replayq

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%% Licensed under the Apache License, Version 2.0 (the "License");
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%% @doc Memory-based queue for the replayq.
-module(replayq_mem_queue).
-behaviour(replayq_mem).

-export([
    new/1,
    peek_all/1,
    peek/1,
    is_empty/1,
    in/2,
    in_r/2,
    in_batch/2,
    out/1,
    destroy/1
]).

-export_type([queue/1]).

-opaque queue(Term) :: queue:queue(Term).

%% @doc Create a new queue.
-spec new(_) -> queue(term()).
new(_) -> queue:new().

%% @doc Peek all items from the queue.
-spec peek_all(queue(Term)) -> [Term].
peek_all(Q) -> queue:to_list(Q).

%% @doc Peek the front item of the queue.
-spec peek(queue(Term)) -> empty | {value, Term}.
peek(Q) -> queue:peek(Q).

%% @doc Return 'true' if the queue is empty.
-spec is_empty(queue(_)) -> boolean().
is_empty(Q) -> queue:is_empty(Q).

%% @doc Enqueue an item to the queue.
-spec in(Term, queue(Term)) -> queue(Term).
in(Item, Q) -> queue:in(Item, Q).

%% @doc Enqueue an item in reverse order.
-spec in_r(Term, queue(Term)) -> queue(Term).
in_r(Item, Q) -> queue:in_r(Item, Q).

%% @doc Enqueue a batch of items to the queue.
-spec in_batch([Term], queue(Term)) -> queue(Term).
in_batch(Items, Q) ->
    case is_empty(Q) of
        true ->
            queue:from_list(Items);
        false ->
            lists:foldl(fun(Item, Q0) -> in(Item, Q0) end, Q, Items)
    end.

%% @doc Dequeue an item from the queue.
-spec out(queue(Term)) -> {empty, queue(Term)} | {{value, Term}, queue(Term)}.
out(Q) -> queue:out(Q).

%% @doc Destroy the queue.
%% This implementation does nothing.
-spec destroy(queue(_)) -> ok.
destroy(_Q) -> ok.

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