Skip to content

Commit accd4d9

Browse files
hasufellhasufell
committed
Add long path support wrt #39 
1 parent e2b5ebc commit accd4d9

File tree

3 files changed

+216
-8
lines changed

3 files changed

+216
-8
lines changed

‎file-io.cabal‎

Lines changed: 11 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -29,6 +29,11 @@ flag os-string
2929
default: False
3030
manual: False
3131

32+
flag long-paths
33+
description: Enable a hack for ad-hoc long path support on Windows
34+
default: True
35+
manual: True
36+
3237
library
3338
default-language: Haskell2010
3439

@@ -51,6 +56,9 @@ library
5156
else
5257
build-depends: filepath >= 1.4.100.0 && < 1.5.0.0
5358

59+
if flag(long-paths)
60+
cpp-options: -DLONG_PATHS
61+
5462
exposed-modules:
5563
System.File.OsPath
5664
System.File.OsPath.Internal
@@ -111,6 +119,8 @@ test-suite Properties
111119
main-is: Properties.hs
112120
type: exitcode-stdio-1.0
113121
default-language: Haskell2010
114-
build-depends: base >=4.13.0.0 && <5, bytestring, tasty, tasty-hunit, file-io, filepath, temporary
122+
build-depends: base >=4.13.0.0 && <5, bytestring, directory, tasty, tasty-hunit, file-io, filepath, temporary
115123
ghc-options: -Wall -threaded -rtsopts "-with-rtsopts=-N10"
124+
if flag(long-paths)
125+
cpp-options: -DLONG_PATHS
116126

‎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(..))
1818
import System.IO
1919
import System.IO.Temp
2020
import qualified Data.ByteString as BS
21+
#if defined(LONG_PATHS)
22+
import Control.Monad (when)
23+
import System.Directory.OsPath (createDirectory, makeAbsolute)
24+
import System.IO.Error (catchIOError)
25+
#endif
2126

2227

2328
main :: IO ()
2429
main = defaultMain $ testGroup "All"
2530
[ testGroup "System.File.OsPath"
26-
[ testCase "readFile . writeFile" writeFileReadFile
31+
[
32+
#if defined(LONG_PATHS)
33+
testCase "writeFile (very long path)" writeFileLongPath,
34+
#endif
35+
testCase "readFile . writeFile" writeFileReadFile
2736
, testCase "readFile . writeFile . writeFile" writeWriteFileReadFile
2837
, testCase "readFile . appendFile . writeFile" appendFileReadFile
2938
, testCase "iomode: ReadFile does not allow write" iomodeReadFile
@@ -56,6 +65,29 @@ main = defaultMain $ testGroup "All"
5665
]
5766
]
5867

68+
#if defined(LONG_PATHS)
69+
writeFileLongPath :: Assertion
70+
writeFileLongPath = do
71+
withSystemTempDirectory "test" $ \baseDir' -> do
72+
baseDir <- OSP.encodeFS baseDir'
73+
let longName = mconcat (replicate 10 [osp|"its_very_long"|])
74+
let longDir = baseDir </> longName </> longName
75+
76+
supportsLongPaths <- do
77+
-- create 2 dirs because 1 path segment by itself can't exceed MAX_PATH
78+
-- tests: [createDirectory]
79+
createDirectory =<< makeAbsolute longName
80+
createDirectory longDir
81+
return True
82+
`catchIOError` \ _ ->
83+
return False
84+
85+
when supportsLongPaths $ do
86+
OSP.writeFile (longDir </> [osp|foo|]) "test"
87+
contents <- OSP.readFile (longDir </> [osp|foo|])
88+
"test" @=? contents
89+
#endif
90+
5991
writeFileReadFile :: Assertion
6092
writeFileReadFile = do
6193
withSystemTempDirectory "test" $ \baseDir' -> do

‎windows/System/File/Platform.hsc‎

Lines changed: 172 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -12,7 +12,6 @@ import System.OsPath.Windows ( WindowsPath )
1212
import qualified System.OsPath.Windows as WS
1313
import Foreign.C.Types
1414

15-
import qualified System.OsString.Windows as WS hiding (decodeFS)
1615
import System.OsString.Windows ( encodeUtf, WindowsString )
1716
import qualified System.Win32 as Win32
1817
import qualified System.Win32.WindowsString.File as WS
@@ -43,18 +42,28 @@ import Text.Printf (printf)
4342

4443
#if MIN_VERSION_filepath(1, 5, 0)
4544
import System.OsString.Encoding
46-
import "os-string" System.OsString.Internal.Types (WindowsString(..), WindowsChar(..))
47-
import qualified "os-string" System.OsString.Data.ByteString.Short as BC
4845
#else
4946
import Data.Coerce (coerce)
5047
import System.OsPath.Encoding
51-
import "filepath" System.OsString.Internal.Types (WindowsString(..), WindowsChar(..))
5248
import qualified "filepath" System.OsPath.Data.ByteString.Short.Word16 as BC
5349
#endif
5450

51+
import System.IO.Error (modifyIOError, ioeSetFileName)
52+
import GHC.IO.Encoding.UTF16 (mkUTF16le)
53+
import GHC.IO.Encoding.Failure (CodingFailureMode(TransliterateCodingFailure))
54+
import Control.Exception (displayException, Exception)
55+
56+
#if defined(LONG_PATHS)
57+
import System.IO.Error (ioeSetLocation, ioeGetLocation, catchIOError)
58+
import Data.Char (isAlpha, isAscii, toUpper)
59+
import qualified System.Win32.WindowsString.Info as WS
60+
#endif
61+
5562
-- | Open a file and return the 'Handle'.
5663
openFile :: WindowsPath -> IOMode -> IO Handle
57-
openFile fp iomode = bracketOnError
64+
openFile fp' iomode = (`ioeSetWsPath` fp') `modifyIOError` do
65+
fp <- furnishPath fp'
66+
bracketOnError
5867
(WS.createFile
5968
fp
6069
accessMode
@@ -104,7 +113,9 @@ writeShareMode =
104113

105114
-- | 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
117+
fp <- furnishPath fp'
118+
bracketOnError
108119
(WS.createFile
109120
fp
110121
accessMode
@@ -248,3 +259,158 @@ any_ = coerce BC.any
248259

249260
#endif
250261

262+
ioeSetWsPath :: IOError -> WindowsPath -> IOError
263+
ioeSetWsPath err =
264+
ioeSetFileName err .
265+
rightOrError .
266+
WS.decodeWith (mkUTF16le TransliterateCodingFailure)
267+
268+
rightOrError :: Exception e => Either e a -> a
269+
rightOrError (Left e) = error (displayException e)
270+
rightOrError (Right a) = a
271+
272+
-- inlined stuff from directory package
273+
furnishPath :: WindowsPath -> IO WindowsPath
274+
#if !defined(LONG_PATHS)
275+
furnishPath path = pure path
276+
#else
277+
furnishPath path = pure path
278+
279+
furnishPath' :: WindowsPath -> IO WindowsPath
280+
furnishPath' path =
281+
(toExtendedLengthPath <$> rawPrependCurrentDirectory path)
282+
`catchIOError` \ _ ->
283+
pure path
284+
285+
toExtendedLengthPath :: WindowsPath -> WindowsPath
286+
toExtendedLengthPath path =
287+
if WS.isRelative path
288+
then simplifiedPath
289+
else
290+
case WS.toChar <$> simplifiedPath' of
291+
'\\' : '?' : '?' : '\\' : _ -> simplifiedPath
292+
'\\' : '\\' : '?' : '\\' : _ -> simplifiedPath
293+
'\\' : '\\' : '.' : '\\' : _ -> simplifiedPath
294+
'\\' : '\\' : _ ->
295+
ws "\\\\?\\UNC" <> WS.pack (drop 1 simplifiedPath')
296+
_ -> 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 .
318+
stripPardirs . expandDots . skipSeps .
319+
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 ->
324+
-- 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 <$>)
331+
stripPardirs | pathIsAbsolute || subpathIsAbsolute = dropWhile (== ws "..")
332+
| otherwise = id
333+
prependSep | subpathIsAbsolute = (WS.pack [WS.pathSeparator] <>)
334+
| otherwise = id
335+
avoidEmpty | not pathIsAbsolute
336+
, drive == mempty || hasTrailingPathSep -- prefer "C:" over "C:."
337+
= emptyToCurDir
338+
| otherwise = id
339+
appendSep p | hasTrailingPathSep, not (pathIsAbsolute && p == mempty)
340+
= WS.addTrailingPathSeparator p
341+
| otherwise = p
342+
pathIsAbsolute = not (WS.isRelative path)
343+
subpathIsAbsolute = any WS.isPathSeparator (take 1 (WS.unpack subpath))
344+
hasTrailingPathSep = WS.hasTrailingPathSeparator subpath
345+
346+
expandDots :: [WindowsPath] -> [WindowsPath]
347+
expandDots = reverse . go []
348+
where
349+
go ys' xs' =
350+
case xs' of
351+
[] -> ys'
352+
x : xs
353+
| x == ws "." -> go ys' xs
354+
| x == ws ".." ->
355+
case ys' of
356+
[] -> go (x : ys') xs
357+
y : ys
358+
| y == ws ".." -> go (x : ys') xs
359+
| otherwise -> go ys xs
360+
| otherwise -> go (x : ys') xs
361+
362+
-- | Remove redundant trailing slashes and pick the right kind of slash.
363+
normaliseTrailingSep :: WindowsPath -> WindowsPath
364+
normaliseTrailingSep path = do
365+
let path' = reverse (WS.unpack path)
366+
let (sep, path'') = span WS.isPathSeparator path'
367+
let addSep = if null sep then id else (WS.pathSeparator :)
368+
WS.pack (reverse (addSep path''))
369+
370+
normalisePathSeps :: WindowsPath -> WindowsPath
371+
normalisePathSeps p = WS.pack (normaliseChar <$> 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))
415+
416+
#endif

0 commit comments

Comments
 (0)