# Module FileUtil

    module FileUtil: sig .. end

POSIX utilities for files and directories.

A module to provide the core POSIX utilities to manipulate files and directories. All functions try to mimic common POSIX utilities but are written in pure OCaml.

- Author(s): Sylvain Le Gall

### Types and exceptions

    exception FileDoesntExist of FilePath.filename

    exception RecursiveLink of FilePath.filename

    type 'a error_handler = string -> 'a -> unit

Generic error handling functions. Whenever such a function is available it helps report the error and allows to raise an exception. The `string` provided is the human readable version of `'a`. In most cases `'a` is a polymorphic variant.

    exception Fatal of string

Exception raised when after an `error_handler` the execution cannot continue. The rest of the workflow logic cannot handle the default case and the whole operation can be in the middle of transformation.

    type action_link =

`|` | `Follow` | `(*` | We consider link as simple directory (it is dangerous) | `*)`
`|` | `Skip` | `(*` | Just skip it | `*)`
`|` | `SkipInform of `(FilePath.filename -> unit)`` | `(*` | Skip and execute an action | `*)`
`|` | `AskFollow of `(FilePath.filename -> bool)`` | `(*` | Ask and wait for input, false means skip | `*)`

Policy concerning links which are directories.

    type interactive =

`|` | `Force` | `(*` | Do it anyway | `*)`
`|` | `Ask of `(FilePath.filename -> bool)`` | `(*` | Promp the user | `*)`

For certain command, you should need to ask the user wether or not he wants to act.

### Permission

    type base_permission = {

`` | `sticky : `bool`;`
`` | `exec : `bool`;`
`` | `write : `bool`;`
`` | `read : `bool`;`

`}`

Base permission. This is the permission corresponding to one user or group.

    type permission = {

`` | `user : `base_permission`;`
`` | `group : `base_permission`;`
`` | `other : `base_permission`;`

`}`

Full permission. All the base permissions of a file.

    val permission_of_int : int -> permission

Translate POSIX integer permission.

    val int_of_permission : permission -> int

Return the POSIX integer permission

    module Mode: sig .. end

Permission symbolic mode.

### Size operation

    type size =

`|` | `TB of `int64`` | `(*` | Tera bytes | `*)`
`|` | `GB of `int64`` | `(*` | Giga bytes | `*)`
`|` | `MB of `int64`` | `(*` | Mega bytes | `*)`
`|` | `KB of `int64`` | `(*` | Kilo bytes | `*)`
`|` | `B of `int64`` | `(*` | Bytes | `*)`

File size

    val byte_of_size : size -> int64

Convert size to bytes.

    val size_add : size -> size -> size

Add two sizes.

    val size_compare : ?fuzzy:bool -> size -> size -> int

Compare two sizes, using the classical compare function. If fuzzy is set to true, the comparison is done on the most significant size unit of both value.

    val string_of_size : ?fuzzy:bool -> size -> string

Convert a value to a string representation. If fuzzy is set to true, only consider the most significant unit

### stat

    type kind =

`|` | `Dir`
`|` | `File`
`|` | `Dev_char`
`|` | `Dev_block`
`|` | `Fifo`
`|` | `Socket`
`|` | `Symlink`

Kind of file. This set is a combination of all POSIX file, some of them doesn't exist at all on certain file system or OS.

    type stat = {

`` | `kind : `kind`;`
`` | `is_link : `bool`;`
`` | `permission : `permission`;`
`` | `size : `size`;`
`` | `owner : `int`;`
`` | `group_owner : `int`;`
`` | `access_time : `float`;`
`` | `modification_time : `float`;`
`` | `creation_time : `float`;`
`` | `device : `int`;`
`` | `inode : `int`;`

`}`

Information about a file. This type is derived from Unix.stat

    val stat : ?dereference:bool -> FilePath.filename -> stat

`stat fln` Return information about the file (like Unix.stat) Non POSIX command.

### umask

    exception UmaskError of string

    type umask_error = [ `Exc of exn | `NoStickyBit of int ]

Possible umask errors.

    val umask : ?error:umask_error error_handler ->
           ?mode:[< `Octal of int | `Symbolic of Mode.t ] ->
           [< `Octal of int -> 'a | `Symbolic of Mode.t -> 'a ] -> 'a

Get or set the file mode creation mask. See POSIX documentation.

    val umask_apply : int -> int

Apply umask to a given file permission.

### test

    type test_file =

`|` | `Is_dev_block` | `(*` | FILE is block special | `*)`
`|` | `Is_dev_char` | `(*` | FILE is character special | `*)`
`|` | `Is_dir` | `(*` | FILE is a directory | `*)`
`|` | `Exists` | `(*` | FILE exists | `*)`
`|` | `Is_file` | `(*` | FILE is a regular file | `*)`
`|` | `Is_set_group_ID` | `(*` | FILE is set-group-ID | `*)`
`|` | `Has_sticky_bit` | `(*` | FILE has its sticky bit set | `*)`
`|` | `Is_link` | `(*` | FILE is a symbolic link | `*)`
`|` | `Is_pipe` | `(*` | FILE is a named pipe | `*)`
`|` | `Is_readable` | `(*` | FILE is readable | `*)`
`|` | `Is_writeable` | `(*` | FILE is writeable | `*)`
`|` | `Size_not_null` | `(*` | FILE has a size greater than zero | `*)`
`|` | `Size_bigger_than of `size`` | `(*` | FILE has a size greater than given size | `*)`
`|` | `Size_smaller_than of `size`` | `(*` | FILE has a size smaller than given size | `*)`
`|` | `Size_equal_to of `size`` | `(*` | FILE has the same size as given size | `*)`
`|` | `Size_fuzzy_equal_to of `size`` | `(*` | FILE has approximatively the same size as given size | `*)`
`|` | `Is_socket` | `(*` | FILE is a socket | `*)`
`|` | `Has_set_user_ID` | `(*` | FILE its set-user-ID bit is set | `*)`
`|` | `Is_exec` | `(*` | FILE is executable | `*)`
`|` | `Is_owned_by_user_ID` | `(*` | FILE is owned by the effective user ID | `*)`
`|` | `Is_owned_by_group_ID` | `(*` | FILE is owned by the effective group ID | `*)`
`|` | `Is_newer_than of `FilePath.filename`` | `(*` | FILE1 is newer (modification date) than FILE2 | `*)`
`|` | `Is_older_than of `FilePath.filename`` | `(*` | FILE1 is older than FILE2 | `*)`
`|` | `Is_newer_than_date of `float`` | `(*` | FILE is newer than given date | `*)`
`|` | `Is_older_than_date of `float`` | `(*` | FILE is older than given date | `*)`
`|` | `And of `test_file * test_file`` | `(*` | Result of TEST1 and TEST2 | `*)`
`|` | `Or of `test_file * test_file`` | `(*` | Result of TEST1 or TEST2 | `*)`
`|` | `Not of `test_file`` | `(*` | Result of not TEST | `*)`
`|` | `Match of `string`` | `(*` | Compilable match (Str or PCRE or ...) | `*)`
`|` | `True` | `(*` | Always true | `*)`
`|` | `False` | `(*` | Always false | `*)`
`|` | `Has_extension of `FilePath.extension`` | `(*` | Check extension | `*)`
`|` | `Has_no_extension` | `(*` | Check absence of extension | `*)`
`|` | `Is_parent_dir` | `(*` | Basename is the parent dir | `*)`
`|` | `Is_current_dir` | `(*` | Basename is the current dir | `*)`
`|` | `Basename_is of `FilePath.filename`` | `(*` | Check the basename | `*)`
`|` | `Dirname_is of `FilePath.filename`` | `(*` | Check the dirname | `*)`
`|` | `Custom of `(FilePath.filename -> bool)`` | `(*` | Custom operation on filename | `*)`

Pattern you can use to test file. If the file doesn't exist the result is always false.

    val test : ?match_compile:(FilePath.filename -> FilePath.filename -> bool) ->
           test_file -> FilePath.filename -> bool

Test a file. See POSIX documentation.

### chmod

    exception ChmodError of string

    type chmod_error = [ `Exc of exn ]

Possible chmod errors.

    val chmod : ?error:chmod_error error_handler ->
           ?recurse:bool ->
           [< `Octal of Unix.file_perm | `Symbolic of Mode.t ] ->
           FilePath.filename list -> unit

Change permissions of files. See POSIX documentation.

### mkdir

    exception MkdirError of string

    type mkdir_error = [ `DirnameAlreadyUsed of FilePath.filename
           | `Exc of exn
           | `MissingComponentPath of FilePath.filename
           | `MkdirChmod of
               FilePath.filename * Unix.file_perm * string * chmod_error ]

Possible mkdir errors.

    val mkdir : ?error:mkdir_error error_handler ->
           ?parent:bool ->
           ?mode:[< `Octal of Unix.file_perm | `Symbolic of Mode.t ] ->
           FilePath.filename -> unit

Create the directory which name is provided. Set `~parent` to true if you also want to create every directory of the path. Use mode to provide some specific right. See POSIX documentation.

### rm

    exception RmError of string

    type rm_error = [ `DirNotEmpty of FilePath.filename
           | `Exc of exn
           | `NoRecurse of FilePath.filename ]

Possible rm errors.

    val rm : ?error:rm_error error_handler ->
           ?force:interactive ->
           ?recurse:bool -> FilePath.filename list -> unit

Remove the filename provided. Set `~recurse` to true in order to completely delete a directory. See POSIX documentation.

### cp

    exception CpError of string

    type cp_error = [ `CannotChmodDstDir of FilePath.filename * exn
           | `CannotCopyDir of FilePath.filename
           | `CannotCopyFilesToFile of FilePath.filename list * FilePath.filename
           | `CannotCreateDir of FilePath.filename * exn
           | `CannotListSrcDir of FilePath.filename * exn
           | `CannotOpenDstFile of FilePath.filename * exn
           | `CannotOpenSrcFile of FilePath.filename * exn
           | `CannotRemoveDstFile of FilePath.filename * exn
           | `DstDirNotDir of FilePath.filename
           | `ErrorRead of FilePath.filename * exn
           | `ErrorWrite of FilePath.filename * exn
           | `Exc of exn
           | `NoSourceFile of FilePath.filename
           | `PartialWrite of FilePath.filename * int * int
           | `SameFile of FilePath.filename * FilePath.filename
           | `UnhandledType of FilePath.filename * kind ]

Possible cp errors.

    val cp : ?follow:action_link ->
           ?force:interactive ->
           ?recurse:bool ->
           ?preserve:bool ->
           ?error:cp_error error_handler ->
           FilePath.filename list -> FilePath.filename -> unit

Copy the hierarchy of files/directory to another destination. See POSIX documentation.

### mv

    exception MvError of string

    type mv_error = [ `Exc of exn
           | `MvCp of FilePath.filename * FilePath.filename * string * cp_error
           | `MvRm of FilePath.filename * string * rm_error
           | `NoSourceFile ]

Possible mv errors.

    val mv : ?error:mv_error error_handler ->
           ?force:interactive -> FilePath.filename -> FilePath.filename -> unit

Move files/directories to another destination. See POSIX documentation.

### touch

    type touch_time_t =

`|` | `Touch_now` | `(*` | Use Unix.gettimeofday | `*)`
`|` | `Touch_file_time of `FilePath.filename`` | `(*` | Get mtime of file | `*)`
`|` | `Touch_timestamp of `float`` | `(*` | Use GMT timestamp | `*)`

Time for file

    val touch : ?atime:bool ->
           ?mtime:bool ->
           ?create:bool -> ?time:touch_time_t -> FilePath.filename -> unit

Modify the timestamp of the given filename. See POSIX documentation. If atime and mtime are not specified, they are both considered true. If only atime or mtime is sepcified, the other is false.

`atime` : modify access time.
`mtime` : modify modification time.
`create` : if file doesn't exist, create it, default true
`time` : what time to set, default Touch_now

### ls

    val filter : test_file -> FilePath.filename list -> FilePath.filename list

Apply a filtering pattern to a filename.

    val ls : FilePath.filename -> FilePath.filename list

List the content of a directory. See POSIX documentation.

### Misc operations

    val pwd : unit -> FilePath.filename

Return the current dir. See POSIX documentation.

    val readlink : FilePath.filename -> FilePath.filename

Resolve to the real filename removing symlink. Non POSIX command.

    val which : ?path:FilePath.filename list -> FilePath.filename -> FilePath.filename

Try to find the executable in the PATH. Use environement variable PATH if none is provided. Non POSIX command.

    val cmp : ?skip1:int ->
           FilePath.filename -> ?skip2:int -> FilePath.filename -> int option

`cmp skip1 fln1 skip2 fln2` Compare files `fln1` and `fln2` starting at pos `skip1` `skip2` and returning the first octect where a difference occurs. Returns `Some -1` if one of the files is not readable or if it is not a file. Returns `None` if given two identical files. See POSIX documentation.

    val du : FilePath.filename list ->
           size * (FilePath.filename * size) list

`du fln_lst` Return the amount of space of all the file which are subdir of fln_lst. Also return details for each file scanned. See POSIX documentation.

    val find : ?follow:action_link ->
           ?match_compile:(FilePath.filename -> FilePath.filename -> bool) ->
           test_file ->
           FilePath.filename -> ('a -> FilePath.filename -> 'a) -> 'a -> 'a

`find ~follow:fol tst fln exec accu` Descend the directory tree starting from the given filename and using the test provided. You cannot match `current_dir` and `parent_dir`. For every file found, the action `exec` is done, using the `accu` to start. For a simple file listing, you can use `find True "." (fun x y -> y :: x) []` See POSIX documentation.

For future release:

- `val pathchk: filename -> boolean * string`, check whether file names are valid or portable
- `val setfacl: filename -> permission -> unit`, set file access control lists (UNIX + extended attribute)
- `val getfacl: filename -> permission`, get file access control lists

ACL related function will be handled through a plugin system to handle at runtime which attribute can be read/write (i.e. Win32 ACL, NFS acl, Linux ACL -- or none).