System.EasyFile

easy-file-0.2.5: Cross-platform File handling

Safe Haskell | None
Language | Haskell2010

System.EasyFile

Contents

- Actions on directories
- Pre-defined directories
- Actions on files
- Existence tests
- Permissions
- Timestamps
- Size
- File/directory information

Description

This is a module of cross-platform file handling for Unix/Mac/Windows.

The standard module System.Directory and System.FilePath have following shortcomings:

- getModificationTime exists in System.Directory. But getAccessTime, getChangeTime, getCreationTime do not exist.
- getModificationTime returns obsoleted type, `ClockTime`. It should return modern type, `UTCTime`, I believe.
- Some file functions are missing. A function to tell the link counter, for instance.
- Path separator is not unified. Even though Windows accepts '/' as a file separator, getCurrentDirectory in System.Directory returns '\' as a file separator. So, we need to specify regular expression like this: "[/\\]foo[/\\]bar[/\\]baz".
- getHomeDirectory returns `HOMEDRIVE`/`HOMEPATH` instead of the `HOME` environment variable on Windows.

This module aims to resolve these problems and provides:

- `getModificationTime`, `getAccessTime`, `getChangeTime`, and `getCreationTime`. They return `UTCTime`.
- `isSymlink`, `getLinkCount`, and `hasSubDirectories`.
- '/' as the single `pathSeparator`. For instance, `getCurrentDirectory` returns a path whose separator is '/' even on Windows.
- `getHomeDirectory2` which refers the `HOME` environment variable.
- Necessary functions in System.Directory and System.FilePath.

Synopsis

- createDirectory :: FilePath -> IO ()
- createDirectoryIfMissing :: Bool -> FilePath -> IO ()
- removeDirectory :: FilePath -> IO ()
- removeDirectoryRecursive :: FilePath -> IO ()
- renameDirectory :: FilePath -> FilePath -> IO ()
- getDirectoryContents :: FilePath -> IO [FilePath]
- getCurrentDirectory :: IO FilePath
- setCurrentDirectory :: FilePath -> IO ()
- getHomeDirectory :: IO FilePath
- getHomeDirectory2 :: IO (Maybe FilePath)
- getAppUserDataDirectory :: String -> IO FilePath
- getUserDocumentsDirectory :: IO FilePath
- getTemporaryDirectory :: IO FilePath
- removeFile :: FilePath -> IO ()
- renameFile :: FilePath -> FilePath -> IO ()
- copyFile :: FilePath -> FilePath -> IO ()
- canonicalizePath :: FilePath -> IO FilePath
- doesFileExist :: FilePath -> IO Bool
- doesDirectoryExist :: FilePath -> IO Bool
- data Permissions
- getPermissions :: FilePath -> IO Permissions
- setPermissions :: FilePath -> Permissions -> IO ()
- copyPermissions :: FilePath -> FilePath -> IO ()
- getCreationTime :: FilePath -> IO (Maybe UTCTime)
- getChangeTime :: FilePath -> IO (Maybe UTCTime)
- getModificationTime :: FilePath -> IO UTCTime
- getAccessTime :: FilePath -> IO UTCTime
- getFileSize :: FilePath -> IO Word64
- setFileSize :: FilePath -> Word64 -> IO ()
- isSymlink :: FilePath -> IO Bool
- getLinkCount :: FilePath -> IO (Maybe Int)
- hasSubDirectories :: FilePath -> IO (Maybe Bool)
- type FilePath = String
- normalise :: FilePath -> FilePath
- dropTrailingPathSeparator :: FilePath -> FilePath
- makeRelative :: FilePath -> FilePath -> FilePath
- (</>) :: FilePath -> FilePath -> FilePath
- pathSeparator :: Char
- pathSeparators :: [Char]
- isPathSeparator :: Char -> Bool
- extSeparator :: Char
- isExtSeparator :: Char -> Bool
- splitExtension :: FilePath -> (String, String)
- takeExtension :: FilePath -> String
- replaceExtension :: FilePath -> String -> FilePath
- (<.>) :: FilePath -> String -> FilePath
- dropExtension :: FilePath -> FilePath
- addExtension :: FilePath -> String -> FilePath
- hasExtension :: FilePath -> Bool
- splitExtensions :: FilePath -> (FilePath, String)
- dropExtensions :: FilePath -> FilePath
- takeExtensions :: FilePath -> String
- splitDrive :: FilePath -> (FilePath, FilePath)
- joinDrive :: FilePath -> FilePath -> FilePath
- takeDrive :: FilePath -> FilePath
- dropDrive :: FilePath -> FilePath
- hasDrive :: FilePath -> Bool
- isDrive :: FilePath -> Bool
- splitFileName :: FilePath -> (String, String)
- replaceFileName :: FilePath -> String -> FilePath
- dropFileName :: FilePath -> FilePath
- takeFileName :: FilePath -> FilePath
- takeBaseName :: FilePath -> String
- replaceBaseName :: FilePath -> String -> FilePath
- hasTrailingPathSeparator :: FilePath -> Bool
- addTrailingPathSeparator :: FilePath -> FilePath
- takeDirectory :: FilePath -> FilePath
- replaceDirectory :: FilePath -> String -> FilePath
- combine :: FilePath -> FilePath -> FilePath
- splitPath :: FilePath -> [FilePath]
- splitDirectories :: FilePath -> [FilePath]
- joinPath :: [FilePath] -> FilePath
- equalFilePath :: FilePath -> FilePath -> Bool
- isRelative :: FilePath -> Bool
- isAbsolute :: FilePath -> Bool

# Actions on directories

createDirectory :: FilePath -> IO () #

``createDirectory` dir` creates a new directory `dir` which is initially empty, or as near to empty as the operating system allows.

The operation may fail with:

- `isPermissionError` The process has insufficient privileges to perform the operation. `[EROFS, EACCES]`
- `isAlreadyExistsError` The operand refers to a directory that already exists. `[EEXIST]`
- `HardwareFault` A physical I/O error has occurred. `[EIO]`
- `InvalidArgument` The operand is not a valid directory name. `[ENAMETOOLONG, ELOOP]`
- `isDoesNotExistError` There is no path to the directory. `[ENOENT, ENOTDIR]`
- `isFullError` Insufficient resources (virtual memory, process file descriptors, physical disk space, etc.) are available to perform the operation. `[EDQUOT, ENOSPC, ENOMEM, EMLINK]`
- `InappropriateType` The path refers to an existing non-directory object. `[EEXIST]`

createDirectoryIfMissing #

Arguments

:: Bool | Create its parents too?
-> FilePath | The path to the directory you want to make
-> IO () |

``createDirectoryIfMissing` parents dir` creates a new directory `dir` if it doesn't exist. If the first argument is `True` the function will also create all parent directories if they are missing.

removeDirectory :: FilePath -> IO () #

``removeDirectory` dir` removes an existing directory dir. The implementation may specify additional constraints which must be satisfied before a directory can be removed (e.g. the directory has to be empty, or may not be in use by other processes). It is not legal for an implementation to partially remove a directory unless the entire directory is removed. A conformant implementation need not support directory removal in all situations (e.g. removal of the root directory).

The operation may fail with:

- `HardwareFault` A physical I/O error has occurred. `[EIO]`
- `InvalidArgument` The operand is not a valid directory name. `[ENAMETOOLONG, ELOOP]`
- `isDoesNotExistError` The directory does not exist. `[ENOENT, ENOTDIR]`
- `isPermissionError` The process has insufficient privileges to perform the operation. `[EROFS, EACCES, EPERM]`
- `UnsatisfiedConstraints` Implementation-dependent constraints are not satisfied. `[EBUSY, ENOTEMPTY, EEXIST]`
- `UnsupportedOperation` The implementation does not support removal in this situation. `[EINVAL]`
- `InappropriateType` The operand refers to an existing non-directory object. `[ENOTDIR]`

removeDirectoryRecursive :: FilePath -> IO () #

``removeDirectoryRecursive` dir` removes an existing directory dir together with its contents and subdirectories. Within this directory, symbolic links are removed without affecting their targets.

On Windows, the operation fails if dir is a directory symbolic link.

This operation is reported to be flaky on Windows so retry logic may be advisable. See: https://github.com/haskell/directory/pull/108

renameDirectory :: FilePath -> FilePath -> IO () #

``renameDirectory` old new` changes the name of an existing directory from old to new. If the new directory already exists, it is atomically replaced by the old directory. If the new directory is neither the old directory nor an alias of the old directory, it is removed as if by `removeDirectory`. A conformant implementation need not support renaming directories in all situations (e.g. renaming to an existing directory, or across different physical devices), but the constraints must be documented.

On Win32 platforms, `renameDirectory` fails if the new directory already exists.

The operation may fail with:

- `HardwareFault` A physical I/O error has occurred. `[EIO]`
- `InvalidArgument` Either operand is not a valid directory name. `[ENAMETOOLONG, ELOOP]`
- `isDoesNotExistError` The original directory does not exist, or there is no path to the target. `[ENOENT, ENOTDIR]`
- `isPermissionError` The process has insufficient privileges to perform the operation. `[EROFS, EACCES, EPERM]`
- `isFullError` Insufficient resources are available to perform the operation. `[EDQUOT, ENOSPC, ENOMEM, EMLINK]`
- `UnsatisfiedConstraints` Implementation-dependent constraints are not satisfied. `[EBUSY, ENOTEMPTY, EEXIST]`
- `UnsupportedOperation` The implementation does not support renaming in this situation. `[EINVAL, EXDEV]`
- `InappropriateType` Either path refers to an existing non-directory object. `[ENOTDIR, EISDIR]`

getDirectoryContents :: FilePath -> IO [FilePath] #

Similar to `listDirectory`, but always includes the special entries (`.` and `..`). (This applies to Windows as well.)

The operation may fail with the same exceptions as `listDirectory`.

getCurrentDirectory :: IO FilePath #

If the operating system has a notion of current directories, `getCurrentDirectory` returns an absolute path to the current directory of the calling process.

The operation may fail with:

- `HardwareFault` A physical I/O error has occurred. `[EIO]`
- `isDoesNotExistError` / `NoSuchThing` There is no path referring to the current directory. `[EPERM, ENOENT, ESTALE...]`
- `isPermissionError` / `PermissionDenied` The process has insufficient privileges to perform the operation. `[EACCES]`
- `ResourceExhausted` Insufficient resources are available to perform the operation.
- `UnsupportedOperation` The operating system has no notion of current directory.

setCurrentDirectory :: FilePath -> IO () #

Change the working directory to the given path.

In a multithreaded program, the current working directory is a global state shared among all threads of the process. Therefore, when performing filesystem operations from multiple threads, it is highly recommended to use absolute rather than relative paths (see: `makeAbsolute`).

The operation may fail with:

- `HardwareFault` A physical I/O error has occurred. `[EIO]`
- `InvalidArgument` The operand is not a valid directory name. `[ENAMETOOLONG, ELOOP]`
- `isDoesNotExistError` The directory does not exist. `[ENOENT, ENOTDIR]`
- `isPermissionError` The process has insufficient privileges to perform the operation. `[EACCES]`
- `UnsupportedOperation` The operating system has no notion of current working directory, or the working directory cannot be dynamically changed.
- `InappropriateType` The path refers to an existing non-directory object. `[ENOTDIR]`

# Pre-defined directories

getHomeDirectory :: IO FilePath #

Returns the current user's home directory.

The directory returned is expected to be writable by the current user, but note that it isn't generally considered good practice to store application-specific data here; use `getAppUserDataDirectory` instead.

On Unix, `getHomeDirectory` returns the value of the `HOME` environment variable. On Windows, the system is queried for a suitable path; a typical path might be `C:Documents And Settingsuser`.

The operation may fail with:

- `UnsupportedOperation` The operating system has no notion of home directory.
- `isDoesNotExistError` The home directory for the current user does not exist, or cannot be found.

getHomeDirectory2 :: IO (Maybe FilePath) #

Returns the current user's home directory from the `HOME` environment variable.

getAppUserDataDirectory :: String -> IO FilePath #

Returns the pathname of a directory in which application-specific data for the current user can be stored. The result of `getAppUserDataDirectory` for a given application is specific to the current user.

The argument should be the name of the application, which will be used to construct the pathname (so avoid using unusual characters that might result in an invalid pathname).

Note: the directory may not actually exist, and may need to be created first. It is expected that the parent directory exists and is writable.

On Unix, this function returns `$HOME/.appName`. On Windows, a typical path might be

    C:/Documents And Settings/user/Application Data/appName

The operation may fail with:

- `UnsupportedOperation` The operating system has no notion of application-specific data directory.
- `isDoesNotExistError` The home directory for the current user does not exist, or cannot be found.

getUserDocumentsDirectory :: IO FilePath #

Returns the current user's document directory.

The directory returned is expected to be writable by the current user, but note that it isn't generally considered good practice to store application-specific data here; use `getAppUserDataDirectory` instead.

On Unix, `getUserDocumentsDirectory` returns the value of the `HOME` environment variable. On Windows, the system is queried for a suitable path; a typical path might be `C:/Documents and Settings/user/My Documents`.

The operation may fail with:

- `UnsupportedOperation` The operating system has no notion of document directory.
- `isDoesNotExistError` The document directory for the current user does not exist, or cannot be found.

getTemporaryDirectory :: IO FilePath #

Returns the current directory for temporary files.

On Unix, `getTemporaryDirectory` returns the value of the `TMPDIR` environment variable or "/tmp" if the variable isn't defined. On Windows, the function checks for the existence of environment variables in the following order and uses the first path found:

- TMP environment variable.
- TEMP environment variable.
- USERPROFILE environment variable.
- The Windows directory

The operation may fail with:

- `UnsupportedOperation` The operating system has no notion of temporary directory.

The function doesn't verify whether the path exists.

# Actions on files

removeFile :: FilePath -> IO () #

`removeFile` file removes the directory entry for an existing file file, where file is not itself a directory. The implementation may specify additional constraints which must be satisfied before a file can be removed (e.g. the file may not be in use by other processes).

The operation may fail with:

- `HardwareFault` A physical I/O error has occurred. `[EIO]`
- `InvalidArgument` The operand is not a valid file name. `[ENAMETOOLONG, ELOOP]`
- `isDoesNotExistError` The file does not exist. `[ENOENT, ENOTDIR]`
- `isPermissionError` The process has insufficient privileges to perform the operation. `[EROFS, EACCES, EPERM]`
- `UnsatisfiedConstraints` Implementation-dependent constraints are not satisfied. `[EBUSY]`
- `InappropriateType` The operand refers to an existing directory. `[EPERM, EINVAL]`

renameFile :: FilePath -> FilePath -> IO () #

``renameFile` old new` changes the name of an existing file system object from old to new. If the new object already exists, it is replaced by the old object. Neither path may refer to an existing directory.

A conformant implementation need not support renaming files in all situations (e.g. renaming across different physical devices), but the constraints must be documented. On Windows, this does not support renaming across different physical devices; if you are looking to do so, consider using `copyFileWithMetadata` and `removeFile`.

On Windows, this calls `MoveFileEx` with `MOVEFILE_REPLACE_EXISTING` set, which is not guaranteed to be atomic (https://github.com/haskell/directory/issues/109).

On other platforms, this operation is atomic.

The operation may fail with:

- `HardwareFault` A physical I/O error has occurred. `[EIO]`
- `InvalidArgument` Either operand is not a valid file name. `[ENAMETOOLONG, ELOOP]`
- `isDoesNotExistError` The original file does not exist, or there is no path to the target. `[ENOENT, ENOTDIR]`
- `isPermissionError` The process has insufficient privileges to perform the operation. `[EROFS, EACCES, EPERM]`
- `isFullError` Insufficient resources are available to perform the operation. `[EDQUOT, ENOSPC, ENOMEM, EMLINK]`
- `UnsatisfiedConstraints` Implementation-dependent constraints are not satisfied. `[EBUSY]`
- `UnsupportedOperation` The implementation does not support renaming in this situation. `[EXDEV]`
- `InappropriateType` Either path refers to an existing directory. `[ENOTDIR, EISDIR, EINVAL, EEXIST, ENOTEMPTY]`

copyFile #

Arguments

:: FilePath | Source filename
-> FilePath | Destination filename
-> IO () |

Copy a file with its permissions. If the destination file already exists, it is replaced atomically. Neither path may refer to an existing directory. No exceptions are thrown if the permissions could not be copied.

canonicalizePath :: FilePath -> IO FilePath #

Make a path absolute, normalize the path, and remove as many indirections from it as possible. Any trailing path separators are discarded via `dropTrailingPathSeparator`. Additionally, on Windows the letter case of the path is canonicalized.

Note: This function is a very big hammer. If you only need an absolute path, `makeAbsolute` is sufficient for removing dependence on the current working directory.

Indirections include the two special directories `.` and `..`, as well as any symbolic links (and junction points on Windows). The input path need not point to an existing file or directory. Canonicalization is performed on the longest prefix of the path that points to an existing file or directory. The remaining portion of the path that does not point to an existing file or directory will still be normalized, but case canonicalization and indirection removal are skipped as they are impossible to do on a nonexistent path.

Most programs should not worry about the canonicity of a path. In particular, despite the name, the function does not truly guarantee canonicity of the returned path due to the presence of hard links, mount points, etc.

If the path points to an existing file or directory, then the output path shall also point to the same file or directory, subject to the condition that the relevant parts of the file system do not change while the function is still running. In other words, the function is definitively not atomic. The results can be utterly wrong if the portions of the path change while this function is running.

Since some indirections (symbolic links on all systems, `..` on non-Windows systems, and junction points on Windows) are dependent on the state of the existing filesystem, the function can only make a conservative attempt by removing such indirections from the longest prefix of the path that still points to an existing file or directory.

Note that on Windows parent directories `..` are always fully expanded before the symbolic links, as consistent with the rest of the Windows API (such as `GetFullPathName`). In contrast, on POSIX systems parent directories `..` are expanded alongside symbolic links from left to right. To put this more concretely: if `L` is a symbolic link for `R/P`, then on Windows `L\..` refers to `.`, whereas on other operating systems `L/..` refers to `R`.

Similar to `normalise`, passing an empty path is equivalent to passing the current directory.

`canonicalizePath` can resolve at least 64 indirections in a single path, more than what is supported by most operating systems. Therefore, it may return the fully resolved path even though the operating system itself would have long given up.

On Windows XP or earlier systems, junction expansion is not performed due to their lack of `GetFinalPathNameByHandle`.

Changes since 1.2.3.0: The function has been altered to be more robust and has the same exception behavior as `makeAbsolute`.

Changes since 1.3.0.0: The function no longer preserves the trailing path separator. File symbolic links that appear in the middle of a path are properly dereferenced. Case canonicalization and symbolic link expansion are now performed on Windows.

# Existence tests

doesFileExist :: FilePath -> IO Bool #

The operation `doesFileExist` returns `True` if the argument file exists and is not a directory, and `False` otherwise.

doesDirectoryExist :: FilePath -> IO Bool #

The operation `doesDirectoryExist` returns `True` if the argument file exists and is either a directory or a symbolic link to a directory, and `False` otherwise.

# Permissions

data Permissions #

#### Instances

Instances details

Read Permissions |
Instance details Defined in System.Directory.Internal.Common Methods readsPrec :: Int -> ReadS Permissions # readList :: ReadS [Permissions] # readPrec :: ReadPrec Permissions # readListPrec :: ReadPrec [Permissions] #
Show Permissions |
Instance details Defined in System.Directory.Internal.Common Methods showsPrec :: Int -> Permissions -> ShowS # show :: Permissions -> String # showList :: [Permissions] -> ShowS #
Eq Permissions |
Instance details Defined in System.Directory.Internal.Common Methods (==) :: Permissions -> Permissions -> Bool # (/=) :: Permissions -> Permissions -> Bool #
Ord Permissions |
Instance details Defined in System.Directory.Internal.Common Methods compare :: Permissions -> Permissions -> Ordering # (<) :: Permissions -> Permissions -> Bool # (<=) :: Permissions -> Permissions -> Bool # (>) :: Permissions -> Permissions -> Bool # (>=) :: Permissions -> Permissions -> Bool # max :: Permissions -> Permissions -> Permissions # min :: Permissions -> Permissions -> Permissions #

getPermissions :: FilePath -> IO Permissions #

Get the permissions of a file or directory.

On Windows, the `writable` permission corresponds to the "read-only" attribute. The `executable` permission is set if the file extension is of an executable file type. The `readable` permission is always set.

On POSIX systems, this returns the result of `access`.

The operation may fail with:

- `isPermissionError` if the user is not permitted to access the permissions, or
- `isDoesNotExistError` if the file or directory does not exist.

setPermissions :: FilePath -> Permissions -> IO () #

Set the permissions of a file or directory.

On Windows, this is only capable of changing the `writable` permission, which corresponds to the "read-only" attribute. Changing the other permissions has no effect.

On POSIX systems, this sets the owner permissions.

The operation may fail with:

- `isPermissionError` if the user is not permitted to set the permissions, or
- `isDoesNotExistError` if the file or directory does not exist.

copyPermissions :: FilePath -> FilePath -> IO () #

This function copy the permission of the first file to the second.

# Timestamps

getCreationTime :: FilePath -> IO (Maybe UTCTime) #

The `getCreationTime` operation returns the UTC time at which the file or directory was created. The time is only available on Windows.

getChangeTime :: FilePath -> IO (Maybe UTCTime) #

The `getChangeTime` operation returns the UTC time at which the file or directory was changed. The time is only available on Unix and Mac. Note that Unix's rename() does not change ctime but MacOS's rename() does.

getModificationTime :: FilePath -> IO UTCTime #

The `getModificationTime` operation returns the UTC time at which the file or directory was last modified.

The operation may fail with:

- `isPermissionError` if the user is not permitted to access the modification time; or
- `isDoesNotExistError` if the file or directory does not exist.

getAccessTime :: FilePath -> IO UTCTime #

The `getModificationTime` operation returns the UTC time at which the file or directory was last accessed.

# Size

getFileSize :: FilePath -> IO Word64 #

Getting the size of the file.

Since: 0.2.0.

setFileSize :: FilePath -> Word64 -> IO () #

Setting the size of the file.

Since: 0.2.4.

# File/directory information

isSymlink :: FilePath -> IO Bool #

This function tells whether or not a file/directory is symbolic link.

getLinkCount :: FilePath -> IO (Maybe Int) #

This function returns the link counter of a file/directory.

hasSubDirectories :: FilePath -> IO (Maybe Bool) #

This function returns whether or not a directory has sub-directories.

type FilePath = String #

File and directory names are values of type `String`, whose precise meaning is operating system dependent. Files can be opened, yielding a handle which can then be used to operate on the contents of that file.

normalise :: FilePath -> FilePath #

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 "\\\\server\\test" == "\\\\server\\test" -- xxx
    Windows: normalise "." == "."
    Posix:   normalise "./" == "./"

dropTrailingPathSeparator :: FilePath -> FilePath #

Remove any trailing path separators

    dropTrailingPathSeparator "file/test/" == "file/test"
    not (hasTrailingPathSeparator (dropTrailingPathSeparator x)) || isDrive x
    dropTrailingPathSeparator "/" == "/"

makeRelative :: FilePath -> FilePath -> FilePath #

Contract a filename, based on a relative path.

There is no corresponding `makeAbsolute` function, instead use `System.Directory.canonicalizePath` which has the same effect.

             Valid y => equalFilePath x y || (isRelative x && makeRelative y x == x) || equalFilePath (y </> makeRelative y x) x
             makeRelative x x == "."
             null y || equalFilePath (makeRelative x (x </> y)) y || null (takeFileName x)
    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"
    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"

(</>) :: FilePath -> FilePath -> FilePath infixr 5 #

A nice alias for `combine`.

pathSeparator :: Char #

The character that separates directories.

    pathSeparator ==  '/'
    isPathSeparator pathSeparator

pathSeparators :: [Char] #

The list of all possible separators.

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

isPathSeparator :: Char -> Bool #

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

    isPathSeparator a == (a `elem` pathSeparators)

extSeparator :: Char #

File extension character

    extSeparator == '.'

isExtSeparator :: Char -> Bool #

Is the character an extension character?

    isExtSeparator a == (a == extSeparator)

splitExtension :: FilePath -> (String, String) #

Split on the extension. `addExtension` is the inverse.

    uncurry (++) (splitExtension x) == 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 :: FilePath -> String #

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

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

replaceExtension :: FilePath -> String -> FilePath #

Set the extension of a file, overwriting one if already present.

    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"

(<.>) :: FilePath -> String -> FilePath infixr 7 #

Alias to `addExtension`, for people who like that sort of thing.

dropExtension :: FilePath -> FilePath #

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

    dropExtension x == fst (splitExtension x)

addExtension :: FilePath -> String -> FilePath #

Add an extension, even if there is already one there. E.g. `addExtension "foo.txt" "bat" -> "foo.txt.bat"`.

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

hasExtension :: FilePath -> Bool #

Does the given filename have an extension?

    null (takeExtension x) == not (hasExtension x)

splitExtensions :: FilePath -> (FilePath, String) #

Split on all extensions

    splitExtensions "file.tar.gz" == ("file",".tar.gz")

dropExtensions :: FilePath -> FilePath #

Drop all extensions

    not $ hasExtension (dropExtensions x)

takeExtensions :: FilePath -> String #

Get all extensions

    takeExtensions "file.tar.gz" == ".tar.gz"

splitDrive :: FilePath -> (FilePath, FilePath) #

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

    uncurry (++) (splitDrive x) == x
    Windows: splitDrive "file" == ("","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") -- xxx
    Posix:   splitDrive "/test" == ("/","test") -- xxx
    Posix:   splitDrive "//test" == ("//","test")
    Posix:   splitDrive "test/file" == ("","test/file")
    Posix:   splitDrive "file" == ("","file")

joinDrive :: FilePath -> FilePath -> FilePath #

Join a drive and the rest of the path.

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

takeDrive :: FilePath -> FilePath #

Get the drive from a filepath.

    takeDrive x == fst (splitDrive x)

dropDrive :: FilePath -> FilePath #

Delete the drive, if it exists.

    dropDrive x == snd (splitDrive x)

hasDrive :: FilePath -> Bool #

Does a path have a drive.

    not (hasDrive x) == null (takeDrive x)

isDrive :: FilePath -> Bool #

Is an element a drive

splitFileName :: FilePath -> (String, String) #

Split a filename into directory and file. `combine` is the inverse.

    uncurry (++) (splitFileName x) == x
    Valid x => uncurry combine (splitFileName x) == x
    splitFileName "file/bob.txt" == ("file/", "bob.txt")
    splitFileName "file/" == ("file/", "")
    splitFileName "bob" == ("", "bob")
    Posix:   splitFileName "/" == ("/","")
    Windows: splitFileName "c:" == ("c:","")

replaceFileName :: FilePath -> String -> FilePath #

Set the filename.

    Valid x => replaceFileName x (takeFileName x) == x

dropFileName :: FilePath -> FilePath #

Drop the filename.

    dropFileName x == fst (splitFileName x)

takeFileName :: FilePath -> FilePath #

Get the file name.

    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)

takeBaseName :: FilePath -> String #

Get the base name, without an extension or path.

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

replaceBaseName :: FilePath -> String -> FilePath #

Set the base name.

    replaceBaseName "file/test.txt" "bob" == "file/bob.txt"
    replaceBaseName "fred" "bill" == "bill"
    replaceBaseName "/dave/fred/bob.gz.tar" "new" == "/dave/fred/new.tar"
    replaceBaseName x (takeBaseName x) == x

hasTrailingPathSeparator :: FilePath -> Bool #

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

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

addTrailingPathSeparator :: FilePath -> FilePath #

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

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

takeDirectory :: FilePath -> FilePath #

Get the directory name, move up one level.

              takeDirectory x `isPrefixOf` x
              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\\bar" -- xxx
    Windows:  takeDirectory "C:/" == "C:/"

replaceDirectory :: FilePath -> String -> FilePath #

Set the directory, keeping the filename the same.

    replaceDirectory x (takeDirectory x) `equalFilePath` x

combine :: FilePath -> FilePath -> FilePath #

Combine two paths, if the second path `isAbsolute`, then it returns the second.

    Valid x => combine (takeDirectory x) (takeFileName x) `equalFilePath` x
    combine "/" "test" == "/test"
    combine "home" "bob" == "home/bob"

splitPath :: FilePath -> [FilePath] #

Split a path by the directory separator.

    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"]

splitDirectories :: FilePath -> [FilePath] #

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

    splitDirectories "test/file" == ["test","file"]
    splitDirectories "/test/file" == ["/","test","file"]
    Valid x => joinPath (splitDirectories x) `equalFilePath` x
    splitDirectories "" == []

joinPath :: [FilePath] -> FilePath #

Join path elements back together.

    Valid x => joinPath (splitPath x) == x
    joinPath [] == ""
    Posix: joinPath ["test","file","path"] == "test/file/path"

equalFilePath :: FilePath -> FilePath -> Bool #

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
    Posix:   equalFilePath "foo" "foo/"
    Posix:   not (equalFilePath "foo" "/foo")
    Posix:   not (equalFilePath "foo" "FOO")
    Windows: equalFilePath "foo" "FOO"

isRelative :: FilePath -> 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:" == True
    Windows: isRelative "\\\\foo" == False
    Windows: isRelative "/foo" == True
    Posix:   isRelative "test/path" == True
    Posix:   isRelative "/test" == False

isAbsolute :: FilePath -> Bool #

    not . isRelative

    isAbsolute x == not (isRelative x)