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