65 lines
2.1 KiB
Erlang
65 lines
2.1 KiB
Erlang
%%%----------------------------------------------------------------------
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%%% File : pubsub_index.erl
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%%% Author : Christophe Romain <christophe.romain@process-one.net>
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%%% Purpose : Provide uniq integer index for pubsub node
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%%% Created : 30 Apr 2009 by Christophe Romain <christophe.romain@process-one.net>
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%%%
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%%%
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%%% ejabberd, Copyright (C) 2002-2020 ProcessOne
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%%%
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%%% This program is free software; you can redistribute it and/or
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%%% modify it under the terms of the GNU General Public License as
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%%% published by the Free Software Foundation; either version 2 of the
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%%% License, or (at your option) any later version.
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%%%
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%%% This program is distributed in the hope that it will be useful,
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%%% but WITHOUT ANY WARRANTY; without even the implied warranty of
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%%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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%%% General Public License for more details.
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%%%
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%%% You should have received a copy of the GNU General Public License along
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%%% with this program; if not, write to the Free Software Foundation, Inc.,
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%%% 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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%%%
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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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ejabberd_mnesia:create(?MODULE, 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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