-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/


-- | Platform-agnostic library for filesystem operations
--   
--   This library provides a basic set of operations for manipulating files
--   and directories in a portable way.
@package directory
@version 1.3.0.0


-- | System-independent interface to directory manipulation.
module System.Directory

-- | <tt><a>createDirectory</a> dir</tt> creates a new directory
--   <tt>dir</tt> which is initially empty, or as near to empty as the
--   operating system allows.
--   
--   The operation may fail with:
--   
--   <ul>
--   <li><a>isPermissionError</a> / <tt>PermissionDenied</tt> The process
--   has insufficient privileges to perform the operation. <tt>[EROFS,
--   EACCES]</tt></li>
--   <li><a>isAlreadyExistsError</a> / <tt>AlreadyExists</tt> The operand
--   refers to a directory that already exists. <tt> [EEXIST]</tt></li>
--   <li><tt>HardwareFault</tt> A physical I/O error has occurred.
--   <tt>[EIO]</tt></li>
--   <li><tt>InvalidArgument</tt> The operand is not a valid directory
--   name. <tt>[ENAMETOOLONG, ELOOP]</tt></li>
--   <li><tt>NoSuchThing</tt> There is no path to the directory.
--   <tt>[ENOENT, ENOTDIR]</tt></li>
--   <li><tt>ResourceExhausted</tt> Insufficient resources (virtual memory,
--   process file descriptors, physical disk space, etc.) are available to
--   perform the operation. <tt>[EDQUOT, ENOSPC, ENOMEM, EMLINK]</tt></li>
--   <li><a>InappropriateType</a> The path refers to an existing
--   non-directory object. <tt>[EEXIST]</tt></li>
--   </ul>
createDirectory :: FilePath -> IO ()

-- | <tt><a>createDirectoryIfMissing</a> parents dir</tt> creates a new
--   directory <tt>dir</tt> if it doesn't exist. If the first argument is
--   <a>True</a> the function will also create all parent directories if
--   they are missing.
createDirectoryIfMissing :: Bool -> FilePath -> IO ()

-- | <tt><a>removeDirectory</a> dir</tt> removes an existing directory
--   <i>dir</i>. 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:
--   
--   <ul>
--   <li><tt>HardwareFault</tt> A physical I/O error has occurred.
--   <tt>[EIO]</tt></li>
--   <li><tt>InvalidArgument</tt> The operand is not a valid directory
--   name. <tt>[ENAMETOOLONG, ELOOP]</tt></li>
--   <li><a>isDoesNotExistError</a> / <tt>NoSuchThing</tt> The directory
--   does not exist. <tt>[ENOENT, ENOTDIR]</tt></li>
--   <li><a>isPermissionError</a> / <tt>PermissionDenied</tt> The process
--   has insufficient privileges to perform the operation. <tt>[EROFS,
--   EACCES, EPERM]</tt></li>
--   <li><tt>UnsatisfiedConstraints</tt> Implementation-dependent
--   constraints are not satisfied. <tt>[EBUSY, ENOTEMPTY,
--   EEXIST]</tt></li>
--   <li><a>UnsupportedOperation</a> The implementation does not support
--   removal in this situation. <tt>[EINVAL]</tt></li>
--   <li><a>InappropriateType</a> The operand refers to an existing
--   non-directory object. <tt>[ENOTDIR]</tt></li>
--   </ul>
removeDirectory :: FilePath -> IO ()

-- | <tt><a>removeDirectoryRecursive</a> dir</tt> removes an existing
--   directory <i>dir</i> together with its contents and subdirectories.
--   Within this directory, symbolic links are removed without affecting
--   their targets.
--   
--   On Windows, the operation fails if <i>dir</i> is a directory symbolic
--   link.
removeDirectoryRecursive :: FilePath -> IO ()

-- | Removes a file or directory at <i>path</i> together with its contents
--   and subdirectories. Symbolic links are removed without affecting their
--   targets. If the path does not exist, nothing happens.
--   
--   Unlike other removal functions, this function will also attempt to
--   delete files marked as read-only or otherwise made unremovable due to
--   permissions. As a result, if the removal is incomplete, the
--   permissions or attributes on the remaining files may be altered.
--   
--   If an entry within the directory vanishes while
--   <tt>removePathForcibly</tt> is running, it is silently ignored.
--   
--   If an exception occurs while removing an entry,
--   <tt>removePathForcibly</tt> will still try to remove as many entries
--   as it can before failing with an exception. The first exception that
--   it encountered is re-thrown.
removePathForcibly :: FilePath -> IO ()

-- | <tt><a>renameDirectory</a> old new</tt> changes the name of an
--   existing directory from <i>old</i> to <i>new</i>. If the <i>new</i>
--   directory already exists, it is atomically replaced by the <i>old</i>
--   directory. If the <i>new</i> directory is neither the <i>old</i>
--   directory nor an alias of the <i>old</i> directory, it is removed as
--   if by <a>removeDirectory</a>. 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, <tt>renameDirectory</tt> fails if the <i>new</i>
--   directory already exists.
--   
--   The operation may fail with:
--   
--   <ul>
--   <li><tt>HardwareFault</tt> A physical I/O error has occurred.
--   <tt>[EIO]</tt></li>
--   <li><tt>InvalidArgument</tt> Either operand is not a valid directory
--   name. <tt>[ENAMETOOLONG, ELOOP]</tt></li>
--   <li><a>isDoesNotExistError</a> / <tt>NoSuchThing</tt> The original
--   directory does not exist, or there is no path to the target.
--   <tt>[ENOENT, ENOTDIR]</tt></li>
--   <li><a>isPermissionError</a> / <tt>PermissionDenied</tt> The process
--   has insufficient privileges to perform the operation. <tt>[EROFS,
--   EACCES, EPERM]</tt></li>
--   <li><tt>ResourceExhausted</tt> Insufficient resources are available to
--   perform the operation. <tt>[EDQUOT, ENOSPC, ENOMEM, EMLINK]</tt></li>
--   <li><tt>UnsatisfiedConstraints</tt> Implementation-dependent
--   constraints are not satisfied. <tt>[EBUSY, ENOTEMPTY,
--   EEXIST]</tt></li>
--   <li><a>UnsupportedOperation</a> The implementation does not support
--   renaming in this situation. <tt>[EINVAL, EXDEV]</tt></li>
--   <li><a>InappropriateType</a> Either path refers to an existing
--   non-directory object. <tt>[ENOTDIR, EISDIR]</tt></li>
--   </ul>
renameDirectory :: FilePath -> FilePath -> IO ()

-- | <tt><a>listDirectory</a> dir</tt> returns a list of <i>all</i> entries
--   in <i>dir</i> without the special entries (<tt>.</tt> and
--   <tt>..</tt>).
--   
--   The operation may fail with:
--   
--   <ul>
--   <li><tt>HardwareFault</tt> A physical I/O error has occurred.
--   <tt>[EIO]</tt></li>
--   <li><tt>InvalidArgument</tt> The operand is not a valid directory
--   name. <tt>[ENAMETOOLONG, ELOOP]</tt></li>
--   <li><a>isDoesNotExistError</a> / <tt>NoSuchThing</tt> The directory
--   does not exist. <tt>[ENOENT, ENOTDIR]</tt></li>
--   <li><a>isPermissionError</a> / <tt>PermissionDenied</tt> The process
--   has insufficient privileges to perform the operation.
--   <tt>[EACCES]</tt></li>
--   <li><tt>ResourceExhausted</tt> Insufficient resources are available to
--   perform the operation. <tt>[EMFILE, ENFILE]</tt></li>
--   <li><a>InappropriateType</a> The path refers to an existing
--   non-directory object. <tt>[ENOTDIR]</tt></li>
--   </ul>
listDirectory :: FilePath -> IO [FilePath]

-- | Similar to <a>listDirectory</a>, but always includes the special
--   entries (<tt>.</tt> and <tt>..</tt>). (This applies to Windows as
--   well.)
--   
--   The operation may fail with the same exceptions as
--   <a>listDirectory</a>.
getDirectoryContents :: FilePath -> IO [FilePath]

-- | Obtain the current working directory as an absolute 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:
--   <a>makeAbsolute</a>).
--   
--   The operation may fail with:
--   
--   <ul>
--   <li><tt>HardwareFault</tt> A physical I/O error has occurred.
--   <tt>[EIO]</tt></li>
--   <li><a>isDoesNotExistError</a> or <tt>NoSuchThing</tt> There is no
--   path referring to the working directory. <tt>[EPERM, ENOENT,
--   ESTALE...]</tt></li>
--   <li><a>isPermissionError</a> or <tt>PermissionDenied</tt> The process
--   has insufficient privileges to perform the operation.
--   <tt>[EACCES]</tt></li>
--   <li><tt>ResourceExhausted</tt> Insufficient resources are available to
--   perform the operation.</li>
--   <li><a>UnsupportedOperation</a> The operating system has no notion of
--   current working directory.</li>
--   </ul>
getCurrentDirectory :: IO FilePath

-- | 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:
--   <a>makeAbsolute</a>).
--   
--   The operation may fail with:
--   
--   <ul>
--   <li><tt>HardwareFault</tt> A physical I/O error has occurred.
--   <tt>[EIO]</tt></li>
--   <li><tt>InvalidArgument</tt> The operand is not a valid directory
--   name. <tt>[ENAMETOOLONG, ELOOP]</tt></li>
--   <li><a>isDoesNotExistError</a> or <tt>NoSuchThing</tt> The directory
--   does not exist. <tt>[ENOENT, ENOTDIR]</tt></li>
--   <li><a>isPermissionError</a> or <tt>PermissionDenied</tt> The process
--   has insufficient privileges to perform the operation.
--   <tt>[EACCES]</tt></li>
--   <li><a>UnsupportedOperation</a> The operating system has no notion of
--   current working directory, or the working directory cannot be
--   dynamically changed.</li>
--   <li><a>InappropriateType</a> The path refers to an existing
--   non-directory object. <tt>[ENOTDIR]</tt></li>
--   </ul>
setCurrentDirectory :: FilePath -> IO ()

-- | Run an <a>IO</a> action with the given working directory and restore
--   the original working directory afterwards, even if the given action
--   fails due to an exception.
--   
--   The operation may fail with the same exceptions as
--   <a>getCurrentDirectory</a> and <a>setCurrentDirectory</a>.
withCurrentDirectory :: FilePath -> IO a -> IO a

-- | 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 <a>getXdgDirectory</a> or
--   <a>getAppUserDataDirectory</a> instead.
--   
--   On Unix, <a>getHomeDirectory</a> returns the value of the
--   <tt>HOME</tt> environment variable. On Windows, the system is queried
--   for a suitable path; a typical path might be
--   <tt>C:/Users/<i>&lt;user&gt;</i></tt>.
--   
--   The operation may fail with:
--   
--   <ul>
--   <li><a>UnsupportedOperation</a> The operating system has no notion of
--   home directory.</li>
--   <li><a>isDoesNotExistError</a> The home directory for the current user
--   does not exist, or cannot be found.</li>
--   </ul>
getHomeDirectory :: IO FilePath

-- | Special directories for storing user-specific application data,
--   configuration, and cache files, as specified by the <a>XDG Base
--   Directory Specification</a>.
--   
--   Note: On Windows, <a>XdgData</a> and <a>XdgConfig</a> map to the same
--   directory.
data XdgDirectory

-- | For data files (e.g. images). Defaults to <tt>~/.local/share</tt> and
--   can be overridden by the <tt>XDG_DATA_HOME</tt> environment variable.
--   On Windows, it is <tt>%APPDATA%</tt> (e.g.
--   <tt>C:/Users/<i>&lt;user&gt;</i>/AppData/Roaming</tt>). Can be
--   considered as the user-specific equivalent of <tt>/usr/share</tt>.
XdgData :: XdgDirectory

-- | For configuration files. Defaults to <tt>~/.config</tt> and can be
--   overridden by the <tt>XDG_CONFIG_HOME</tt> environment variable. On
--   Windows, it is <tt>%APPDATA%</tt> (e.g.
--   <tt>C:/Users/<i>&lt;user&gt;</i>/AppData/Roaming</tt>). Can be
--   considered as the user-specific equivalent of <tt>/etc</tt>.
XdgConfig :: XdgDirectory

-- | For non-essential files (e.g. cache). Defaults to <tt>~/.cache</tt>
--   and can be overridden by the <tt>XDG_CACHE_HOME</tt> environment
--   variable. On Windows, it is <tt>%LOCALAPPDATA%</tt> (e.g.
--   <tt>C:/Users/<i>&lt;user&gt;</i>/AppData/Local</tt>). Can be
--   considered as the user-specific equivalent of <tt>/var/cache</tt>.
XdgCache :: XdgDirectory

-- | Obtain the paths to special directories for storing user-specific
--   application data, configuration, and cache files, conforming to the
--   <a>XDG Base Directory Specification</a>. Compared with
--   <a>getAppUserDataDirectory</a>, this function provides a more
--   fine-grained hierarchy as well as greater flexibility for the user.
--   
--   It also works on Windows, although in that case <a>XdgData</a> and
--   <a>XdgConfig</a> will map to the same directory.
--   
--   The second argument is usually the name of the application. Since it
--   will be integrated into the path, it must consist of valid path
--   characters.
--   
--   Note: The directory may not actually exist, in which case you would
--   need to create it with file mode <tt>700</tt> (i.e. only accessible by
--   the owner).
getXdgDirectory :: XdgDirectory -> FilePath -> IO FilePath

-- | Obtain the path to a special directory for storing user-specific
--   application data (traditional Unix location). Newer applications may
--   prefer the the XDG-conformant location provided by
--   <a>getXdgDirectory</a> (<a>migration guide</a>).
--   
--   The argument is usually the name of the application. Since it will be
--   integrated into the path, it must consist of valid path characters.
--   
--   <ul>
--   <li>On Unix-like systems, the path is
--   <tt>~/.<i>&lt;app&gt;</i></tt>.</li>
--   <li>On Windows, the path is <tt>%APPDATA%/<i>&lt;app&gt;</i></tt>
--   (e.g.
--   <tt>C:/Users/<i>&lt;user&gt;</i>/AppData/Roaming/<i>&lt;app&gt;</i></tt>)</li>
--   </ul>
--   
--   Note: the directory may not actually exist, in which case you would
--   need to create it. It is expected that the parent directory exists and
--   is writable.
--   
--   The operation may fail with:
--   
--   <ul>
--   <li><a>UnsupportedOperation</a> The operating system has no notion of
--   application-specific data directory.</li>
--   <li><a>isDoesNotExistError</a> The home directory for the current user
--   does not exist, or cannot be found.</li>
--   </ul>
getAppUserDataDirectory :: FilePath -> 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 <a>getXdgDirectory</a> or
--   <a>getAppUserDataDirectory</a> instead.
--   
--   On Unix, <a>getUserDocumentsDirectory</a> returns the value of the
--   <tt>HOME</tt> environment variable. On Windows, the system is queried
--   for a suitable path; a typical path might be
--   <tt>C:/Users/<i>&lt;user&gt;</i>/Documents</tt>.
--   
--   The operation may fail with:
--   
--   <ul>
--   <li><a>UnsupportedOperation</a> The operating system has no notion of
--   document directory.</li>
--   <li><a>isDoesNotExistError</a> The document directory for the current
--   user does not exist, or cannot be found.</li>
--   </ul>
getUserDocumentsDirectory :: IO FilePath

-- | Returns the current directory for temporary files.
--   
--   On Unix, <a>getTemporaryDirectory</a> returns the value of the
--   <tt>TMPDIR</tt> 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:
--   
--   <ul>
--   <li>TMP environment variable.</li>
--   <li>TEMP environment variable.</li>
--   <li>USERPROFILE environment variable.</li>
--   <li>The Windows directory</li>
--   </ul>
--   
--   The operation may fail with:
--   
--   <ul>
--   <li><a>UnsupportedOperation</a> The operating system has no notion of
--   temporary directory.</li>
--   </ul>
--   
--   The function doesn't verify whether the path exists.
getTemporaryDirectory :: IO FilePath

-- | <a>removeFile</a> <i>file</i> removes the directory entry for an
--   existing file <i>file</i>, where <i>file</i> 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:
--   
--   <ul>
--   <li><tt>HardwareFault</tt> A physical I/O error has occurred.
--   <tt>[EIO]</tt></li>
--   <li><tt>InvalidArgument</tt> The operand is not a valid file name.
--   <tt>[ENAMETOOLONG, ELOOP]</tt></li>
--   <li><a>isDoesNotExistError</a> / <tt>NoSuchThing</tt> The file does
--   not exist. <tt>[ENOENT, ENOTDIR]</tt></li>
--   <li><a>isPermissionError</a> / <tt>PermissionDenied</tt> The process
--   has insufficient privileges to perform the operation. <tt>[EROFS,
--   EACCES, EPERM]</tt></li>
--   <li><tt>UnsatisfiedConstraints</tt> Implementation-dependent
--   constraints are not satisfied. <tt>[EBUSY]</tt></li>
--   <li><a>InappropriateType</a> The operand refers to an existing
--   directory. <tt>[EPERM, EINVAL]</tt></li>
--   </ul>
removeFile :: FilePath -> IO ()

-- | <tt><a>renameFile</a> old new</tt> changes the name of an existing
--   file system object from <i>old</i> to <i>new</i>. If the <i>new</i>
--   object already exists, it is atomically replaced by the <i>old</i>
--   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.
--   
--   The operation may fail with:
--   
--   <ul>
--   <li><tt>HardwareFault</tt> A physical I/O error has occurred.
--   <tt>[EIO]</tt></li>
--   <li><tt>InvalidArgument</tt> Either operand is not a valid file name.
--   <tt>[ENAMETOOLONG, ELOOP]</tt></li>
--   <li><a>isDoesNotExistError</a> / <tt>NoSuchThing</tt> The original
--   file does not exist, or there is no path to the target. <tt>[ENOENT,
--   ENOTDIR]</tt></li>
--   <li><a>isPermissionError</a> / <tt>PermissionDenied</tt> The process
--   has insufficient privileges to perform the operation. <tt>[EROFS,
--   EACCES, EPERM]</tt></li>
--   <li><tt>ResourceExhausted</tt> Insufficient resources are available to
--   perform the operation. <tt>[EDQUOT, ENOSPC, ENOMEM, EMLINK]</tt></li>
--   <li><tt>UnsatisfiedConstraints</tt> Implementation-dependent
--   constraints are not satisfied. <tt>[EBUSY]</tt></li>
--   <li><a>UnsupportedOperation</a> The implementation does not support
--   renaming in this situation. <tt>[EXDEV]</tt></li>
--   <li><a>InappropriateType</a> Either path refers to an existing
--   directory. <tt>[ENOTDIR, EISDIR, EINVAL, EEXIST, ENOTEMPTY]</tt></li>
--   </ul>
renameFile :: FilePath -> FilePath -> IO ()

-- | Rename a file or directory. If the destination path already exists, it
--   is replaced atomically. The destination path must not point 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.
--   
--   The operation may fail with:
--   
--   <ul>
--   <li><tt>HardwareFault</tt> A physical I/O error has occurred.
--   <tt>[EIO]</tt></li>
--   <li><tt>InvalidArgument</tt> Either operand is not a valid file name.
--   <tt>[ENAMETOOLONG, ELOOP]</tt></li>
--   <li><a>isDoesNotExistError</a> / <tt>NoSuchThing</tt> The original
--   file does not exist, or there is no path to the target. <tt>[ENOENT,
--   ENOTDIR]</tt></li>
--   <li><a>isPermissionError</a> / <tt>PermissionDenied</tt> The process
--   has insufficient privileges to perform the operation. <tt>[EROFS,
--   EACCES, EPERM]</tt></li>
--   <li><tt>ResourceExhausted</tt> Insufficient resources are available to
--   perform the operation. <tt>[EDQUOT, ENOSPC, ENOMEM, EMLINK]</tt></li>
--   <li><tt>UnsatisfiedConstraints</tt> Implementation-dependent
--   constraints are not satisfied. <tt>[EBUSY]</tt></li>
--   <li><a>UnsupportedOperation</a> The implementation does not support
--   renaming in this situation. <tt>[EXDEV]</tt></li>
--   <li><a>InappropriateType</a> Either the destination path refers to an
--   existing directory, or one of the parent segments in the destination
--   path is not a directory. <tt>[ENOTDIR, EISDIR, EINVAL, EEXIST,
--   ENOTEMPTY]</tt></li>
--   </ul>
renamePath :: FilePath -> FilePath -> 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.
copyFile :: FilePath -> FilePath -> IO ()

-- | Copy a file with its associated metadata. If the destination file
--   already exists, it is overwritten. There is no guarantee of atomicity
--   in the replacement of the destination file. Neither path may refer to
--   an existing directory. If the source and/or destination are symbolic
--   links, the copy is performed on the targets of the links.
--   
--   On Windows, it behaves like the Win32 function <a>CopyFile</a>, which
--   copies various kinds of metadata including file attributes and
--   security resource properties.
--   
--   On Unix-like systems, permissions, access time, and modification time
--   are preserved. If possible, the owner and group are also preserved.
--   Note that the very act of copying can change the access time of the
--   source file, hence the access times of the two files may differ after
--   the operation completes.
copyFileWithMetadata :: FilePath -> FilePath -> IO ()

-- | Make a path absolute, <a>normalise</a> the path, and remove as many
--   indirections from it as possible. Any trailing path separators are
--   discarded via <a>dropTrailingPathSeparator</a>. Additionally, on
--   Windows the letter case of the path is canonicalized.
--   
--   <b>Note</b>: This function is a very big hammer. If you only need an
--   absolute path, <a>makeAbsolute</a> is sufficient for removing
--   dependence on the current working directory.
--   
--   Indirections include the two special directories <tt>.</tt> and
--   <tt>..</tt>, as well as any symbolic links. 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 undergo <a>normalise</a>, 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 symbolic links (and, on non-Windows systems, parent directories
--   <tt>..</tt>) 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 <tt>..</tt> are always fully
--   expanded before the symbolic links, as consistent with the rest of the
--   Windows API (such as <tt>GetFullPathName</tt>). In contrast, on POSIX
--   systems parent directories <tt>..</tt> are expanded alongside symbolic
--   links from left to right. To put this more concretely: if <tt>L</tt>
--   is a symbolic link for <tt>R/P</tt>, then on Windows <tt>L\..</tt>
--   refers to <tt>.</tt>, whereas on other operating systems <tt>L/..</tt>
--   refers to <tt>R</tt>.
--   
--   Similar to <a>normalise</a>, passing an empty path is equivalent to
--   passing the current directory.
--   
--   <i>Known bugs</i>: When the path contains an existing symbolic link,
--   but the target of the link does not exist, then the path is not
--   dereferenced (bug #64). Symbolic link expansion is not performed on
--   Windows XP or earlier due to the absence of
--   <tt>GetFinalPathNameByHandle</tt>.
--   
--   <i>Changes since 1.2.3.0:</i> The function has been altered to be more
--   robust and has the same exception behavior as <a>makeAbsolute</a>.
--   
--   <i>Changes since 1.3.0.0:</i> 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.
canonicalizePath :: FilePath -> IO FilePath

-- | Convert a path into an absolute path. If the given path is relative,
--   the current directory is prepended and then the combined result is
--   <a>normalise</a>d. If the path is already absolute, the path is simply
--   <a>normalise</a>d. The function preserves the presence or absence of
--   the trailing path separator unless the path refers to the root
--   directory <tt>/</tt>.
--   
--   If the path is already absolute, the operation never fails. Otherwise,
--   the operation may fail with the same exceptions as
--   <a>getCurrentDirectory</a>.
makeAbsolute :: FilePath -> IO FilePath

-- | Construct a path relative to the current directory, similar to
--   <a>makeRelative</a>.
--   
--   The operation may fail with the same exceptions as
--   <a>getCurrentDirectory</a>.
makeRelativeToCurrentDirectory :: FilePath -> IO FilePath

-- | Given an executable file name, searches for such file in the
--   directories listed in system PATH. The returned value is the path to
--   the found executable or Nothing if an executable with the given name
--   was not found. For example (findExecutable "ghc") gives you the path
--   to GHC.
--   
--   The path returned by <a>findExecutable</a> corresponds to the program
--   that would be executed by <a>createProcess</a> when passed the same
--   string (as a RawCommand, not a ShellCommand).
--   
--   On Windows, <a>findExecutable</a> calls the Win32 function
--   <tt>SearchPath</tt>, which may search other places before checking the
--   directories in <tt>PATH</tt>. Where it actually searches depends on
--   registry settings, but notably includes the directory containing the
--   current executable. See
--   <a>http://msdn.microsoft.com/en-us/library/aa365527.aspx</a> for more
--   details.
findExecutable :: String -> IO (Maybe FilePath)

-- | Given a file name, searches for the file and returns a list of all
--   occurences that are executable.
--   
--   On Windows, this only returns the first ocurrence, if any. It uses the
--   <tt>SearchPath</tt> from the Win32 API, so the caveats noted in
--   <a>findExecutable</a> apply here as well.
findExecutables :: String -> IO [FilePath]

-- | Given a file name, searches for the file on the given paths and
--   returns a list of all occurences that are executable.
findExecutablesInDirectories :: [FilePath] -> String -> IO [FilePath]

-- | Search through the given set of directories for the given file.
findFile :: [FilePath] -> String -> IO (Maybe FilePath)

-- | Search through the given set of directories for the given file and
--   returns a list of paths where the given file exists.
findFiles :: [FilePath] -> String -> IO [FilePath]

-- | Search through the given set of directories for the given file and
--   with the given property (usually permissions) and returns the file
--   path where the given file exists and has the property.
findFileWith :: (FilePath -> IO Bool) -> [FilePath] -> String -> IO (Maybe FilePath)

-- | Search through the given set of directories for the given file and
--   with the given property (usually permissions) and returns a list of
--   paths where the given file exists and has the property.
findFilesWith :: (FilePath -> IO Bool) -> [FilePath] -> String -> IO [FilePath]

-- | Filename extension for executable files (including the dot if any)
--   (usually <tt>""</tt> on POSIX systems and <tt>".exe"</tt> on Windows
--   or OS/2).
exeExtension :: String

-- | Obtain the size of a file in bytes.
getFileSize :: FilePath -> IO Integer

-- | Test whether the given path points to an existing filesystem object.
--   If the user lacks necessary permissions to search the parent
--   directories, this function may return false even if the file does
--   actually exist.
doesPathExist :: FilePath -> IO Bool

-- | The operation <a>doesFileExist</a> returns <a>True</a> if the argument
--   file exists and is not a directory, and <a>False</a> otherwise.
doesFileExist :: FilePath -> IO Bool

-- | The operation <a>doesDirectoryExist</a> returns <a>True</a> if the
--   argument file exists and is either a directory or a symbolic link to a
--   directory, and <a>False</a> otherwise.
doesDirectoryExist :: FilePath -> IO Bool

-- | Check whether the path refers to a symbolic link. On Windows, this
--   tests for <tt>FILE_ATTRIBUTE_REPARSE_POINT</tt>.
pathIsSymbolicLink :: FilePath -> IO Bool
data Permissions
emptyPermissions :: Permissions
readable :: Permissions -> Bool
writable :: Permissions -> Bool
executable :: Permissions -> Bool
searchable :: Permissions -> Bool
setOwnerReadable :: Bool -> Permissions -> Permissions
setOwnerWritable :: Bool -> Permissions -> Permissions
setOwnerExecutable :: Bool -> Permissions -> Permissions
setOwnerSearchable :: Bool -> Permissions -> Permissions

-- | The <a>getPermissions</a> operation returns the permissions for the
--   file or directory.
--   
--   The operation may fail with:
--   
--   <ul>
--   <li><a>isPermissionError</a> if the user is not permitted to access
--   the permissions; or</li>
--   <li><a>isDoesNotExistError</a> if the file or directory does not
--   exist.</li>
--   </ul>
getPermissions :: FilePath -> IO Permissions

-- | The <a>setPermissions</a> operation sets the permissions for the file
--   or directory.
--   
--   The operation may fail with:
--   
--   <ul>
--   <li><a>isPermissionError</a> if the user is not permitted to set the
--   permissions; or</li>
--   <li><a>isDoesNotExistError</a> if the file or directory does not
--   exist.</li>
--   </ul>
setPermissions :: FilePath -> Permissions -> IO ()
copyPermissions :: FilePath -> FilePath -> IO ()

-- | Obtain the time at which the file or directory was last accessed.
--   
--   The operation may fail with:
--   
--   <ul>
--   <li><a>isPermissionError</a> if the user is not permitted to read the
--   access time; or</li>
--   <li><a>isDoesNotExistError</a> if the file or directory does not
--   exist.</li>
--   </ul>
--   
--   Caveat for POSIX systems: This function returns a timestamp with
--   sub-second resolution only if this package is compiled against
--   <tt>unix-2.6.0.0</tt> or later and the underlying filesystem supports
--   them.
getAccessTime :: FilePath -> IO UTCTime

-- | Obtain the time at which the file or directory was last modified.
--   
--   The operation may fail with:
--   
--   <ul>
--   <li><a>isPermissionError</a> if the user is not permitted to read the
--   modification time; or</li>
--   <li><a>isDoesNotExistError</a> if the file or directory does not
--   exist.</li>
--   </ul>
--   
--   Caveat for POSIX systems: This function returns a timestamp with
--   sub-second resolution only if this package is compiled against
--   <tt>unix-2.6.0.0</tt> or later and the underlying filesystem supports
--   them.
getModificationTime :: FilePath -> IO UTCTime

-- | Change the time at which the file or directory was last accessed.
--   
--   The operation may fail with:
--   
--   <ul>
--   <li><a>isPermissionError</a> if the user is not permitted to alter the
--   access time; or</li>
--   <li><a>isDoesNotExistError</a> if the file or directory does not
--   exist.</li>
--   </ul>
--   
--   Some caveats for POSIX systems:
--   
--   <ul>
--   <li>Not all systems support <tt>utimensat</tt>, in which case the
--   function can only emulate the behavior by reading the modification
--   time and then setting both the access and modification times together.
--   On systems where <tt>utimensat</tt> is supported, the access time is
--   set atomically with nanosecond precision.</li>
--   <li>If compiled against a version of <tt>unix</tt> prior to
--   <tt>2.7.0.0</tt>, the function would not be able to set timestamps
--   with sub-second resolution. In this case, there would also be loss of
--   precision in the modification time.</li>
--   </ul>
setAccessTime :: FilePath -> UTCTime -> IO ()

-- | Change the time at which the file or directory was last modified.
--   
--   The operation may fail with:
--   
--   <ul>
--   <li><a>isPermissionError</a> if the user is not permitted to alter the
--   modification time; or</li>
--   <li><a>isDoesNotExistError</a> if the file or directory does not
--   exist.</li>
--   </ul>
--   
--   Some caveats for POSIX systems:
--   
--   <ul>
--   <li>Not all systems support <tt>utimensat</tt>, in which case the
--   function can only emulate the behavior by reading the access time and
--   then setting both the access and modification times together. On
--   systems where <tt>utimensat</tt> is supported, the modification time
--   is set atomically with nanosecond precision.</li>
--   <li>If compiled against a version of <tt>unix</tt> prior to
--   <tt>2.7.0.0</tt>, the function would not be able to set timestamps
--   with sub-second resolution. In this case, there would also be loss of
--   precision in the access time.</li>
--   </ul>
setModificationTime :: FilePath -> UTCTime -> IO ()

-- | <i>Deprecated: Use <a>pathIsSymbolicLink</a> instead</i>
isSymbolicLink :: FilePath -> IO Bool
instance GHC.Show.Show System.Directory.XdgDirectory
instance GHC.Read.Read System.Directory.XdgDirectory
instance GHC.Classes.Ord System.Directory.XdgDirectory
instance GHC.Classes.Eq System.Directory.XdgDirectory
instance GHC.Enum.Enum System.Directory.XdgDirectory
instance GHC.Enum.Bounded System.Directory.XdgDirectory
instance GHC.Show.Show System.Directory.DirectoryType
instance GHC.Read.Read System.Directory.DirectoryType
instance GHC.Classes.Ord System.Directory.DirectoryType
instance GHC.Classes.Eq System.Directory.DirectoryType
instance GHC.Enum.Enum System.Directory.DirectoryType
instance GHC.Show.Show System.Directory.Permissions
instance GHC.Read.Read System.Directory.Permissions
instance GHC.Classes.Ord System.Directory.Permissions
instance GHC.Classes.Eq System.Directory.Permissions
