diff options
Diffstat (limited to 'lib/stdlib/src/gen_statem.erl')
| -rw-r--r-- | lib/stdlib/src/gen_statem.erl | 582 |
1 files changed, 314 insertions, 268 deletions
diff --git a/lib/stdlib/src/gen_statem.erl b/lib/stdlib/src/gen_statem.erl index 7f437404ed..aedcfc932f 100644 --- a/lib/stdlib/src/gen_statem.erl +++ b/lib/stdlib/src/gen_statem.erl @@ -47,13 +47,16 @@ %% Type exports for templates -export_type( [event_type/0, - callback_mode/0, + state_name/0, + callback_mode_result/0, state_function_result/0, + state_function_enter_result/0, handle_event_result/0, + handle_event_enter_result/0, action/0]). %% Fix problem for doc build --export_type([state_entry_mode/0,transition_option/0]). +-export_type([transition_option/0]). %%%========================================================================== %%% Interface functions. @@ -72,10 +75,12 @@ -type event_type() :: {'call',From :: from()} | 'cast' | - 'info' | 'timeout' | 'enter' | 'internal'. + 'info' | 'timeout' | 'internal'. +-type callback_mode_result() :: + callback_mode() | [callback_mode() | state_enter()]. -type callback_mode() :: 'state_functions' | 'handle_event_function'. --type state_entry_mode() :: 'state_entry_events'. +-type state_enter() :: 'state_enter'. -type transition_option() :: postpone() | hibernate() | event_timeout(). @@ -109,6 +114,14 @@ 'postpone' | % Set the postpone option {'postpone', Postpone :: postpone()} | %% + %% All 'next_event' events are kept in a list and then + %% inserted at state changes so the first in the + %% action() list is the first to be delivered. + {'next_event', % Insert event as the next to handle + EventType :: event_type(), + EventContent :: term()} | + enter_action(). +-type enter_action() :: 'hibernate' | % Set the hibernate option {'hibernate', Hibernate :: hibernate()} | %% @@ -116,14 +129,7 @@ {'timeout', % Set the event timeout option Time :: event_timeout(), EventContent :: term()} | %% - reply_action() | - %% - %% All 'next_event' events are kept in a list and then - %% inserted at state changes so the first in the - %% action() list is the first to be delivered. - {'next_event', % Insert event as the next to handle - EventType :: event_type(), - EventContent :: term()}. + reply_action(). -type reply_action() :: {'reply', % Reply to a caller From :: from(), Reply :: term()}. @@ -137,6 +143,16 @@ NewData :: data(), Actions :: [action()] | action()} | common_state_callback_result(). +-type state_function_enter_result() :: + {'next_state', % {next_state,NextStateName,NewData,[]} + NextStateName :: state_name(), + NewData :: data()} | + {'next_state', % State transition, maybe to the same state + NextStateName :: state_name(), + NewData :: data(), + Actions :: [enter_action()] | enter_action()} | + common_state_callback_result(). + -type handle_event_result() :: {'next_state', % {next_state,NextState,NewData,[]} NextState :: state(), @@ -146,6 +162,16 @@ NewData :: data(), Actions :: [action()] | action()} | common_state_callback_result(). +-type handle_event_enter_result() :: + {'next_state', % {next_state,NextState,NewData,[]} + NextState :: state(), + NewData :: data()} | + {'next_state', % State transition, maybe to the same state + NextState :: state(), + NewData :: data(), + Actions :: [enter_action()] | enter_action()} | + common_state_callback_result(). + -type common_state_callback_result() :: 'stop' | % {stop,normal} {'stop', % Stop the server @@ -164,10 +190,10 @@ NewData :: data()} | {'keep_state', % Keep state, change data NewData :: data(), - Actions :: [action()] | action()} | + Actions :: [ActionType] | ActionType} | 'keep_state_and_data' | % {keep_state_and_data,[]} {'keep_state_and_data', % Keep state and data -> only actions - Actions :: [action()] | action()}. + Actions :: [ActionType] | ActionType}. %% The state machine init function. It is called only once and @@ -184,9 +210,7 @@ %% %% It is called once after init/0 and code_change/4 but before %% the first state callback StateName/3 or handle_event/4. --callback callback_mode() -> - callback_mode() | - [callback_mode() | state_entry_mode()]. +-callback callback_mode() -> callback_mode_result(). %% Example state callback for StateName = 'state_name' %% when callback_mode() =:= state_functions. @@ -197,7 +221,11 @@ %% StateName/3 callbacks and terminate/3, so the state name %% 'terminate' is unusable in this mode. -callback state_name( - event_type(), + 'enter', + OldStateName :: state_name(), + Data :: data()) -> + state_function_enter_result(); + (event_type(), EventContent :: term(), Data :: data()) -> state_function_result(). @@ -205,7 +233,12 @@ %% State callback for all states %% when callback_mode() =:= handle_event_function. -callback handle_event( - event_type(), + 'enter', + OldState :: state(), + State :: state(), % Current state + Data :: data()) -> + handle_event_enter_result(); + (event_type(), EventContent :: term(), State :: state(), % Current state Data :: data()) -> @@ -547,7 +580,7 @@ enter(Module, Opts, State, Data, Server, Actions, Parent) -> Name = gen:get_proc_name(Server), Debug = gen:debug_options(Name, Opts), P = Events = [], - Event = {internal,initial_state}, + Event = {internal,init_state}, %% We enforce {postpone,false} to ensure that %% our fake Event gets discarded, thought it might get logged NewActions = @@ -559,7 +592,7 @@ enter(Module, Opts, State, Data, Server, Actions, Parent) -> end, S = #{ callback_mode => undefined, - state_entry_events => false, + state_enter => false, module => Module, name => Name, %% The rest of the fields are set from to the arguments to @@ -886,51 +919,13 @@ loop_events_done(Parent, Debug, S, Timer, State, Data, P, Hibernate) -> -parse_callback_mode([], CBMode, SEntry) -> - {CBMode,SEntry}; -parse_callback_mode([H|T], CBMode, SEntry) -> - case callback_mode(H) of - true -> - parse_callback_mode(T, H, SEntry); - false -> - case H of - state_entry_events -> - parse_callback_mode(T, CBMode, true); - _ -> - {undefined,SEntry} - end - end; -parse_callback_mode(_, _CBMode, SEntry) -> - {undefined,SEntry}. - -call_callback_mode(S, CallbackMode) -> - case - parse_callback_mode( - if - is_atom(CallbackMode) -> - [CallbackMode]; - true -> - CallbackMode - end, undefined, false) - of - {undefined,_} -> - {error, - {bad_return_from_callback_mode,CallbackMode}, - ?STACKTRACE()}; - {CBMode,SEntry} -> - {ok, - S#{ - callback_mode := CBMode, - state_entry_events := SEntry}} - end. - call_callback_mode(#{module := Module} = S) -> try Module:callback_mode() of CallbackMode -> - call_callback_mode(S, CallbackMode) + call_callback_mode_result(S, CallbackMode) catch CallbackMode -> - call_callback_mode(S, CallbackMode); + call_callback_mode_result(S, CallbackMode); error:undef -> %% Process undef to check for the simple mistake %% of calling a nonexistent state function @@ -948,38 +943,57 @@ call_callback_mode(#{module := Module} = S) -> {Class,Reason,erlang:get_stacktrace()} end. -loop_event( - Parent, Debug, +call_callback_mode_result(S, CallbackMode) -> + case + parse_callback_mode( + if + is_atom(CallbackMode) -> + [CallbackMode]; + true -> + CallbackMode + end, undefined, false) + of + {undefined,_} -> + {error, + {bad_return_from_callback_mode,CallbackMode}, + ?STACKTRACE()}; + {CBMode,StateEnter} -> + {ok, + S#{ + callback_mode := CBMode, + state_enter := StateEnter}} + end. + +parse_callback_mode([], CBMode, StateEnter) -> + {CBMode,StateEnter}; +parse_callback_mode([H|T], CBMode, StateEnter) -> + case callback_mode(H) of + true -> + parse_callback_mode(T, H, StateEnter); + false -> + case H of + state_enter -> + parse_callback_mode(T, CBMode, true); + _ -> + {undefined,StateEnter} + end + end; +parse_callback_mode(_, _CBMode, StateEnter) -> + {undefined,StateEnter}. + +call_state_function( #{callback_mode := undefined} = S, - Events, - State, Data, P, Event, Hibernate) -> - %% This happens after code_change/4 + Type, Content, State, Data) -> case call_callback_mode(S) of {ok,NewS} -> - loop_event( - Parent, Debug, NewS, Events, - State, Data, P, Event, Hibernate); - {Class,Reason,Stacktrace} -> - terminate( - Class, Reason, Stacktrace, - Debug, S, [Event|Events], State, Data, P) + call_state_function(NewS, Type, Content, State, Data); + Error -> + Error end; -loop_event( - Parent, Debug, +call_state_function( #{callback_mode := CallbackMode, 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 - %% might depend on i.e collect garbage which - %% would have happened if we actually hibernated - %% and immediately was awakened - Hibernate andalso garbage_collect(), - %% + Type, Content, State, Data) -> try case CallbackMode of state_functions -> @@ -989,12 +1003,10 @@ loop_event( end of Result -> - loop_event_result( - Parent, Debug, S, Events, State, Data, P, Event, Result) + {ok,Result,S} catch Result -> - loop_event_result( - Parent, Debug, S, Events, State, Data, P, Event, Result); + {ok,Result,S}; error:badarg -> case erlang:get_stacktrace() of [{erlang,apply, @@ -1004,15 +1016,11 @@ loop_event( when CallbackMode =:= state_functions -> %% We get here e.g if apply fails %% due to State not being an atom - terminate( - error, - {undef_state_function,{Module,State,Args}}, - Stacktrace, - Debug, S, [Event|Events], State, Data, P); + {error, + {undef_state_function,{Module,State,Args}}, + Stacktrace}; Stacktrace -> - terminate( - error, badarg, Stacktrace, - Debug, S, [Event|Events], State, Data, P) + {error,badarg,Stacktrace} end; error:undef -> %% Process undef to check for the simple mistake @@ -1022,34 +1030,54 @@ loop_event( [{Module,State,[Type,Content,Data]=Args,_} |Stacktrace] when CallbackMode =:= state_functions -> - terminate( - error, - {undef_state_function,{Module,State,Args}}, - Stacktrace, - Debug, S, [Event|Events], State, Data, P); + {error, + {undef_state_function,{Module,State,Args}}, + Stacktrace}; [{Module,handle_event,[Type,Content,State,Data]=Args,_} |Stacktrace] when CallbackMode =:= handle_event_function -> - terminate( - error, - {undef_state_function,{Module,handle_event,Args}}, - Stacktrace, - Debug, S, [Event|Events], State, Data, P); + {error, + {undef_state_function,{Module,handle_event,Args}}, + Stacktrace}; Stacktrace -> - terminate( - error, undef, Stacktrace, - Debug, S, [Event|Events], State, Data, P) + {error,undef,Stacktrace} end; Class:Reason -> - Stacktrace = erlang:get_stacktrace(), + {Class,Reason,erlang:get_stacktrace()} + end. + +loop_event( + Parent, Debug, 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 + %% might depend on i.e collect garbage which + %% would have happened if we actually hibernated + %% and immediately was awakened + Hibernate andalso garbage_collect(), + case call_state_function(S, Type, Content, State, Data) of + {ok,Result,NewS} -> + {NewData,NextState,Actions} = + parse_event_result( + Parent, Debug, NewS, Events, + State, Data, P, Event, + Result, true), + loop_event_actions( + Parent, Debug, S, Events, + State, NewData, P, Event, NextState, Actions); + {Class,Reason,Stacktrace} -> terminate( Class, Reason, Stacktrace, Debug, S, [Event|Events], State, Data, P) end. %% Interpret all callback return variants -loop_event_result( - Parent, Debug, S, Events, State, Data, P, Event, Result) -> +parse_event_result( + _Parent, Debug, S, Events, State, Data, P, Event, + Result, AllowStateChange) -> case Result of stop -> terminate( @@ -1073,30 +1101,22 @@ loop_event_result( reply_then_terminate( exit, Reason, ?STACKTRACE(), Debug, S, Q, State, NewData, P, Replies); - {next_state,NextState,NewData} -> - loop_event_actions( - Parent, Debug, S, Events, - State, NewData, P, Event, NextState, []); - {next_state,NextState,NewData,Actions} -> - loop_event_actions( - Parent, Debug, S, Events, - State, NewData, P, Event, NextState, Actions); + {next_state,State,NewData} -> + {NewData,State,[]}; + {next_state,NextState,NewData} when AllowStateChange -> + {NewData,NextState,[]}; + {next_state,State,NewData,Actions} -> + {NewData,State,Actions}; + {next_state,NextState,NewData,Actions} when AllowStateChange -> + {NewData,NextState,Actions}; {keep_state,NewData} -> - loop_event_actions( - Parent, Debug, S, Events, - State, NewData, P, Event, State, []); + {NewData,State,[]}; {keep_state,NewData,Actions} -> - loop_event_actions( - Parent, Debug, S, Events, - State, NewData, P, Event, State, Actions); + {NewData,State,Actions}; keep_state_and_data -> - loop_event_actions( - Parent, Debug, S, Events, - State, Data, P, Event, State, []); + {Data,State,[]}; {keep_state_and_data,Actions} -> - loop_event_actions( - Parent, Debug, S, Events, - State, Data, P, Event, State, Actions); + {Data,State,Actions}; _ -> terminate( error, @@ -1105,134 +1125,178 @@ loop_event_result( Debug, S, [Event|Events], State, Data, P) end. -loop_event_actions( - Parent, Debug, S, Events, State, NewData, P, Event, NextState, Actions) -> - Postpone = false, % Shall we postpone this event; boolean() +parse_enter_actions(Debug, S, State, Actions, Hibernate, Timeout) -> + Postpone = forbidden, + NextEvents = forbidden, + parse_actions( + Debug, S, State, listify(Actions), + Hibernate, Timeout, Postpone, NextEvents). + +parse_actions(Debug, S, State, Actions) -> + Postpone = false, Hibernate = false, Timeout = undefined, NextEvents = [], - loop_event_actions( - Parent, Debug, S, Events, State, NewData, P, Event, NextState, - if - is_list(Actions) -> - Actions; - true -> - [Actions] - end, - Postpone, Hibernate, Timeout, NextEvents). + parse_actions( + Debug, S, State, listify(Actions), + Hibernate, Timeout, Postpone, NextEvents). %% -%% Process all actions -loop_event_actions( - Parent, Debug, S, Events, - State, NewData, P, Event, NextState, [Action|Actions], - Postpone, Hibernate, Timeout, NextEvents) -> +parse_actions( + Debug, _S, _State, [], Hibernate, Timeout, Postpone, NextEvents) -> + {ok,Debug,Hibernate,Timeout,Postpone,NextEvents}; +parse_actions( + Debug, S, State, [Action|Actions], + Hibernate, Timeout, Postpone, NextEvents) -> case Action of %% Actual actions {reply,From,Reply} -> case from(From) of true -> NewDebug = do_reply(Debug, S, State, From, Reply), - loop_event_actions( - Parent, NewDebug, S, Events, - State, NewData, P, Event, NextState, Actions, - Postpone, Hibernate, Timeout, NextEvents); + parse_actions( + NewDebug, S, State, Actions, + Hibernate, Timeout, Postpone, NextEvents); false -> - terminate( - error, - {bad_action_from_state_function,Action}, - ?STACKTRACE(), - Debug, S, [Event|Events], State, NewData, P) - end; - {next_event,Type,Content} -> - case event_type(Type) of - true -> - NewDebug = - sys_debug(Debug, S, State, {in,{Type,Content}}), - loop_event_actions( - Parent, NewDebug, S, Events, - State, NewData, P, Event, NextState, Actions, - Postpone, Hibernate, Timeout, - [{Type,Content}|NextEvents]); - false -> - terminate( - error, - {bad_action_from_state_function,Action}, - ?STACKTRACE(), - Debug, S, [Event|Events], State, NewData, P) + {error, + {bad_action_from_state_function,Action}, + ?STACKTRACE()} end; %% Actions that set options - {postpone,NewPostpone} when is_boolean(NewPostpone) -> - loop_event_actions( - Parent, Debug, S, Events, - State, NewData, P, Event, NextState, Actions, - NewPostpone, Hibernate, Timeout, NextEvents); - {postpone,_} -> - terminate( - error, - {bad_action_from_state_function,Action}, - ?STACKTRACE(), - Debug, S, [Event|Events], State, NewData, P); - postpone -> - loop_event_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, - State, NewData, P, Event, NextState, Actions, - Postpone, NewHibernate, Timeout, NextEvents); + parse_actions( + Debug, S, State, Actions, + NewHibernate, Timeout, Postpone, NextEvents); {hibernate,_} -> - terminate( - error, - {bad_action_from_state_function,Action}, - ?STACKTRACE(), - Debug, S, [Event|Events], State, NewData, P); + {error, + {bad_action_from_state_function,Action}, + ?STACKTRACE()}; hibernate -> - loop_event_actions( - Parent, Debug, S, Events, - State, NewData, P, Event, NextState, Actions, - Postpone, true, Timeout, NextEvents); + parse_actions( + Debug, S, State, Actions, + true, Timeout, Postpone, NextEvents); {timeout,infinity,_} -> % Clear timer - it will never trigger - loop_event_actions( - Parent, Debug, S, Events, - State, NewData, P, Event, NextState, Actions, - Postpone, Hibernate, undefined, NextEvents); + parse_actions( + Debug, S, State, Actions, + Hibernate, undefined, Postpone, NextEvents); {timeout,Time,_} = NewTimeout when is_integer(Time), Time >= 0 -> - loop_event_actions( - Parent, Debug, S, Events, - State, NewData, P, Event, NextState, Actions, - Postpone, Hibernate, NewTimeout, NextEvents); + parse_actions( + Debug, S, State, Actions, + Hibernate, NewTimeout, Postpone, NextEvents); {timeout,_,_} -> - terminate( - error, - {bad_action_from_state_function,Action}, - ?STACKTRACE(), - Debug, S, [Event|Events], State, NewData, P); + {error, + {bad_action_from_state_function,Action}, + ?STACKTRACE()}; infinity -> % Clear timer - it will never trigger - loop_event_actions( - Parent, Debug, S, Events, - State, NewData, P, Event, NextState, Actions, - Postpone, Hibernate, undefined, NextEvents); + parse_actions( + Debug, S, State, Actions, + Hibernate, undefined, Postpone, NextEvents); Time when is_integer(Time), Time >= 0 -> NewTimeout = {timeout,Time,Time}, - loop_event_actions( - Parent, Debug, S, Events, - State, NewData, P, Event, NextState, Actions, - Postpone, Hibernate, NewTimeout, NextEvents); + parse_actions( + Debug, S, State, Actions, + Hibernate, NewTimeout, Postpone, NextEvents); + {postpone,NewPostpone} + when is_boolean(NewPostpone), Postpone =/= forbidden -> + parse_actions( + Debug, S, State, Actions, + Hibernate, Timeout, NewPostpone, NextEvents); + {postpone,_} -> + {error, + {bad_action_from_state_function,Action}, + ?STACKTRACE()}; + postpone when Postpone =/= forbidden -> + parse_actions( + Debug, S, State, Actions, + Hibernate, Timeout, true, NextEvents); + {next_event,Type,Content} -> + case event_type(Type) of + true when NextEvents =/= forbidden -> + NewDebug = + sys_debug(Debug, S, State, {in,{Type,Content}}), + parse_actions( + NewDebug, S, State, Actions, + Hibernate, Timeout, Postpone, + [{Type,Content}|NextEvents]); + _ -> + {error, + {bad_action_from_state_function,Action}, + ?STACKTRACE()} + end; _ -> + {error, + {bad_action_from_state_function,Action}, + ?STACKTRACE()} + end. + +loop_event_actions( + Parent, Debug, #{state_enter := StateEnter} = S, Events, + State, NewData, P, Event, NextState, Actions) -> + case parse_actions(Debug, S, State, Actions) of + {ok,NewDebug,Hibernate,Timeout,Postpone,NextEvents} -> + case + StateEnter andalso + ((NextState =/= State) + orelse maps:is_key(init_state, S)) of + true -> + loop_event_enter( + Parent, NewDebug, S, Events, + State, NewData, P, Event, NextState, + Hibernate, Timeout, Postpone, NextEvents); + false -> + loop_event_result( + Parent, NewDebug, S, Events, + State, NewData, P, Event, NextState, + Hibernate, Timeout, Postpone, NextEvents) + end; + {Class,Reason,Stacktrace} -> terminate( - error, - {bad_action_from_state_function,Action}, - ?STACKTRACE(), + Class, Reason, Stacktrace, Debug, S, [Event|Events], State, NewData, P) - end; -%% -%% End of actions list -loop_event_actions( - Parent, Debug, #{state_entry_events := SEEvents} = S, Events, - State, NewData, P0, Event, NextState, [], - Postpone, Hibernate, Timeout, NextEvents) -> + end. + +loop_event_enter( + Parent, Debug, S, Events, + State, NewData, P, Event, NextState, + Hibernate, Timeout, Postpone, NextEvents) -> + case call_state_function(S, enter, State, NextState, NewData) of + {ok,Result,NewS} -> + {NewerData,_,Actions} = + parse_event_result( + Parent, Debug, NewS, Events, + NextState, NewData, P, Event, + Result, false), + loop_event_enter_actions( + Parent, Debug, NewS, Events, + State, NewerData, P, Event, NextState, + Hibernate, Timeout, Postpone, NextEvents, Actions); + {Class,Reason,Stacktrace} -> + terminate( + Class, Reason, Stacktrace, + Debug, S, [Event|Events], NextState, NewData, P) + end. + +loop_event_enter_actions( + Parent, Debug, S, Events, + State, NewData, P, Event, NextState, + Hibernate, Timeout, Postpone, NextEvents, Actions) -> + case + parse_enter_actions(Debug, S, NextState, Actions, Hibernate, Timeout) + of + {ok,NewDebug,NewHibernate,NewTimeout,_,_} -> + loop_event_result( + Parent, NewDebug, S, Events, + State, NewData, P, Event, NextState, + NewHibernate, NewTimeout, Postpone, NextEvents); + {Class,Reason,Stacktrace} -> + terminate( + Class, Reason, Stacktrace, + Debug, S, [Event|Events], NextState, NewData, P) + end. + +loop_event_result( + Parent, Debug, S, Events, + State, NewData, P0, Event, NextState, + Hibernate, Timeout, Postpone, NextEvents) -> %% %% All options have been collected and next_events are buffered. %% Do the actual state transition. @@ -1252,44 +1316,21 @@ loop_event_actions( {lists:reverse(P1, Events),[]} end, %% Place next events first in queue - Q3 = lists:reverse(NextEvents, Q2), - %% State entry events - Q = - case SEEvents of - true -> - %% Generate state entry events - case - (NextState =/= State) - orelse maps:is_key(init_state, S) - of - true -> - %% State change or initial state - [{enter,State}|Q3]; - false -> - Q3 - end; - false -> - Q3 - end, + Q = lists:reverse(NextEvents, Q2), %% NewDebug = sys_debug( Debug, S, State, case Postpone of true -> - {postpone,Event,NextState}; + {postpone,Event,State}; false -> - {consume,Event,NextState} + {consume,Event,State} end), loop_events( Parent, NewDebug, %% Avoid infinite loop in initial state with state entry events - case maps:is_key(init_state, S) of - true -> - maps:remove(init_state, S); - false -> - S - end, + maps:remove(init_state, S), Q, NextState, NewData, P, Hibernate, Timeout). %%--------------------------------------------------------------------------- @@ -1369,7 +1410,7 @@ error_info( Class, Reason, Stacktrace, #{name := Name, callback_mode := CallbackMode, - state_entry_events := SEEvents}, + state_enter := StateEnter}, Q, P, FmtData) -> {FixedReason,FixedStacktrace} = case Stacktrace of @@ -1397,9 +1438,9 @@ error_info( _ -> {Reason,Stacktrace} end, CBMode = - case SEEvents of + case StateEnter of true -> - [CallbackMode,state_entry_events]; + [CallbackMode,state_enter]; false -> CallbackMode end, @@ -1471,3 +1512,8 @@ format_status_default(Opt, State, Data) -> _ -> [{data,[{"State",StateData}]}] end. + +listify(Item) when is_list(Item) -> + Item; +listify(Item) -> + [Item]. |