Source file atomic_write.ml

(*
 * Copyright (c) 2018-2021 Tarides <contact@tarides.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *)

open! Import
include Atomic_write_intf

module Value = struct
  module type S = Value

  module Of_hash (X : Irmin.Hash.S) = struct
    type t = X.t [@@deriving irmin ~of_bin_string]

    let null =
      match of_bin_string (String.make X.hash_size '\000') with
      | Ok x -> x
      | Error _ -> assert false
  end
end

(* FIXME: remove code duplication with irmin/atomic_write *)
module Closeable (AW : S) = struct
  type t = { closed : bool ref; t : AW.t }
  type key = AW.key
  type value = AW.value

  let check_not_closed t = if !(t.closed) then raise Irmin.Closed

  let mem t k =
    check_not_closed t;
    AW.mem t.t k

  let find t k =
    check_not_closed t;
    AW.find t.t k

  let set t k v =
    check_not_closed t;
    AW.set t.t k v

  let test_and_set t k ~test ~set =
    check_not_closed t;
    AW.test_and_set t.t k ~test ~set

  let remove t k =
    check_not_closed t;
    AW.remove t.t k

  let list t =
    check_not_closed t;
    AW.list t.t

  type watch = AW.watch

  let watch t ?init f =
    check_not_closed t;
    AW.watch t.t ?init f

  let watch_key t k ?init f =
    check_not_closed t;
    AW.watch_key t.t k ?init f

  let unwatch t w =
    check_not_closed t;
    AW.unwatch t.t w

  let make_closeable t = { closed = ref false; t }

  let close t =
    if !(t.closed) then Lwt.return_unit
    else (
      t.closed := true;
      AW.close t.t)

  let clear t =
    check_not_closed t;
    AW.clear t.t

  let flush t =
    check_not_closed t;
    AW.flush t.t
end