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-rw-r--r--lib/stdlib/src/gen_statem.erl1051
1 files changed, 659 insertions, 392 deletions
diff --git a/lib/stdlib/src/gen_statem.erl b/lib/stdlib/src/gen_statem.erl
index 3b3477b282..17d1ebecec 100644
--- a/lib/stdlib/src/gen_statem.erl
+++ b/lib/stdlib/src/gen_statem.erl
@@ -44,15 +44,20 @@
-export(
[wakeup_from_hibernate/3]).
-%% Type exports for templates
+%% Type exports for templates and callback modules
-export_type(
[event_type/0,
- callback_mode/0,
+ init_result/0,
+ callback_mode_result/0,
state_function_result/0,
handle_event_result/0,
+ state_enter_result/1,
+ event_handler_result/1,
+ reply_action/0,
+ enter_action/0,
action/0]).
-%% Fix problem for doc build
+%% Type that is exported just to be documented
-export_type([transition_option/0]).
%%%==========================================================================
@@ -63,7 +68,7 @@
{To :: pid(), Tag :: term()}. % Reply-to specifier for call
-type state() ::
- state_name() | % For StateName/3 callback functios
+ state_name() | % For StateName/3 callback functions
term(). % For handle_event/4 callback function
-type state_name() :: atom().
@@ -72,9 +77,12 @@
-type event_type() ::
{'call',From :: from()} | 'cast' |
- 'info' | 'timeout' | 'internal'.
+ 'info' | 'timeout' | 'state_timeout' | 'internal'.
+-type callback_mode_result() ::
+ callback_mode() | [callback_mode() | state_enter()].
-type callback_mode() :: 'state_functions' | 'handle_event_function'.
+-type state_enter() :: 'state_enter'.
-type transition_option() ::
postpone() | hibernate() | event_timeout().
@@ -89,6 +97,10 @@
%% Generate a ('timeout', EventContent, ...) event after Time
%% unless some other event is delivered
Time :: timeout().
+-type state_timeout() ::
+ %% Generate a ('state_timeout', EventContent, ...) event after Time
+ %% unless the state is changed
+ Time :: timeout().
-type action() ::
%% During a state change:
@@ -108,44 +120,67 @@
'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()} |
%%
(Timeout :: event_timeout()) | % {timeout,Timeout}
- {'timeout', % Set the event timeout option
+ {'timeout', % Set the event_timeout option
Time :: event_timeout(), EventContent :: term()} |
+ {'state_timeout', % Set the state_timeout option
+ Time :: state_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()}.
+-type init_result() ::
+ {ok, state(), data()} |
+ {ok, state(), data(), [action()] | action()} |
+ 'ignore' |
+ {'stop', Reason :: term()}.
+
+%% Old, not advertised
-type state_function_result() ::
- {'next_state', % {next_state,NextStateName,NewData,[]}
- NextStateName :: state_name(),
+ event_handler_result(state_name()).
+-type handle_event_result() ::
+ event_handler_result(state()).
+%%
+-type state_enter_result(StateType) ::
+ {'next_state', % {next_state,NextState,NewData,[]}
+ State :: StateType,
NewData :: data()} |
{'next_state', % State transition, maybe to the same state
- NextStateName :: state_name(),
+ State :: StateType,
NewData :: data(),
- Actions :: [action()] | action()} |
- common_state_callback_result().
--type handle_event_result() ::
+ Actions :: [enter_action()] | enter_action()} |
+ state_callback_result(enter_action()).
+-type event_handler_result(StateType) ::
{'next_state', % {next_state,NextState,NewData,[]}
- NextState :: state(),
+ NextState :: StateType,
NewData :: data()} |
{'next_state', % State transition, maybe to the same state
- NextState :: state(),
+ NextState :: StateType,
NewData :: data(),
Actions :: [action()] | action()} |
- common_state_callback_result().
--type common_state_callback_result() ::
+ state_callback_result(action()).
+-type state_callback_result(ActionType) ::
+ {'keep_state', % {keep_state,NewData,[]}
+ NewData :: data()} |
+ {'keep_state', % Keep state, change data
+ NewData :: data(),
+ Actions :: [ActionType] | ActionType} |
+ 'keep_state_and_data' | % {keep_state_and_data,[]}
+ {'keep_state_and_data', % Keep state and data -> only actions
+ Actions :: [ActionType] | ActionType} |
'stop' | % {stop,normal}
{'stop', % Stop the server
Reason :: term()} |
@@ -158,32 +193,20 @@
{'stop_and_reply', % Reply then stop the server
Reason :: term(),
Replies :: [reply_action()] | reply_action(),
- NewData :: data()} |
- {'keep_state', % {keep_state,NewData,[]}
- NewData :: data()} |
- {'keep_state', % Keep state, change data
- NewData :: data(),
- Actions :: [action()] | action()} |
- 'keep_state_and_data' | % {keep_state_and_data,[]}
- {'keep_state_and_data', % Keep state and data -> only actions
- Actions :: [action()] | action()}.
+ NewData :: data()}.
%% The state machine init function. It is called only once and
%% the server is not running until this function has returned
%% an {ok, ...} tuple. Thereafter the state callbacks are called
%% for all events to this server.
--callback init(Args :: term()) ->
- {ok, state(), data()} |
- {ok, state(), data(), [action()] | action()} |
- 'ignore' |
- {'stop', Reason :: term()}.
+-callback init(Args :: term()) -> init_result().
%% This callback shall return the callback mode of the callback module.
%%
%% 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 callback_mode() -> callback_mode_result().
%% Example state callback for StateName = 'state_name'
%% when callback_mode() =:= state_functions.
@@ -194,19 +217,28 @@
%% 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_enter_result('state_name');
+ (event_type(),
EventContent :: term(),
Data :: data()) ->
- state_function_result().
+ event_handler_result(state_name()).
%%
%% 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()) ->
+ state_enter_result(state());
+ (event_type(),
EventContent :: term(),
State :: state(), % Current state
Data :: data()) ->
- handle_event_result().
+ event_handler_result(state()).
%% Clean up before the server terminates.
-callback terminate(
@@ -385,53 +417,79 @@ call(ServerRef, Request) ->
-spec call(
ServerRef :: server_ref(),
Request :: term(),
- Timeout :: timeout()) ->
+ Timeout ::
+ timeout() |
+ {'clean_timeout',T :: timeout()} |
+ {'dirty_timeout',T :: timeout()}) ->
Reply :: term().
-call(ServerRef, Request, infinity) ->
- try gen:call(ServerRef, '$gen_call', Request, infinity) of
- {ok,Reply} ->
- Reply
- catch
- Class:Reason ->
- erlang:raise(
- Class,
- {Reason,{?MODULE,call,[ServerRef,Request,infinity]}},
- erlang:get_stacktrace())
- end;
call(ServerRef, Request, Timeout) ->
- %% Call server through proxy process to dodge any late reply
- Ref = make_ref(),
- Self = self(),
- Pid = spawn(
- fun () ->
- Self !
- try gen:call(
- ServerRef, '$gen_call', Request, Timeout) of
- Result ->
- {Ref,Result}
- catch Class:Reason ->
- {Ref,Class,Reason,erlang:get_stacktrace()}
- end
- end),
- Mref = monitor(process, Pid),
- receive
- {Ref,Result} ->
- demonitor(Mref, [flush]),
- case Result of
+ case parse_timeout(Timeout) of
+ {dirty_timeout,T} ->
+ try gen:call(ServerRef, '$gen_call', Request, T) of
{ok,Reply} ->
Reply
+ catch
+ Class:Reason ->
+ erlang:raise(
+ Class,
+ {Reason,{?MODULE,call,[ServerRef,Request,Timeout]}},
+ erlang:get_stacktrace())
+ end;
+ {clean_timeout,T} ->
+ %% Call server through proxy process to dodge any late reply
+ Ref = make_ref(),
+ Self = self(),
+ Pid = spawn(
+ fun () ->
+ Self !
+ try gen:call(
+ ServerRef, '$gen_call', Request, T) of
+ Result ->
+ {Ref,Result}
+ catch Class:Reason ->
+ {Ref,Class,Reason,
+ erlang:get_stacktrace()}
+ end
+ end),
+ Mref = monitor(process, Pid),
+ receive
+ {Ref,Result} ->
+ demonitor(Mref, [flush]),
+ case Result of
+ {ok,Reply} ->
+ Reply
+ end;
+ {Ref,Class,Reason,Stacktrace} ->
+ demonitor(Mref, [flush]),
+ erlang:raise(
+ Class,
+ {Reason,{?MODULE,call,[ServerRef,Request,Timeout]}},
+ Stacktrace);
+ {'DOWN',Mref,_,_,Reason} ->
+ %% There is a theoretical possibility that the
+ %% proxy process gets killed between try--of and !
+ %% so this clause is in case of that
+ exit(Reason)
end;
- {Ref,Class,Reason,Stacktrace} ->
- demonitor(Mref, [flush]),
- erlang:raise(
- Class,
- {Reason,{?MODULE,call,[ServerRef,Request,Timeout]}},
- Stacktrace);
- {'DOWN',Mref,_,_,Reason} ->
- %% There is a theoretical possibility that the
- %% proxy process gets killed between try--of and !
- %% so this clause is in case of that
- exit(Reason)
+ Error when is_atom(Error) ->
+ erlang:error(Error, [ServerRef,Request,Timeout])
+ end.
+
+parse_timeout(Timeout) ->
+ case Timeout of
+ {clean_timeout,infinity} ->
+ {dirty_timeout,infinity};
+ {clean_timeout,_} ->
+ Timeout;
+ {dirty_timeout,_} ->
+ Timeout;
+ {_,_} ->
+ %% Be nice and throw a badarg for speling errors
+ badarg;
+ infinity ->
+ {dirty_timeout,infinity};
+ T ->
+ {clean_timeout,T}
end.
%% Reply from a state machine callback to whom awaits in call/2
@@ -517,8 +575,9 @@ enter(Module, Opts, 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),
- P = Events = [],
- Event = {internal,initial_state},
+ Events = [],
+ P = [],
+ Event = {internal,init_state},
%% We enforce {postpone,false} to ensure that
%% our fake Event gets discarded, thought it might get logged
NewActions =
@@ -530,19 +589,31 @@ enter(Module, Opts, State, Data, Server, Actions, Parent) ->
end,
S = #{
callback_mode => undefined,
+ state_enter => false,
module => Module,
name => Name,
- %% 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,
postponed => P,
- hibernate => false,
- timer => undefined},
+ %% The rest of the fields are set from to the arguments to
+ %% loop_event_actions/9 when it finally loops back to loop/3
+ %% in loop_events_done/9
+ %%
+ %% Marker for initial state, cleared immediately when used
+ init_state => true
+ },
NewDebug = sys_debug(Debug, S, State, {enter,Event,State}),
- loop_event_actions(
- Parent, NewDebug, S, Events,
- State, Data, P, Event, State, NewActions).
+ case call_callback_mode(S) of
+ {ok,NewS} ->
+ StateTimer = undefined,
+ loop_event_actions(
+ Parent, NewDebug, NewS, StateTimer,
+ Events, Event, State, Data, NewActions);
+ {Class,Reason,Stacktrace} ->
+ terminate(
+ Class, Reason, Stacktrace,
+ NewDebug, S, [Event|Events])
+ end.
%%%==========================================================================
%%% gen callbacks
@@ -563,7 +634,9 @@ init_it(Starter, Parent, ServerRef, Module, Args, Opts) ->
proc_lib:init_ack(Starter, {error,Reason}),
error_info(
Class, Reason, Stacktrace,
- #{name => Name, callback_mode => undefined},
+ #{name => Name,
+ callback_mode => undefined,
+ state_enter => false},
[], [], undefined),
erlang:raise(Class, Reason, Stacktrace)
end.
@@ -594,7 +667,9 @@ init_result(Starter, Parent, ServerRef, Module, Result, Opts) ->
proc_lib:init_ack(Starter, {error,Error}),
error_info(
error, Error, ?STACKTRACE(),
- #{name => Name, callback_mode => undefined},
+ #{name => Name,
+ callback_mode => undefined,
+ state_enter => false},
[], [], undefined),
exit(Error)
end.
@@ -605,12 +680,10 @@ init_result(Starter, Parent, ServerRef, Module, Result, Opts) ->
system_continue(Parent, Debug, S) ->
loop(Parent, Debug, S).
-system_terminate(
- Reason, _Parent, Debug,
- #{state := State, data := Data, postponed := P} = S) ->
+system_terminate(Reason, _Parent, Debug, S) ->
terminate(
exit, Reason, ?STACKTRACE(),
- Debug, S, [], State, Data, P).
+ Debug, S, []).
system_code_change(
#{module := Module,
@@ -647,7 +720,7 @@ system_replace_state(
format_status(
Opt,
[PDict,SysState,Parent,Debug,
- #{name := Name, postponed := P, state := State, data := Data} = S]) ->
+ #{name := Name, postponed := P} = S]) ->
Header = gen:format_status_header("Status for state machine", Name),
Log = sys:get_debug(log, Debug, []),
[{header,Header},
@@ -656,7 +729,7 @@ format_status(
{"Parent",Parent},
{"Logged Events",Log},
{"Postponed",P}]} |
- case format_status(Opt, PDict, S, State, Data) of
+ case format_status(Opt, PDict, S) of
L when is_list(L) -> L;
T -> [T]
end].
@@ -732,7 +805,8 @@ loop(Parent, Debug, #{hibernate := Hibernate} = S) ->
end.
%% Entry point for wakeup_from_hibernate/3
-loop_receive(Parent, Debug, #{timer := Timer} = S) ->
+loop_receive(
+ Parent, Debug, #{timer := Timer, state_timer := StateTimer} = S) ->
receive
Msg ->
case Msg of
@@ -743,34 +817,23 @@ loop_receive(Parent, Debug, #{timer := Timer} = S) ->
sys:handle_system_msg(
Req, Pid, Parent, ?MODULE, Debug, S, Hibernate);
{'EXIT',Parent,Reason} = EXIT ->
- #{state := State, data := Data, postponed := P} = S,
%% EXIT is not a 2-tuple and therefore
%% not an event and has no event_type(),
%% but this will stand out in the crash report...
terminate(
- exit, Reason, ?STACKTRACE(),
- Debug, S, [EXIT], State, Data, P);
- {timeout,Timer,Content} when Timer =/= undefined ->
+ exit, Reason, ?STACKTRACE(), Debug, S, [EXIT]);
+ {timeout,Timer,Content}
+ when Timer =/= undefined ->
loop_receive_result(
- Parent, Debug, S, {timeout,Content});
+ Parent, Debug, S, StateTimer,
+ {timeout,Content});
+ {timeout,StateTimer,Content}
+ when StateTimer =/= undefined ->
+ loop_receive_result(
+ Parent, Debug, S, undefined,
+ {state_timeout,Content});
_ ->
- %% Cancel Timer if running
- case Timer of
- undefined ->
- ok;
- _ ->
- case erlang:cancel_timer(Timer) of
- TimeLeft when is_integer(TimeLeft) ->
- ok;
- false ->
- receive
- {timeout,Timer,_} ->
- ok
- after 0 ->
- ok
- end
- end
- end,
+ cancel_timer(Timer),
Event =
case Msg of
{'$gen_call',From,Request} ->
@@ -780,112 +843,185 @@ loop_receive(Parent, Debug, #{timer := Timer} = S) ->
_ ->
{info,Msg}
end,
- loop_receive_result(Parent, Debug, S, Event)
+ loop_receive_result(
+ Parent, Debug, S, StateTimer, Event)
end
end.
-loop_receive_result(
- Parent, Debug,
- #{state := State,
- data := Data,
- postponed := P} = S,
- Event) ->
- %% The engine state map S is now dismantled
- %% and will not be restored until we return to loop/3.
- %%
- %% 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.
+loop_receive_result(Parent, Debug, #{state := State} = S, StateTimer, Event) ->
+ %% The fields 'timer', 'state_timer' and 'hibernate'
+ %% are now invalid in state map S - they will be recalculated
+ %% and restored when we return to loop/3
%%
NewDebug = sys_debug(Debug, S, State, {in,Event}),
%% Here the queue of not yet handled events is created
Events = [],
Hibernate = false,
- loop_event(
- Parent, NewDebug, S, Events, State, Data, P, Event, Hibernate).
+ loop_event(Parent, NewDebug, S, StateTimer, Events, Event, Hibernate).
%% 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) ->
+ Parent, Debug, S, StateTimeout,
+ [Event|Events], _Timeout, State, Data, P, Hibernate) ->
%%
- %% If there was a state timer requested we just ignore that
+ %% If there was an event 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);
+ Parent, Debug, S, StateTimeout,
+ Events, Event, State, Data, P, Hibernate);
loop_events(
- Parent, Debug, S, [],
- State, Data, P, Hibernate, Timeout) ->
+ Parent, Debug, S, {state_timeout,Time,EventContent},
+ [] = Events, Timeout, State, Data, P, Hibernate) ->
+ if
+ Time =:= 0 ->
+ %% Simulate an immediate timeout
+ %% so we do not get the timeout message
+ %% after any received event
+ %%
+ %% This faked event will cancel
+ %& any not yet started event timer
+ Event = {state_timeout,EventContent},
+ StateTimer = undefined,
+ loop_event(
+ Parent, Debug, S, StateTimer,
+ Events, Event, State, Data, P, Hibernate);
+ true ->
+ StateTimer = erlang:start_timer(Time, self(), EventContent),
+ loop_events(
+ Parent, Debug, S, StateTimer,
+ Events, Timeout, State, Data, P, Hibernate)
+ end;
+loop_events(
+ Parent, Debug, S, StateTimer,
+ [] = Events, Timeout, State, Data, P, Hibernate) ->
case Timeout of
{timeout,0,EventContent} ->
- %% Immediate timeout - simulate it
+ %% Simulate an immediate timeout
%% so we do not get the timeout message
%% after any received event
+ %%
+ Event = {timeout,EventContent},
loop_event(
- Parent, Debug, S, [],
- State, Data, P, {timeout,EventContent}, Hibernate);
+ Parent, Debug, S, StateTimer,
+ Events, Event, State, Data, P, 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);
+ Parent, Debug, S, StateTimer,
+ State, Data, P, Hibernate, Timer);
undefined ->
- %% No state timeout has been requested
+ %% No event timeout has been requested
Timer = undefined,
loop_events_done(
- Parent, Debug, S, Timer, State, Data, P, Hibernate)
+ Parent, Debug, S, StateTimer,
+ State, Data, P, Hibernate, Timer)
end.
-%%
-loop_events_done(Parent, Debug, S, Timer, State, Data, P, Hibernate) ->
+
+%% Back to the top
+loop_events_done(
+ Parent, Debug, S, StateTimer,
+ State, Data, P, Hibernate, Timer) ->
NewS =
S#{
state := State,
data := Data,
postponed := P,
- hibernate := Hibernate,
- timer := Timer},
+ hibernate => Hibernate,
+ timer => Timer,
+ state_timer => StateTimer},
loop(Parent, Debug, NewS).
-loop_event(
- Parent, Debug,
+
+
+call_callback_mode(#{module := Module} = S) ->
+ try Module:callback_mode() of
+ CallbackMode ->
+ callback_mode_result(S, CallbackMode)
+ catch
+ CallbackMode ->
+ callback_mode_result(S, CallbackMode);
+ error:undef ->
+ %% Process undef to check for the simple mistake
+ %% of calling a nonexistent state function
+ %% to make the undef more precise
+ case erlang:get_stacktrace() of
+ [{Module,callback_mode,[]=Args,_}
+ |Stacktrace] ->
+ {error,
+ {undef_callback,{Module,callback_mode,Args}},
+ Stacktrace};
+ Stacktrace ->
+ {error,undef,Stacktrace}
+ end;
+ Class:Reason ->
+ {Class,Reason,erlang:get_stacktrace()}
+ end.
+
+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,
+ Type, Content, State, Data) ->
+ case call_callback_mode(S) of
+ {ok,NewS} ->
+ call_state_function(NewS, Type, Content, State, Data);
+ Error ->
+ Error
+ end;
+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
- undefined ->
- Module:callback_mode();
state_functions ->
erlang:apply(Module, State, [Type,Content,Data]);
handle_event_function ->
Module:handle_event(Type, Content, State, Data)
end
of
- Result when CallbackMode =:= undefined ->
- loop_event_callback_mode(
- Parent, Debug, S, Events, State, Data, P, Event, Result);
Result ->
- loop_event_result(
- Parent, Debug, S, Events, State, Data, P, Event, Result)
+ {ok,Result,S}
catch
- Result when CallbackMode =:= undefined ->
- loop_event_callback_mode(
- Parent, Debug, S, Events, State, Data, P, Event, Result);
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,
@@ -895,329 +1031,425 @@ 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
%% of calling a nonexistent state function
%% to make the undef more precise
case erlang:get_stacktrace() of
- [{Module,callback_mode,[]=Args,_}
- |Stacktrace]
- when CallbackMode =:= undefined ->
- terminate(
- error,
- {undef_callback,{Module,callback_mode,Args}},
- Stacktrace,
- Debug, S, [Event|Events], State, Data, P);
[{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(),
- terminate(
- Class, Reason, Stacktrace,
- Debug, S, [Event|Events], State, Data, P)
+ {Class,Reason,erlang:get_stacktrace()}
end.
-%% Interpret callback_mode() result
-loop_event_callback_mode(
- Parent, Debug, S, Events, State, Data, P, Event, CallbackMode) ->
- case callback_mode(CallbackMode) of
- true ->
- Hibernate = false, % We have already GC:ed recently
- loop_event(
- Parent, Debug,
- S#{callback_mode := CallbackMode},
- Events,
- State, Data, P, Event, Hibernate);
- false ->
+%% Update S and continue
+loop_event(
+ Parent, Debug, S, StateTimer,
+ Events, Event, State, Data, P, Hibernate) ->
+ NewS =
+ S#{
+ state := State,
+ data := Data,
+ postponed := P},
+ loop_event(Parent, Debug, NewS, StateTimer, Events, Event, Hibernate).
+
+loop_event(
+ Parent, Debug, #{state := State, data := Data} = S, StateTimer,
+ Events, {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 rely 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(
+ true, Debug, NewS, Result,
+ Events, Event, State, Data),
+ loop_event_actions(
+ Parent, Debug, S, StateTimer,
+ Events, Event, NextState, NewData, Actions);
+ {Class,Reason,Stacktrace} ->
terminate(
- error,
- {bad_return_from_callback_mode,CallbackMode},
- ?STACKTRACE(),
- Debug, S, [Event|Events], State, Data, P)
+ Class, Reason, Stacktrace, Debug, S, [Event|Events])
end.
%% Interpret all callback return variants
-loop_event_result(
- Parent, Debug, S, Events, State, Data, P, Event, Result) ->
+parse_event_result(
+ AllowStateChange, Debug, S, Result, Events, Event, State, Data) ->
case Result of
stop ->
terminate(
- exit, normal, ?STACKTRACE(),
- Debug, S, [Event|Events], State, Data, P);
+ exit, normal, ?STACKTRACE(), Debug, S, [Event|Events]);
{stop,Reason} ->
terminate(
- exit, Reason, ?STACKTRACE(),
- Debug, S, [Event|Events], State, Data, P);
+ exit, Reason, ?STACKTRACE(), Debug, S, [Event|Events]);
{stop,Reason,NewData} ->
terminate(
exit, Reason, ?STACKTRACE(),
- Debug, S, [Event|Events], State, NewData, P);
+ Debug, S#{data := NewData}, [Event|Events]);
{stop_and_reply,Reason,Replies} ->
Q = [Event|Events],
reply_then_terminate(
exit, Reason, ?STACKTRACE(),
- Debug, S, Q, State, Data, P, Replies);
+ Debug, S, Q, Replies);
{stop_and_reply,Reason,Replies,NewData} ->
Q = [Event|Events],
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);
+ Debug, S#{data := NewData}, Q, Replies);
+ {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,
{bad_return_from_state_function,Result},
?STACKTRACE(),
- Debug, S, [Event|Events], State, Data, P)
+ Debug, S, [Event|Events])
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, StateTimeout) ->
+ Postpone = forbidden,
+ NextEvents = forbidden,
+ parse_actions(
+ Debug, S, State, listify(Actions),
+ Hibernate, Timeout, StateTimeout, Postpone, NextEvents).
+
+parse_actions(Debug, S, State, Actions) ->
Hibernate = false,
Timeout = undefined,
+ StateTimeout = undefined,
+ Postpone = false,
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, StateTimeout, 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, StateTimeout, Postpone, NextEvents) ->
+ {ok,Debug,Hibernate,Timeout,StateTimeout,Postpone,NextEvents};
+parse_actions(
+ Debug, S, State, [Action|Actions],
+ Hibernate, Timeout, StateTimeout, 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, StateTimeout,
+ 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, StateTimeout, 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, StateTimeout, Postpone, NextEvents);
+ {state_timeout,Time,_} = NewStateTimeout
+ when is_integer(Time), Time >= 0;
+ Time =:= infinity ->
+ parse_actions(
+ Debug, S, State, Actions,
+ Hibernate, Timeout, NewStateTimeout, Postpone, NextEvents);
+ {state_timeout,_,_} ->
+ {error,
+ {bad_action_from_state_function,Action},
+ ?STACKTRACE()};
{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, StateTimeout, 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, StateTimeout, 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, StateTimeout, 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, StateTimeout, Postpone, NextEvents);
+ {postpone,NewPostpone}
+ when is_boolean(NewPostpone), Postpone =/= forbidden ->
+ parse_actions(
+ Debug, S, State, Actions,
+ Hibernate, Timeout, StateTimeout, NewPostpone, NextEvents);
+ {postpone,_} ->
+ {error,
+ {bad_action_from_state_function,Action},
+ ?STACKTRACE()};
+ postpone when Postpone =/= forbidden ->
+ parse_actions(
+ Debug, S, State, Actions,
+ Hibernate, Timeout, StateTimeout, 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, StateTimeout,
+ Postpone, [{Type,Content}|NextEvents]);
+ _ ->
+ {error,
+ {bad_action_from_state_function,Action},
+ ?STACKTRACE()}
+ end;
_ ->
- terminate(
- error,
- {bad_action_from_state_function,Action},
- ?STACKTRACE(),
- Debug, S, [Event|Events], State, NewData, P)
- end;
-%%
-%% End of actions list
+ {error,
+ {bad_action_from_state_function,Action},
+ ?STACKTRACE()}
+ end.
+
loop_event_actions(
- Parent, Debug, S, Events,
- State, NewData, P0, Event, NextState, [],
- Postpone, Hibernate, Timeout, NextEvents) ->
+ Parent, Debug,
+ #{state := State, state_enter := StateEnter} = S, StateTimer,
+ Events, Event, NextState, NewData, Actions) ->
+ case parse_actions(Debug, S, State, Actions) of
+ {ok,NewDebug,Hibernate,Timeout,StateTimeout,Postpone,NextEvents} ->
+ if
+ StateEnter, NextState =/= State ->
+ loop_event_enter(
+ Parent, NewDebug, S, StateTimer,
+ Events, Event, NextState, NewData,
+ Hibernate, Timeout, StateTimeout, Postpone, NextEvents);
+ StateEnter ->
+ case maps:is_key(init_state, S) of
+ true ->
+ %% Avoid infinite loop in initial state
+ %% with state entry events
+ NewS = maps:remove(init_state, S),
+ loop_event_enter(
+ Parent, NewDebug, NewS, StateTimer,
+ Events, Event, NextState, NewData,
+ Hibernate, Timeout, StateTimeout,
+ Postpone, NextEvents);
+ false ->
+ loop_event_result(
+ Parent, NewDebug, S, StateTimer,
+ Events, Event, NextState, NewData,
+ Hibernate, Timeout, StateTimeout,
+ Postpone, NextEvents)
+ end;
+ true ->
+ loop_event_result(
+ Parent, NewDebug, S, StateTimer,
+ Events, Event, NextState, NewData,
+ Hibernate, Timeout, StateTimeout, Postpone, NextEvents)
+ end;
+ {Class,Reason,Stacktrace} ->
+ terminate(
+ Class, Reason, Stacktrace,
+ Debug, S#{data := NewData}, [Event|Events])
+ end.
+
+loop_event_enter(
+ Parent, Debug, #{state := State} = S, StateTimer,
+ Events, Event, NextState, NewData,
+ Hibernate, Timeout, StateTimeout, Postpone, NextEvents) ->
+ case call_state_function(S, enter, State, NextState, NewData) of
+ {ok,Result,NewS} ->
+ {NewerData,_,Actions} =
+ parse_event_result(
+ false, Debug, NewS, Result,
+ Events, Event, NextState, NewData),
+ loop_event_enter_actions(
+ Parent, Debug, NewS, StateTimer,
+ Events, Event, NextState, NewerData,
+ Hibernate, Timeout, StateTimeout, Postpone, NextEvents, Actions);
+ {Class,Reason,Stacktrace} ->
+ terminate(
+ Class, Reason, Stacktrace,
+ Debug, S#{state := NextState, data := NewData},
+ [Event|Events])
+ end.
+
+loop_event_enter_actions(
+ Parent, Debug, S, StateTimer,
+ Events, Event, NextState, NewData,
+ Hibernate, Timeout, StateTimeout, Postpone, NextEvents, Actions) ->
+ case
+ parse_enter_actions(
+ Debug, S, NextState, Actions,
+ Hibernate, Timeout, StateTimeout)
+ of
+ {ok,NewDebug,NewHibernate,NewTimeout,NewStateTimeout,_,_} ->
+ loop_event_result(
+ Parent, NewDebug, S, StateTimer,
+ Events, Event, NextState, NewData,
+ NewHibernate, NewTimeout, NewStateTimeout, Postpone, NextEvents);
+ {Class,Reason,Stacktrace} ->
+ terminate(
+ Class, Reason, Stacktrace,
+ Debug, S#{state := NextState, data := NewData},
+ [Event|Events])
+ end.
+
+loop_event_result(
+ Parent, Debug,
+ #{state := State, postponed := P_0} = S, StateTimer,
+ Events, Event, NextState, NewData,
+ Hibernate, Timeout, StateTimeout, Postpone, NextEvents) ->
%%
%% All options have been collected and next_events are buffered.
%% Do the actual state transition.
%%
- P1 = % Move current event to postponed if Postpone
+ NewStateTimeout =
+ case StateTimeout of
+ {state_timeout,Time,_} ->
+ %% New timeout -> cancel timer
+ case StateTimer of
+ {state_timeout,_,_} ->
+ ok;
+ _ ->
+ cancel_timer(StateTimer)
+ end,
+ case Time of
+ infinity ->
+ undefined;
+ _ ->
+ StateTimeout
+ end;
+ undefined when NextState =/= State ->
+ %% State change -> cancel timer
+ case StateTimer of
+ {state_timeout,_,_} ->
+ ok;
+ _ ->
+ cancel_timer(StateTimer)
+ end,
+ undefined;
+ undefined ->
+ StateTimer
+ end,
+ %%
+ P_1 = % Move current event to postponed if Postpone
case Postpone of
true ->
- [Event|P0];
+ [Event|P_0];
false ->
- P0
+ P_0
end,
- {Q2,P} = % Move all postponed events to queue if state change
+ {Events_1,NewP} = % Move all postponed events to queue if state change
if
NextState =:= State ->
- {Events,P1};
+ {Events,P_1};
true ->
- {lists:reverse(P1, Events),[]}
+ {lists:reverse(P_1, Events),[]}
end,
%% Place next events first in queue
- Q = lists:reverse(NextEvents, Q2),
+ NewEvents = lists:reverse(NextEvents, Events_1),
%%
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, S, Q, NextState, NewData, P, Hibernate, Timeout).
+ Parent, NewDebug, S, NewStateTimeout,
+ NewEvents, Timeout, NextState, NewData, NewP, Hibernate).
%%---------------------------------------------------------------------------
%% Server helpers
reply_then_terminate(
Class, Reason, Stacktrace,
- Debug, S, Q, State, Data, P, Replies) ->
+ Debug, #{state := State} = S, Q, Replies) ->
if
is_list(Replies) ->
do_reply_then_terminate(
Class, Reason, Stacktrace,
- Debug, S, Q, State, Data, P, Replies);
+ Debug, S, Q, Replies, State);
true ->
do_reply_then_terminate(
Class, Reason, Stacktrace,
- Debug, S, Q, State, Data, P, [Replies])
+ Debug, S, Q, [Replies], State)
end.
%%
do_reply_then_terminate(
- Class, Reason, Stacktrace, Debug, S, Q, State, Data, P, []) ->
- terminate(Class, Reason, Stacktrace, Debug, S, Q, State, Data, P);
+ Class, Reason, Stacktrace, Debug, S, Q, [], _State) ->
+ terminate(Class, Reason, Stacktrace, Debug, S, Q);
do_reply_then_terminate(
- Class, Reason, Stacktrace, Debug, S, Q, State, Data, P, [R|Rs]) ->
+ Class, Reason, Stacktrace, Debug, S, Q, [R|Rs], State) ->
case R of
{reply,{_To,_Tag}=From,Reply} ->
NewDebug = do_reply(Debug, S, State, From, Reply),
do_reply_then_terminate(
- Class, Reason, Stacktrace,
- NewDebug, S, Q, State, Data, P, Rs);
+ Class, Reason, Stacktrace, NewDebug, S, Q, Rs, State);
_ ->
terminate(
error,
{bad_reply_action_from_state_function,R},
?STACKTRACE(),
- Debug, S, Q, State, Data, P)
+ Debug, S, Q)
end.
do_reply(Debug, S, State, From, Reply) ->
@@ -1227,7 +1459,9 @@ do_reply(Debug, S, State, From, Reply) ->
terminate(
Class, Reason, Stacktrace,
- Debug, #{module := Module} = S, Q, State, Data, P) ->
+ Debug,
+ #{module := Module, state := State, data := Data, postponed := P} = S,
+ Q) ->
try Module:terminate(Reason, State, Data) of
_ -> ok
catch
@@ -1236,7 +1470,7 @@ terminate(
ST = erlang:get_stacktrace(),
error_info(
C, R, ST, S, Q, P,
- format_status(terminate, get(), S, State, Data)),
+ format_status(terminate, get(), S)),
sys:print_log(Debug),
erlang:raise(C, R, ST)
end,
@@ -1247,7 +1481,7 @@ terminate(
_ ->
error_info(
Class, Reason, Stacktrace, S, Q, P,
- format_status(terminate, get(), S, State, Data)),
+ format_status(terminate, get(), S)),
sys:print_log(Debug)
end,
case Stacktrace of
@@ -1259,7 +1493,9 @@ terminate(
error_info(
Class, Reason, Stacktrace,
- #{name := Name, callback_mode := CallbackMode},
+ #{name := Name,
+ callback_mode := CallbackMode,
+ state_enter := StateEnter},
Q, P, FmtData) ->
{FixedReason,FixedStacktrace} =
case Stacktrace of
@@ -1286,6 +1522,13 @@ error_info(
end;
_ -> {Reason,Stacktrace}
end,
+ CBMode =
+ case StateEnter of
+ true ->
+ [CallbackMode,state_enter];
+ false ->
+ CallbackMode
+ end,
error_logger:format(
"** State machine ~p terminating~n" ++
case Q of
@@ -1312,8 +1555,9 @@ error_info(
[] -> [];
[Event|_] -> [Event]
end] ++
- [FmtData,Class,FixedReason,
- CallbackMode] ++
+ [FmtData,
+ Class,FixedReason,
+ CBMode] ++
case Q of
[_|[_|_] = Events] -> [Events];
_ -> []
@@ -1329,7 +1573,9 @@ error_info(
%% Call Module:format_status/2 or return a default value
-format_status(Opt, PDict, #{module := Module}, State, Data) ->
+format_status(
+ Opt, PDict,
+ #{module := Module, state := State, data := Data}) ->
case erlang:function_exported(Module, format_status, 2) of
true ->
try Module:format_status(Opt, [PDict,State,Data])
@@ -1353,3 +1599,24 @@ format_status_default(Opt, State, Data) ->
_ ->
[{data,[{"State",StateData}]}]
end.
+
+listify(Item) when is_list(Item) ->
+ Item;
+listify(Item) ->
+ [Item].
+
+cancel_timer(undefined) ->
+ ok;
+cancel_timer(TRef) ->
+ case erlang:cancel_timer(TRef) of
+ false ->
+ %% We have to assume that TRef is the ref of a running timer
+ %% and if so the timer has expired
+ %% hence we must wait for the timeout message
+ receive
+ {timeout,TRef,_} ->
+ ok
+ end;
+ _TimeLeft ->
+ ok
+ end.