From 596ce157fd43e9e946f7949bbbb53523ee873410 Mon Sep 17 00:00:00 2001
From: Andrew Mayorov <encube.ul@gmail.com>
Date: Fri, 8 Sep 2023 12:48:31 +0400
Subject: [PATCH] refactor(exproto): make timer names equal to messages they
 send

Because keeping timer names different from the messages they send
complicates understanding of the control flow, and spends few
reductions per timer operation unnecessarily.
---
 .../src/emqx_exproto_channel.erl              | 31 +++++++------------
 1 file changed, 12 insertions(+), 19 deletions(-)

diff --git a/apps/emqx_gateway_exproto/src/emqx_exproto_channel.erl b/apps/emqx_gateway_exproto/src/emqx_exproto_channel.erl
index 80d3282c5..a1d598923 100644
--- a/apps/emqx_gateway_exproto/src/emqx_exproto_channel.erl
+++ b/apps/emqx_gateway_exproto/src/emqx_exproto_channel.erl
@@ -74,12 +74,6 @@
 
 -type replies() :: emqx_types:packet() | reply() | [reply()].
 
--define(TIMER_TABLE, #{
-    alive_timer => keepalive,
-    force_timer => force_close,
-    idle_timer => force_close_idle
-}).
-
 -define(INFO_KEYS, [conninfo, conn_state, clientinfo, session, will_msg]).
 
 %%--------------------------------------------------------------------
@@ -224,7 +218,7 @@ address({Host, Port}) ->
 
 %% avoid udp connection process leak
 start_idle_checking_timer(Channel = #channel{conninfo = #{socktype := udp}}) ->
-    ensure_timer(idle_timer, Channel);
+    ensure_timer(force_close_idle, Channel);
 start_idle_checking_timer(Channel) ->
     Channel.
 
@@ -293,10 +287,10 @@ handle_timeout(
     case emqx_keepalive:check(StatVal, Keepalive) of
         {ok, NKeepalive} ->
             NChannel = Channel#channel{keepalive = NKeepalive},
-            {ok, reset_timer(alive_timer, NChannel)};
+            {ok, reset_timer(keepalive, NChannel)};
         {error, timeout} ->
             Req = #{type => 'KEEPALIVE'},
-            NChannel = remove_timer_ref(alive_timer, Channel),
+            NChannel = remove_timer_ref(keepalive, Channel),
             %% close connection if keepalive timeout
             Replies = [{event, disconnected}, {close, keepalive_timeout}],
             NChannel1 = dispatch(on_timer_timeout, Req, NChannel#channel{
@@ -419,7 +413,7 @@ handle_call(
     NConnInfo = ConnInfo#{keepalive => Interval},
     NClientInfo = ClientInfo#{keepalive => Interval},
     NChannel = Channel#channel{conninfo = NConnInfo, clientinfo = NClientInfo},
-    {reply, ok, [{event, updated}], ensure_keepalive(cancel_timer(idle_timer, NChannel))};
+    {reply, ok, [{event, updated}], ensure_keepalive(cancel_timer(force_close_idle, NChannel))};
 handle_call(
     {subscribe_from_client, TopicFilter, Qos},
     _From,
@@ -529,7 +523,7 @@ handle_info(
                     _ ->
                         Channel
                 end,
-            Channel2 = ensure_timer(force_timer, Channel1),
+            Channel2 = ensure_timer(force_close, Channel1),
             {ok, ensure_disconnected(Reason, Channel2)}
     end;
 handle_info(
@@ -547,13 +541,13 @@ handle_info(
 
     ShutdownNow =
         emqx_exproto_gcli:is_empty(GClient) andalso
-            maps:get(force_timer, Timers, undefined) =/= undefined,
+            maps:get(force_close, Timers, undefined) =/= undefined,
     case Result of
         ok when not ShutdownNow ->
             GClient1 = emqx_exproto_gcli:maybe_shoot(GClient),
             {ok, Channel#channel{gcli = GClient1}};
         ok when ShutdownNow ->
-            Channel1 = cancel_timer(force_timer, Channel),
+            Channel1 = cancel_timer(force_close, Channel),
             {shutdown, Channel1#channel.closed_reason, Channel1};
         {error, Reason} ->
             {shutdown, {error, {FunName, Reason}}, Channel}
@@ -711,7 +705,7 @@ ensure_keepalive_timer(Interval, Channel) when Interval =< 0 ->
 ensure_keepalive_timer(Interval, Channel) ->
     StatVal = emqx_gateway_conn:keepalive_stats(recv),
     Keepalive = emqx_keepalive:init(StatVal, timer:seconds(Interval)),
-    ensure_timer(alive_timer, Channel#channel{keepalive = Keepalive}).
+    ensure_timer(keepalive, Channel#channel{keepalive = Keepalive}).
 
 ensure_timer(Name, Channel = #channel{timers = Timers}) ->
     TRef = maps:get(Name, Timers, undefined),
@@ -723,8 +717,7 @@ ensure_timer(Name, Channel = #channel{timers = Timers}) ->
     end.
 
 ensure_timer(Name, Time, Channel = #channel{timers = Timers}) ->
-    Msg = maps:get(Name, ?TIMER_TABLE),
-    TRef = emqx_utils:start_timer(Time, Msg),
+    TRef = emqx_utils:start_timer(Time, Name),
     Channel#channel{timers = Timers#{Name => TRef}}.
 
 reset_timer(Name, Channel) ->
@@ -737,11 +730,11 @@ cancel_timer(Name, Channel = #channel{timers = Timers}) ->
 remove_timer_ref(Name, Channel = #channel{timers = Timers}) ->
     Channel#channel{timers = maps:remove(Name, Timers)}.
 
-interval(idle_timer, #channel{conninfo = #{idle_timeout := IdleTimeout}}) ->
+interval(force_close_idle, #channel{conninfo = #{idle_timeout := IdleTimeout}}) ->
     IdleTimeout;
-interval(force_timer, _) ->
+interval(force_close, _) ->
     15000;
-interval(alive_timer, #channel{keepalive = Keepalive}) ->
+interval(keepalive, #channel{keepalive = Keepalive}) ->
     emqx_keepalive:info(interval, Keepalive).
 
 %%--------------------------------------------------------------------