Use rabbit_ws_handler as a regular module, not a parameterized one

Parameterized modules are removed in Erlang 21. There is a new compiler
option to emulate parameterized modules, but it's easy enough to change
the plugin to use regular module calling convention.

[#157964874]

deps/rabbitmq_web_stomp/src/rabbit_ws_client.erl

@@ -54,12 +54,12 @@ init({SupPid, Conn, Heartbeat}) ->
                   heartbeat_mode = Heartbeat},
            #state.stats_timer)}.
 
-init_processor_state(Conn) ->
+init_processor_state({ConnMod, ConnProps}) ->
     SendFun = fun (_Sync, Data) ->
-                      Conn:send(Data),
+                      ConnMod:send(ConnProps, Data),
                       ok
               end,
-    Info = Conn:info(),
+    Info = ConnMod:info(ConnProps),
     Headers = proplists:get_value(headers, Info),
 
     UseHTTPAuth = application:get_env(rabbitmq_web_stomp, use_http_auth, false),
@@ -166,13 +166,13 @@ handle_info({start_heartbeats, _},
 handle_info({start_heartbeats, {0, 0}}, State) ->
     {noreply, State};
 handle_info({start_heartbeats, {SendTimeout, ReceiveTimeout}},
-            State = #state{conn = Conn,
+            State = #state{conn = {ConnMod, ConnProps},
                            heartbeat_sup = SupPid,
                            heartbeat_mode = heartbeat}) ->
-    Info = Conn:info(),
+    Info = ConnMod:info(ConnProps),
     Sock = proplists:get_value(socket, Info),
     Pid = self(),
-    SendFun = fun () -> Conn:send(<<$\n>>), ok end,
+    SendFun = fun () -> ConnMod:send(ConnProps, <<$\n>>), ok end,
     ReceiveFun = fun() -> gen_server2:cast(Pid, client_timeout) end,
     Heartbeat = rabbit_heartbeat:start(SupPid, Sock, SendTimeout,
                                        SendFun, ReceiveTimeout, ReceiveFun),
@@ -202,11 +202,12 @@ handle_info(Info, State) ->
 handle_call(Request, _From, State) ->
     {stop, {odd_request, Request}, State}.
 
-terminate(_Reason, State = #state{conn = Conn, proc_state = ProcessorState}) ->
+terminate(_Reason, State = #state{conn = {ConnMod, ConnProps},
+                                  proc_state = ProcessorState}) ->
     maybe_emit_stats(State),
     ok = file_handle_cache:release(),
     rabbit_stomp_processor:flush_and_die(ProcessorState),
-    Conn:close(1000, "STOMP died"),
+    ConnMod:close(ConnProps, 1000, "STOMP died"),
     ok.
 
 code_change(_OldVsn, State, _Extra) ->
@@ -248,8 +249,8 @@ emit_stats(State=#state{connection = C}) when C == none; C == undefined ->
     %% established, as this causes orphan entries on the stats database
     State1 = rabbit_event:reset_stats_timer(State, #state.stats_timer),
     State1;
-emit_stats(State=#state{conn=Conn, connection=ConnPid}) ->
-    Info = Conn:info(),
+emit_stats(State=#state{conn={ConnMod, ConnProps}, connection=ConnPid}) ->
+    Info = ConnMod:info(ConnProps),
     Sock = proplists:get_value(socket, Info),
     SockInfos = case rabbit_net:getstat(Sock,
             [recv_oct, recv_cnt, send_oct, send_cnt, send_pend]) of

deps/rabbitmq_web_stomp/src/rabbit_ws_handler.erl

@@ -55,12 +55,14 @@ init(Req0, Opts) ->
     {cowboy_websocket, Req, {Socket, Peername, Sockname, Headers, FrameType}}.
 
 websocket_init({Socket, Peername, Sockname, Headers, FrameType}) ->
-    Conn = {?MODULE, self(), [
-        {socket, Socket},
+    Info = [{socket, Socket},
             {peername, Peername},
             {sockname, Sockname},
-        {headers, Headers}]},
-    {ok, _Sup, Pid} = rabbit_ws_sup:start_client({Conn, heartbeat}),
+            {headers, Headers}],
+    {ok, _Sup, Pid} = rabbit_ws_sup:start_client({{?MODULE,
+                                                   #{pid  => self(),
+                                                     info => Info}},
+                                                  heartbeat}),
     {ok, #state{pid=Pid, type=FrameType}}.
 
 websocket_handle({text, Data}, State=#state{pid=Pid}) ->
@@ -109,13 +111,13 @@ filter_stomp_protocols(Protocols) ->
 %% within the Websocket process. This could be a good refactoring
 %% once SockJS gets removed.
 
-info({?MODULE, _, Info}) ->
+info(#{info := Info}) ->
     Info.
 
-send(Data, {?MODULE, Pid, _}) ->
+send(#{pid := Pid}, Data) ->
     Pid ! {send, Data},
     ok.
 
-close(Code, Reason, {?MODULE, Pid, _}) ->
+close(#{pid := Pid}, Code, Reason) ->
     Pid ! {close, Code, Reason},
     ok.