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-rw-r--r--lib/stdlib/src/gen_statem.erl86
1 files changed, 31 insertions, 55 deletions
diff --git a/lib/stdlib/src/gen_statem.erl b/lib/stdlib/src/gen_statem.erl
index 6d9a828319..7a23a2a681 100644
--- a/lib/stdlib/src/gen_statem.erl
+++ b/lib/stdlib/src/gen_statem.erl
@@ -1131,16 +1131,14 @@ loop_event_result(
%% Place next events last in reversed queue
Events_2R = lists:reverse(Events_1, NextEventsR),
%% Enqueue immediate timeout events and start event timer
- {TimerRefs_3,TimerTypes_3,Events_3R} =
- process_timeout_events(
- TimerRefs_2, TimerTypes_2, TimeoutEvents, Events_2R),
+ Events_3R = prepend_timeout_events(TimeoutEvents, Events_2R),
S_1 =
S_0#{
state := NextState,
data := NewData,
postponed := P_2,
- timer_refs := TimerRefs_3,
- timer_types := TimerTypes_3,
+ timer_refs := TimerRefs_2,
+ timer_types := TimerTypes_2,
cancel_timers := CancelTimers_2,
hibernate := Hibernate},
case lists:reverse(Events_3R) of
@@ -1361,7 +1359,7 @@ parse_enter_actions(Debug, S, State, Actions, Hibernate, TimeoutsR) ->
parse_actions(Debug, S, State, Actions) ->
Hibernate = false,
- TimeoutsR = [],
+ TimeoutsR = [{timeout,infinity,infinity}], %% Will cancel event timer
Postpone = false,
NextEventsR = [],
parse_actions(
@@ -1413,12 +1411,9 @@ parse_actions(
{error,
{bad_action_from_state_function,Action},
?STACKTRACE()};
- {timeout,infinity,_} ->
- %% Ignore - timeout will never happen and is already cancelled
- parse_actions(
- Debug, S, State, Actions,
- Hibernate, TimeoutsR, Postpone, NextEventsR);
- {timeout,Time,_} = Timeout when is_integer(Time), Time >= 0 ->
+ {timeout,Time,_} = Timeout
+ when is_integer(Time), Time >= 0;
+ Time =:= infinity ->
parse_actions(
Debug, S, State, Actions,
Hibernate, [Timeout|TimeoutsR], Postpone, NextEventsR);
@@ -1426,11 +1421,9 @@ parse_actions(
{error,
{bad_action_from_state_function,Action},
?STACKTRACE()};
- infinity -> % Ignore - timeout will never happen
- parse_actions(
- Debug, S, State, Actions,
- Hibernate, TimeoutsR, Postpone, NextEventsR);
- Time when is_integer(Time), Time >= 0 ->
+ Time
+ when is_integer(Time), Time >= 0;
+ Time =:= infinity ->
Timeout = {timeout,Time,Time},
parse_actions(
Debug, S, State, Actions,
@@ -1493,11 +1486,6 @@ parse_timers(
%% Unseen type - handle
NewSeen = Seen#{TimerType => true},
if
- TimerType =:= timeout ->
- %% Handle event timer later
- parse_timers(
- TimerRefs, TimerTypes, CancelTimers, TimeoutsR,
- NewSeen, [Timeout|TimeoutEvents]);
Time =:= infinity ->
%% Cancel any running timer
{NewTimerTypes,NewCancelTimers} =
@@ -1541,39 +1529,27 @@ parse_timers(
end
end.
-%% Enqueue immediate timeout events and start event timer
-process_timeout_events(TimerRefs, TimerTypes, [], EventsR) ->
- {TimerRefs, TimerTypes, EventsR};
-process_timeout_events(
- TimerRefs, TimerTypes,
- [{timeout,0,TimerMsg}|TimeoutEvents], []) ->
- %% No enqueued events - insert a timeout zero event
- TimeoutEvent = {timeout,TimerMsg},
- process_timeout_events(
- TimerRefs, TimerTypes,
- TimeoutEvents, [TimeoutEvent]);
-process_timeout_events(
- TimerRefs, TimerTypes,
- [{timeout,Time,TimerMsg}], []) ->
- %% No enqueued events - start event timer
- TimerRef = erlang:start_timer(Time, self(), TimerMsg),
- process_timeout_events(
- TimerRefs#{TimerRef => timeout}, TimerTypes#{timeout => TimerRef},
- [], []);
-process_timeout_events(
- TimerRefs, TimerTypes,
- [{timeout,_Time,_TimerMsg}|TimeoutEvents], EventsR) ->
- %% There will be some other event so optimize by not starting
- %% an event timer to just have to cancel it again
- process_timeout_events(
- TimerRefs, TimerTypes,
- TimeoutEvents, EventsR);
-process_timeout_events(
- TimerRefs, TimerTypes,
- [{_TimeoutType,_TimeoutMsg} = TimeoutEvent|TimeoutEvents], EventsR) ->
- process_timeout_events(
- TimerRefs, TimerTypes,
- TimeoutEvents, [TimeoutEvent|EventsR]).
+%% Enqueue immediate timeout events (timeout 0 events)
+%%
+%% Event timer timeout 0 events gets special treatment since
+%% an event timer is cancelled by any received event,
+%% so if there are enqueued events before the event timer
+%% timeout 0 event - the event timer is cancelled hence no event.
+%%
+%% Other (state_timeout) timeout 0 events that are after
+%% the event timer timeout 0 events are considered to
+%% belong to timers that were started after the event timer
+%% timeout 0 event fired, so they do not cancel the event timer.
+%%
+prepend_timeout_events([], EventsR) ->
+ EventsR;
+prepend_timeout_events([{timeout,_} = TimeoutEvent|TimeoutEvents], []) ->
+ prepend_timeout_events(TimeoutEvents, [TimeoutEvent]);
+prepend_timeout_events([{timeout,_}|TimeoutEvents], EventsR) ->
+ prepend_timeout_events(TimeoutEvents, EventsR);
+prepend_timeout_events([TimeoutEvent|TimeoutEvents], EventsR) ->
+ %% Just prepend all others
+ prepend_timeout_events(TimeoutEvents, [TimeoutEvent|EventsR]).