87 lines
3.5 KiB
Erlang
87 lines
3.5 KiB
Erlang
%%%-----------------------------------------------------------------------------
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%%% @Copyright (C) 2012-2015, Feng Lee <feng@emqtt.io>
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%%%
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%%% Permission is hereby granted, free of charge, to any person obtaining a copy
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%%% of this software and associated documentation files (the "Software"), to deal
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%%% in the Software without restriction, including without limitation the rights
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%%% to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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%%% copies of the Software, and to permit persons to whom the Software is
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%%% furnished to do so, subject to the following conditions:
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%%%
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%%% The above copyright notice and this permission notice shall be included in all
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%%% copies or substantial portions of the Software.
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%%%
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%%% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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%%% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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%%% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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%%% AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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%%% LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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%%% OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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%%% SOFTWARE.
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%%%-----------------------------------------------------------------------------
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%%% @doc
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%%% emqttd keepalive.
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%%%
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%%% @end
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%%%-----------------------------------------------------------------------------
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-module(emqttd_keepalive).
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-author('feng@emqtt.io').
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-export([new/3, resume/1, cancel/1]).
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-record(keepalive, {transport, socket, recv_oct, timeout_sec, timeout_msg, timer_ref}).
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%%------------------------------------------------------------------------------
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%% @doc
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%% Create a keepalive.
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%%
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%% @end
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%%------------------------------------------------------------------------------
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new({Transport, Socket}, TimeoutSec, TimeoutMsg) when TimeoutSec > 0 ->
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{ok, [{recv_oct, RecvOct}]} = Transport:getstat(Socket, [recv_oct]),
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Ref = erlang:send_after(TimeoutSec*1000, self(), TimeoutMsg),
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#keepalive {transport = Transport,
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socket = Socket,
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recv_oct = RecvOct,
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timeout_sec = TimeoutSec,
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timeout_msg = TimeoutMsg,
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timer_ref = Ref}.
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%%------------------------------------------------------------------------------
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%% @doc
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%% Try to resume keepalive, called when timeout.
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%%
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%% @end
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%%------------------------------------------------------------------------------
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resume(KeepAlive = #keepalive {transport = Transport,
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socket = Socket,
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recv_oct = RecvOct,
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timeout_sec = TimeoutSec,
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timeout_msg = TimeoutMsg,
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timer_ref = Ref }) ->
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{ok, [{recv_oct, NewRecvOct}]} = Transport:getstat(Socket, [recv_oct]),
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if
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NewRecvOct =:= RecvOct ->
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timeout;
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true ->
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%need?
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cancel(Ref),
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NewRef = erlang:send_after(TimeoutSec*1000, self(), TimeoutMsg),
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{resumed, KeepAlive#keepalive{recv_oct = NewRecvOct, timer_ref = NewRef}}
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end.
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%%------------------------------------------------------------------------------
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%% @doc
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%% Cancel Keepalive.
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%%
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%% @end
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%%------------------------------------------------------------------------------
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cancel(#keepalive{timer_ref = Ref}) ->
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cancel(Ref);
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cancel(undefined) ->
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undefined;
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cancel(Ref) ->
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catch erlang:cancel_timer(Ref).
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