Modulepath-io-1.8.2GHC2021

Path.IO

This module provides an interface to System.Directory for users of the Path module. It also implements some extra functionality like recursive scanning and copying of directories, working with temporary files/directories, etc.

4 types
1 class
73 values

Packagepath-io-1.8.2
Exports78
LanguageGHC2021
LicenceBSD-3-Clause
SourceIO.hs

Actions on directories

14 declarations

valuecreateDir :: MonadIO m => Path b Dir -> m ()

createDir 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 / PermissionDenied The process has insufficient privileges to perform the operation. [EROFS, EACCES]
isAlreadyExistsError / AlreadyExists 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]
NoSuchThing There is no path to the directory. [ENOENT, ENOTDIR]
ResourceExhausted 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]

valuecreateDirIfMissing

:: MonadIO m
=> Bool
Create its parents too?
-> Path b Dir
The path to the directory you want to make
-> m ()

createDirIfMissing 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.

valueensureDir :: MonadIO m => Path b Dir -> m ()

Ensure that a directory exists creating it and its parent directories if necessary. This is just a handy shortcut:

ensureDir = createDirIfMissing True

valueremoveDir :: MonadIO m => Path b Dir -> m ()

removeDir 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 / NoSuchThing The directory does not exist. [ENOENT, ENOTDIR]
isPermissionError / PermissionDenied 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]

valueremoveDirRecur :: MonadIO m => Path b Dir -> m ()

removeDirRecur dir removes an existing directory dir together with its contents and sub-directories. Within this directory, symbolic links are removed without affecting their targets.

valueremovePathForcibly :: MonadIO m => Path b t -> m ()

Remove a file or directory at path 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 there are hard links in the directory, then permissions on all related hard links may be altered.

If an entry within the directory vanishes while removePathForcibly is running, it is silently ignored.

If an exception occurs while removing an entry, removePathForcibly 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.

valuerenameDir

:: MonadIO m
=> Path b0 Dir
Old name
-> Path b1 Dir
New name
-> m ()

renameDir 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 removeDir. 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, renameDir 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 / NoSuchThing The original directory does not exist, or there is no path to the target. [ENOENT, ENOTDIR]
isPermissionError / PermissionDenied The process has insufficient privileges to perform the operation. [EROFS, EACCES, EPERM]
ResourceExhausted 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]

valuerenamePath :: MonadIO m => Path b0 t -> Path b1 t -> m ()

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:

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]
System.IO.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 the destination path refers to an existing directory, or one of the parent segments in the destination path is not a directory. [ENOTDIR, EISDIR, EINVAL, EEXIST, ENOTEMPTY]

valuelistDir

:: MonadIO m
=> Path b Dir
Directory to list
-> m ([Path Abs Dir], [Path Abs File])
Sub-directories and files

listDir dir returns a list of all entries in dir without the special entries (. and ..). Entries are not sorted.

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 / NoSuchThing The directory does not exist. [ENOENT, ENOTDIR]
isPermissionError / PermissionDenied The process has insufficient privileges to perform the operation. [EACCES]
ResourceExhausted Insufficient resources are available to perform the operation. [EMFILE, ENFILE]
InappropriateType The path refers to an existing non-directory object. [ENOTDIR]

valuelistDirRel

:: MonadIO m
=> Path b Dir
Directory to list
-> m ([Path Rel Dir], [Path Rel File])
Sub-directories and files

The same as listDir but returns relative paths.

valuelistDirRecur

:: MonadIO m
=> Path b Dir
Directory to list
-> m ([Path Abs Dir], [Path Abs File])
Sub-directories and files

Similar to listDir, but recursively traverses every sub-directory excluding symbolic links, and returns all files and directories found. This can fail with the same exceptions as listDir.

Note: before version 1.3.0, this function followed symlinks.

valuelistDirRecurRel

:: MonadIO m
=> Path b Dir
Directory to list
-> m ([Path Rel Dir], [Path Rel File])
Sub-directories and files

The same as listDirRecur but returns paths that are relative to the given directory.

valuecopyDirRecur

:: MonadIO m
=> Path b0 Dir
Source
-> Path b1 Dir
Destination
-> m ()

Copies a directory recursively. It does not follow symbolic links and preserves permissions when possible. If the destination directory already exists, new files and sub-directories complement its structure, possibly overwriting old files if they happen to have the same name as the new ones.

Note: before version 1.3.0, this function followed symlinks.

Note: before version 1.6.0, the function created empty directories in the destination directory when the source directory contained directory symlinks. The symlinked directories were not recursively traversed. It also copied symlinked files creating normal regular files in the target directory as the result. This was fixed in the version 1.6.0 so that the function now behaves much like the cp utility, not traversing symlinked directories, but recreating symlinks in the target directory according to their targets in the source directory.

valuecopyDirRecur'

:: MonadIO m
=> Path b0 Dir
Source
-> Path b1 Dir
Destination
-> m ()

The same as copyDirRecur, but it does not preserve directory permissions. This may be useful, for example, if the directory you want to copy is “read-only”, but you want your copy to be editable.

Note: before version 1.3.0, this function followed symlinks.

Walking directory trees

datadata WalkAction b

Action returned by the traversal handler function. The action controls how the traversal will proceed.

Note: in version 1.4.0 the type was adjusted to have the b type parameter.

Constructors

WalkFinish
Finish the entire walk altogether
WalkExclude [Path b Dir]
List of sub-directories to exclude from descending

Instances2Eq, Show

Eq (WalkAction b)Defined in path-io-1.8.2 · Path.IO
Show (WalkAction b)Defined in path-io-1.8.2 · Path.IO

valuewalkDir

:: MonadIO m
=> (Path Abs Dir -> [Path Abs Dir] -> [Path Abs File] -> m (WalkAction Abs))
Handler (dir -> subdirs -> files -> WalkAction)
-> Path b Dir
Directory where traversal begins
-> m ()

Traverse a directory tree using depth first pre-order traversal, calling a handler function at each directory node traversed. The absolute paths of the parent directory, sub-directories and the files in the directory are provided as arguments to the handler.

The function is capable of detecting and avoiding traversal loops in the directory tree. Note that the traversal follows symlinks by default, an appropriate traversal handler can be used to avoid that when necessary.

valuewalkDirRel

:: MonadIO m
=> (Path Rel Dir -> [Path Rel Dir] -> [Path Rel File] -> m (WalkAction Rel))
Handler (dir -> subdirs -> files -> WalkAction)
-> Path b Dir
Directory where traversal begins
-> m ()

The same as walkDir but uses relative paths. The handler is given dir, directory relative to the directory where traversal begins. Sub-directories and files are relative to dir.

valuewalkDirAccum

:: (MonadIO m, Monoid o)
=> Maybe (Path Abs Dir -> [Path Abs Dir] -> [Path Abs File] -> m (WalkAction Abs))
Descend handler (dir -> subdirs -> files -> WalkAction), descend the whole tree if omitted
-> (Path Abs Dir -> [Path Abs Dir] -> [Path Abs File] -> m o)
Output writer (dir -> subdirs -> files -> o)
-> Path b Dir
Directory where traversal begins
-> m o
Accumulation of outputs generated by the output writer invocations

Similar to walkDir but accepts a Monoid-returning output writer as well. Values returned by the output writer invocations are accumulated and returned.

Both, the descend handler as well as the output writer can be used for side effects but keep in mind that the output writer runs before the descend handler.

valuewalkDirAccumRel

:: (MonadIO m, Monoid o)
=> Maybe (Path Rel Dir -> [Path Rel Dir] -> [Path Rel File] -> m (WalkAction Rel))
Descend handler (dir -> subdirs -> files -> WalkAction), descend the whole tree if omitted
-> (Path Rel Dir -> [Path Rel Dir] -> [Path Rel File] -> m o)
Output writer (dir -> subdirs -> files -> o)
-> Path b Dir
Directory where traversal begins
-> m o
Accumulation of outputs generated by the output writer invocations

The same as walkDirAccum but uses relative paths. The handler and writer are given dir, directory relative to the directory where traversal begins. Sub-directories and files are relative to dir.

Current working directory

valuegetCurrentDir :: MonadIO m => m (Path Abs Dir)

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: makeAbsolute).

The operation may fail with:

HardwareFault A physical I/O error has occurred. [EIO]
isDoesNotExistError or NoSuchThing There is no path referring to the working directory. [EPERM, ENOENT, ESTALE...]
isPermissionError or 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 working directory.

valuesetCurrentDir :: MonadIO m => Path b Dir -> m ()

Change the working directory to the given path.

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 or NoSuchThing The directory does not exist. [ENOENT, ENOTDIR]
isPermissionError or PermissionDenied 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]

valuewithCurrentDir

:: (MonadIO m, MonadMask m)
=> Path b Dir
Directory to execute in
-> m a
Action to be executed
-> m a

Run an IO 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 getCurrentDir and setCurrentDir.

Pre-defined directories

8 declarations

valuegetHomeDir :: MonadIO m => m (Path Abs Dir)

Return 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 getAppUserDataDir instead.

On Unix, getHomeDir returns the value of the HOME environment variable. On Windows, the system is queried for a suitable path; a typical path might be C:/Users/<user>.

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.

valuegetAppUserDataDir

:: MonadIO m
=> String
Name of application (used in path construction)
-> m (Path Abs Dir)

Obtain the path to a special directory for storing user-specific application data (traditional Unix location).

The argument is usually the name of the application. Since it will be integrated into the path, it must consist of valid path characters.

On Unix-like systems, the path is ~/.<app>.
On Windows, the path is %APPDATA%/<app> (e.g. C:/Users/<user>/AppData/Roaming/<app>)

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:

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.

valuegetUserDocsDir :: MonadIO m => m (Path Abs Dir)

Return the current user's document directory.

On Unix, getUserDocsDir returns the value of the HOME environment variable. On Windows, the system is queried for a suitable path; a typical path might be C:/Users/<user>/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.

valuegetTempDir :: MonadIO m => m (Path Abs Dir)

Return the current directory for temporary files.

On Unix, getTempDir 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.

datadata XdgDirectory

Special directories for storing user-specific application data, configuration, and cache files, as specified by the XDG Base Directory Specification.

Note: On Windows, XdgData and XdgConfig usually map to the same directory.

Constructors

XdgData
For data files (e.g. images). It uses the XDG_DATA_HOME environment variable. On non-Windows systems, the default is ~/.local/share. On Windows, the default is %APPDATA% (e.g. C:/Users/<user>/AppData/Roaming). Can be considered as the user-specific equivalent of /usr/share.
XdgConfig
For configuration files. It uses the XDG_CONFIG_HOME environment variable. On non-Windows systems, the default is ~/.config. On Windows, the default is %APPDATA% (e.g. C:/Users/<user>/AppData/Roaming). Can be considered as the user-specific equivalent of /etc.
XdgCache
For non-essential files (e.g. cache). It uses the XDG_CACHE_HOME environment variable. On non-Windows systems, the default is ~/.cache. On Windows, the default is %LOCALAPPDATA% (e.g. C:/Users/<user>/AppData/Local). Can be considered as the user-specific equivalent of /var/cache.
XdgState
For data that should persist between (application) restarts, but that is not important or portable enough to the user that it should be stored in XdgData. It uses the XDG_STATE_HOME environment variable. On non-Windows sytems, the default is ~/.local/state. On Windows, the default is %LOCALAPPDATA% (e.g. C:/Users/<user>/AppData/Local).

Instances6Bounded, Enum, Eq, Ord, Read, Show

Bounded XdgDirectoryDefined in directory-1.3.8.5 · System.Directory.Internal.Common
Enum XdgDirectoryDefined in directory-1.3.8.5 · System.Directory.Internal.Common
Eq XdgDirectoryDefined in directory-1.3.8.5 · System.Directory.Internal.Common
Ord XdgDirectoryDefined in directory-1.3.8.5 · System.Directory.Internal.Common
Read XdgDirectoryDefined in directory-1.3.8.5 · System.Directory.Internal.Common
Show XdgDirectoryDefined in directory-1.3.8.5 · System.Directory.Internal.Common

valuegetXdgDir

:: MonadIO m
=> XdgDirectory
Which special directory
-> Maybe (Path Rel Dir)
A relative path that is appended to the path; if Nothing, the base path is returned
-> m (Path Abs Dir)

Obtain the paths to special directories for storing user-specific application data, configuration, and cache files, conforming to the XDG Base Directory Specification. Compared with getAppUserDataDir, 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 XdgData and XdgConfig will map to the same directory.

Note: The directory may not actually exist, in which case you would need to create it with file mode 700 (i.e. only accessible by the owner).

Note also: this is a piece of conditional API, only available if directory-1.2.3.0 or later is used.

datadata XdgDirectoryList

Search paths for various application data, as specified by the XDG Base Directory Specification.

The list of paths is split using System.FilePath.searchPathSeparator, which on Windows is a semicolon.

Note: On Windows, XdgDataDirs and XdgConfigDirs usually yield the same result.

Constructors

XdgDataDirs
For data files (e.g. images). It uses the XDG_DATA_DIRS environment variable. On non-Windows systems, the default is /usr/local/share/ and /usr/share/. On Windows, the default is %PROGRAMDATA% or %ALLUSERSPROFILE% (e.g. C:/ProgramData).
XdgConfigDirs
For configuration files. It uses the XDG_CONFIG_DIRS environment variable. On non-Windows systems, the default is /etc/xdg. On Windows, the default is %PROGRAMDATA% or %ALLUSERSPROFILE% (e.g. C:/ProgramData).

Instances6Bounded, Enum, Eq, Ord, Read, Show

Bounded XdgDirectoryListDefined in directory-1.3.8.5 · System.Directory.Internal.Common
Enum XdgDirectoryListDefined in directory-1.3.8.5 · System.Directory.Internal.Common
Eq XdgDirectoryListDefined in directory-1.3.8.5 · System.Directory.Internal.Common
Ord XdgDirectoryListDefined in directory-1.3.8.5 · System.Directory.Internal.Common
Read XdgDirectoryListDefined in directory-1.3.8.5 · System.Directory.Internal.Common
Show XdgDirectoryListDefined in directory-1.3.8.5 · System.Directory.Internal.Common

valuegetXdgDirList

:: MonadIO m
=> XdgDirectoryList
Which special directory list
-> m [Path Abs Dir]

Similar to getXdgDir but retrieves the entire list of XDG directories.

On Windows, XdgDataDirs and XdgConfigDirs usually map to the same list of directories unless overridden.

Refer to the docs of XdgDirectoryList for more details.

Path transformation

5 declarations

classclass AnyPath path where

Class of things (Paths) that can be canonicalized, made absolute, and made relative to a some base directory.

Associated types

type family AbsPath path
Type of absolute version of the given path.
type family RelPath path
Type of relative version of the given path.

Methods

canonicalizePath :: MonadIO m => path -> m (AbsPath path)
Make a path absolute and remove as many indirections from it as possible. Indirections include the two special directories . and .., as well as any symbolic links. The input path need not point to an existing file or directory.
Note: if you require only an absolute path, use makeAbsolute instead. Most programs need not care about whether a path contains symbolic links.
Due to the fact that symbolic links are dependent on the state of the existing filesystem, the function can only make a conservative, best-effort attempt. Nevertheless, if the input path points to an existing file or directory, then the output path shall also point to the same file or directory.
Formally, symbolic links are removed from the longest prefix of the path that still points to an existing file. The function is not atomic, therefore concurrent changes in the filesystem may lead to incorrect results.
(Despite the name, the function does not guarantee canonicity of the returned path due to the presence of hard links, mount points, etc.)
Known bug(s): on Windows, the function does not resolve symbolic links.
Please note that before version 1.2.3.0 of the directory package, this function had unpredictable behavior on non-existent paths.
makeAbsolute :: MonadIO m => path -> m (AbsPath path)
Make a path absolute by prepending the current directory (if it isn't already absolute) and applying normalise to the result.
If the path is already absolute, the operation never fails. Otherwise, the operation may fail with the same exceptions as getCurrentDir.
makeRelative :: MonadThrow m => Path Abs Dir -> path -> m (RelPath path)
Make a path relative to a given directory.
makeRelativeToCurrentDir :: MonadIO m => path -> m (RelPath path)
Make a path relative to current working directory.

Instances4AnyPath

AnyPath (SomeBase Dir)Defined in path-io-1.8.2 · Path.IO
AnyPath (SomeBase File)Defined in path-io-1.8.2 · Path.IO
AnyPath (Path b Dir)Defined in path-io-1.8.2 · Path.IO
AnyPath (Path b File)Defined in path-io-1.8.2 · Path.IO

valueresolveFile

:: MonadIO m
=> Path Abs Dir
Base directory
-> FilePath
Path to resolve
-> m (Path Abs File)

Append stringly-typed path to an absolute path and then canonicalize it.

valueresolveFile'

:: MonadIO m
=> FilePath
Path to resolve
-> m (Path Abs File)

The same as resolveFile, but uses current working directory.

valueresolveDir

:: MonadIO m
=> Path Abs Dir
Base directory
-> FilePath
Path to resolve
-> m (Path Abs Dir)

The same as resolveFile, but for directories.

valueresolveDir'

:: MonadIO m
=> FilePath
Path to resolve
-> m (Path Abs Dir)

The same as resolveDir, but uses current working directory.

Actions on files

8 declarations

valueremoveFile :: MonadIO m => Path b File -> m ()

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 / NoSuchThing The file does not exist. [ENOENT, ENOTDIR]
isPermissionError / PermissionDenied 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]

valuerenameFile

:: MonadIO m
=> Path b0 File
Original location
-> Path b1 File
New location
-> m ()

renameFile old new changes the name of an existing file system object from old to new. If the new object already exists, it is atomically 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.

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 / NoSuchThing The original file does not exist, or there is no path to the target. [ENOENT, ENOTDIR]
isPermissionError / PermissionDenied The process has insufficient privileges to perform the operation. [EROFS, EACCES, EPERM]
ResourceExhausted 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]

valuecopyFile

:: MonadIO m
=> Path b0 File
Original location
-> Path b1 File
Where to put copy
-> m ()

copyFile old new copies the existing file from old to new. If the new file already exists, it is atomically replaced by the old file. Neither path may refer to an existing directory. The permissions of old are copied to new, if possible.

valuegetFileSize :: MonadIO m => Path b File -> m Integer

Obtain the size of a file in bytes.

valuefindExecutable

:: MonadIO m
=> Path Rel File
Executable file name
-> m (Maybe (Path Abs File))
Path to found executable

Given an executable file name, search 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 findExecutable corresponds to the program that would be executed by createProcess when passed the same string (as a RawCommand, not a ShellCommand).

On Windows, findExecutable calls the Win32 function SearchPath, which may search other places before checking the directories in PATH. Where it actually searches depends on registry settings, but notably includes the directory containing the current executable. See http://msdn.microsoft.com/en-us/library/aa365527.aspx for more details.

valuefindFile

:: MonadIO m
=> [Path b Dir]
Set of directories to search in
-> Path Rel File
Filename of interest
-> m (Maybe (Path Abs File))
Absolute path to file (if found)

Search through the given set of directories for the given file.

valuefindFiles

:: MonadIO m
=> [Path b Dir]
Set of directories to search in
-> Path Rel File
Filename of interest
-> m [Path Abs File]
Absolute paths to all found files

Search through the given set of directories for the given file and return a list of paths where the given file exists.

valuefindFilesWith

:: MonadIO m
=> (Path Abs File -> m Bool)
How to test the files
-> [Path b Dir]
Set of directories to search in
-> Path Rel File
Filename of interest
-> m [Path Abs File]
Absolute paths to all found files

Search through the given set of directories for the given file and with the given property (usually permissions) and return a list of paths where the given file exists and has the property.

Symbolic links

5 declarations

valuecreateFileLink

:: MonadIO m
=> Path b0 File
Path to the target file
-> Path b1 File
Path to the link to be created
-> m ()

Create a file symbolic link. The target path can be either absolute or relative and need not refer to an existing file. The order of arguments follows the POSIX convention.

To remove an existing file symbolic link, use removeFile.

Although the distinction between file symbolic links and directory symbolic links does not exist on POSIX systems, on Windows this is an intrinsic property of every symbolic link and cannot be changed without recreating the link. A file symbolic link that actually points to a directory will fail to dereference and vice versa. Moreover, creating symbolic links on Windows may require privileges unavailable to users outside the Administrators group. Portable programs that use symbolic links should take both into consideration.

On Windows, the function is implemented using CreateSymbolicLink. Since 1.3.3.0, the SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE flag is included if supported by the operating system. On POSIX, the function uses symlink and is therefore atomic.

Windows-specific errors: This operation may fail with permissionErrorType if the user lacks the privileges to create symbolic links. It may also fail with illegalOperationErrorType if the file system does not support symbolic links.

valuecreateDirLink

:: MonadIO m
=> Path b0 Dir
Path to the target directory
-> Path b1 Dir
Path to the link to be created
-> m ()

Create a directory symbolic link. The target path can be either absolute or relative and need not refer to an existing directory. The order of arguments follows the POSIX convention.

To remove an existing directory symbolic link, use removeDirLink.

On Windows, the function is implemented using CreateSymbolicLink with SYMBOLIC_LINK_FLAG_DIRECTORY. Since 1.3.3.0, the SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE flag is also included if supported by the operating system. On POSIX, this is an alias for createFileLink and is therefore atomic.

valueremoveDirLink

:: MonadIO m
=> Path b Dir
Path to the link to be removed
-> m ()

Remove an existing directory symbolic link.

On Windows, this is an alias for removeDir. On POSIX systems, this is an alias for removeFile.

See also: removeFile, which can remove an existing file symbolic link.

valuegetSymlinkTarget

:: MonadIO m
=> Path b t
Symlink path
-> m FilePath

Retrieve the target path of either a file or directory symbolic link. The returned path may not exist, and may not even be a valid path.

On Windows systems, this calls DeviceIoControl with FSCTL_GET_REPARSE_POINT. In addition to symbolic links, the function also works on junction points. On POSIX systems, this calls readlink.

Windows-specific errors: This operation may fail with illegalOperationErrorType if the file system does not support symbolic links.

valueisSymlink :: MonadIO m => Path b t -> m Bool

Check whether the path refers to a symbolic link. An exception is thrown if the path does not exist or is inaccessible.

On Windows, this checks for FILE_ATTRIBUTE_REPARSE_POINT. In addition to symbolic links, the function also returns true on junction points. On POSIX systems, this checks for S_IFLNK.

Check if the given path is a symbolic link.

Temporary files and directories

7 declarations

valuewithTempFile

:: (MonadIO m, MonadMask m)
=> Path b Dir
Directory to create the file in
-> String
File name template, see openTempFile
-> (Path Abs File -> Handle -> m a)
Callback that can use the file
-> m a

Use a temporary file that doesn't already exist.

Creates a new temporary file inside the given directory, making use of the template. The temporary file is deleted after use.

valuewithTempDir

:: (MonadIO m, MonadMask m)
=> Path b Dir
Directory to create the file in
-> String
Directory name template, see openTempFile
-> (Path Abs Dir -> m a)
Callback that can use the directory
-> m a

Create and use a temporary directory.

Creates a new temporary directory inside the given directory, making use of the template. The temporary directory is deleted after use.

valuewithSystemTempFile

:: (MonadIO m, MonadMask m)
=> String
File name template, see openTempFile
-> (Path Abs File -> Handle -> m a)
Callback that can use the file
-> m a

Create and use a temporary file in the system standard temporary directory.

Behaves exactly the same as withTempFile, except that the parent temporary directory will be that returned by getTempDir.

valuewithSystemTempDir

:: (MonadIO m, MonadMask m)
=> String
Directory name template, see openTempFile
-> (Path Abs Dir -> m a)
Callback that can use the directory
-> m a

Create and use a temporary directory in the system standard temporary directory.

Behaves exactly the same as withTempDir, except that the parent temporary directory will be that returned by getTempDir.

valueopenTempFile

:: MonadIO m
=> Path b Dir
Directory to create file in
-> String
File name template; if the template is "foo.ext" then the created file will be "fooXXX.ext" where XXX is some random number
-> m (Path Abs File, Handle)
Name of created file and its Handle

The function creates a temporary file in rw mode. The created file isn't deleted automatically, so you need to delete it manually.

The file is created with permissions such that only the current user can read/write it.

With some exceptions (see below), the file will be created securely in the sense that an attacker should not be able to cause openTempFile to overwrite another file on the filesystem using your credentials, by putting symbolic links (on Unix) in the place where the temporary file is to be created. On Unix the O_CREAT and O_EXCL flags are used to prevent this attack, but note that O_EXCL is sometimes not supported on NFS filesystems, so if you rely on this behaviour it is best to use local filesystems only.

valueopenBinaryTempFile

:: MonadIO m
=> Path b Dir
Directory to create file in
-> String
File name template, see openTempFile
-> m (Path Abs File, Handle)
Name of created file and its Handle

Like openTempFile, but opens the file in binary mode. On Windows, reading a file in text mode (which is the default) will translate CRLF to LF, and writing will translate LF to CRLF. This is usually what you want with text files. With binary files this is undesirable; also, as usual under Microsoft operating systems, text mode treats control-Z as EOF. Binary mode turns off all special treatment of end-of-line and end-of-file characters.

valuecreateTempDir

:: MonadIO m
=> Path b Dir
Directory to create file in
-> String
Directory name template, see openTempFile
-> m (Path Abs Dir)
Name of created temporary directory

Create a temporary directory. The created directory isn't deleted automatically, so you need to delete it manually.

The directory is created with permissions such that only the current user can read/write it.

Existence tests

6 declarations

valuedoesPathExist :: MonadIO m => Path b t -> m Bool

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.

valuedoesFileExist :: MonadIO m => Path b File -> m Bool

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

valuedoesDirExist :: MonadIO m => Path b Dir -> m Bool

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

valueisLocationOccupied :: MonadIO m => Path b t -> m Bool

Check if there is a file or directory on specified path.

valueforgivingAbsence :: (MonadIO m, MonadCatch m) => m a -> m (Maybe a)

If argument of the function throws a doesNotExistErrorType, Nothing is returned (other exceptions propagate). Otherwise the result is returned inside a Just.

valueignoringAbsence :: (MonadIO m, MonadCatch m) => m a -> m ()

The same as forgivingAbsence, but ignores result.

Permissions

13 declarations

datadata Permissions

Instances4Eq, Ord, Read, Show

Eq PermissionsDefined in directory-1.3.8.5 · System.Directory.Internal.Common
Ord PermissionsDefined in directory-1.3.8.5 · System.Directory.Internal.Common
Read PermissionsDefined in directory-1.3.8.5 · System.Directory.Internal.Common
Show PermissionsDefined in directory-1.3.8.5 · System.Directory.Internal.Common

valueemptyPermissions :: Permissions

valuereadable :: Permissions -> Bool

valuewritable :: Permissions -> Bool

valueexecutable :: Permissions -> Bool

valuesearchable :: Permissions -> Bool

valuesetOwnerReadable :: Bool -> Permissions -> Permissions

valuesetOwnerWritable :: Bool -> Permissions -> Permissions

valuesetOwnerExecutable :: Bool -> Permissions -> Permissions

valuesetOwnerSearchable :: Bool -> Permissions -> Permissions

valuegetPermissions :: MonadIO m => Path b t -> m Permissions

The getPermissions operation returns the permissions for the file or directory.

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.

valuesetPermissions :: MonadIO m => Path b t -> Permissions -> m ()

The setPermissions operation sets the permissions for the file or directory.

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.

valuecopyPermissions

:: MonadIO m
=> Path b0 t0
From where to copy
-> Path b1 t1
What to modify
-> m ()

Set permissions for the object found on second given path so they match permissions of the object on the first path.

Timestamps

4 declarations

valuegetAccessTime :: MonadIO m => Path b t -> m UTCTime

Obtain the time at which the file or directory was last accessed.

The operation may fail with:

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

Caveat for POSIX systems: This function returns a timestamp with sub-second resolution only if this package is compiled against unix-2.6.0.0 or later and the underlying filesystem supports them.

Note: this is a piece of conditional API, only available if directory-1.2.3.0 or later is used.

valuesetAccessTime :: MonadIO m => Path b t -> UTCTime -> m ()

Change the time at which the file or directory was last accessed.

The operation may fail with:

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

Some caveats for POSIX systems:

Not all systems support utimensat, 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 utimensat is supported, the access time is set atomically with nanosecond precision.
If compiled against a version of unix prior to 2.7.0.0, 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.

Note: this is a piece of conditional API, only available if directory-1.2.3.0 or later is used.

valuesetModificationTime :: MonadIO m => Path b t -> UTCTime -> m ()

Change the time at which the file or directory was last modified.

The operation may fail with:

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

Some caveats for POSIX systems:

Not all systems support utimensat, 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 utimensat is supported, the modification time is set atomically with nanosecond precision.
If compiled against a version of unix prior to 2.7.0.0, 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.

Note: this is a piece of conditional API, only available if directory-1.2.3.0 or later is used.

valuegetModificationTime :: MonadIO m => Path b t -> m UTCTime

Obtain the time at which the file or directory was last modified.

The operation may fail with:

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

Caveat for POSIX systems: This function returns a timestamp with sub-second resolution only if this package is compiled against unix-2.6.0.0 or later and the underlying filesystem supports them.