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%%% ====================================================================
%%% ``The contents of this file are subject to the Erlang Public License,
%%% Version 1.1, (the "License"); you may not use this file except in
%%% compliance with the License. You should have received a copy of the
%%% Erlang Public License along with this software. If not, it can be
%%% retrieved via the world wide web at http://www.erlang.org/.
%%%
%%%
%%% Software distributed under the License is distributed on an "AS IS"
%%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%%% the License for the specific language governing rights and limitations
%%% under the License.
%%%
%%%
%%% The Initial Developer of the Original Code is ProcessOne.
%%% Portions created by ProcessOne are Copyright 2006-2015, ProcessOne
%%% All Rights Reserved.''
%%% This software is copyright 2006-2015, ProcessOne.
%%%
%%%
%%% @copyright 2006-2015 ProcessOne
%%% @author Christophe Romain <christophe.romain@process-one.net>
%%% [http://www.process-one.net/]
%%% @version {@vsn}, {@date} {@time}
%%% @end
%%% ====================================================================
%% important note:
%% new/1 and free/2 MUST be called inside a transaction bloc
-module(pubsub_index).
-author('christophe.romain@process-one.net').
-include("pubsub.hrl").
-export([init/3, new/1, free/2]).
init(_Host, _ServerHost, _Opts) ->
mnesia:create_table(pubsub_index,
[{disc_copies, [node()]},
{attributes, record_info(fields, pubsub_index)}]).
new(Index) ->
case mnesia:read({pubsub_index, Index}) of
[I] ->
case I#pubsub_index.free of
[] ->
Id = I#pubsub_index.last + 1,
mnesia:write(I#pubsub_index{last = Id}),
Id;
[Id | Free] ->
mnesia:write(I#pubsub_index{free = Free}), Id
end;
_ ->
mnesia:write(#pubsub_index{index = Index, last = 1, free = []}),
1
end.
free(Index, Id) ->
case mnesia:read({pubsub_index, Index}) of
[I] ->
Free = I#pubsub_index.free,
mnesia:write(I#pubsub_index{free = [Id | Free]});
_ ->
ok
end.
|
