63 lines
3.2 KiB
OCaml
63 lines
3.2 KiB
OCaml
(*****************************************************************************)
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(* *)
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(* Open Source License *)
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(* Copyright (c) 2018 Dynamic Ledger Solutions, Inc. <contact@tezos.com> *)
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(* *)
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(* Permission is hereby granted, free of charge, to any person obtaining a *)
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(* copy of this software and associated documentation files (the "Software"),*)
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(* to deal in the Software without restriction, including without limitation *)
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(* the rights to use, copy, modify, merge, publish, distribute, sublicense, *)
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(* and/or sell copies of the Software, and to permit persons to whom the *)
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(* Software is furnished to do so, subject to the following conditions: *)
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(* *)
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(* The above copyright notice and this permission notice shall be included *)
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(* in all copies or substantial portions of the Software. *)
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(* *)
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(* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR*)
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(* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, *)
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(* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL *)
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(* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER*)
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(* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING *)
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(* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER *)
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(* DEALINGS IN THE SOFTWARE. *)
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(* *)
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(*****************************************************************************)
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(** A 'dropbox' with a single element. *)
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type 'a t
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(** Type of dropbox holding a value of type ['a] *)
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val create: unit -> 'a t
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(** Create an empty dropbox. *)
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val put: 'a t -> 'a -> unit
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(** Put an element inside the dropbox. If the dropbox was already
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containing an element, the old element is replaced by the new one.
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The function might return [Closed] if the dropbox has been closed
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with [close]. *)
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val take: 'a t -> 'a Lwt.t
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(** Wait until the dropbox contains an element, then returns the elements.
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The elements is removed from the dropbox. The function might return
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[Closed] if the dropbox is empty and closed. *)
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val take_with_timeout: unit Lwt.t -> 'a t -> 'a option Lwt.t
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(** Like [take] except that it returns [None] after [timeout seconds]
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if the dropbox is still empty. *)
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val peek: 'a t -> 'a option
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(** Read the current element of the dropbox without removing it. It
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immediatly returns [None] if the dropbox is empty. *)
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exception Closed
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(** The exception returned when trying to access a 'closed' dropbox. *)
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val close: 'a t -> unit
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(** Close the dropox. It terminates all the waiting reader with the
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exception [Closed]. All further read or write will also immediatly
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fail with [Closed], except if the dropbox is not empty when
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[close] is called. In that can, a single (and last) [take] will
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succeed. *)
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