System.AbstractFilePath.Windows

Types

data WindowsString

Commonly used windows string as UTF16 bytes.

Instances

Eq WindowsString

Defined in System.OsString.Internal.Types

Methods

(==) :: WindowsString -> WindowsString -> Bool

(/=) :: WindowsString -> WindowsString -> Bool

Ord WindowsString

Defined in System.OsString.Internal.Types

Methods

compare :: WindowsString -> WindowsString -> Ordering

(<) :: WindowsString -> WindowsString -> Bool

(<=) :: WindowsString -> WindowsString -> Bool

(>) :: WindowsString -> WindowsString -> Bool

(>=) :: WindowsString -> WindowsString -> Bool

max :: WindowsString -> WindowsString -> WindowsString

min :: WindowsString -> WindowsString -> WindowsString

Read WindowsString

Encodes as UTF-16LE.

Defined in System.OsString.Internal.Types

Methods

readsPrec :: Int -> ReadS WindowsString

readList :: ReadS [WindowsString]

readPrec :: ReadPrec WindowsString

readListPrec :: ReadPrec [WindowsString]

Show WindowsString

Decodes as UTF-16LE.

Defined in System.OsString.Internal.Types

Methods

showsPrec :: Int -> WindowsString -> ShowS

show :: WindowsString -> String

showList :: [WindowsString] -> ShowS

IsString WindowsString

Defined in System.OsString.Internal.Types

Methods

fromString :: String -> WindowsString

Generic WindowsString

Defined in System.OsString.Internal.Types

Associated Types

type Rep WindowsString :: Type -> Type

Methods

from :: WindowsString -> Rep WindowsString x

to :: Rep WindowsString x -> WindowsString

Semigroup WindowsString

Defined in System.OsString.Internal.Types

Methods

(<>) :: WindowsString -> WindowsString -> WindowsString

sconcat :: NonEmpty WindowsString -> WindowsString

stimes :: Integral b => b -> WindowsString -> WindowsString

Monoid WindowsString

Defined in System.OsString.Internal.Types

Methods

mempty :: WindowsString

mappend :: WindowsString -> WindowsString -> WindowsString

mconcat :: [WindowsString] -> WindowsString

NFData WindowsString

Defined in System.OsString.Internal.Types

Methods

rnf :: WindowsString -> ()

Lift WindowsString

Defined in System.OsString.Internal.Types

Methods

lift :: WindowsString -> Q Exp

liftTyped :: WindowsString -> Q (TExp WindowsString)

type Rep WindowsString

Defined in System.OsString.Internal.Types

type Rep WindowsString = D1 ('MetaData "WindowsString" "System.OsString.Internal.Types" "filepath-2.0.0.3-inplace" 'True) (C1 ('MetaCons "WS" 'PrefixI 'True) (S1 ('MetaSel ('Just "unWFP") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 ShortByteString)))

data WindowsChar

Instances

Eq WindowsChar

Defined in System.OsString.Internal.Types

Methods

(==) :: WindowsChar -> WindowsChar -> Bool

(/=) :: WindowsChar -> WindowsChar -> Bool

Ord WindowsChar

Defined in System.OsString.Internal.Types

Methods

compare :: WindowsChar -> WindowsChar -> Ordering

(<) :: WindowsChar -> WindowsChar -> Bool

(<=) :: WindowsChar -> WindowsChar -> Bool

(>) :: WindowsChar -> WindowsChar -> Bool

(>=) :: WindowsChar -> WindowsChar -> Bool

max :: WindowsChar -> WindowsChar -> WindowsChar

min :: WindowsChar -> WindowsChar -> WindowsChar

Show WindowsChar

Defined in System.OsString.Internal.Types

Methods

showsPrec :: Int -> WindowsChar -> ShowS

show :: WindowsChar -> String

showList :: [WindowsChar] -> ShowS

Generic WindowsChar

Defined in System.OsString.Internal.Types

Associated Types

type Rep WindowsChar :: Type -> Type

Methods

from :: WindowsChar -> Rep WindowsChar x

to :: Rep WindowsChar x -> WindowsChar

NFData WindowsChar

Defined in System.OsString.Internal.Types

Methods

rnf :: WindowsChar -> ()

type Rep WindowsChar

Defined in System.OsString.Internal.Types

type Rep WindowsChar = D1 ('MetaData "WindowsChar" "System.OsString.Internal.Types" "filepath-2.0.0.3-inplace" 'True) (C1 ('MetaCons "WW" 'PrefixI 'True) (S1 ('MetaSel ('Just "unWW") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Word16)))

type WindowsFilePath = WindowsString

Filepaths are UTF16 data on windows as passed to syscalls.

Filepath construction

toPlatformStringUtf :: MonadThrow m => String -> m WindowsString

Convert a String.

On windows this encodes as UTF16, which is a pretty good guess. On unix this encodes as UTF8, which is a good guess.

Throws a EncodingException if encoding fails.

toPlatformStringEnc :: TextEncoding -> String -> Either EncodingException WindowsString

Like toPlatformStringUtf, except allows to provide an encoding.

toPlatformStringFS :: String -> IO WindowsString

Like toPlatformStringUtf, except on unix this uses the current filesystem locale for encoding instead of always UTF8.

Looking up the locale requires IO. If you're not worried about calls to setFileSystemEncoding, then unsafePerformIO may be feasible (make sure to deeply evaluate the result to catch exceptions).

Throws a EncodingException if encoding fails.

pstr :: QuasiQuoter

QuasiQuote a WindowsString. This accepts Unicode characters and encodes as UTF-16 on windows.

packPlatformString :: [WindowsChar] -> WindowsString

Pack a list of platform words to a platform string.

Note that using this in conjunction with unsafeFromChar to convert from [Char] to platform string is probably not what you want, because it will truncate unicode code points.

Filepath deconstruction

fromPlatformStringUtf :: MonadThrow m => WindowsString -> m String

Partial unicode friendly decoding.

On windows this decodes as UTF16-LE (which is the expected filename encoding). On unix this decodes as UTF8 (which is a good guess). Note that filenames on unix are encoding agnostic char arrays.

Throws a EncodingException if decoding fails.

fromPlatformStringEnc :: TextEncoding -> WindowsString -> Either EncodingException String

Like fromPlatformStringUtf, except allows to provide a text encoding.

The String is forced into memory to catch all exceptions.

fromPlatformStringFS :: WindowsString -> IO String

Like fromPlatformStringUt, except on unix this uses the current filesystem locale for decoding instead of always UTF8. On windows, uses UTF-16LE.

Looking up the locale requires IO. If you're not worried about calls to setFileSystemEncoding, then unsafePerformIO may be feasible (make sure to deeply evaluate the result to catch exceptions).

Throws EncodingException if decoding fails.

unpackPlatformString :: WindowsString -> [WindowsChar]

Unpack a platform string to a list of platform words.

Word construction

unsafeFromChar :: Char -> WindowsChar

Truncates to 2 octets.

Word deconstruction

toChar :: WindowsChar -> Char

Converts back to a unicode codepoint (total).

Separator predicates

pathSeparator :: WindowsChar

The character that separates directories. In the case where more than one character is possible, pathSeparator is the 'ideal' one.

Windows: pathSeparator == '\\'
Posix:   pathSeparator ==  '/'
isPathSeparator pathSeparator

pathSeparators :: [WindowsChar]

The list of all possible separators.

Windows: pathSeparators == ['\\', '/']
Posix:   pathSeparators == ['/']
pathSeparator `elem` pathSeparators

isPathSeparator :: WindowsChar -> Bool

Rather than using (== pathSeparator), use this. Test if something is a path separator.

isPathSeparator a == (a `elem` pathSeparators)

searchPathSeparator :: WindowsChar

Is the character a file separator?

isSearchPathSeparator a == (a == searchPathSeparator)

isSearchPathSeparator :: WindowsChar -> Bool

Is the character a file separator?

isSearchPathSeparator a == (a == searchPathSeparator)

extSeparator :: WindowsChar

File extension character

extSeparator == '.'

isExtSeparator :: WindowsChar -> Bool

Is the character an extension character?

isExtSeparator a == (a == extSeparator)

$PATH methods

splitSearchPath :: WindowsString -> [WindowsFilePath]

Take a string, split it on the searchPathSeparator character. Blank items are ignored on Windows, and converted to . on Posix. On Windows path elements are stripped of quotes.

Follows the recommendations in http://www.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap08.html

Posix:   splitSearchPath "File1:File2:File3"  == ["File1","File2","File3"]
Posix:   splitSearchPath "File1::File2:File3" == ["File1",".","File2","File3"]
Windows: splitSearchPath "File1;File2;File3"  == ["File1","File2","File3"]
Windows: splitSearchPath "File1;;File2;File3" == ["File1","File2","File3"]
Windows: splitSearchPath "File1;\"File2\";File3" == ["File1","File2","File3"]

Extension functions

splitExtension :: WindowsFilePath -> (WindowsFilePath, WindowsString)

Split on the extension. addExtension is the inverse.

splitExtension "/directory/path.ext" == ("/directory/path",".ext")
uncurry (<>) (splitExtension x) == x
Valid x => uncurry addExtension (splitExtension x) == x
splitExtension "file.txt" == ("file",".txt")
splitExtension "file" == ("file","")
splitExtension "file/file.txt" == ("file/file",".txt")
splitExtension "file.txt/boris" == ("file.txt/boris","")
splitExtension "file.txt/boris.ext" == ("file.txt/boris",".ext")
splitExtension "file/path.txt.bob.fred" == ("file/path.txt.bob",".fred")
splitExtension "file/path.txt/" == ("file/path.txt/","")

takeExtension :: WindowsFilePath -> WindowsString

Get the extension of a file, returns "" for no extension, .ext otherwise.

takeExtension "/directory/path.ext" == ".ext"
takeExtension x == snd (splitExtension x)
Valid x => takeExtension (addExtension x "ext") == ".ext"
Valid x => takeExtension (replaceExtension x "ext") == ".ext"

replaceExtension :: WindowsFilePath -> WindowsString -> WindowsFilePath

Set the extension of a file, overwriting one if already present, equivalent to -<.>.

replaceExtension "/directory/path.txt" "ext" == "/directory/path.ext"
replaceExtension "/directory/path.txt" ".ext" == "/directory/path.ext"
replaceExtension "file.txt" ".bob" == "file.bob"
replaceExtension "file.txt" "bob" == "file.bob"
replaceExtension "file" ".bob" == "file.bob"
replaceExtension "file.txt" "" == "file"
replaceExtension "file.fred.bob" "txt" == "file.fred.txt"
replaceExtension x y == addExtension (dropExtension x) y

(-<.>) :: WindowsFilePath -> WindowsString -> WindowsFilePath

Remove the current extension and add another, equivalent to replaceExtension.

"/directory/path.txt" -<.> "ext" == "/directory/path.ext"
"/directory/path.txt" -<.> ".ext" == "/directory/path.ext"
"foo.o" -<.> "c" == "foo.c"

dropExtension :: WindowsFilePath -> WindowsFilePath

Remove last extension, and the "." preceding it.

dropExtension "/directory/path.ext" == "/directory/path"
dropExtension x == fst (splitExtension x)

addExtension :: WindowsFilePath -> WindowsString -> WindowsFilePath

Add an extension, even if there is already one there, equivalent to <.>.

addExtension "/directory/path" "ext" == "/directory/path.ext"
addExtension "file.txt" "bib" == "file.txt.bib"
addExtension "file." ".bib" == "file..bib"
addExtension "file" ".bib" == "file.bib"
addExtension "/" "x" == "/.x"
addExtension x "" == x
Valid x => takeFileName (addExtension (addTrailingPathSeparator x) "ext") == ".ext"
Windows: addExtension "\\\\share" ".txt" == "\\\\share\\.txt"

hasExtension :: WindowsFilePath -> Bool

Does the given filename have an extension?

hasExtension "/directory/path.ext" == True
hasExtension "/directory/path" == False
null (takeExtension x) == not (hasExtension x)

(<.>) :: WindowsFilePath -> WindowsString -> WindowsFilePath

Add an extension, even if there is already one there, equivalent to addExtension.

"/directory/path" <.> "ext" == "/directory/path.ext"
"/directory/path" <.> ".ext" == "/directory/path.ext"

splitExtensions :: WindowsFilePath -> (WindowsFilePath, WindowsString)

Split on all extensions.

splitExtensions "/directory/path.ext" == ("/directory/path",".ext")
splitExtensions "file.tar.gz" == ("file",".tar.gz")
uncurry (<>) (splitExtensions x) == x
Valid x => uncurry addExtension (splitExtensions x) == x
splitExtensions "file.tar.gz" == ("file",".tar.gz")

dropExtensions :: WindowsFilePath -> WindowsFilePath

Drop all extensions.

dropExtensions "/directory/path.ext" == "/directory/path"
dropExtensions "file.tar.gz" == "file"
not $ hasExtension $ dropExtensions x
not $ any isExtSeparator $ takeFileName $ dropExtensions x

takeExtensions :: WindowsFilePath -> WindowsString

Get all extensions.

takeExtensions "/directory/path.ext" == ".ext"
takeExtensions "file.tar.gz" == ".tar.gz"

replaceExtensions :: WindowsFilePath -> WindowsString -> WindowsFilePath

Replace all extensions of a file with a new extension. Note that replaceExtension and addExtension both work for adding multiple extensions, so only required when you need to drop all extensions first.

replaceExtensions "file.fred.bob" "txt" == "file.txt"
replaceExtensions "file.fred.bob" "tar.gz" == "file.tar.gz"

isExtensionOf :: WindowsString -> WindowsFilePath -> Bool

Does the given filename have the specified extension?

"png" `isExtensionOf` "/directory/file.png" == True
".png" `isExtensionOf` "/directory/file.png" == True
".tar.gz" `isExtensionOf` "bar/foo.tar.gz" == True
"ar.gz" `isExtensionOf` "bar/foo.tar.gz" == False
"png" `isExtensionOf` "/directory/file.png.jpg" == False
"csv/table.csv" `isExtensionOf` "/data/csv/table.csv" == False

stripExtension :: WindowsString -> WindowsFilePath -> Maybe WindowsFilePath

Drop the given extension from a filepath, and the "." preceding it. Returns Nothing if the filepath does not have the given extension, or Just and the part before the extension if it does.

This function can be more predictable than dropExtensions, especially if the filename might itself contain . characters.

stripExtension "hs.o" "foo.x.hs.o" == Just "foo.x"
stripExtension "hi.o" "foo.x.hs.o" == Nothing
dropExtension x == fromJust (stripExtension (takeExtension x) x)
dropExtensions x == fromJust (stripExtension (takeExtensions x) x)
stripExtension ".c.d" "a.b.c.d"  == Just "a.b"
stripExtension ".c.d" "a.b..c.d" == Just "a.b."
stripExtension "baz"  "foo.bar"  == Nothing
stripExtension "bar"  "foobar"   == Nothing
stripExtension ""     x          == Just x

Filename/directory functions

splitFileName :: WindowsFilePath -> (WindowsFilePath, WindowsFilePath)

Split a filename into directory and file. </> is the inverse. The first component will often end with a trailing slash.

splitFileName "/directory/file.ext" == ("/directory/","file.ext")
Valid x => uncurry (</>) (splitFileName x) == x || fst (splitFileName x) == "./"
Valid x => isValid (fst (splitFileName x))
splitFileName "file/bob.txt" == ("file/", "bob.txt")
splitFileName "file/" == ("file/", "")
splitFileName "bob" == ("./", "bob")
Posix:   splitFileName "/" == ("/","")
Windows: splitFileName "c:" == ("c:","")

takeFileName :: WindowsFilePath -> WindowsFilePath

Get the file name.

takeFileName "/directory/file.ext" == "file.ext"
takeFileName "test/" == ""
takeFileName x `isSuffixOf` x
takeFileName x == snd (splitFileName x)
Valid x => takeFileName (replaceFileName x "fred") == "fred"
Valid x => takeFileName (x </> "fred") == "fred"
Valid x => isRelative (takeFileName x)

replaceFileName :: WindowsFilePath -> WindowsString -> WindowsFilePath

Set the filename.

replaceFileName "/directory/other.txt" "file.ext" == "/directory/file.ext"
Valid x => replaceFileName x (takeFileName x) == x

dropFileName :: WindowsFilePath -> WindowsFilePath

Drop the filename. Unlike takeDirectory, this function will leave a trailing path separator on the directory.

dropFileName "/directory/file.ext" == "/directory/"
dropFileName x == fst (splitFileName x)

takeBaseName :: WindowsFilePath -> WindowsFilePath

Get the base name, without an extension or path.

takeBaseName "/directory/file.ext" == "file"
takeBaseName "file/test.txt" == "test"
takeBaseName "dave.ext" == "dave"
takeBaseName "" == ""
takeBaseName "test" == "test"
takeBaseName (addTrailingPathSeparator x) == ""
takeBaseName "file/file.tar.gz" == "file.tar"

replaceBaseName :: WindowsFilePath -> WindowsString -> WindowsFilePath

Set the base name.

replaceBaseName "/directory/other.ext" "file" == "/directory/file.ext"
replaceBaseName "file/test.txt" "bob" == "file/bob.txt"
replaceBaseName "fred" "bill" == "bill"
replaceBaseName "/dave/fred/bob.gz.tar" "new" == "/dave/fred/new.tar"
Valid x => replaceBaseName x (takeBaseName x) == x

takeDirectory :: WindowsFilePath -> WindowsFilePath

Get the directory name, move up one level.

          takeDirectory "/directory/other.ext" == "/directory"
          takeDirectory x `isPrefixOf` x || takeDirectory x == "."
          takeDirectory "foo" == "."
          takeDirectory "/" == "/"
          takeDirectory "/foo" == "/"
          takeDirectory "/foo/bar/baz" == "/foo/bar"
          takeDirectory "/foo/bar/baz/" == "/foo/bar/baz"
          takeDirectory "foo/bar/baz" == "foo/bar"
Windows:  takeDirectory "foo\\bar" == "foo"
Windows:  takeDirectory "foo\\bar\\\\" == "foo\\bar"
Windows:  takeDirectory "C:\\" == "C:\\"

replaceDirectory :: WindowsFilePath -> WindowsFilePath -> WindowsFilePath

Set the directory, keeping the filename the same.

replaceDirectory "root/file.ext" "/directory/" == "/directory/file.ext"
Valid x => replaceDirectory x (takeDirectory x) `equalFilePath` x

combine :: WindowsFilePath -> WindowsFilePath -> WindowsFilePath

An alias for </>.

(</>) :: WindowsFilePath -> WindowsFilePath -> WindowsFilePath

Combine two paths with a path separator. If the second path starts with a path separator or a drive letter, then it returns the second. The intention is that readFile (dir </> file) will access the same file as setCurrentDirectory dir; readFile file.

Posix:   "/directory" </> "file.ext" == "/directory/file.ext"
Windows: "/directory" </> "file.ext" == "/directory\\file.ext"
         "directory" </> "/file.ext" == "/file.ext"
Valid x => (takeDirectory x </> takeFileName x) `equalFilePath` x

Combined:

Posix:   "/" </> "test" == "/test"
Posix:   "home" </> "bob" == "home/bob"
Posix:   "x:" </> "foo" == "x:/foo"
Windows: "C:\\foo" </> "bar" == "C:\\foo\\bar"
Windows: "home" </> "bob" == "home\\bob"

Not combined:

Posix:   "home" </> "/bob" == "/bob"
Windows: "home" </> "C:\\bob" == "C:\\bob"

Not combined (tricky):

On Windows, if a filepath starts with a single slash, it is relative to the root of the current drive. In [1], this is (confusingly) referred to as an absolute path. The current behavior of </> is to never combine these forms.

Windows: "home" </> "/bob" == "/bob"
Windows: "home" </> "\\bob" == "\\bob"
Windows: "C:\\home" </> "\\bob" == "\\bob"

On Windows, from [1]: "If a file name begins with only a disk designator but not the backslash after the colon, it is interpreted as a relative path to the current directory on the drive with the specified letter." The current behavior of </> is to never combine these forms.

Windows: "D:\\foo" </> "C:bar" == "C:bar"
Windows: "C:\\foo" </> "C:bar" == "C:bar"

splitPath :: WindowsFilePath -> [WindowsFilePath]

Split a path by the directory separator.

splitPath "/directory/file.ext" == ["/","directory/","file.ext"]
concat (splitPath x) == x
splitPath "test//item/" == ["test//","item/"]
splitPath "test/item/file" == ["test/","item/","file"]
splitPath "" == []
Windows: splitPath "c:\\test\\path" == ["c:\\","test\\","path"]
Posix:   splitPath "/file/test" == ["/","file/","test"]

joinPath :: [WindowsFilePath] -> WindowsFilePath

Join path elements back together.

joinPath z == foldr (</>) "" z
joinPath ["/","directory/","file.ext"] == "/directory/file.ext"
Valid x => joinPath (splitPath x) == x
joinPath [] == ""
Posix: joinPath ["test","file","path"] == "test/file/path"

splitDirectories :: WindowsFilePath -> [WindowsFilePath]

Just as splitPath, but don't add the trailing slashes to each element.

         splitDirectories "/directory/file.ext" == ["/","directory","file.ext"]
         splitDirectories "test/file" == ["test","file"]
         splitDirectories "/test/file" == ["/","test","file"]
Windows: splitDirectories "C:\\test\\file" == ["C:\\", "test", "file"]
         Valid x => joinPath (splitDirectories x) `equalFilePath` x
         splitDirectories "" == []
Windows: splitDirectories "C:\\test\\\\\\file" == ["C:\\", "test", "file"]
         splitDirectories "/test///file" == ["/","test","file"]

Drive functions

splitDrive :: WindowsFilePath -> (WindowsFilePath, WindowsFilePath)

Split a path into a drive and a path. On Posix, / is a Drive.

uncurry (<>) (splitDrive x) == x
Windows: splitDrive "file" == ("","file")
Windows: splitDrive "c:/file" == ("c:/","file")
Windows: splitDrive "c:\\file" == ("c:\\","file")
Windows: splitDrive "\\\\shared\\test" == ("\\\\shared\\","test")
Windows: splitDrive "\\\\shared" == ("\\\\shared","")
Windows: splitDrive "\\\\?\\UNC\\shared\\file" == ("\\\\?\\UNC\\shared\\","file")
Windows: splitDrive "\\\\?\\UNCshared\\file" == ("\\\\?\\","UNCshared\\file")
Windows: splitDrive "\\\\?\\d:\\file" == ("\\\\?\\d:\\","file")
Windows: splitDrive "/d" == ("","/d")
Posix:   splitDrive "/test" == ("/","test")
Posix:   splitDrive "//test" == ("//","test")
Posix:   splitDrive "test/file" == ("","test/file")
Posix:   splitDrive "file" == ("","file")

joinDrive :: WindowsFilePath -> WindowsFilePath -> WindowsFilePath

Join a drive and the rest of the path.

Valid x => uncurry joinDrive (splitDrive x) == x
Windows: joinDrive "C:" "foo" == "C:foo"
Windows: joinDrive "C:\\" "bar" == "C:\\bar"
Windows: joinDrive "\\\\share" "foo" == "\\\\share\\foo"
Windows: joinDrive "/:" "foo" == "/:\\foo"

takeDrive :: WindowsFilePath -> WindowsFilePath

Get the drive from a filepath.

takeDrive x == fst (splitDrive x)

hasDrive :: WindowsFilePath -> Bool

Does a path have a drive.

not (hasDrive x) == null (takeDrive x)
Posix:   hasDrive "/foo" == True
Windows: hasDrive "C:\\foo" == True
Windows: hasDrive "C:foo" == True
         hasDrive "foo" == False
         hasDrive "" == False

dropDrive :: WindowsFilePath -> WindowsFilePath

Delete the drive, if it exists.

dropDrive x == snd (splitDrive x)

isDrive :: WindowsFilePath -> Bool

Is an element a drive

Posix:   isDrive "/" == True
Posix:   isDrive "/foo" == False
Windows: isDrive "C:\\" == True
Windows: isDrive "C:\\foo" == False
         isDrive "" == False

Trailing slash functions

hasTrailingPathSeparator :: WindowsFilePath -> Bool

Is an item either a directory or the last character a path separator?

hasTrailingPathSeparator "test" == False
hasTrailingPathSeparator "test/" == True

addTrailingPathSeparator :: WindowsFilePath -> WindowsFilePath

Add a trailing file path separator if one is not already present.

hasTrailingPathSeparator (addTrailingPathSeparator x)
hasTrailingPathSeparator x ==> addTrailingPathSeparator x == x
Posix:    addTrailingPathSeparator "test/rest" == "test/rest/"

dropTrailingPathSeparator :: WindowsFilePath -> WindowsFilePath

Remove any trailing path separators

dropTrailingPathSeparator "file/test/" == "file/test"
          dropTrailingPathSeparator "/" == "/"
Windows:  dropTrailingPathSeparator "\\" == "\\"
Posix:    not (hasTrailingPathSeparator (dropTrailingPathSeparator x)) || isDrive x

File name manipulations

normalise :: WindowsFilePath -> WindowsFilePath

Normalise a file

• // outside of the drive can be made blank
• / -> pathSeparator
• ./ -> ""

Does not remove "..", because of symlinks.

Posix:   normalise "/file/\\test////" == "/file/\\test/"
Posix:   normalise "/file/./test" == "/file/test"
Posix:   normalise "/test/file/../bob/fred/" == "/test/file/../bob/fred/"
Posix:   normalise "../bob/fred/" == "../bob/fred/"
Posix:   normalise "/a/../c" == "/a/../c"
Posix:   normalise "./bob/fred/" == "bob/fred/"
Windows: normalise "c:\\file/bob\\" == "C:\\file\\bob\\"
Windows: normalise "c:\\" == "C:\\"
Windows: normalise "C:.\\" == "C:"
Windows: normalise "\\\\server\\test" == "\\\\server\\test"
Windows: normalise "//server/test" == "\\\\server\\test"
Windows: normalise "c:/file" == "C:\\file"
Windows: normalise "/file" == "\\file"
Windows: normalise "\\" == "\\"
Windows: normalise "/./" == "\\"
         normalise "." == "."
Posix:   normalise "./" == "./"
Posix:   normalise "./." == "./"
Posix:   normalise "/./" == "/"
Posix:   normalise "/" == "/"
Posix:   normalise "bob/fred/." == "bob/fred/"
Posix:   normalise "//home" == "/home"

equalFilePath :: WindowsFilePath -> WindowsFilePath -> Bool

Equality of two filepaths. If you call System.Directory.canonicalizePath first this has a much better chance of working. Note that this doesn't follow symlinks or DOSNAM~1s.

Similar to normalise, this does not expand "..", because of symlinks.

         x == y ==> equalFilePath x y
         normalise x == normalise y ==> equalFilePath x y
         equalFilePath "foo" "foo/"
         not (equalFilePath "/a/../c" "/c")
         not (equalFilePath "foo" "/foo")
Posix:   not (equalFilePath "foo" "FOO")
Windows: equalFilePath "foo" "FOO"
Windows: not (equalFilePath "C:" "C:/")

makeRelative :: WindowsFilePath -> WindowsFilePath -> WindowsFilePath

Contract a filename, based on a relative path. Note that the resulting path will never introduce .. paths, as the presence of symlinks means ../b may not reach a/b if it starts from a/c. For a worked example see this blog post.

The corresponding makeAbsolute function can be found in System.Directory.

         makeRelative "/directory" "/directory/file.ext" == "file.ext"
         Valid x => makeRelative (takeDirectory x) x `equalFilePath` takeFileName x
         makeRelative x x == "."
         Valid x y => equalFilePath x y || (isRelative x && makeRelative y x == x) || equalFilePath (y </> makeRelative y x) x
Windows: makeRelative "C:\\Home" "c:\\home\\bob" == "bob"
Windows: makeRelative "C:\\Home" "c:/home/bob" == "bob"
Windows: makeRelative "C:\\Home" "D:\\Home\\Bob" == "D:\\Home\\Bob"
Windows: makeRelative "C:\\Home" "C:Home\\Bob" == "C:Home\\Bob"
Windows: makeRelative "/Home" "/home/bob" == "bob"
Windows: makeRelative "/" "//" == "//"
Posix:   makeRelative "/Home" "/home/bob" == "/home/bob"
Posix:   makeRelative "/home/" "/home/bob/foo/bar" == "bob/foo/bar"
Posix:   makeRelative "/fred" "bob" == "bob"
Posix:   makeRelative "/file/test" "/file/test/fred" == "fred"
Posix:   makeRelative "/file/test" "/file/test/fred/" == "fred/"
Posix:   makeRelative "some/path" "some/path/a/b/c" == "a/b/c"

isRelative :: WindowsFilePath -> Bool

Is a path relative, or is it fixed to the root?

Windows: isRelative "path\\test" == True
Windows: isRelative "c:\\test" == False
Windows: isRelative "c:test" == True
Windows: isRelative "c:\\" == False
Windows: isRelative "c:/" == False
Windows: isRelative "c:" == True
Windows: isRelative "\\\\foo" == False
Windows: isRelative "\\\\?\\foo" == False
Windows: isRelative "\\\\?\\UNC\\foo" == False
Windows: isRelative "/foo" == True
Windows: isRelative "\\foo" == True
Posix:   isRelative "test/path" == True
Posix:   isRelative "/test" == False
Posix:   isRelative "/" == False

According to [1]:

• "A UNC name of any format [is never relative]."
• "You cannot use the "\?" prefix with a relative path."

isAbsolute :: WindowsFilePath -> Bool

not . isRelative

isAbsolute x == not (isRelative x)

isValid :: WindowsFilePath -> Bool

Is a filepath valid, i.e. could you create a file like it? This function checks for invalid names, and invalid characters, but does not check if length limits are exceeded, as these are typically filesystem dependent.

         isValid "" == False
         isValid "\0" == False
Posix:   isValid "/random_ path:*" == True
Posix:   isValid x == not (null x)
Windows: isValid "c:\\test" == True
Windows: isValid "c:\\test:of_test" == False
Windows: isValid "test*" == False
Windows: isValid "c:\\test\\nul" == False
Windows: isValid "c:\\test\\prn.txt" == False
Windows: isValid "c:\\nul\\file" == False
Windows: isValid "\\\\" == False
Windows: isValid "\\\\\\foo" == False
Windows: isValid "\\\\?\\D:file" == False
Windows: isValid "foo\tbar" == False
Windows: isValid "nul .txt" == False
Windows: isValid " nul.txt" == True

makeValid :: WindowsFilePath -> WindowsFilePath

Take a filepath and make it valid; does not change already valid filepaths.

isValid (makeValid x)
isValid x ==> makeValid x == x
makeValid "" == "_"
makeValid "file\0name" == "file_name"
Windows: makeValid "c:\\already\\/valid" == "c:\\already\\/valid"
Windows: makeValid "c:\\test:of_test" == "c:\\test_of_test"
Windows: makeValid "test*" == "test_"
Windows: makeValid "c:\\test\\nul" == "c:\\test\\nul_"
Windows: makeValid "c:\\test\\prn.txt" == "c:\\test\\prn_.txt"
Windows: makeValid "c:\\test/prn.txt" == "c:\\test/prn_.txt"
Windows: makeValid "c:\\nul\\file" == "c:\\nul_\\file"
Windows: makeValid "\\\\\\foo" == "\\\\drive"
Windows: makeValid "\\\\?\\D:file" == "\\\\?\\D:\\file"
Windows: makeValid "nul .txt" == "nul _.txt"