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+{- path manipulation
+ -
+ - Copyright 2010-2014 Joey Hess <joey@kitenet.net>
+ -
+ - License: BSD-2-clause
+ -}
+
+{-# LANGUAGE PackageImports, CPP #-}
+
+module Utility.Path where
+
+import Data.String.Utils
+import System.FilePath
+import System.Directory
+import Data.List
+import Data.Maybe
+import Data.Char
+import Control.Applicative
+
+#ifdef mingw32_HOST_OS
+import qualified System.FilePath.Posix as Posix
+#else
+import System.Posix.Files
+#endif
+
+import qualified "MissingH" System.Path as MissingH
+import Utility.Monad
+import Utility.UserInfo
+
+{- Simplifies a path, removing any ".." or ".", and removing the trailing
+ - path separator.
+ -
+ - On Windows, preserves whichever style of path separator might be used in
+ - the input FilePaths. This is done because some programs in Windows
+ - demand a particular path separator -- and which one actually varies!
+ -
+ - This does not guarantee that two paths that refer to the same location,
+ - and are both relative to the same location (or both absolute) will
+ - yeild the same result. Run both through normalise from System.FilePath
+ - to ensure that.
+ -}
+simplifyPath :: FilePath -> FilePath
+simplifyPath path = dropTrailingPathSeparator $
+ joinDrive drive $ joinPath $ norm [] $ splitPath path'
+ where
+ (drive, path') = splitDrive path
+
+ norm c [] = reverse c
+ norm c (p:ps)
+ | p' == ".." = norm (drop 1 c) ps
+ | p' == "." = norm c ps
+ | otherwise = norm (p:c) ps
+ where
+ p' = dropTrailingPathSeparator p
+
+{- Makes a path absolute.
+ -
+ - The first parameter is a base directory (ie, the cwd) to use if the path
+ - is not already absolute.
+ -
+ - Does not attempt to deal with edge cases or ensure security with
+ - untrusted inputs.
+ -}
+absPathFrom :: FilePath -> FilePath -> FilePath
+absPathFrom dir path = simplifyPath (combine dir path)
+
+{- On Windows, this converts the paths to unix-style, in order to run
+ - MissingH's absNormPath on them. Resulting path will use / separators. -}
+absNormPathUnix :: FilePath -> FilePath -> Maybe FilePath
+#ifndef mingw32_HOST_OS
+absNormPathUnix dir path = MissingH.absNormPath dir path
+#else
+absNormPathUnix dir path = todos <$> MissingH.absNormPath (fromdos dir) (fromdos path)
+ where
+ fromdos = replace "\\" "/"
+ todos = replace "/" "\\"
+#endif
+
+{- Returns the parent directory of a path.
+ -
+ - To allow this to be easily used in loops, which terminate upon reaching the
+ - top, the parent of / is "" -}
+parentDir :: FilePath -> FilePath
+parentDir dir
+ | null dirs = ""
+ | otherwise = joinDrive drive (join s $ init dirs)
+ where
+ -- on Unix, the drive will be "/" when the dir is absolute, otherwise ""
+ (drive, path) = splitDrive dir
+ dirs = filter (not . null) $ split s path
+ s = [pathSeparator]
+
+prop_parentDir_basics :: FilePath -> Bool
+prop_parentDir_basics dir
+ | null dir = True
+ | dir == "/" = parentDir dir == ""
+ | otherwise = p /= dir
+ where
+ p = parentDir dir
+
+{- Checks if the first FilePath is, or could be said to contain the second.
+ - For example, "foo/" contains "foo/bar". Also, "foo", "./foo", "foo/" etc
+ - are all equivilant.
+ -}
+dirContains :: FilePath -> FilePath -> Bool
+dirContains a b = a == b || a' == b' || (addTrailingPathSeparator a') `isPrefixOf` b'
+ where
+ a' = norm a
+ b' = norm b
+ norm = normalise . simplifyPath
+
+{- Converts a filename into an absolute path.
+ -
+ - Unlike Directory.canonicalizePath, this does not require the path
+ - already exists. -}
+absPath :: FilePath -> IO FilePath
+absPath file = do
+ cwd <- getCurrentDirectory
+ return $ absPathFrom cwd file
+
+{- Constructs a relative path from the CWD to a file.
+ -
+ - For example, assuming CWD is /tmp/foo/bar:
+ - relPathCwdToFile "/tmp/foo" == ".."
+ - relPathCwdToFile "/tmp/foo/bar" == ""
+ -}
+relPathCwdToFile :: FilePath -> IO FilePath
+relPathCwdToFile f = relPathDirToFile <$> getCurrentDirectory <*> absPath f
+
+{- Constructs a relative path from a directory to a file.
+ -
+ - Both must be absolute, and cannot contain .. etc. (eg use absPath first).
+ -}
+relPathDirToFile :: FilePath -> FilePath -> FilePath
+relPathDirToFile from to = join s $ dotdots ++ uncommon
+ where
+ s = [pathSeparator]
+ pfrom = split s from
+ pto = split s to
+ common = map fst $ takeWhile same $ zip pfrom pto
+ same (c,d) = c == d
+ uncommon = drop numcommon pto
+ dotdots = replicate (length pfrom - numcommon) ".."
+ numcommon = length common
+
+prop_relPathDirToFile_basics :: FilePath -> FilePath -> Bool
+prop_relPathDirToFile_basics from to
+ | from == to = null r
+ | otherwise = not (null r)
+ where
+ r = relPathDirToFile from to
+
+prop_relPathDirToFile_regressionTest :: Bool
+prop_relPathDirToFile_regressionTest = same_dir_shortcurcuits_at_difference
+ where
+ {- Two paths have the same directory component at the same
+ - location, but it's not really the same directory.
+ - Code used to get this wrong. -}
+ same_dir_shortcurcuits_at_difference =
+ relPathDirToFile (joinPath [pathSeparator : "tmp", "r", "lll", "xxx", "yyy", "18"])
+ (joinPath [pathSeparator : "tmp", "r", ".git", "annex", "objects", "18", "gk", "SHA256-foo", "SHA256-foo"])
+ == joinPath ["..", "..", "..", "..", ".git", "annex", "objects", "18", "gk", "SHA256-foo", "SHA256-foo"]
+
+{- Given an original list of paths, and an expanded list derived from it,
+ - generates a list of lists, where each sublist corresponds to one of the
+ - original paths. When the original path is a directory, any items
+ - in the expanded list that are contained in that directory will appear in
+ - its segment.
+ -}
+segmentPaths :: [FilePath] -> [FilePath] -> [[FilePath]]
+segmentPaths [] new = [new]
+segmentPaths [_] new = [new] -- optimisation
+segmentPaths (l:ls) new = [found] ++ segmentPaths ls rest
+ where
+ (found, rest)=partition (l `dirContains`) new
+
+{- This assumes that it's cheaper to call segmentPaths on the result,
+ - than it would be to run the action separately with each path. In
+ - the case of git file list commands, that assumption tends to hold.
+ -}
+runSegmentPaths :: ([FilePath] -> IO [FilePath]) -> [FilePath] -> IO [[FilePath]]
+runSegmentPaths a paths = segmentPaths paths <$> a paths
+
+{- Converts paths in the home directory to use ~/ -}
+relHome :: FilePath -> IO String
+relHome path = do
+ home <- myHomeDir
+ return $ if dirContains home path
+ then "~/" ++ relPathDirToFile home path
+ else path
+
+{- Checks if a command is available in PATH.
+ -
+ - The command may be fully-qualified, in which case, this succeeds as
+ - long as it exists. -}
+inPath :: String -> IO Bool
+inPath command = isJust <$> searchPath command
+
+{- Finds a command in PATH and returns the full path to it.
+ -
+ - The command may be fully qualified already, in which case it will
+ - be returned if it exists.
+ -}
+searchPath :: String -> IO (Maybe FilePath)
+searchPath command
+ | isAbsolute command = check command
+ | otherwise = getSearchPath >>= getM indir
+ where
+ indir d = check $ d </> command
+ check f = firstM doesFileExist
+#ifdef mingw32_HOST_OS
+ [f, f ++ ".exe"]
+#else
+ [f]
+#endif
+
+{- Checks if a filename is a unix dotfile. All files inside dotdirs
+ - count as dotfiles. -}
+dotfile :: FilePath -> Bool
+dotfile file
+ | f == "." = False
+ | f == ".." = False
+ | f == "" = False
+ | otherwise = "." `isPrefixOf` f || dotfile (takeDirectory file)
+ where
+ f = takeFileName file
+
+{- Converts a DOS style path to a Cygwin style path. Only on Windows.
+ - Any trailing '\' is preserved as a trailing '/' -}
+toCygPath :: FilePath -> FilePath
+#ifndef mingw32_HOST_OS
+toCygPath = id
+#else
+toCygPath p
+ | null drive = recombine parts
+ | otherwise = recombine $ "/cygdrive" : driveletter drive : parts
+ where
+ (drive, p') = splitDrive p
+ parts = splitDirectories p'
+ driveletter = map toLower . takeWhile (/= ':')
+ recombine = fixtrailing . Posix.joinPath
+ fixtrailing s
+ | hasTrailingPathSeparator p = Posix.addTrailingPathSeparator s
+ | otherwise = s
+#endif
+
+{- Maximum size to use for a file in a specified directory.
+ -
+ - Many systems have a 255 byte limit to the name of a file,
+ - so that's taken as the max if the system has a larger limit, or has no
+ - limit.
+ -}
+fileNameLengthLimit :: FilePath -> IO Int
+#ifdef mingw32_HOST_OS
+fileNameLengthLimit _ = return 255
+#else
+fileNameLengthLimit dir = do
+ l <- fromIntegral <$> getPathVar dir FileNameLimit
+ if l <= 0
+ then return 255
+ else return $ minimum [l, 255]
+ where
+#endif
+
+{- Given a string that we'd like to use as the basis for FilePath, but that
+ - was provided by a third party and is not to be trusted, returns the closest
+ - sane FilePath.
+ -
+ - All spaces and punctuation and other wacky stuff are replaced
+ - with '_', except for '.' "../" will thus turn into ".._", which is safe.
+ -}
+sanitizeFilePath :: String -> FilePath
+sanitizeFilePath = map sanitize
+ where
+ sanitize c
+ | c == '.' = c
+ | isSpace c || isPunctuation c || isSymbol c || isControl c || c == '/' = '_'
+ | otherwise = c
+
+{- Similar to splitExtensions, but knows that some things in FilePaths
+ - after a dot are too long to be extensions. -}
+splitShortExtensions :: FilePath -> (FilePath, [String])
+splitShortExtensions = splitShortExtensions' 5 -- enough for ".jpeg"
+splitShortExtensions' :: Int -> FilePath -> (FilePath, [String])
+splitShortExtensions' maxextension = go []
+ where
+ go c f
+ | len > 0 && len <= maxextension && not (null base) =
+ go (ext:c) base
+ | otherwise = (f, c)
+ where
+ (base, ext) = splitExtension f
+ len = length ext