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-rw-r--r--lib/stdlib/src/gen_statem.erl133
1 files changed, 68 insertions, 65 deletions
diff --git a/lib/stdlib/src/gen_statem.erl b/lib/stdlib/src/gen_statem.erl
index c02e6a1a19..6d7b461ee3 100644
--- a/lib/stdlib/src/gen_statem.erl
+++ b/lib/stdlib/src/gen_statem.erl
@@ -24,7 +24,7 @@
[start/3,start/4,start_link/3,start_link/4,
stop/1,stop/3,
cast/2,call/2,call/3,
- enter_loop/5,enter_loop/6,enter_loop/7,
+ enter_loop/4,enter_loop/5,enter_loop/6,
reply/1,reply/2]).
%% gen callbacks
@@ -63,8 +63,8 @@
{To :: pid(), Tag :: term()}. % Reply-to specifier for call
-type state() ::
- state_name() | % For state callback function StateName/5
- term(). % For state callback function handle_event/5
+ state_name() | % For StateName/3 callback functios
+ term(). % For handle_event/4 callback function
-type state_name() :: atom().
@@ -174,28 +174,33 @@
%% an {ok, ...} tuple. Thereafter the state callbacks are called
%% for all events to this server.
-callback init(Args :: term()) ->
- {callback_mode(), state(), data()} |
- {callback_mode(), state(), data(), [action()] | action()} |
+ {ok, state(), data()} |
+ {ok, state(), data(), [action()] | action()} |
'ignore' |
{'stop', Reason :: term()}.
-%% Example state callback for callback_mode() =:= state_functions
-%% state name 'state_name'.
+%% This callback shall return the callback mode of the callback module.
%%
-%% In this mode all states has to be type state_name() i.e atom().
+%% 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().
+
+%% Example state callback for StateName = 'state_name'
+%% when callback_mode() =:= state_functions.
+%%
+%% In this mode all states has to be of type state_name() i.e atom().
%%
-%% Note that state callbacks and only state callbacks have arity 5
-%% and that is intended.
+%% Note that the only callbacks that have arity 3 are these
+%% StateName/3 callbacks and terminate/3, so the state name
+%% 'terminate' is unusable in this mode.
-callback state_name(
event_type(),
EventContent :: term(),
Data :: data()) ->
state_function_result().
%%
-%% State callback for callback_mode() =:= handle_event_function.
-%%
-%% Note that state callbacks and only state callbacks have arity 5
-%% and that is intended.
+%% State callback for all states
+%% when callback_mode() =:= handle_event_function.
-callback handle_event(
event_type(),
EventContent :: term(),
@@ -219,9 +224,7 @@
OldState :: state(),
OldData :: data(),
Extra :: term()) ->
- {CallbackMode :: callback_mode(),
- NewState :: state(),
- NewData :: data()} |
+ {ok, NewState :: state(), NewData :: data()} |
(Reason :: term()).
%% Format the callback module state in some sensible that is
@@ -240,10 +243,13 @@
[init/1, % One may use enter_loop/5,6,7 instead
format_status/2, % Has got a default implementation
%%
- state_name/3, % Example for callback_mode =:= state_functions:
- %% there has to be a StateName/5 callback function for every StateName.
+ state_name/3, % Example for callback_mode() =:= state_functions:
+ %% there has to be a StateName/3 callback function
+ %% for every StateName in your state machine but the state name
+ %% 'state_name' does of course not have to be used.
%%
- handle_event/4]). % For callback_mode =:= handle_event_function
+ handle_event/4 % For callback_mode() =:= handle_event_function
+ ]).
%% Type validation functions
callback_mode(CallbackMode) ->
@@ -451,43 +457,35 @@ reply({To,Tag}, Reply) when is_pid(To) ->
%% the same arguments as you would have returned from init/1
-spec enter_loop(
Module :: module(), Opts :: [debug_opt()],
- CallbackMode :: callback_mode(),
State :: state(), Data :: data()) ->
no_return().
-enter_loop(Module, Opts, CallbackMode, State, Data) ->
- enter_loop(Module, Opts, CallbackMode, State, Data, self()).
+enter_loop(Module, Opts, State, Data) ->
+ enter_loop(Module, Opts, State, Data, self()).
%%
-spec enter_loop(
Module :: module(), Opts :: [debug_opt()],
- CallbackMode :: callback_mode(),
State :: state(), Data :: data(),
Server_or_Actions ::
server_name() | pid() | [action()]) ->
no_return().
-enter_loop(Module, Opts, CallbackMode, State, Data, Server_or_Actions) ->
+enter_loop(Module, Opts, State, Data, Server_or_Actions) ->
if
is_list(Server_or_Actions) ->
- enter_loop(
- Module, Opts, CallbackMode, State, Data,
- self(), Server_or_Actions);
+ enter_loop(Module, Opts, State, Data, self(), Server_or_Actions);
true ->
- enter_loop(
- Module, Opts, CallbackMode, State, Data,
- Server_or_Actions, [])
+ enter_loop(Module, Opts, State, Data, Server_or_Actions, [])
end.
%%
-spec enter_loop(
Module :: module(), Opts :: [debug_opt()],
- CallbackMode :: callback_mode(),
State :: state(), Data :: data(),
Server :: server_name() | pid(),
Actions :: [action()] | action()) ->
no_return().
-enter_loop(Module, Opts, CallbackMode, State, Data, Server, Actions) ->
+enter_loop(Module, Opts, State, Data, Server, Actions) ->
is_atom(Module) orelse error({atom,Module}),
- callback_mode(CallbackMode) orelse error({callback_mode,CallbackMode}),
Parent = gen:get_parent(),
- enter(Module, Opts, CallbackMode, State, Data, Server, Actions, Parent).
+ enter(Module, Opts, State, Data, Server, Actions, Parent).
%%---------------------------------------------------------------------------
%% API helpers
@@ -515,7 +513,7 @@ send(Proc, Msg) ->
end.
%% Here the init_it/6 and enter_loop/5,6,7 functions converge
-enter(Module, Opts, CallbackMode, State, Data, Server, Actions, Parent) ->
+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),
@@ -531,7 +529,7 @@ enter(Module, Opts, CallbackMode, State, Data, Server, Actions, Parent) ->
[Actions,{postpone,false}]
end,
S = #{
- callback_mode => CallbackMode,
+ callback_mode => undefined,
module => Module,
name => Name,
%% All fields below will be replaced according to the arguments to
@@ -569,30 +567,12 @@ init_it(Starter, Parent, ServerRef, Module, Args, Opts) ->
init_result(Starter, Parent, ServerRef, Module, Result, Opts) ->
case Result of
- {CallbackMode,State,Data} ->
- case callback_mode(CallbackMode) of
- true ->
- proc_lib:init_ack(Starter, {ok,self()}),
- enter(
- Module, Opts, CallbackMode, State, Data,
- ServerRef, [], Parent);
- false ->
- Error = {callback_mode,CallbackMode},
- proc_lib:init_ack(Starter, {error,Error}),
- exit(Error)
- end;
- {CallbackMode,State,Data,Actions} ->
- case callback_mode(CallbackMode) of
- true ->
- proc_lib:init_ack(Starter, {ok,self()}),
- enter(
- Module, Opts, CallbackMode, State, Data,
- ServerRef, Actions, Parent);
- false ->
- Error = {callback_mode,CallbackMode},
- proc_lib:init_ack(Starter, {error,Error}),
- exit(Error)
- end;
+ {ok,State,Data} ->
+ proc_lib:init_ack(Starter, {ok,self()}),
+ enter(Module, Opts, State, Data, ServerRef, [], Parent);
+ {ok,State,Data,Actions} ->
+ proc_lib:init_ack(Starter, {ok,self()}),
+ enter(Module, Opts, State, Data, ServerRef, Actions, Parent);
{stop,Reason} ->
gen:unregister_name(ServerRef),
proc_lib:init_ack(Starter, {error,Reason}),
@@ -631,11 +611,9 @@ system_code_change(
Result -> Result
end
of
- {CallbackMode,NewState,NewData} ->
- callback_mode(CallbackMode) orelse
- error({callback_mode,CallbackMode}),
+ {ok,NewState,NewData} ->
{ok,
- S#{callback_mode := CallbackMode,
+ S#{callback_mode := undefined,
state := NewState,
data := NewData}};
{ok,_} = Error ->
@@ -859,6 +837,31 @@ loop_events_done(Parent, Debug, S, Timer, State, Data, P, Hibernate) ->
loop_event(
Parent, Debug,
+ #{callback_mode := undefined,
+ module := Module} = S,
+ Events,
+ State, Data, P, Event, Hibernate) ->
+ %% Cache the callback_mode() value
+ case
+ try Module:callback_mode()
+ catch
+ Result -> Result
+ end
+ of
+ CallbackMode ->
+ case callback_mode(CallbackMode) of
+ true ->
+ loop_event(
+ Parent, Debug,
+ S#{callback_mode := CallbackMode},
+ Events,
+ State, Data, P, Event, Hibernate);
+ false ->
+ error({callback_mode,CallbackMode})
+ end
+ end;
+loop_event(
+ Parent, Debug,
#{callback_mode := CallbackMode,
module := Module} = S,
Events,
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-26 07:11:57 +0000