ram

%% ==========================================================================================================
%% Ram - An in-memory distributed KV store for Erlang and Elixir.
%%
%% The MIT License (MIT)
%%
%% Copyright (c) 2019-2021 Roberto Ostinelli <roberto@ostinelli.net> and Neato Robotics, Inc.
%%
%% Permission is hereby granted, free of charge, to any person obtaining a copy
%% of this software and associated documentation files (the "Software"), to deal
%% in the Software without restriction, including without limitation the rights
%% to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
%% copies of the Software, and to permit persons to whom the Software is
%% furnished to do so, subject to the following conditions:
%%
%% The above copyright notice and this permission notice shall be included in
%% all copies or substantial portions of the Software.
%%
%% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
%% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
%% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
%% AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
%% LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
%% OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
%% THE SOFTWARE.
%% ==========================================================================================================
%% @private
-module(ram_event_handler).

%% API
-export([do_resolve_conflict/3]).

%% ===================================================================
%% API
%% ===================================================================
%% @private
-spec do_resolve_conflict(
    Key :: term(),
    {Node1 :: node(), Value1 :: term(), Time1 :: non_neg_integer(), Deleted1 :: boolean()},
    {Node2 :: node(), Value2 :: term(), Time2 :: non_neg_integer(), Deleted1 :: boolean()}
) -> {ok, ValueToKeep :: term(), DeletedToKeep :: boolean()}.
do_resolve_conflict(_Key, {_Node1, Value1, Time1, Deleted1}, {_Node2, Value2, Time2, Deleted2}) ->
    %% by default, keep value registered more recently
    %% NB: this is a simple mechanism that can be imprecise
    {ValueToKeep, DeletedToKeep} = case Time1 > Time2 of
        true -> {Value1, Deleted1};
        _ -> {Value2, Deleted2}
    end,
    {ok, ValueToKeep, DeletedToKeep}.