#if __GLASGOW_HASKELL__ >= 704 {-# LANGUAGE Safe #-} #endif {-# LANGUAGE PatternGuards #-} -- This template expects CPP definitions for: -- MODULE_NAME = Posix | Windows -- IS_WINDOWS = False | True -- | -- Module : System.FilePath.MODULE_NAME -- Copyright : (c) Neil Mitchell 2005-2014 -- License : BSD3 -- -- Maintainer : ndmitchell@gmail.com -- Stability : stable -- Portability : portable -- -- A library for 'FilePath' manipulations, using MODULE_NAME style paths on -- all platforms. Importing "System.FilePath" is usually better. -- -- Given the example 'FilePath': @\/directory\/file.ext@ -- -- We can use the following functions to extract pieces. -- -- * 'takeFileName' gives @\"file.ext\"@ -- -- * 'takeDirectory' gives @\"\/directory\"@ -- -- * 'takeExtension' gives @\".ext\"@ -- -- * 'dropExtension' gives @\"\/directory\/file\"@ -- -- * 'takeBaseName' gives @\"file\"@ -- -- And we could have built an equivalent path with the following expressions: -- -- * @\"\/directory\" '' \"file.ext\"@. -- -- * @\"\/directory\/file" '<.>' \"ext\"@. -- -- * @\"\/directory\/file.txt" '-<.>' \"ext\"@. -- -- Each function in this module is documented with several examples, -- which are also used as tests. -- -- Here are a few examples of using the @filepath@ functions together: -- -- /Example 1:/ Find the possible locations of a Haskell module @Test@ imported from module @Main@: -- -- @['replaceFileName' path_to_main \"Test\" '<.>' ext | ext <- [\"hs\",\"lhs\"] ]@ -- -- /Example 2:/ Download a file from @url@ and save it to disk: -- -- @do let file = 'makeValid' url -- System.Directory.createDirectoryIfMissing True ('takeDirectory' file)@ -- -- /Example 3:/ Compile a Haskell file, putting the @.hi@ file under @interface@: -- -- @'takeDirectory' file '' \"interface\" '' ('takeFileName' file '-<.>' \"hi\")@ -- -- References: -- [1] (Microsoft MSDN) module System.FilePath.MODULE_NAME ( -- * Separator predicates FilePath, pathSeparator, pathSeparators, isPathSeparator, searchPathSeparator, isSearchPathSeparator, extSeparator, isExtSeparator, -- * @$PATH@ methods splitSearchPath, getSearchPath, -- * Extension functions splitExtension, takeExtension, replaceExtension, (-<.>), dropExtension, addExtension, hasExtension, (<.>), splitExtensions, dropExtensions, takeExtensions, replaceExtensions, isExtensionOf, stripExtension, -- * Filename\/directory functions splitFileName, takeFileName, replaceFileName, dropFileName, takeBaseName, replaceBaseName, takeDirectory, replaceDirectory, combine, (), splitPath, joinPath, splitDirectories, -- * Drive functions splitDrive, joinDrive, takeDrive, hasDrive, dropDrive, isDrive, -- * Trailing slash functions hasTrailingPathSeparator, addTrailingPathSeparator, dropTrailingPathSeparator, -- * File name manipulations normalise, equalFilePath, makeRelative, isRelative, isAbsolute, isValid, makeValid ) where import Data.Char(toLower, toUpper, isAsciiLower, isAsciiUpper) import Data.Maybe(isJust) import Data.List(stripPrefix, isSuffixOf) import System.Environment(getEnv) infixr 7 <.>, -<.> infixr 5 --------------------------------------------------------------------- -- Platform Abstraction Methods (private) -- | Is the operating system Unix or Linux like isPosix :: Bool isPosix = not isWindows -- | Is the operating system Windows like isWindows :: Bool isWindows = IS_WINDOWS --------------------------------------------------------------------- -- The basic functions -- | 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 pathSeparator :: Char pathSeparator = if isWindows then '\\' else '/' -- | The list of all possible separators. -- -- > Windows: pathSeparators == ['\\', '/'] -- > Posix: pathSeparators == ['/'] -- > pathSeparator `elem` pathSeparators pathSeparators :: [Char] pathSeparators = if isWindows then "\\/" else "/" -- | Rather than using @(== 'pathSeparator')@, use this. Test if something -- is a path separator. -- -- > isPathSeparator a == (a `elem` pathSeparators) isPathSeparator :: Char -> Bool isPathSeparator '/' = True isPathSeparator '\\' = isWindows isPathSeparator _ = False -- | The character that is used to separate the entries in the $PATH environment variable. -- -- > Windows: searchPathSeparator == ';' -- > Posix: searchPathSeparator == ':' searchPathSeparator :: Char searchPathSeparator = if isWindows then ';' else ':' -- | Is the character a file separator? -- -- > isSearchPathSeparator a == (a == searchPathSeparator) isSearchPathSeparator :: Char -> Bool isSearchPathSeparator = (== searchPathSeparator) -- | File extension character -- -- > extSeparator == '.' extSeparator :: Char extSeparator = '.' -- | Is the character an extension character? -- -- > isExtSeparator a == (a == extSeparator) isExtSeparator :: Char -> Bool isExtSeparator = (== extSeparator) --------------------------------------------------------------------- -- Path methods (environment $PATH) -- | 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 -- -- -- > 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"] splitSearchPath :: String -> [FilePath] splitSearchPath = f where f xs = case break isSearchPathSeparator xs of (pre, [] ) -> g pre (pre, _:post) -> g pre ++ f post g "" = ["." | isPosix] g ('\"':x@(_:_)) | isWindows && last x == '\"' = [init x] g x = [x] -- | Get a list of 'FilePath's in the $PATH variable. getSearchPath :: IO [FilePath] getSearchPath = fmap splitSearchPath (getEnv "PATH") --------------------------------------------------------------------- -- Extension methods -- | 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/","") splitExtension :: FilePath -> (String, String) splitExtension x = case nameDot of "" -> (x,"") _ -> (dir ++ init nameDot, extSeparator : ext) where (dir,file) = splitFileName_ x (nameDot,ext) = breakEnd isExtSeparator file -- | 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" takeExtension :: FilePath -> String takeExtension = snd . splitExtension -- | 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" (-<.>) :: FilePath -> String -> FilePath (-<.>) = replaceExtension -- | 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 replaceExtension :: FilePath -> String -> FilePath replaceExtension x y = dropExtension x <.> y -- | 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" (<.>) :: FilePath -> String -> FilePath (<.>) = addExtension -- | Remove last extension, and the \".\" preceding it. -- -- > dropExtension "/directory/path.ext" == "/directory/path" -- > dropExtension x == fst (splitExtension x) dropExtension :: FilePath -> FilePath dropExtension = fst . splitExtension -- | 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" addExtension :: FilePath -> String -> FilePath addExtension file "" = file addExtension file xs@(x:_) = joinDrive a res where res = if isExtSeparator x then b ++ xs else b ++ [extSeparator] ++ xs (a,b) = splitDrive file -- | Does the given filename have an extension? -- -- > hasExtension "/directory/path.ext" == True -- > hasExtension "/directory/path" == False -- > null (takeExtension x) == not (hasExtension x) hasExtension :: FilePath -> Bool hasExtension = any isExtSeparator . takeFileName -- | 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 isExtensionOf :: String -> FilePath -> Bool isExtensionOf ext@('.':_) = isSuffixOf ext . takeExtensions isExtensionOf ext = isSuffixOf ('.':ext) . takeExtensions -- | 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 stripExtension :: String -> FilePath -> Maybe FilePath stripExtension [] path = Just path stripExtension ext@(x:_) path = stripSuffix dotExt path where dotExt = if isExtSeparator x then ext else '.':ext -- | 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") splitExtensions :: FilePath -> (FilePath, String) splitExtensions x = (a ++ c, d) where (a,b) = splitFileName_ x (c,d) = break isExtSeparator b -- | Drop all extensions. -- -- > dropExtensions "/directory/path.ext" == "/directory/path" -- > dropExtensions "file.tar.gz" == "file" -- > not $ hasExtension $ dropExtensions x -- > not $ any isExtSeparator $ takeFileName $ dropExtensions x dropExtensions :: FilePath -> FilePath dropExtensions = fst . splitExtensions -- | Get all extensions. -- -- > takeExtensions "/directory/path.ext" == ".ext" -- > takeExtensions "file.tar.gz" == ".tar.gz" takeExtensions :: FilePath -> String takeExtensions = snd . splitExtensions -- | 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" replaceExtensions :: FilePath -> String -> FilePath replaceExtensions x y = dropExtensions x <.> y --------------------------------------------------------------------- -- Drive methods -- | Is the given character a valid drive letter? -- only a-z and A-Z are letters, not isAlpha which is more unicodey isLetter :: Char -> Bool isLetter x = isAsciiLower x || isAsciiUpper x -- | 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") splitDrive :: FilePath -> (FilePath, FilePath) splitDrive x | isPosix = span (== '/') x splitDrive x | Just y <- readDriveLetter x = y splitDrive x | Just y <- readDriveUNC x = y splitDrive x | Just y <- readDriveShare x = y splitDrive x = ("",x) addSlash :: FilePath -> FilePath -> (FilePath, FilePath) addSlash a xs = (a++c,d) where (c,d) = span isPathSeparator xs -- See [1]. -- "\\?\D:\" or "\\?\UNC\\" readDriveUNC :: FilePath -> Maybe (FilePath, FilePath) readDriveUNC (s1:s2:'?':s3:xs) | all isPathSeparator [s1,s2,s3] = case map toUpper xs of ('U':'N':'C':s4:_) | isPathSeparator s4 -> let (a,b) = readDriveShareName (drop 4 xs) in Just (s1:s2:'?':s3:take 4 xs ++ a, b) _ -> case readDriveLetter xs of -- Extended-length path. Just (a,b) -> Just (s1:s2:'?':s3:a,b) Nothing -> Nothing readDriveUNC _ = Nothing {- c:\ -} readDriveLetter :: String -> Maybe (FilePath, FilePath) readDriveLetter (x:':':y:xs) | isLetter x && isPathSeparator y = Just $ addSlash [x,':'] (y:xs) readDriveLetter (x:':':xs) | isLetter x = Just ([x,':'], xs) readDriveLetter _ = Nothing {- \\sharename\ -} readDriveShare :: String -> Maybe (FilePath, FilePath) readDriveShare (s1:s2:xs) | isPathSeparator s1 && isPathSeparator s2 = Just (s1:s2:a,b) where (a,b) = readDriveShareName xs readDriveShare _ = Nothing {- assume you have already seen \\ -} {- share\bob -> "share\", "bob" -} readDriveShareName :: String -> (FilePath, FilePath) readDriveShareName name = addSlash a b where (a,b) = break isPathSeparator name -- | 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" joinDrive :: FilePath -> FilePath -> FilePath joinDrive = combineAlways -- | Get the drive from a filepath. -- -- > takeDrive x == fst (splitDrive x) takeDrive :: FilePath -> FilePath takeDrive = fst . splitDrive -- | Delete the drive, if it exists. -- -- > dropDrive x == snd (splitDrive x) dropDrive :: FilePath -> FilePath dropDrive = snd . splitDrive -- | 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 hasDrive :: FilePath -> Bool hasDrive = not . null . takeDrive -- | Is an element a drive -- -- > Posix: isDrive "/" == True -- > Posix: isDrive "/foo" == False -- > Windows: isDrive "C:\\" == True -- > Windows: isDrive "C:\\foo" == False -- > isDrive "" == False isDrive :: FilePath -> Bool isDrive x = not (null x) && null (dropDrive x) --------------------------------------------------------------------- -- Operations on a filepath, as a list of directories -- | 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:","") splitFileName :: FilePath -> (String, String) splitFileName x = (if null dir then "./" else dir, name) where (dir, name) = splitFileName_ x -- version of splitFileName where, if the FilePath has no directory -- component, the returned directory is "" rather than "./". This -- is used in cases where we are going to combine the returned -- directory to make a valid FilePath, and having a "./" appear would -- look strange and upset simple equality properties. See -- e.g. replaceFileName. splitFileName_ :: FilePath -> (String, String) splitFileName_ x = (drv ++ dir, file) where (drv,pth) = splitDrive x (dir,file) = breakEnd isPathSeparator pth -- | Set the filename. -- -- > replaceFileName "/directory/other.txt" "file.ext" == "/directory/file.ext" -- > Valid x => replaceFileName x (takeFileName x) == x replaceFileName :: FilePath -> String -> FilePath replaceFileName x y = a y where (a,_) = splitFileName_ x -- | 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) dropFileName :: FilePath -> FilePath dropFileName = fst . splitFileName -- | 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) takeFileName :: FilePath -> FilePath takeFileName = snd . splitFileName -- | 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" takeBaseName :: FilePath -> String takeBaseName = dropExtension . takeFileName -- | 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 replaceBaseName :: FilePath -> String -> FilePath replaceBaseName pth nam = combineAlways a (nam <.> ext) where (a,b) = splitFileName_ pth ext = takeExtension b -- | Is an item either a directory or the last character a path separator? -- -- > hasTrailingPathSeparator "test" == False -- > hasTrailingPathSeparator "test/" == True hasTrailingPathSeparator :: FilePath -> Bool hasTrailingPathSeparator "" = False hasTrailingPathSeparator x = isPathSeparator (last x) hasLeadingPathSeparator :: FilePath -> Bool hasLeadingPathSeparator "" = False hasLeadingPathSeparator x = isPathSeparator (head x) -- | 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/" addTrailingPathSeparator :: FilePath -> FilePath addTrailingPathSeparator x = if hasTrailingPathSeparator x then x else x ++ [pathSeparator] -- | Remove any trailing path separators -- -- > dropTrailingPathSeparator "file/test/" == "file/test" -- > dropTrailingPathSeparator "/" == "/" -- > Windows: dropTrailingPathSeparator "\\" == "\\" -- > Posix: not (hasTrailingPathSeparator (dropTrailingPathSeparator x)) || isDrive x dropTrailingPathSeparator :: FilePath -> FilePath dropTrailingPathSeparator x = if hasTrailingPathSeparator x && not (isDrive x) then let x' = dropWhileEnd isPathSeparator x in if null x' then [last x] else x' else x -- | 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:\\" takeDirectory :: FilePath -> FilePath takeDirectory = dropTrailingPathSeparator . dropFileName -- | Set the directory, keeping the filename the same. -- -- > replaceDirectory "root/file.ext" "/directory/" == "/directory/file.ext" -- > Valid x => replaceDirectory x (takeDirectory x) `equalFilePath` x replaceDirectory :: FilePath -> String -> FilePath replaceDirectory x dir = combineAlways dir (takeFileName x) -- | An alias for ''. combine :: FilePath -> FilePath -> FilePath combine a b | hasLeadingPathSeparator b || hasDrive b = b | otherwise = combineAlways a b -- | Combine two paths, assuming rhs is NOT absolute. combineAlways :: FilePath -> FilePath -> FilePath combineAlways a b | null a = b | null b = a | hasTrailingPathSeparator a = a ++ b | otherwise = case a of [a1,':'] | isWindows && isLetter a1 -> a ++ b _ -> a ++ [pathSeparator] ++ b -- | 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" () :: FilePath -> FilePath -> FilePath () = combine -- | 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"] splitPath :: FilePath -> [FilePath] splitPath x = [drive | drive /= ""] ++ f path where (drive,path) = splitDrive x f "" = [] f y = (a++c) : f d where (a,b) = break isPathSeparator y (c,d) = span isPathSeparator b -- | 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"] splitDirectories :: FilePath -> [FilePath] splitDirectories = map dropTrailingPathSeparator . splitPath -- | Join path elements back together. -- -- > joinPath ["/","directory/","file.ext"] == "/directory/file.ext" -- > Valid x => joinPath (splitPath x) == x -- > joinPath [] == "" -- > Posix: joinPath ["test","file","path"] == "test/file/path" joinPath :: [FilePath] -> FilePath -- Note that this definition on c:\\c:\\, join then split will give c:\\. joinPath = foldr combine "" --------------------------------------------------------------------- -- File name manipulators -- | Equality of two 'FilePath's. -- 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. -- -- > x == y ==> equalFilePath x y -- > normalise x == normalise y ==> equalFilePath x y -- > equalFilePath "foo" "foo/" -- > not (equalFilePath "foo" "/foo") -- > Posix: not (equalFilePath "foo" "FOO") -- > Windows: equalFilePath "foo" "FOO" -- > Windows: not (equalFilePath "C:" "C:/") equalFilePath :: FilePath -> FilePath -> Bool equalFilePath a b = f a == f b where f x | isWindows = dropTrailingPathSeparator $ map toLower $ normalise x | otherwise = dropTrailingPathSeparator $ normalise x -- | 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 -- . -- -- 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" makeRelative :: FilePath -> FilePath -> FilePath makeRelative root path | equalFilePath root path = "." | takeAbs root /= takeAbs path = path | otherwise = f (dropAbs root) (dropAbs path) where f "" y = dropWhile isPathSeparator y f x y = let (x1,x2) = g x (y1,y2) = g y in if equalFilePath x1 y1 then f x2 y2 else path g x = (dropWhile isPathSeparator a, dropWhile isPathSeparator b) where (a,b) = break isPathSeparator $ dropWhile isPathSeparator x -- on windows, need to drop '/' which is kind of absolute, but not a drive dropAbs x | hasLeadingPathSeparator x && not (hasDrive x) = tail x dropAbs x = dropDrive x takeAbs x | hasLeadingPathSeparator x && not (hasDrive x) = [pathSeparator] takeAbs x = map (\y -> if isPathSeparator y then pathSeparator else toLower y) $ takeDrive x -- | Normalise a file -- -- * \/\/ outside of the drive can be made blank -- -- * \/ -> 'pathSeparator' -- -- * .\/ -> \"\" -- -- > 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 "./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" normalise :: FilePath -> FilePath normalise path = result ++ [pathSeparator | addPathSeparator] where (drv,pth) = splitDrive path result = joinDrive' (normaliseDrive drv) (f pth) joinDrive' "" "" = "." joinDrive' d p = joinDrive d p addPathSeparator = isDirPath pth && not (hasTrailingPathSeparator result) && not (isRelativeDrive drv) isDirPath xs = hasTrailingPathSeparator xs || not (null xs) && last xs == '.' && hasTrailingPathSeparator (init xs) f = joinPath . dropDots . propSep . splitDirectories propSep (x:xs) | all isPathSeparator x = [pathSeparator] : xs | otherwise = x : xs propSep [] = [] dropDots = filter ("." /=) normaliseDrive :: FilePath -> FilePath normaliseDrive "" = "" normaliseDrive _ | isPosix = [pathSeparator] normaliseDrive drive = if isJust $ readDriveLetter x2 then map toUpper x2 else x2 where x2 = map repSlash drive repSlash x = if isPathSeparator x then pathSeparator else x -- Information for validity functions on Windows. See [1]. isBadCharacter :: Char -> Bool isBadCharacter x = x >= '\0' && x <= '\31' || x `elem` ":*?><|\"" badElements :: [FilePath] badElements = ["CON","PRN","AUX","NUL","CLOCK$" ,"COM1","COM2","COM3","COM4","COM5","COM6","COM7","COM8","COM9" ,"LPT1","LPT2","LPT3","LPT4","LPT5","LPT6","LPT7","LPT8","LPT9"] -- | 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 isValid :: FilePath -> Bool isValid "" = False isValid x | '\0' `elem` x = False isValid _ | isPosix = True isValid path = not (any isBadCharacter x2) && not (any f $ splitDirectories x2) && not (isJust (readDriveShare x1) && all isPathSeparator x1) && not (isJust (readDriveUNC x1) && not (hasTrailingPathSeparator x1)) where (x1,x2) = splitDrive path f x = map toUpper (dropWhileEnd (== ' ') $ dropExtensions x) `elem` badElements -- | 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" makeValid :: FilePath -> FilePath makeValid "" = "_" makeValid path | isPosix = map (\x -> if x == '\0' then '_' else x) path | isJust (readDriveShare drv) && all isPathSeparator drv = take 2 drv ++ "drive" | isJust (readDriveUNC drv) && not (hasTrailingPathSeparator drv) = makeValid (drv ++ [pathSeparator] ++ pth) | otherwise = joinDrive drv $ validElements $ validChars pth where (drv,pth) = splitDrive path validChars = map f f x = if isBadCharacter x then '_' else x validElements x = joinPath $ map g $ splitPath x g x = h a ++ b where (a,b) = break isPathSeparator x h x = if map toUpper (dropWhileEnd (== ' ') a) `elem` badElements then a ++ "_" <.> b else x where (a,b) = splitExtensions x -- | 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." isRelative :: FilePath -> Bool isRelative x = null drive || isRelativeDrive drive where drive = takeDrive x {- c:foo -} -- 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." isRelativeDrive :: String -> Bool isRelativeDrive x = maybe False (not . hasTrailingPathSeparator . fst) (readDriveLetter x) -- | @not . 'isRelative'@ -- -- > isAbsolute x == not (isRelative x) isAbsolute :: FilePath -> Bool isAbsolute = not . isRelative ----------------------------------------------------------------------------- -- dropWhileEnd (>2) [1,2,3,4,1,2,3,4] == [1,2,3,4,1,2]) -- Note that Data.List.dropWhileEnd is only available in base >= 4.5. dropWhileEnd :: (a -> Bool) -> [a] -> [a] dropWhileEnd p = reverse . dropWhile p . reverse -- takeWhileEnd (>2) [1,2,3,4,1,2,3,4] == [3,4]) takeWhileEnd :: (a -> Bool) -> [a] -> [a] takeWhileEnd p = reverse . takeWhile p . reverse -- spanEnd (>2) [1,2,3,4,1,2,3,4] = ([1,2,3,4,1,2], [3,4]) spanEnd :: (a -> Bool) -> [a] -> ([a], [a]) spanEnd p xs = (dropWhileEnd p xs, takeWhileEnd p xs) -- breakEnd (< 2) [1,2,3,4,1,2,3,4] == ([1,2,3,4,1],[2,3,4]) breakEnd :: (a -> Bool) -> [a] -> ([a], [a]) breakEnd p = spanEnd (not . p) -- | The stripSuffix function drops the given suffix from a list. It returns -- Nothing if the list did not end with the suffix given, or Just the list -- before the suffix, if it does. stripSuffix :: Eq a => [a] -> [a] -> Maybe [a] stripSuffix xs ys = fmap reverse $ stripPrefix (reverse xs) (reverse ys)