ocaml-containers/src/core/CCIO.mli
2023-05-28 21:07:29 -04:00

299 lines
9.8 KiB
OCaml

(* This file is free software, part of containers. See file "license" for more details. *)
(** IO Utils
Simple utilities to deal with basic Input/Output tasks in a resource-safe
way. For advanced IO tasks, the user is advised to use something
like Lwt or Async, that are far more comprehensive.
Examples:
- obtain the list of lines of a file:
{[
# let l = CCIO.(with_in "/tmp/some_file" read_lines_l);;
]}
- transfer one file into another:
{[
# CCIO.(
with_in "/tmp/input"
(fun ic ->
let chunks = read_chunks_gen ic in
with_out ~flags:[Open_binary; Open_creat] ~mode:0o644 "/tmp/output"
(fun oc ->
write_gen oc chunks
)
)
) ;;
]}
- Note that the lifetime of an IO generator is tied to the underlying
channel. In the example above, [chunks] must be used in the scope of [ic].
This will raise an error:
{[
# CCIO.(
let chunks =
with_in "/tmp/input"
(fun ic -> read_chunks_gen ic)
in
with_out ~flags:[Open_binary;Open_creat] ~mode:0o644 "/tmp/output"
(fun oc ->
write_gen oc chunks
)
) ;;
]}
@since 0.6
@before 0.12 was in 'containers.io', now moved into 'containers'
*)
type 'a or_error = ('a, string) result
type 'a iter = ('a -> unit) -> unit
type 'a gen = unit -> 'a option
(** See [Gen] in the {{: https://github.com/c-cube/gen} gen library}. *)
(** {2 Input} *)
val with_in :
?mode:int -> ?flags:open_flag list -> string -> (in_channel -> 'a) -> 'a
(** Open an input file with the given optional flag list, calls the function
on the input channel. When the function raises or returns, the
channel is closed.
@raise Sys_error in case of error (same as {!open_in} and {!close_in}).
@param flags opening flags (default [[Open_text]]). [Open_rdonly] is used in any cases. *)
val read_chunks_gen : ?size:int -> in_channel -> string gen
(** Read the channel's content into chunks of size at most [size].
{b NOTE} the generator must be used within the lifetime of the channel,
see warning at the top of the file. *)
val read_chunks_seq : ?size:int -> in_channel -> string Seq.t
(** Read the channel's content into chunks of size at most [size].
{b NOTE} the generator must be used within the lifetime of the channel,
see warning at the top of the file.
@since 3.5 *)
val read_chunks_iter : ?size:int -> in_channel -> string iter
(** Read the channel's content into chunks of size at most [size]
@since 3.6 *)
val read_line : in_channel -> string option
(** Read a line from the channel. Returns [None] if the input is terminated.
The "\n" is removed from the line. *)
val read_lines_gen : in_channel -> string gen
(** Read all lines. The generator should be traversed only once.
{b NOTE} the generator must be used within the lifetime of the channel,
see warning at the top of the file. *)
val read_lines_seq : in_channel -> string Seq.t
(** Read all lines.
{b NOTE} the seq must be used within the lifetime of the channel,
see warning at the top of the file.
@since 3.5 *)
val read_lines_iter : in_channel -> string iter
(** Read all lines.
@since 3.6 *)
val read_lines_l : in_channel -> string list
(** Read all lines into a list. *)
val read_all : ?size:int -> in_channel -> string
(** Read the whole channel into a buffer, then converted into a string.
@param size the internal buffer size.
@since 0.7 *)
val read_all_bytes : ?size:int -> in_channel -> Bytes.t
(** Read the whole channel into a mutable byte array.
@param size the internal buffer size.
@since 0.12 *)
(** {2 Output} *)
val with_out :
?mode:int -> ?flags:open_flag list -> string -> (out_channel -> 'a) -> 'a
(** Like {!with_in} but for an output channel.
@param flags opening flags (default [[Open_creat; Open_trunc; Open_text]]).
@raise Sys_error in case of error (same as {!open_out} and {!close_out}).
[Open_wronly] is used in any cases. *)
val with_out_a :
?mode:int -> ?flags:open_flag list -> string -> (out_channel -> 'a) -> 'a
(** Like {!with_out} but with the [[Open_append; Open_creat; Open_wronly]]
flags activated, to append to the file.
@raise Sys_error in case of error (same as {!open_out} and {!close_out}). *)
val write_line : out_channel -> string -> unit
(** Write the given string on the channel, followed by "\n". *)
val write_gen : ?sep:string -> out_channel -> string gen -> unit
(** Write the given strings on the output. If provided, add [sep] between
every two strings (but not at the end). *)
val write_seq : ?sep:string -> out_channel -> string Seq.t -> unit
(** Write the given strings on the output. If provided, add [sep] between
every two strings (but not at the end).
@since 3.5 *)
val write_lines : out_channel -> string gen -> unit
(** Write every string on the output, followed by "\n". *)
val write_lines_iter : out_channel -> string iter -> unit
(** Write every string on the output, followed by "\n".
@since 3.6 *)
val write_lines_seq : out_channel -> string Seq.t -> unit
(** Write every string on the output, followed by "\n".
@since 3.5 *)
val write_lines_l : out_channel -> string list -> unit
(** {2 Both} *)
val with_in_out :
?mode:int ->
?flags:open_flag list ->
string ->
(in_channel -> out_channel -> 'a) ->
'a
(** Combines {!with_in} and {!with_out}.
@param flags opening flags (default [[Open_creat]]).
@raise Sys_error in case of error.
@since 0.12 *)
val copy_into : ?bufsize:int -> in_channel -> out_channel -> unit
(** [copy_into ic oc] writes the content of [ic] into [oc].
It is a blocking call.
@since 3.0 *)
(** {2 Misc for Generators} *)
val tee : ('a -> unit) list -> 'a gen -> 'a gen
(** [tee funs gen] behaves like [gen], but each element is given to
every function [f] in [funs] at the time the element is produced.
The returned generator will raise any exception that [f] raises *)
(** {2 File and file names}
How to list recursively files in a directory:
{[
# let files = CCIO.File.read_dir ~recurse:true (CCIO.File.make "/tmp");;
# CCIO.write_lines stdout files;;
]}
See {!File.walk} if you also need to list directories:
{[
# let content = CCIO.File.walk (CCIO.File.make "/tmp");;
# Gen.map CCIO.File.show_walk_item content |> CCIO.write_lines stdout;;
]}
*)
module File : sig
type t = string
(** A file should be represented by its absolute path, but currently
this is not enforced. *)
val to_string : t -> string
val make : string -> t
(** Build a file representation from a path (absolute or relative). *)
val exists : t -> bool
val is_directory : t -> bool
val remove_exn : t -> unit
(** [remove_exn path] tries to remove the file at [path] from the
file system.
@raise Sys_error if there is no file at [path] or access rights are wrong.
@since 0.8 *)
val remove : t -> unit or_error
(** Like [remove_exn] but with an error monad.
@since 0.8 *)
val remove_noerr : t -> unit
(** Like [remove_exn] but do not raise any exception on failure.
@since 0.8 *)
val read_dir : ?recurse:bool -> t -> t gen
(** [read_dir d] returns a sequence of files and directory contained
in the directory [d] (or an empty stream if [d] is not a directory).
@raise Sys_error in case of error (e.g. permission denied).
@param recurse if true (default [false]), sub-directories are also
explored, and the sequence only contains files. *)
val read_exn : t -> string
(** Read the content of the given file, or raises some exception.
@raise Sys_error in case of error.
@since 0.16 *)
val read : t -> string or_error
(** Read the content of the given file.
@since 0.16 *)
val append_exn : t -> string -> unit
(** Append the given string into the given file, possibly raising.
@raise Sys_error in case of error.
@since 0.16 *)
val append : t -> string -> unit or_error
(** Append the given string into the given file.
@since 0.16 *)
val write_exn : t -> string -> unit
(** Write the given string into the given file, possibly raising.
@raise Sys_error in case of error.
@since 0.16 *)
val write : t -> string -> unit or_error
(** Write the given string into the given file.
@since 0.16 *)
type walk_item = [ `File | `Dir ] * t
val walk : t -> walk_item gen
(** [walk p] generates the files and directories contained in a directory
tree by walking the tree. {!walk} treats anything for which {!is_directory}
returns [false] (including symlinks, etc.) as a file.
The argument is treated as part of its own directory tree, so the
result of [walk p] always includes [p].
This is similar to {!read_dir} with [recurse=true], except that {!read_dir}
with [recurse=true] only generates file entries.
@raise Sys_error in case of error (e.g. permission denied) during iteration. *)
val walk_iter : t -> walk_item iter
(** Like {!walk} but with an imperative iterator.
@since 3.6 *)
val walk_l : t -> walk_item list
(** Like {!walk} but returns a list (therefore it's eager and might
take some time on large directories).
@since 1.1 *)
val walk_seq : t -> walk_item Seq.t
(** Like {!walk} but returns a Seq
@since 3.6 *)
val show_walk_item : walk_item -> string
val with_temp :
?temp_dir:string -> prefix:string -> suffix:string -> (string -> 'a) -> 'a
(** [with_temp ~prefix ~suffix f] will call [f] with the name of a new
temporary file (located in [temp_dir]).
After [f] returns, the file is deleted. Best to be used in
combination with {!with_out}.
See {!Filename.temp_file}.
@since 0.17 *)
end