aboutsummaryrefslogtreecommitdiffstats
path: root/erts/emulator/test/socket_test_ttest_tcp_client.erl
blob: f28819ca6998a38be99200a3355db6f40e4b0196 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
%%
%% %CopyrightBegin%
%% 
%% Copyright Ericsson AB 2018-2019. All Rights Reserved.
%% 
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%%     http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%% 
%% %CopyrightEnd%
%%

%% ==========================================================================
%%
%% This is the "simple" client using gen_tcp. The client is supposed to be
%% as simple as possible in order to incur as little overhead as possible.
%%
%% There are three ways to run the client: active, passive or active-once.
%%
%% The client is the entity that controls the test, timing and counting.
%%
%% ==========================================================================
%%
%% Before the actual test starts, the client performs a "warmup".
%% The warmup has two functions. First, to ensure that everything is "loaded"
%% and, second, to calculate an approximate roundtrip time, in order to
%% "know" how many iterations we should make (to run for the expected time).
%% This is not intended to be exact, but just to ensure that all tests take
%% approx the same time to run.
%%
%% ==========================================================================

-module(socket_test_ttest_tcp_client).

-export([
         %% These are for the test suite
         start_monitor/5, start_monitor/6, start_monitor/8,

         %% These are for starting in a shell when run "manually"
         start/3, start/4, start/6, start/7,
         stop/1
        ]).

%% Internal exports
-export([
         do_start/9
        ]).

-include_lib("kernel/include/inet.hrl").
-include("socket_test_ttest.hrl").
-include("socket_test_ttest_client.hrl").

-define(RECV_TIMEOUT,              10000).
-define(MAX_OUTSTANDING_DEFAULT_1, 100).
-define(MAX_OUTSTANDING_DEFAULT_2, 10).
-define(MAX_OUTSTANDING_DEFAULT_3, 3).

-define(LIB,            socket_test_ttest_lib).
-define(I(F),           ?LIB:info(F)).
-define(I(F,A),         ?LIB:info(F, A)).
-define(E(F,A),         ?LIB:error(F, A)).
-define(F(F,A),         ?LIB:format(F, A)).
-define(FORMAT_TIME(T), ?LIB:format_time(T)).
-define(T(),            ?LIB:t()).
-define(TDIFF(T1,T2),   ?LIB:tdiff(T1, T2)).

-type active()          :: once | boolean().
-type msg_id()          :: 1..3.
-type max_outstanding() :: pos_integer().
-type runtime()         :: pos_integer().


%% ==========================================================================

start_monitor(Node, Notify, Transport, ServerInfo, Active) ->
    start_monitor(Node, Notify, Transport, ServerInfo, Active, ?MSG_ID_DEFAULT).

start_monitor(Node, Notify, Transport, ServerInfo, Active, 1 = MsgID) ->
    start_monitor(Node, Notify, Transport, ServerInfo, Active, MsgID,
                  ?MAX_OUTSTANDING_DEFAULT_1, ?RUNTIME_DEFAULT);
start_monitor(Node, Notify, Transport, ServerInfo, Active, 2 = MsgID) ->
    start_monitor(Node, Notify, Transport, ServerInfo, Active, MsgID,
                  ?MAX_OUTSTANDING_DEFAULT_2, ?RUNTIME_DEFAULT);
start_monitor(Node, Notify, Transport, ServerInfo, Active, 3 = MsgID) ->
    start_monitor(Node, Notify, Transport, ServerInfo, Active, MsgID,
                  ?MAX_OUTSTANDING_DEFAULT_3, ?RUNTIME_DEFAULT).

start_monitor(Node, Notify, Transport, ServerInfo, Active,
              MsgID, MaxOutstanding, RunTime)
  when (Node =/= node()) ->
    Args = [false,
	    self(), Notify,
            Transport, ServerInfo, Active, MsgID, MaxOutstanding, RunTime],
    case rpc:call(Node, ?MODULE, do_start, Args) of
        {badrpc, _} = Reason ->
            {error, Reason};
        {ok, Pid} when is_pid(Pid) ->
            MRef = erlang:monitor(process, Pid),
            {ok, {Pid, MRef}};
        {error, _} = ERROR ->
            ERROR
    end;
start_monitor(_, Notify, Transport, ServerInfo, Active,
              MsgID, MaxOutstanding, RunTime) ->
    case do_start(false,
		  self(), Notify,
                  Transport, Active, ServerInfo,
                  MsgID, MaxOutstanding, RunTime) of
        {ok, Pid} ->
            MRef = erlang:monitor(process, Pid),
            {ok, {Pid, MRef}};
        {error, _} = ERROR ->
            ERROR
    end.


start(Transport, ServerInfo, Active) ->
    start(Transport, ServerInfo, Active, ?MSG_ID_DEFAULT).

start(Transport, ServerInfo, Active, 1 = MsgID) ->
    start(false,
	  Transport, ServerInfo, Active, MsgID,
          ?MAX_OUTSTANDING_DEFAULT_1, ?RUNTIME_DEFAULT);
start(Transport, ServerInfo, Active, 2 = MsgID) ->
    start(false,
	  Transport, ServerInfo, Active, MsgID,
          ?MAX_OUTSTANDING_DEFAULT_2, ?RUNTIME_DEFAULT);
start(Transport, ServerInfo, Active, 3 = MsgID) ->
    start(false,
	  Transport, ServerInfo, Active, MsgID,
          ?MAX_OUTSTANDING_DEFAULT_3, ?RUNTIME_DEFAULT).

start(Transport, ServerInfo, Active, MsgID, MaxOutstanding, RunTime) ->
    start(false,
	  Transport, ServerInfo, Active, MsgID, MaxOutstanding, RunTime).

start(Quiet, Transport, ServerInfo, Active, MsgID, MaxOutstanding, RunTime) ->
    Notify = fun(R) -> present_results(R) end,
    do_start(Quiet,
	     self(), Notify,
             Transport, ServerInfo, Active, MsgID, MaxOutstanding, RunTime).
                      

-spec do_start(Quiet,
	       Parent,
               Notify,
               Transport,
               ServerInfo,
               Active,
               MsgID,
               MaxOutstanding,
               RunTime) -> {ok, Pid} | {error, Reason} when
      Quiet          :: boolean(),
      Parent         :: pid(),
      Notify         :: function(),
      Transport      :: atom() | tuple(),
      ServerInfo     :: {inet:ip_address(), inet:port_number()} | string(),
      Active         :: active(),
      MsgID          :: msg_id(),
      MaxOutstanding :: max_outstanding(),
      RunTime        :: runtime(),
      Pid            :: pid(),
      Reason         :: term().

do_start(Quiet,
	 Parent, Notify,
         Transport, ServerInfo, Active, MsgID, MaxOutstanding, RunTime)
  when is_boolean(Quiet) andalso
       is_pid(Parent) andalso
       is_function(Notify) andalso
       (is_atom(Transport) orelse is_tuple(Transport)) andalso
       (is_boolean(Active) orelse (Active =:= once)) andalso
       (is_tuple(ServerInfo) orelse is_list(ServerInfo)) andalso 
       (is_integer(MsgID) andalso (MsgID >= 1) andalso (MsgID =< 3)) andalso
       (is_integer(MaxOutstanding) andalso (MaxOutstanding > 0)) andalso
       (is_integer(RunTime) andalso (RunTime > 0)) ->
    Starter = self(),
    Init = fun() -> put(sname, "client"),
                    init(Quiet,
			 Starter, 
                         Parent,
                         Notify,
                         Transport, Active, ServerInfo,
                         MsgID, MaxOutstanding, RunTime)
           end,
    {Pid, MRef} = spawn_monitor(Init),
    receive
        {'DOWN', MRef, process, Pid, Reason} ->
            {error, Reason};
        {?MODULE, Pid, ok} ->
            erlang:demonitor(MRef),
            {ok, Pid};
        {?MODULE, Pid, {error, _} = ERROR} ->
            erlang:demonitor(MRef, [flush]),
            ERROR
    end.


%% We should not normally stop this (it terminates when its done).
stop(Pid) when is_pid(Pid) ->
    req(Pid, stop).


%% ==========================================================================

init(Quiet,
     Starter,
     Parent, Notify,
     Transport, Active, ServerInfo,
     MsgID, MaxOutstanding, RunTime) ->
    if
	not Quiet ->
	    ?I("init with"
	       "~n   Transport:            ~p"
	       "~n   Active:               ~p"
	       "~n   ServerInfo:           ~s"
	       "~n   Msg ID:               ~p (=> 16 + ~w bytes)"
	       "~n   Max Outstanding:      ~p"
	       "~n   (Suggested) Run Time: ~p ms",
	       [Transport, Active,
                case ServerInfo of
                    {Addr, Port} ->
                        ?F("Addr: ~s, Port: ~w", [inet:ntoa(Addr), Port]);
                    Path ->
                        Path
                end,
		MsgID, size(which_msg_data(MsgID)), MaxOutstanding, RunTime]);
	true ->
	    ok
    end,
    {Mod, Connect} = process_transport(Transport),
    case Connect(ServerInfo) of
        {ok, Sock} ->
            if not Quiet -> ?I("connected");
	       true      -> ok
	    end,
            Starter ! {?MODULE, self(), ok},
	    initial_activation(Mod, Sock, Active),
            Results = loop(#{quiet           => Quiet,
			     slogan          => run,
			     runtime         => RunTime,
			     start           => ?T(),
			     parent          => Parent,
			     mod             => Mod,
			     sock            => Sock,
			     active          => Active,
			     msg_data        => which_msg_data(MsgID),
			     outstanding     => 0,
			     max_outstanding => MaxOutstanding,
			     sid             => 1,
			     rid             => 1,
			     scnt            => 0,
			     rcnt            => 0,
			     bcnt            => 0,
			     num             => undefined,
			     acc             => <<>>}),
            Notify(Results),
            (catch Mod:close(Sock)),
            exit(normal);
        {error, Reason} ->
            ?E("connect failed: ~p"
	       "~n   ~p", [Reason, ServerInfo]),
            exit({connect, Reason, ServerInfo})
    end.

process_transport(Mod) when is_atom(Mod) ->
    %% In this case we assume it to be a plain tcp socket
    {Mod, fun({A, P}) -> Mod:connect(A, P) end};
process_transport({Mod, #{domain := Domain} = Opts}) ->
    Connect =
        case Domain of
            local -> fun(Path)   -> Mod:connect(Path, Opts) end;
            _     -> fun({A, P}) -> Mod:connect(A, P, Opts) end
        end,
    {Mod, Connect}.

            
which_msg_data(1) -> ?MSG_DATA1;
which_msg_data(2) -> ?MSG_DATA2;
which_msg_data(3) -> ?MSG_DATA3.


present_results(#{status  := ok,
		  runtime := RunTime,
                  bcnt    := ByteCnt,
                  cnt     := NumIterations}) ->
    ?I("Results: "
       "~n   Run Time:      ~s"
       "~n   ByteCnt:       ~s"
       "~n   NumIterations: ~s", 
       [?FORMAT_TIME(RunTime), 
        if ((ByteCnt =:= 0) orelse (RunTime =:= 0)) ->
                ?F("~w, ~w", [ByteCnt, RunTime]);
          true ->
                ?F("~p => ~p byte / ms", [ByteCnt, ByteCnt div RunTime])
       end,
       if (RunTime =:= 0) ->
               "-";
          true ->
               ?F("~p => ~p iterations / ms",
                  [NumIterations, NumIterations div RunTime])
       end]),
    ok;
present_results(#{status  := Failure,
		  runtime := RunTime,
		  sid     := SID,
		  rid     := RID,
                  scnt    := SCnt,
                  rcnt    := RCnt,
                  bcnt    := BCnt,
		  num     := Num}) ->
    ?I("Time Test failed: "
       "~n   ~p"
       "~n"
       "~nwhen"
       "~n"
       "~n   Run Time:       ~s"
       "~n   Send ID:        ~p"
       "~n   Recv ID:        ~p"
       "~n   Send Count:     ~p"
       "~n   Recv Count:     ~p"
       "~n   Byte Count:     ~p"
       "~n   Num Iterations: ~p",
       [Failure,
        ?FORMAT_TIME(RunTime),
        SID, RID, SCnt, RCnt, BCnt, Num]).



loop(#{runtime := RunTime} = State) ->
    erlang:start_timer(RunTime, self(), stop),
    try do_loop(State)
    catch
        throw:Results ->
            Results
    end.

do_loop(State) ->
    do_loop( handle_message( msg_exchange(State) ) ).

msg_exchange(#{rcnt := Num, num := Num} = State) ->
    finish(ok, State);
msg_exchange(#{scnt := Num, num := Num} = State) ->
    %% We are done sending more requests - now we will just await 
    %% the replies for the (still) outstanding replies.
    msg_exchange( recv_reply(State) );
msg_exchange(#{outstanding     := Outstanding,
               max_outstanding := MaxOutstanding} = State)
  when (Outstanding < MaxOutstanding) ->
    msg_exchange( send_request(State) );
msg_exchange(State) ->
    send_request( recv_reply(State) ).


finish(ok,
       #{start := Start, bcnt  := BCnt, num := Num}) ->
    Stop = ?T(),
    throw(#{status  => ok,
	    runtime => ?TDIFF(Start, Stop),
            bcnt    => BCnt,
            cnt     => Num});
finish(Reason,
       #{start := Start,
	 sid  := SID, rid := RID,
	 scnt := SCnt, rcnt := RCnt, bcnt := BCnt,
	 num  := Num}) ->
    Stop = ?T(),
    throw(#{status  => Reason,
	    runtime => ?TDIFF(Start, Stop),
	    sid     => SID,
	    rid     => RID,
            scnt    => SCnt,
            rcnt    => RCnt,
            bcnt    => BCnt,
            num     => Num}).
    
send_request(#{mod             := Mod,
	       sock            := Sock, 
	       sid             := ID,
	       scnt            := Cnt,
	       outstanding     := Outstanding,
	       max_outstanding := MaxOutstanding,
	       msg_data        := Data} = State)
  when (MaxOutstanding > Outstanding) ->
    SZ   = size(Data),
    Req  = <<?TTEST_TAG:32,
	     ?TTEST_TYPE_REQUEST:32,
	     ID:32,
	     SZ:32,
	     Data/binary>>,
    case Mod:send(Sock, Req) of
        ok ->
            State#{sid         => next_id(ID),
		   scnt        => Cnt + 1,
		   outstanding => Outstanding + 1};
        {error, Reason} ->
            ?E("Failed sending request: ~p", [Reason]),
            exit({send, Reason})
    end;
send_request(State) ->
    State.



recv_reply(#{mod         := Mod,
	     sock        := Sock, 
             rid         := ID,
             active      := false,
             bcnt        := BCnt,
             rcnt        := Cnt,
	     outstanding := Outstanding} = State) ->
    case recv_reply_message1(Mod, Sock, ID) of
	{ok, MsgSz} ->
	    State#{rid         => next_id(ID),
		   bcnt        => BCnt + MsgSz,
		   rcnt        => Cnt + 1,
		   outstanding => Outstanding - 1};

	{error, timeout} ->
	    ?I("receive timeout"),
	    State;

	{error, Reason} ->
	    finish(Reason, State)
    end;
recv_reply(#{mod         := Mod,
	     sock        := Sock,
             rid         := ID,
             active      := Active,
             bcnt        := BCnt,
             scnt        := SCnt,
             rcnt        := RCnt,
	     outstanding := Outstanding,
	     acc         := Acc} = State) ->
    case recv_reply_message2(Mod, Sock, ID, Acc) of
	{ok, {MsgSz, NewAcc}} when is_integer(MsgSz) andalso is_binary(NewAcc) ->
	    maybe_activate(Mod, Sock, Active),
	    State#{rid         => next_id(ID),
		   bcnt        => BCnt + MsgSz,
		   rcnt        => RCnt + 1,
		   outstanding => Outstanding - 1,
		   acc         => NewAcc};

	ok ->
	    State;

	{error, stop} ->
	    ?I("receive [~w] -> stop", [Active]),
	    %% This will have the effect that no more requests are sent...
	    State#{num => SCnt, stop_started => ?T()};

	{error, timeout} ->
	    ?I("receive[~w] -> timeout", [Active]),
	    State;

	{error, Reason} ->
	    finish(Reason, State)
    end.


%% This function reads exactly one (reply) message. No more no less.	
recv_reply_message1(Mod, Sock, ID) ->
    case Mod:recv(Sock, 4*4, ?RECV_TIMEOUT) of
        {ok, <<?TTEST_TAG:32,
               ?TTEST_TYPE_REPLY:32,
               ID:32,
               SZ:32>> = Hdr} ->
            %% Receive the ping-pong reply boby
            case Mod:recv(Sock, SZ, ?RECV_TIMEOUT) of
                {ok, Data} when (size(Data) =:= SZ) ->
		    {ok, size(Hdr) + size(Data)};
                {error, Reason2} ->
		    ?E("Failed reading body: "
                       "~n   ~p: ~p", [Reason2]),
                    {error, {recv_body, Reason2}}
            end;

        {ok, <<BadTag:32,
               BadType:32,
               BadID:32,
               BadSZ:32>>} ->
            {error, {invalid_hdr, 
		     {?TTEST_TAG,        BadTag},
		     {?TTEST_TYPE_REPLY, BadType},
		     {ID,                BadID},
		     BadSZ}};
        {ok, _InvHdr} ->
            {error, invalid_hdr};

        {error, Reason1} ->
	    ?E("Feiled reading header: "
	      "~n   ~p", [Reason1]),
            {error, {recv_hdr, Reason1}}
    end.


%% This function first attempts to process the data we have already
%% accumulated. If that is not enough for a (complete) reply, it
%% will attempt to receive more.
recv_reply_message2(Mod, Sock, ID, Acc) ->
    case process_acc_data(ID, Acc) of
	ok ->
	    %% No or insufficient data, so get more
	    recv_reply_message3(Mod, Sock, ID, Acc);

	{ok, _} = OK -> % We already had a reply accumulated - no need to read more
	    OK;

	{error, _} = ERROR ->
	    ERROR
    end.

%% This function receives a "chunk" of data, then it tries to extract
%% one (reply) message from the accumulated and new data (combined).
recv_reply_message3(_Mod, Sock, ID, Acc) ->
    receive
	{timeout, _TRef, stop} ->
	    {error, stop};

        {TagClosed, Sock} when (TagClosed =:= tcp_closed) orelse
			       (TagClosed =:= socket_closed) ->
            {error, closed};

        {TagErr, Sock, Reason} when (TagErr =:= tcp_error) orelse
				    (TagErr =:= socket_error) ->
            {error, Reason};

        {Tag, Sock, Msg} when (Tag =:= tcp) orelse
			      (Tag =:= socket) ->
            process_acc_data(ID, <<Acc/binary, Msg/binary>>)
        
    after ?RECV_TIMEOUT ->
            ?I("timeout when"
               "~n   ID:        ~p"
               "~n   size(Acc): ~p",
               [ID, size(Acc)]),
            %% {error, timeout}
            recv_reply_message3(_Mod, Sock, ID, Acc)
    end.


process_acc_data(ID, <<?TTEST_TAG:32,
		       ?TTEST_TYPE_REPLY:32,
		       ID:32,
		       SZ:32,
		       Data/binary>>) when (SZ =< size(Data)) ->
    <<_Body:SZ/binary, Rest/binary>> = Data,
    {ok, {4*4+SZ, Rest}};
process_acc_data(ID, <<BadTag:32,
		       BadType:32,
		       BadID:32,
		       BadSZ:32,
		       _Data/binary>>) 
  when ((BadTag  =/= ?TTEST_TAG) orelse
	(BadType =/= ?TTEST_TYPE_REPLY) orelse
	(BadID   =/= ID)) ->
    {error, {invalid_hdr, 
	     {?TTEST_TAG,        BadTag},
	     {?TTEST_TYPE_REPLY, BadType},
	     {ID,                BadID},
	     BadSZ}};
%% Not enough for an entire (reply) message
process_acc_data(_ID, _Data) ->
    ok.

    
handle_message(#{quiet  := Quiet,
		 parent := Parent, sock := Sock, scnt := SCnt} = State) ->
    receive
	{timeout, _TRef, stop} ->
	    if not Quiet -> ?I("STOP");
	       true      -> ok
	    end,
	    %% This will have the effect that no more requests are sent...
	    State#{num => SCnt, stop_started => ?T()};

        {?MODULE, Ref, Parent, stop} ->
            %% This *aborts* the test
            reply(Parent, Ref, ok),
            exit(normal);
	
	%% Only when active
        {TagClosed, Sock, Reason} when (TagClosed =:= tcp_closed) orelse
				       (TagClosed =:= socket_closed) ->
            %% We should never get this (unless the server crashed)
            exit({closed, Reason});

	%% Only when active
        {TagErr, Sock, Reason} when (TagErr =:= tcp_error) orelse
				    (TagErr =:= socket_error) ->
            exit({error, Reason})
            
    after 0 ->
            State
    end.
        

initial_activation(_Mod, _Sock, false = _Active) ->
    ok;
initial_activation(Mod, Sock, Active) ->
    Mod:active(Sock, Active).


maybe_activate(Mod, Sock, once = Active) ->
    Mod:active(Sock, Active);
maybe_activate(_, _, _) ->
    ok.
                  

%% ==========================================================================

req(Pid, Req) ->
    Ref = make_ref(),
    Pid ! {?MODULE, Ref, Pid, Req},
    receive
        {'EXIT', Pid, Reason} ->
            {error, {exit, Reason}};
        {?MODULE, Ref, Reply} ->
            Reply
    end.

reply(Pid, Ref, Reply) ->
    Pid ! {?MODULE, Ref, Reply}.


%% ==========================================================================

next_id(ID) when (ID < ?MAX_ID) ->
    ID + 1;
next_id(_) ->
    1.


%% ==========================================================================

%% t() ->
%%     os:timestamp().

%% tdiff({A1, B1, C1} = _T1x, {A2, B2, C2} = _T2x) ->
%%     T1 = A1*1000000000+B1*1000+(C1 div 1000), 
%%     T2 = A2*1000000000+B2*1000+(C2 div 1000), 
%%     T2 - T1.

%% formated_timestamp() ->
%%     format_timestamp(os:timestamp()).

%% format_timestamp({_N1, _N2, N3} = TS) ->
%%     {_Date, Time}  = calendar:now_to_local_time(TS),
%%     {Hour,Min,Sec} = Time,
%%     FormatTS = io_lib:format("~.2.0w:~.2.0w:~.2.0w.4~w",
%%                              [Hour, Min, Sec, round(N3/1000)]),  
%%     lists:flatten(FormatTS).

%% %% Time is always in number os ms (milli seconds)
%% format_time(T) ->
%%     f("~p", [T]).


%% ==========================================================================

%% f(F, A) ->
%%     lists:flatten(io_lib:format(F, A)).

%% %% e(F) ->
%% %%     i("<ERROR> " ++ F).

%% e(F, A) ->
%%     p(get(sname), "<ERROR> " ++ F, A).

%% i(F) ->
%%     i(F, []).

%% i(F, A) ->
%%     p(get(sname), "<INFO> " ++ F, A).

%% p(undefined, F, A) ->
%%     p("- ", F, A);
%% p(Prefix, F, A) ->
%%     io:format("[~s, ~s] " ++ F ++ "~n", [formated_timestamp(), Prefix |A]).