%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2010-2017. 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%
%%
-module(receive_SUITE).
%% Tests receive after.
-include_lib("common_test/include/ct.hrl").
-export([all/0, suite/0,
call_with_huge_message_queue/1,receive_in_between/1,
receive_opt_exception/1,receive_opt_recursion/1]).
suite() ->
[{ct_hooks,[ts_install_cth]},
{timetrap, {minutes, 3}}].
all() ->
[call_with_huge_message_queue, receive_in_between,
receive_opt_exception, receive_opt_recursion].
call_with_huge_message_queue(Config) when is_list(Config) ->
Pid = spawn_link(fun echo_loop/0),
_WarmUpTime = time_calls(Pid),
Time = time_calls(Pid),
_ = [self() ! {msg,N} || N <- lists:seq(1, 500000)],
io:format("Time for empty message queue: ~p", [Time]),
erlang:garbage_collect(),
call_with_huge_message_queue_1(Pid, Time, 5).
call_with_huge_message_queue_1(_Pid, _Time, 0) ->
ct:fail(bad_ratio);
call_with_huge_message_queue_1(Pid, Time, NumTries) ->
HugeTime = time_calls(Pid),
io:format("Time for huge message queue: ~p", [HugeTime]),
case (HugeTime+1) / (Time+1) of
Q when Q < 10 ->
ok;
Q ->
io:format("Too high ratio: ~p\n", [Q]),
call_with_huge_message_queue_1(Pid, Time, NumTries-1)
end.
%% Time a number calls. Try to avoid returning a zero time.
time_calls(Pid) ->
time_calls(Pid, 10).
time_calls(_Pid, 0) ->
0;
time_calls(Pid, NumTries) ->
case timer:tc(fun() -> calls(Pid) end) of
{0,ok} ->
time_calls(Pid, NumTries-1);
{Time,ok} ->
Time
end.
calls(Pid) ->
calls(100, Pid).
calls(0, _) -> ok;
calls(N, Pid) ->
{ok,{ultimate_answer,42}} = call(Pid, {ultimate_answer,42}),
calls(N-1, Pid).
call(Pid, Msg) ->
Mref = erlang:monitor(process, Pid),
Pid ! {Mref,{self(),Msg}},
receive
{Mref, Reply} ->
erlang:demonitor(Mref, [flush]),
{ok, Reply};
{'DOWN', Mref, _, _, Reason} ->
exit(Reason)
end.
receive_in_between(Config) when is_list(Config) ->
Pid = spawn_link(fun echo_loop/0),
[{ok,{a,b}} = call2(Pid, {a,b}) || _ <- lists:seq(1, 100000)],
ok.
call2(Pid, Msg) ->
self() ! dummy,
Mref = erlang:monitor(process, Pid),
Pid ! {Mref,{self(),Msg}},
receive_one(),
receive
{Mref,Reply} ->
erlang:demonitor(Mref, [flush]),
{ok,Reply};
{'DOWN',Mref,_,_,Reason} ->
exit(Reason)
end.
receive_one() ->
receive
dummy -> ok
end.
receive_opt_exception(_Config) ->
Recurse = fun() ->
%% Overwrite with the same mark,
%% and never consume it.
ThrowFun = fun() -> throw(aborted) end,
aborted = (catch do_receive_opt_exception(ThrowFun)),
ok
end,
do_receive_opt_exception(Recurse),
%% Eat the second message.
receive
Ref when is_reference(Ref) -> ok
end.
do_receive_opt_exception(Disturber) ->
%% Create a receive mark.
Ref = make_ref(),
self() ! Ref,
Disturber(),
receive
Ref ->
ok
after 0 ->
error(the_expected_message_was_not_there)
end.
receive_opt_recursion(_Config) ->
Recurse = fun() ->
%% Overwrite with the same mark,
%% and never consume it.
NoOp = fun() -> ok end,
BlackHole = spawn(NoOp),
expected = do_receive_opt_recursion(BlackHole, NoOp, true),
ok
end,
do_receive_opt_recursion(self(), Recurse, false),
ok.
do_receive_opt_recursion(Recipient, Disturber, IsInner) ->
Ref = make_ref(),
Recipient ! Ref,
Disturber(),
receive
Ref -> ok
after 0 ->
case IsInner of
true ->
expected;
false ->
error(the_expected_message_was_not_there)
end
end.
%%%
%%% Common helpers.
%%%
echo_loop() ->
receive
{Ref,{Pid,Msg}} ->
Pid ! {Ref,Msg},
echo_loop()
end.
