72 lines
2.7 KiB
Erlang
72 lines
2.7 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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-module(emqtt_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, {socket, recv_oct, timeout_sec, timeout_msg, timer_ref}).
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%%
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%% @doc create a keepalive.
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%%
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new(Socket, TimeoutSec, TimeoutMsg) when TimeoutSec > 0 ->
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{ok, [{recv_oct, RecvOct}]} = inet:getstat(Socket, [recv_oct]),
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Ref = erlang:send_after(TimeoutSec*1000, self(), TimeoutMsg),
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#keepalive { 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 try to resume keepalive, called when timeout.
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%%
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resume(KeepAlive = #keepalive { 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}]} = inet: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 cancel keepalive
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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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