafeFromChar is safe here since all characters are ASCII.
314+
WS.pack (WS.unsafeFromChar (toUpper (WS.toChar c)) : WS.unsafeFromChar ':' : s)
315+
_ -> d
316+
skipSeps =
317+
(WS.pack <$>) .
318+
filter (not . (`elem` (pure <$> WS.pathSeparators))) .
319+
(WS.unpack <$>)
320+
stripPardirs | pathIsAbsolute || subpathIsAbsolute = dropWhile (== ws "..")
321+
| otherwise = id
322+
prependSep | subpathIsAbsolute = (WS.pack [WS.pathSeparator] <>)
323+
| otherwise = id
324+
avoidEmpty | not pathIsAbsolute
325+
, drive == mempty || hasTrailingPathSep -- prefer "C:" over "C:."
326+
= emptyToCurDir
327+
| otherwise = id
328+
appendSep p | hasTrailingPathSep, not (pathIsAbsolute && p == mempty)
329+
= WS.addTrailingPathSeparator p
330+
| otherwise = p
331+
pathIsAbsolute = not (WS.isRelative path)
332+
subpathIsAbsolute = any WS.isPathSeparator (take 1 (WS.unpack subpath))
333+
hasTrailingPathSep = WS.hasTrailingPathSeparator subpath
334+
335+
expandDots :: [WindowsPath] -> [WindowsPath]
336+
expandDots = reverse . go []
337+
where
338+
go ys' xs' =
339+
case xs' of
340+
[] -> ys'
341+
x : xs
342+
| x == ws "." -> go ys' xs
343+
| x == ws ".." ->
344+
case ys' of
345+
[] -> go (x : ys') xs
346+
y : ys
347+
| y == ws ".." -> go (x : ys') xs
348+
| otherwise -> go ys xs
349+
| otherwise -> go (x : ys') xs
350+
351+
-- | Remove redundant trailing slashes and pick the right kind of slash.
352+
normaliseTrailingSep :: WindowsPath -> WindowsPath
353+
normaliseTrailingSep path = do
354+
let path' = reverse (WS.unpack path)
355+
let (sep, path'') = span WS.isPathSeparator path'
356+
let addSep = if null sep then id else (WS.pathSeparator :)
357+
WS.pack (reverse (addSep path''))
358+
359+
normalisePathSeps :: WindowsPath -> WindowsPath
360+
normalisePathSeps p = WS.pack (normaliseChar <$> WS.unpack p)
361+
where normaliseChar c = if WS.isPathSeparator c then WS.pathSeparator else c
362+
363+
emptyToCurDir :: WindowsPath -> WindowsPath
364+
emptyToCurDir path
365+
| path == mempty = ws "."
366+
| otherwise = path
367+
368+
ws :: String -> WindowsString
369+
ws = rightOrError . WS.encodeUtf
370+
371+
rightOrError :: Exception e => Either e a -> a
372+
rightOrError (Left e) = error (displayException e)
373+
rightOrError (Right a) = a
374+
375+
getFullPathName :: WindowsPath -> IO WindowsPath
376+
getFullPathName path =
377+
fromExtendedLengthPath <$> WS.getFullPathName (toExtendedLengthPath path)
378+
379+
ioeSetWsPath :: IOError -> WindowsPath -> IOError
380+
ioeSetWsPath err =
381+
ioeSetFileName err .
382+
rightOrError .
383+
WS.decodeWith (mkUTF16le TransliterateCodingFailure)
384+
385+
ioeAddLocation :: IOError -> String -> IOError
386+
ioeAddLocation e loc = do
387+
ioeSetLocation e newLoc
388+
where
389+
newLoc = loc <> if null oldLoc then "" else ":" <> oldLoc
390+
oldLoc = ioeGetLocation e
391+
392+
fromExtendedLengthPath :: WindowsPath -> WindowsPath
393+
fromExtendedLengthPath ePath =
394+
case WS.unpack ePath of
395+
c1 : c2 : c3 : c4 : path
396+
| (WS.toChar <$> [c1, c2, c3, c4]) == "\\\\?\\" ->
397+
case path of
398+
c5 : c6 : c7 : subpath@(c8 : _)
399+
| (WS.toChar <$> [c5, c6, c7, c8]) == "UNC\\" ->
400+
WS.pack (c8 : subpath)
401+
drive : col : subpath
402+
-- if the path is not "regular", then the prefix is necessary
403+
-- to ensure the path is interpreted literally
404+
| WS.toChar col == ':', isDriveChar drive, isPathRegular subpath ->
405+
WS.pack path
406+
_ -> ePath
407+
_ -> ePath
408+
where
409+
isDriveChar drive = isAlpha (WS.toChar drive) && isAscii (WS.toChar drive)
410+
isPathRegular path =
411+
not ('/' `elem` (WS.toChar <$> path) ||
412+
ws "." `elem` WS.splitDirectories (WS.pack path) ||
413+
ws ".." `elem` WS.splitDirectories (WS.pack path))
414+
415+
#endif

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