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-rw-r--r--lib/stdlib/src/gen_statem.erl309
1 files changed, 176 insertions, 133 deletions
diff --git a/lib/stdlib/src/gen_statem.erl b/lib/stdlib/src/gen_statem.erl
index f9e2e5f7d2..36476b56ae 100644
--- a/lib/stdlib/src/gen_statem.erl
+++ b/lib/stdlib/src/gen_statem.erl
@@ -97,7 +97,7 @@
%% * Postponing the current event is performed
%% iff 'postpone' is 'true'.
%% * A state timer is started iff 'timeout' is set.
- %% * Pending events are processed or if there are
+ %% * Pending events are handled or if there are
%% no pending events the server goes into receive
%% or hibernate (iff 'hibernate' is 'true')
%%
@@ -523,12 +523,15 @@ send(Proc, Msg) ->
ok
end.
-%% Here init_it/6 and enter_loop/5,6,7 functions converge
+%% Here the init_it/6 and enter_loop/5,6,7 functions converge
enter(Module, Opts, CallbackMode, State, Data, Server, Actions, Parent) ->
%% The values should already have been type checked
Name = gen:get_proc_name(Server),
Debug = gen:debug_options(Name, Opts),
- PrevState = make_ref(), % Will be discarded by loop_event_actions/9
+ P = Events = [],
+ Event = {internal,initial_state},
+ %% We enforce {postpone,false} to ensure that
+ %% our fake Event gets discarded, thought it might get logged
NewActions =
if
is_list(Actions) ->
@@ -540,15 +543,17 @@ enter(Module, Opts, CallbackMode, State, Data, Server, Actions, Parent) ->
callback_mode => CallbackMode,
module => Module,
name => Name,
- state => PrevState,
+ %% All fields below will be replaced according to the arguments to
+ %% loop_event_actions/10 when it finally loops back to loop/3
+ state => State,
data => Data,
- timer => undefined,
- postponed => [],
- hibernate => false},
+ postponed => P,
+ hibernate => false,
+ timer => undefined},
+ NewDebug = sys_debug(Debug, S, {enter,Event,State}),
loop_event_actions(
- Parent, Debug, S, [],
- {event,undefined}, % Will be discarded thanks to {postpone,false}
- PrevState, State, Data, NewActions).
+ Parent, NewDebug, S, Events,
+ State, Data, P, Event, State, NewActions).
%%%==========================================================================
%%% gen callbacks
@@ -681,13 +686,13 @@ print_event(Dev, {out,Reply,{To,_Tag}}, #{name := Name}) ->
io:format(
Dev, "*DBG* ~p sent ~p to ~p~n",
[Name,Reply,To]);
-print_event(Dev, {Tag,Event,NewState}, #{name := Name, state := State}) ->
+print_event(Dev, {Tag,Event,NextState}, #{name := Name, state := State}) ->
StateString =
- case NewState of
+ case NextState of
State ->
io_lib:format("~p", [State]);
_ ->
- io_lib:format("~p => ~p", [State,NewState])
+ io_lib:format("~p => ~p", [State,NextState])
end,
io:format(
Dev, "*DBG* ~p ~w ~s in state ~s~n",
@@ -697,8 +702,8 @@ event_string(Event) ->
case Event of
{{call,{Pid,_Tag}},Request} ->
io_lib:format("call ~p from ~w", [Request,Pid]);
- {Tag,Content} ->
- io_lib:format("~w ~p", [Tag,Content])
+ {EventType,EventContent} ->
+ io_lib:format("~w ~p", [EventType,EventContent])
end.
sys_debug(Debug, S, Entry) ->
@@ -754,7 +759,8 @@ loop_receive(Parent, Debug, #{timer := Timer} = S) ->
%% but this will stand out in the crash report...
?TERMINATE(exit, Reason, Debug, S, [EXIT]);
{timeout,Timer,Content} when Timer =/= undefined ->
- loop_event(Parent, Debug, S, {timeout,Content});
+ loop_receive_result(
+ Parent, Debug, S, {timeout,Content});
_ ->
%% Cancel Timer if running
case Timer of
@@ -782,30 +788,81 @@ loop_receive(Parent, Debug, #{timer := Timer} = S) ->
_ ->
{info,Msg}
end,
- loop_event(Parent, Debug, S, Event)
+ loop_receive_result(Parent, Debug, S, Event)
end
end.
-loop_event(Parent, Debug, S, Event) ->
- %% The timer field and the hibernate flag in S
- %% are now invalid and ignored until we get back to loop/3
+loop_receive_result(
+ Parent, Debug,
+ #{state := State,
+ data := Data,
+ postponed := P} = S,
+ Event) ->
+ %% The S map is now dismantled and will not be restored
+ %% until we return to loop/3 or have to terminate.
+ %%
+ %% The fields 'callback_mode', 'module', and 'name' are still valid.
+ %% The fields 'state', 'data', and 'postponed' are held in arguments.
+ %% The fields 'timer' and 'hibernate' will be recalculated.
+ %%
NewDebug = sys_debug(Debug, S, {in,Event}),
- %% Here the queue of not yet processed events is created
- loop_events(Parent, NewDebug, S, [Event], false).
+ %% Here the queue of not yet handled events is created
+ Events = [],
+ Hibernate = false,
+ loop_event(
+ Parent, NewDebug, S, Events, State, Data, P, Event, Hibernate).
-%% Process first the event queue, or if it is empty
-%% loop back to receive a new event
-loop_events(Parent, Debug, S, [], _Hibernate) ->
- loop(Parent, Debug, S);
+%% Process the event queue, or if it is empty
+%% loop back to loop/3 to receive a new event
+loop_events(
+ Parent, Debug, S, [Event|Events],
+ State, Data, P, Hibernate, _Timeout) ->
+ %%
+ %% If there was a state timer requested we just ignore that
+ %% since we have events to handle which cancels the timer
+ loop_event(
+ Parent, Debug, S, Events, State, Data, P, Event, Hibernate);
loop_events(
+ Parent, Debug, S, [],
+ State, Data, P, Hibernate, Timeout) ->
+ case Timeout of
+ {timeout,0,EventContent} ->
+ %% Immediate timeout - simulate it
+ %% so we do not get the timeout message
+ %% after any received event
+ loop_event(
+ Parent, Debug, S, [],
+ State, Data, P, {timeout,EventContent}, Hibernate);
+ {timeout,Time,EventContent} ->
+ %% Actually start a timer
+ Timer = erlang:start_timer(Time, self(), EventContent),
+ loop_events_done(
+ Parent, Debug, S, Timer, State, Data, P, Hibernate);
+ undefined ->
+ %% No state timeout has been requested
+ Timer = undefined,
+ loop_events_done(
+ Parent, Debug, S, Timer, State, Data, P, Hibernate)
+ end.
+%%
+loop_events_done(Parent, Debug, S, Timer, State, Data, P, Hibernate) ->
+ NewS =
+ S#{
+ state := State,
+ data := Data,
+ postponed := P,
+ hibernate := Hibernate,
+ timer := Timer},
+ loop(Parent, Debug, NewS).
+
+loop_event(
Parent, Debug,
#{callback_mode := CallbackMode,
- module := Module,
- state := State,
- data := Data} = S,
- [{Type,Content} = Event|Events] = Q,
- Hibernate) ->
- %% If the Hibernate flag is true here it can only be
+ module := Module} = S,
+ Events,
+ State, Data, P, {Type,Content} = Event, Hibernate) ->
+ %%
+ %% If Hibernate is true here it can only be
%% because it was set from an event action
%% and we did not go into hibernation since there
%% were events in queue, so we do what the user
@@ -813,6 +870,7 @@ loop_events(
%% would have happened if we actually hibernated
%% and immediately was awakened
Hibernate andalso garbage_collect(),
+ %%
try
case CallbackMode of
state_functions ->
@@ -822,11 +880,11 @@ loop_events(
end of
Result ->
loop_event_result(
- Parent, Debug, S, Events, Event, Result)
+ Parent, Debug, S, Events, State, Data, P, Event, Result)
catch
Result ->
loop_event_result(
- Parent, Debug, S, Events, Event, Result);
+ Parent, Debug, S, Events, State, Data, P, Event, Result);
error:badarg when CallbackMode =:= state_functions ->
case erlang:get_stacktrace() of
[{erlang,apply,[Module,State,_],_}|Stacktrace] ->
@@ -835,9 +893,9 @@ loop_events(
error,
{undef_state_function,{Module,State,Args}},
Stacktrace,
- Debug, S, Q);
+ Debug, S, [Event|Events]);
Stacktrace ->
- terminate(error, badarg, Stacktrace, Debug, S, Q)
+ terminate(error, badarg, Stacktrace, Debug, S, [Event|Events])
end;
error:undef ->
%% Process an undef to check for the simple mistake
@@ -852,7 +910,7 @@ loop_events(
error,
{undef_state_function,{Module,State,Args}},
Stacktrace,
- Debug, S, Q);
+ Debug, S, [Event|Events]);
[{Module,handle_event,
[Type,Content,State,Data]=Args,
_}
@@ -863,40 +921,42 @@ loop_events(
{undef_state_function,
{Module,handle_event,Args}},
Stacktrace,
- Debug, S, Q);
+ Debug, S, [Event|Events]);
Stacktrace ->
- terminate(error, undef, Stacktrace, Debug, S, Q)
+ terminate(
+ error, undef, Stacktrace, Debug, S, [Event|Events])
end;
Class:Reason ->
Stacktrace = erlang:get_stacktrace(),
- terminate(Class, Reason, Stacktrace, Debug, S, Q)
+ terminate(Class, Reason, Stacktrace, Debug, S, [Event|Events])
end.
%% Interpret all callback return variants
loop_event_result(
- Parent, Debug,
- #{state := State, data := Data} = S,
- Events, Event, Result) ->
- %% From now until we loop back to the loop_events/4
- %% the state and data fields in S are old
+ Parent, Debug, S, Events, State, Data, P, Event, Result) ->
case Result of
stop ->
- ?TERMINATE(exit, normal, Debug, S, [Event|Events]);
+ NewS = S#{state := State, data := Data, postponed := P},
+ Q = [Event|Events],
+ ?TERMINATE(exit, normal, Debug, NewS, Q);
{stop,Reason} ->
- ?TERMINATE(exit, Reason, Debug, S, [Event|Events]);
+ NewS = S#{state := State, data := Data, postponed := P},
+ Q = [Event|Events],
+ ?TERMINATE(exit, Reason, Debug, NewS, Q);
{stop,Reason,NewData} ->
- NewS = S#{data := NewData},
+ NewS = S#{state := State, data := NewData, postponed := P},
Q = [Event|Events],
?TERMINATE(exit, Reason, Debug, NewS, Q);
{stop_and_reply,Reason,Replies} ->
+ NewS = S#{state := State, data := Data, postponed := P},
Q = [Event|Events],
[Class,NewReason,Stacktrace,NewDebug] =
reply_then_terminate(
- exit, Reason, ?STACKTRACE(), Debug, S, Q, Replies),
+ exit, Reason, ?STACKTRACE(), Debug, NewS, Q, Replies),
%% Since we got back here Replies was bad
- terminate(Class, NewReason, Stacktrace, NewDebug, S, Q);
+ terminate(Class, NewReason, Stacktrace, NewDebug, NewS, Q);
{stop_and_reply,Reason,Replies,NewData} ->
- NewS = S#{data := NewData},
+ NewS = S#{state := State, data := NewData, postponed := P},
Q = [Event|Events],
[Class,NewReason,Stacktrace,NewDebug] =
reply_then_terminate(
@@ -905,41 +965,43 @@ loop_event_result(
terminate(Class, NewReason, Stacktrace, NewDebug, NewS, Q);
{next_state,NextState,NewData} ->
loop_event_actions(
- Parent, Debug, S, Events, Event,
- State, NextState, NewData, []);
+ Parent, Debug, S, Events,
+ State, NewData, P, Event, NextState, []);
{next_state,NextState,NewData,Actions} ->
loop_event_actions(
- Parent, Debug, S, Events, Event,
- State, NextState, NewData, Actions);
+ Parent, Debug, S, Events,
+ State, NewData, P, Event, NextState, Actions);
{keep_state,NewData} ->
loop_event_actions(
- Parent, Debug, S, Events, Event,
- State, State, NewData, []);
+ Parent, Debug, S, Events,
+ State, NewData, P, Event, State, []);
{keep_state,NewData,Actions} ->
loop_event_actions(
- Parent, Debug, S, Events, Event,
- State, State, NewData, Actions);
+ Parent, Debug, S, Events,
+ State, NewData, P, Event, State, Actions);
keep_state_and_data ->
loop_event_actions(
- Parent, Debug, S, Events, Event,
- State, State, Data, []);
+ Parent, Debug, S, Events,
+ State, Data, P, Event, State, []);
{keep_state_and_data,Actions} ->
loop_event_actions(
- Parent, Debug, S, Events, Event,
- State, State, Data, Actions);
+ Parent, Debug, S, Events,
+ State, Data, P, Event, State, Actions);
_ ->
+ NewS = S#{state := State, data := Data, postponed := P},
+ Q = [Event|Events],
?TERMINATE(
- error, {bad_return_value,Result}, Debug, S, [Event|Events])
+ error, {bad_return_value,Result}, Debug, NewS, Q)
end.
loop_event_actions(
- Parent, Debug, S, Events, Event, State, NextState, NewData, Actions) ->
- Postpone = false, % Shall we postpone this event, true or false
+ Parent, Debug, S, Events, State, NewData, P, Event, NextState, Actions) ->
+ Postpone = false, % Shall we postpone this event; boolean()
Hibernate = false,
Timeout = undefined,
NextEvents = [],
loop_event_actions(
- Parent, Debug, S, Events, Event, State, NextState, NewData,
+ Parent, Debug, S, Events, State, NewData, P, Event, NextState,
if
is_list(Actions) ->
Actions;
@@ -948,10 +1010,10 @@ loop_event_actions(
end,
Postpone, Hibernate, Timeout, NextEvents).
%%
-%% Process all action()s
+%% Process all actions
loop_event_actions(
- Parent, Debug, S, Events, Event,
- State, NextState, NewData, [Action|Actions],
+ Parent, Debug, S, Events,
+ State, NewData, P, Event, NextState, [Action|Actions],
Postpone, Hibernate, Timeout, NextEvents) ->
case Action of
%% Actual actions
@@ -960,85 +1022,99 @@ loop_event_actions(
true ->
NewDebug = do_reply(Debug, S, From, Reply),
loop_event_actions(
- Parent, NewDebug, S, Events, Event,
- State, NextState, NewData, Actions,
+ Parent, NewDebug, S, Events,
+ State, NewData, P, Event, NextState, Actions,
Postpone, Hibernate, Timeout, NextEvents);
false ->
+ NewS =
+ S#{state := State, data := NewData, postponed := P},
+ Q = [Event|Events],
?TERMINATE(
- error, {bad_action,Action}, Debug, S, [Event|Events])
+ error, {bad_action,Action}, Debug, NewS, Q)
end;
{next_event,Type,Content} ->
case event_type(Type) of
true ->
loop_event_actions(
- Parent, Debug, S, Events, Event,
- State, NextState, NewData, Actions,
+ Parent, Debug, S, Events,
+ State, NewData, P, Event, NextState, Actions,
Postpone, Hibernate, Timeout,
[{Type,Content}|NextEvents]);
false ->
+ NewS =
+ S#{state := State, data := NewData, postponed := P},
+ Q = [Event|Events],
?TERMINATE(
- error, {bad_action,Action}, Debug, S, [Event|Events])
+ error, {bad_action,Action}, Debug, NewS, Q)
end;
%% Actions that set options
{postpone,NewPostpone} when is_boolean(NewPostpone) ->
loop_event_actions(
- Parent, Debug, S, Events, Event,
- State, NextState, NewData, Actions,
+ Parent, Debug, S, Events,
+ State, NewData, P, Event, NextState, Actions,
NewPostpone, Hibernate, Timeout, NextEvents);
{postpone,_} ->
+ NewS = S#{state := State, data := NewData, postponed := P},
+ Q = [Event|Events],
?TERMINATE(
- error, {bad_action,Action}, Debug, S, [Event|Events]);
+ error, {bad_action,Action}, Debug, NewS, Q);
postpone ->
loop_event_actions(
- Parent, Debug, S, Events, Event,
- State, NextState, NewData, Actions,
+ Parent, Debug, S, Events,
+ State, NewData, P, Event, NextState, Actions,
true, Hibernate, Timeout, NextEvents);
{hibernate,NewHibernate} when is_boolean(NewHibernate) ->
loop_event_actions(
- Parent, Debug, S, Events, Event,
- State, NextState, NewData, Actions,
+ Parent, Debug, S, Events,
+ State, NewData, P, Event, NextState, Actions,
Postpone, NewHibernate, Timeout, NextEvents);
{hibernate,_} ->
+ NewS = S#{state := State, data := NewData, postponed := P},
+ Q = [Event|Events],
?TERMINATE(
- error, {bad_action,Action}, Debug, S, [Event|Events]);
+ error, {bad_action,Action}, Debug, NewS, Q);
hibernate ->
loop_event_actions(
- Parent, Debug, S, Events, Event,
- State, NextState, NewData, Actions,
+ Parent, Debug, S, Events,
+ State, NewData, P, Event, NextState, Actions,
Postpone, true, Timeout, NextEvents);
{timeout,infinity,_} -> % Clear timer - it will never trigger
loop_event_actions(
- Parent, Debug, S, Events, Event,
- State, NextState, NewData, Actions,
+ Parent, Debug, S, Events,
+ State, NewData, P, Event, NextState, Actions,
Postpone, Hibernate, undefined, NextEvents);
{timeout,Time,_} = NewTimeout when is_integer(Time), Time >= 0 ->
loop_event_actions(
- Parent, Debug, S, Events, Event,
- State, NextState, NewData, Actions,
+ Parent, Debug, S, Events,
+ State, NewData, P, Event, NextState, Actions,
Postpone, Hibernate, NewTimeout, NextEvents);
{timeout,_,_} ->
+ NewS = S#{state := State, data := NewData, postponed := P},
+ Q = [Event|Events],
?TERMINATE(
- error, {bad_action,Action}, Debug, S, [Event|Events]);
+ error, {bad_action,Action}, Debug, NewS, Q);
infinity -> % Clear timer - it will never trigger
loop_event_actions(
- Parent, Debug, S, Events, Event,
- State, NextState, NewData, Actions,
+ Parent, Debug, S, Events,
+ State, NewData, P, Event, NextState, Actions,
Postpone, Hibernate, undefined, NextEvents);
Time when is_integer(Time), Time >= 0 ->
NewTimeout = {timeout,Time,Time},
loop_event_actions(
- Parent, Debug, S, Events, Event,
- State, NextState, NewData, Actions,
+ Parent, Debug, S, Events,
+ State, NewData, P, Event, NextState, Actions,
Postpone, Hibernate, NewTimeout, NextEvents);
_ ->
+ NewS = S#{state := State, data := NewData, postponed := P},
+ Q = [Event|Events],
?TERMINATE(
- error, {bad_action,Action}, Debug, S, [Event|Events])
+ error, {bad_action,Action}, Debug, NewS, Q)
end;
%%
%% End of actions list
loop_event_actions(
- Parent, Debug, #{postponed := P0} = S, Events, Event,
- State, NextState, NewData, [],
+ Parent, Debug, S, Events,
+ State, NewData, P0, Event, NextState, [],
Postpone, Hibernate, Timeout, NextEvents) ->
%%
%% All options have been collected and next_events are buffered.
@@ -1059,7 +1135,7 @@ loop_event_actions(
{lists:reverse(P1, Events),[]}
end,
%% Place next events first in queue
- Q3 = lists:reverse(NextEvents, Q2),
+ Q = lists:reverse(NextEvents, Q2),
%%
NewDebug =
sys_debug(
@@ -1070,41 +1146,8 @@ loop_event_actions(
false ->
{consume,Event,NextState}
end),
- %% Have a peek on the event queue so we can avoid starting
- %% the state timer unless we have to
- {Q,Timer} =
- case Timeout of
- undefined ->
- %% No state timeout has been requested
- {Q3,undefined};
- {timeout,Time,EventContent} ->
- %% A state timeout has been requested
- case Q3 of
- [] when Time =:= 0 ->
- %% Immediate timeout - simulate it
- %% so we do not get the timeout message
- %% after any received event
- {[{timeout,EventContent}],undefined};
- [] ->
- %% Actually start a timer
- {Q3,erlang:start_timer(Time, self(), EventContent)};
- _ ->
- %% Do not start a timer since any queued
- %% event cancels the state timer so we pretend
- %% that the timer has been started and cancelled
- {Q3,undefined}
- end
- end,
- %% Loop to top of event queue loop; process next event
loop_events(
- Parent, NewDebug,
- S#{
- state := NextState,
- data := NewData,
- timer := Timer,
- postponed := P,
- hibernate := Hibernate},
- Q, Hibernate).
+ Parent, NewDebug, S, Q, NextState, NewData, P, Hibernate, Timeout).
%%---------------------------------------------------------------------------
%% Server helpers
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-02 21:10:34 +0000