package irmin-pack

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package irmin-pack
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Low level IO abstraction. A typical implementation is unix. This abstraction is meant to be dead simple. Not a lot of documentation is required.

It is not resistant to race condictions. There should not be concurrent modifications of the files.

type t

Errors

type misc_error

An abstract error type that contains the IO-backend specific errors. (e.g. Unix.error)

val misc_error_t : misc_error Irmin.Type.t
type create_error = [
  1. | `Io_misc of misc_error
  2. | `File_exists of string
]
type open_error = [
  1. | `Io_misc of misc_error
  2. | `No_such_file_or_directory
  3. | `Not_a_file
]
type read_error = [
  1. | `Io_misc of misc_error
  2. | `Read_out_of_bounds
  3. | `Read_on_closed
  4. | `Invalid_argument
]
type write_error = [
  1. | `Io_misc of misc_error
  2. | `Ro_not_allowed
  3. | `Write_on_closed
]
type close_error = [
  1. | `Io_misc of misc_error
  2. | `Double_close
]
type mkdir_error = [
  1. | `Io_misc of misc_error
  2. | `File_exists of string
  3. | `No_such_file_or_directory
  4. | `Invalid_parent_directory
]

Safe Functions

None of the functions in this section raise exceptions. They may however perform effects that are always continued.

Life Cycle

val create : path:string -> overwrite:bool -> (t, [> create_error ]) Stdlib.result
val open_ : path:string -> readonly:bool -> (t, [> open_error ]) Stdlib.result
val close : t -> (unit, [> close_error ]) Stdlib.result

Write Functions

val write_string : t -> off:Optint.Int63.t -> string -> (unit, [> write_error ]) Stdlib.result

write_string t ~off s writes s at offset in t.

val fsync : t -> (unit, [> write_error ]) Stdlib.result

fsync t persists to the file system the effects of previous create or write.

val move_file : src:string -> dst:string -> (unit, [> `Sys_error of string ]) Stdlib.result
val mkdir : string -> (unit, [> mkdir_error ]) Stdlib.result

Read Functions

val read_to_string : t -> off:Optint.Int63.t -> len:int -> (string, [> read_error ]) Stdlib.result

read_to_string t ~off ~len are the len bytes of t at off.

val read_size : t -> (Optint.Int63.t, [> read_error ]) Stdlib.result

read_size t is the number of bytes of the file handled by t.

This function is expensive in the unix implementation because it performs syscalls.

val classify_path : string -> [> `File | `Directory | `No_such_file_or_directory | `Other ]

MISC.

val readonly : t -> bool
val path : t -> string
val page_size : int

Unsafe Functions

These functions are equivalents to exising safe ones, but using exceptions instead of the result monad for performances reasons.

val read_exn : t -> off:Optint.Int63.t -> len:int -> bytes -> unit

read_exn t ~off ~len b reads the len bytes of t at off to b.

Raises Errors.Pack_error and Errors.RO_not_allowed.

Also raises backend-specific exceptions (e.g. Unix.Unix_error for the unix backend).

val write_exn : t -> off:Optint.Int63.t -> len:int -> string -> unit

write_exn t ~off b writes b to t at offset off.

Raises Errors.Pack_error and Errors.RO_not_allowed.

Also raises backend-specific exceptions (e.g. Unix.Unix_error for the unix backend).

val raise_misc_error : misc_error -> 'a
val catch_misc_error : (unit -> 'a) -> ('a, [> `Io_misc of misc_error ]) Stdlib.result
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