package irmin-pack

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Irmin backend which stores values in a pack file

Install 

dune-project
 Dependency

github.com Readme Changelog ISC License Edit opam file Versions (9)

Authors

  1. T
    Thomas Gazagnaire

Maintainers

  1. T
    thomas@gazagnaire.org

Sources

irmin-3.6.1.tbz
sha256=11fc2570bdbfd48478c89113fc801084a84a9a2c12d9bf8c64e05ce64ae19bd7
sha512=2171699ca24dec5c9c908a2676b272e034c14eb17f7052a794535e52af0be40be68a689e59c0a640ee244b11703320483f4d0c261542e6242ba23a8f1272b9b0

doc/irmin-pack.unix/Irmin_pack_unix/File_manager/Make/argument-3-Mapping_file/index.html

Parameter Make.Mapping_file

type t

A mapping file is a collection of chunks which contain 3 integers. A length, the global offset (off) of the chunk and the offset of the chunk in the prefix file (poff).

The chunks have consecutive poff with respect to their lengths.

There is no need to close a t because its underlying file-descriptor is always closed.

module Io = Io
module Errs : Io_errors.S with module Io = Io
type open_error := [
  1. | `Corrupted_mapping_file of string
  2. | `No_such_file_or_directory
]
val create : ?report_mapping_size:(Optint.Int63.t -> unit) -> root:string -> generation:int -> register_entries: (register_entry:(off:Optint.Int63.t -> len:int -> unit) -> unit) -> unit -> (t, Errs.t) result

create creates a mapping file inside the directory root.

register_entries is a user callback that is responsible for calling register_entry for each live entry. It must be called with strictly decreasing offsets (or fails otherwise).

Returns an error if the platform is not 64bits.

val open_map : root:string -> generation:int -> (t, [> open_error ]) result

open_map ~root ~generation opens a mapping file.

val iter : t -> (off:Optint.Int63.t -> len:int -> unit) -> (unit, Errs.t) result

iter mapping f calls f on each (off,len) pair in mapping.

It is guaranteed for the offsets to be iterated in monotonic order.

It is guaranteed that entries don't overlap.

The exceptions raised by f are caught and returned (as long as they are known by Errs).

val iter_exn : t -> (off:Optint.Int63.t -> len:int -> unit) -> unit

Similar to iter mapping f but raises exceptions.

type entry = {
  1. off : Optint.Int63.t;
  2. poff : Optint.Int63.t;
  3. len : int;
}
val find_nearest_leq : t -> Optint.Int63.t -> entry option

find_nearest_leq t off returns the entry in t whose offset is the nearest <= the given off