diff options
Diffstat (limited to 'lib/stdlib')
| -rw-r--r-- | lib/stdlib/doc/src/gen_statem.xml | 247 | ||||
| -rw-r--r-- | lib/stdlib/src/gen_statem.erl | 260 | ||||
| -rw-r--r-- | lib/stdlib/test/gen_statem_SUITE.erl | 121 |
3 files changed, 351 insertions, 277 deletions
diff --git a/lib/stdlib/doc/src/gen_statem.xml b/lib/stdlib/doc/src/gen_statem.xml index ed44eef912..3322571b2c 100644 --- a/lib/stdlib/doc/src/gen_statem.xml +++ b/lib/stdlib/doc/src/gen_statem.xml @@ -97,6 +97,9 @@ gen_statem module Callback module gen_statem:start gen_statem:start_link -----> Module:init/1 +Server start or code change + -----> Module:callback_mode/0 + gen_statem:stop -----> Module:terminate/3 gen_statem:call @@ -116,9 +119,11 @@ erlang:'!' -----> Module:StateName/3 </p> <p> If a callback function fails or returns a bad value, - the <c>gen_statem</c> terminates. However, an exception of class + the <c>gen_statem</c> terminates, unless otherwise stated. + However, an exception of class <seealso marker="erts:erlang#throw/1"><c>throw</c></seealso> - is not regarded as an error but as a valid return. + is not regarded as an error but as a valid return + from all callback functions. </p> <marker id="state_function"/> <p> @@ -127,7 +132,8 @@ erlang:'!' -----> Module:StateName/3 in a <c>gen_statem</c> is the callback function that is called for all events in this state. It is selected depending on which <seealso marker="#type-callback_mode"><em>callback mode</em></seealso> - that the implementation specifies when the server starts. + that the callback module defines with the callback function + <seealso marker="#Module:callback_mode/0"><c>Module:callback_mode/0</c></seealso>. </p> <p> When the @@ -138,9 +144,9 @@ erlang:'!' -----> Module:StateName/3 This gathers all code for a specific state in one function as the <c>gen_statem</c> engine branches depending on state name. - Notice that in this mode the mandatory callback function + Notice the fact that there is a mandatory callback function <seealso marker="#Module:terminate/3"><c>Module:terminate/3</c></seealso> - makes the state name <c>terminate</c> unusable. + makes the state name <c>terminate</c> unusable in this mode. </p> <p> When the @@ -249,11 +255,10 @@ erlang:'!' -----> Module:StateName/3 -behaviour(gen_statem). -export([start/0,push/0,get_count/0,stop/0]). --export([terminate/3,code_change/4,init/1]). +-export([terminate/3,code_change/4,init/1,callback_mode/0]). -export([on/3,off/3]). name() -> pushbutton_statem. % The registered server name -callback_mode() -> state_functions. %% API. This example uses a registered name name() %% and does not link to the caller. @@ -270,15 +275,14 @@ stop() -> terminate(_Reason, _State, _Data) -> void. code_change(_Vsn, State, Data, _Extra) -> - {callback_mode(),State,Data}. + {ok,State,Data}. init([]) -> - %% Set the callback mode and initial state + data. - %% Data is used only as a counter. + %% Set the initial state + data. Data is used only as a counter. State = off, Data = 0, - {callback_mode(),State,Data}. - + {ok,State,Data}. +callback_mode() -> state_functions. -%%% State functions +%%% State function(s) off({call,From}, push, Data) -> %% Go to 'on', increment count and reply @@ -326,18 +330,13 @@ ok To compare styles, here follows the same example using <seealso marker="#type-callback_mode"><em>callback mode</em></seealso> <c>state_functions</c>, or rather the code to replace - from function <c>init/1</c> of the <c>pushbutton.erl</c> + after function <c>init/1</c> of the <c>pushbutton.erl</c> example file above: </p> <code type="erl"> -init([]) -> - %% Set the callback mode and initial state + data. - %% Data is used only as a counter. - State = off, Data = 0, - {handle_event_function,State,Data}. - +callback_mode() -> handle_event_function. -%%% Event handling +%%% State function(s) handle_event({call,From}, push, off, Data) -> %% Go to 'on', increment count and reply @@ -426,8 +425,8 @@ handle_event(_, _, State, Data) -> <desc> <p> Debug option that can be used when starting - a <c>gen_statem</c> server through, for example, - <seealso marker="#enter_loop/5"><c>enter_loop/5</c></seealso>. + a <c>gen_statem</c> server through, + <seealso marker="#enter_loop/4"><c>enter_loop/4-6</c></seealso>. </p> <p> For every entry in <c><anno>Dbgs</anno></c>, @@ -525,12 +524,9 @@ handle_event(_, _, State, Data) -> <desc> <p> The <em>callback mode</em> is selected when starting the - <c>gen_statem</c> using the return value from - <seealso marker="#Module:init/1"><c>Module:init/1</c></seealso> - or when calling - <seealso marker="#enter_loop/5"><c>enter_loop/5,6,7</c></seealso>, - and with the return value from - <seealso marker="#Module:code_change/4"><c>Module:code_change/4</c></seealso>. + <c>gen_statem</c> and after code change + using the return value from + <seealso marker="#Module:callback_mode/0"><c>Module:callback_mode/0</c></seealso>. </p> <taglist> <tag><c>state_functions</c></tag> @@ -691,7 +687,7 @@ handle_event(_, _, State, Data) -> <seealso marker="#state_function">state function</seealso>, from <seealso marker="#Module:init/1"><c>Module:init/1</c></seealso> or by giving them to - <seealso marker="#enter_loop/6"><c>enter_loop/6,7</c></seealso>. + <seealso marker="#enter_loop/5"><c>enter_loop/5,6</c></seealso>. </p> <p> Actions are executed in the containing list order. @@ -923,7 +919,8 @@ handle_event(_, _, State, Data) -> </p> <note> <p> - To avoid getting a late reply in the caller's + For <c><anno>Timeout</anno> =/= infinity</c>, + to avoid getting a late reply in the caller's inbox, this function spawns a proxy process that does the call. A late reply gets delivered to the dead proxy process, hence gets discarded. This is @@ -958,35 +955,36 @@ handle_event(_, _, State, Data) -> </func> <func> - <name name="enter_loop" arity="5"/> + <name name="enter_loop" arity="4"/> <fsummary>Enter the <c>gen_statem</c> receive loop.</fsummary> <desc> <p> The same as - <seealso marker="#enter_loop/7"><c>enter_loop/7</c></seealso> - except that no + <seealso marker="#enter_loop/6"><c>enter_loop/6</c></seealso> + with <c>Actions = []</c> except that no <seealso marker="#type-server_name"><c>server_name()</c></seealso> - must have been registered. + must have been registered. This creates an anonymous server. </p> </desc> </func> <func> - <name name="enter_loop" arity="6"/> + <name name="enter_loop" arity="5"/> <fsummary>Enter the <c>gen_statem</c> receive loop.</fsummary> <desc> <p> If <c><anno>Server_or_Actions</anno></c> is a <c>list()</c>, the same as - <seealso marker="#enter_loop/7"><c>enter_loop/7</c></seealso> + <seealso marker="#enter_loop/6"><c>enter_loop/6</c></seealso> except that no <seealso marker="#type-server_name"><c>server_name()</c></seealso> must have been registered and <c>Actions = <anno>Server_or_Actions</anno></c>. + This creates an anonymous server. </p> <p> Otherwise the same as - <seealso marker="#enter_loop/7"><c>enter_loop/7</c></seealso> + <seealso marker="#enter_loop/6"><c>enter_loop/6</c></seealso> with <c>Server = <anno>Server_or_Actions</anno></c> and <c>Actions = []</c>. @@ -995,7 +993,7 @@ handle_event(_, _, State, Data) -> </func> <func> - <name name="enter_loop" arity="7"/> + <name name="enter_loop" arity="6"/> <fsummary>Enter the <c>gen_statem</c> receive loop.</fsummary> <desc> <p> @@ -1015,21 +1013,31 @@ handle_event(_, _, State, Data) -> the <c>gen_statem</c> behavior provides. </p> <p> - <c><anno>Module</anno></c>, <c><anno>Opts</anno></c>, and - <c><anno>Server</anno></c> have the same meanings - as when calling + <c><anno>Module</anno></c>, <c><anno>Opts</anno></c> + have the same meaning as when calling <seealso marker="#start_link/3"><c>start[_link]/3,4</c></seealso>. + </p> + <p> + If <c><anno>Server</anno></c> is <c>self()</c> an anonymous + server is created just as when using + <seealso marker="#start_link/3"><c>start[_link]/3</c></seealso>. + If <c><anno>Server</anno></c> is a + <seealso marker="#type-server_name"><c>server_name()</c></seealso> + a named server is created just as when using + <seealso marker="#start_link/4"><c>start[_link]/4</c></seealso>. However, the <seealso marker="#type-server_name"><c>server_name()</c></seealso> name must have been registered accordingly - <em>before</em> this function is called.</p> + <em>before</em> this function is called. + </p> <p> - <c><anno>CallbackMode</anno></c>, <c><anno>State</anno></c>, - <c><anno>Data</anno></c>, and <c><anno>Actions</anno></c> + <c><anno>State</anno></c>, <c><anno>Data</anno></c>, + and <c><anno>Actions</anno></c> have the same meanings as in the return value of <seealso marker="#Module:init/1"><c>Module:init/1</c></seealso>. - Also, the callback module <c><anno>Module</anno></c> - does not need to export an <c>init/1</c> function. + Also, the callback module does not need to export a + <seealso marker="#Module:init/1"><c>Module:init/1</c></seealso> + function. </p> <p> The function fails if the calling process was not started by a @@ -1253,6 +1261,48 @@ handle_event(_, _, State, Data) -> <funcs> <func> + <name>Module:callback_mode() -> CallbackMode</name> + <fsummary>Update the internal state during upgrade/downgrade.</fsummary> + <type> + <v> + CallbackMode = + <seealso marker="#type-callback_mode">callback_mode()</seealso> + </v> + </type> + <desc> + <p> + This function is called by a <c>gen_statem</c> + when it needs to find out the + <seealso marker="#type-callback_mode"><em>callback mode</em></seealso> + of the callback module. The value is cached by <c>gen_statem</c> + for efficiency reasons, so this function is only called + once after server start and after code change, + but before the first + <seealso marker="#state_function">state function</seealso> + is called. More occasions may be added in future versions + of <c>gen_statem</c>. + </p> + <p> + Server start happens either when + <seealso marker="#Module:init/1"><c>Module:init/1</c></seealso> + returns or when + <seealso marker="#enter_loop/4"><c>enter_loop/4-6</c></seealso> + is called. Code change happens when + <seealso marker="#Module:code_change/4"><c>Module:code_change/4</c></seealso> + returns. + </p> + <note> + <p> + If this function's body does not consist of solely one of two + possible + <seealso marker="#type-callback_mode">atoms</seealso> + the callback module is doing something strange. + </p> + </note> + </desc> + </func> + + <func> <name>Module:code_change(OldVsn, OldState, OldData, Extra) -> Result </name> @@ -1262,11 +1312,7 @@ handle_event(_, _, State, Data) -> <v> Vsn = term()</v> <v>OldState = NewState = term()</v> <v>Extra = term()</v> - <v>Result = {CallbackMode,NewState,NewData} | Reason</v> - <v> - CallbackMode = - <seealso marker="#type-callback_mode">callback_mode()</seealso> - </v> + <v>Result = {ok,NewState,NewData} | Reason</v> <v> OldState = NewState = <seealso marker="#type-state">state()</seealso> @@ -1295,21 +1341,6 @@ handle_event(_, _, State, Data) -> <c>Module</c>. If no such attribute is defined, the version is the checksum of the Beam file. </p> - <note> - <p> - If you would dare to change - <seealso marker="#type-callback_mode"><em>callback mode</em></seealso> - during release upgrade/downgrade, the upgrade is no problem, - as the new code surely knows what <em>callback mode</em> - it needs. However, for a downgrade this function must - know from argument <c>Extra</c> that comes from the - <seealso marker="sasl:appup"><c>sasl:appup</c></seealso> - file what <em>callback mode</em> the old code did use. - It can also be possible to figure this out - from argument <c>{down,Vsn}</c>, as <c>Vsn</c> - in effect defines the old callback module version. - </p> - </note> <p> <c>OldState</c> and <c>OldData</c> is the internal state of the <c>gen_statem</c>. @@ -1321,39 +1352,32 @@ handle_event(_, _, State, Data) -> <p> If successful, the function must return the updated internal state in an - <c>{CallbackMode,NewState,NewData}</c> tuple. + <c>{ok,NewState,NewData}</c> tuple. </p> <p> If the function returns a failure <c>Reason</c>, the ongoing upgrade fails and rolls back to the old release. - Note that <c>Reason</c> can not be a 3-tuple since that - will be regarded as a - <c>{CallbackMode,NewState,NewData}</c> tuple, + Note that <c>Reason</c> can not be an <c>{ok,_,_}</c> tuple + since that will be regarded as a + <c>{ok,NewState,NewData}</c> tuple, and that a tuple matching <c>{ok,_}</c> - is an invalid failure <c>Reason</c>. + is an also invalid failure <c>Reason</c>. It is recommended to use an atom as <c>Reason</c> since it will be wrapped in an <c>{error,Reason}</c> tuple. </p> - <p> - This function can use - <seealso marker="erts:erlang#throw/1"><c>erlang:throw/1</c></seealso> - to return <c>Result</c> or <c>Reason</c>. - </p> </desc> </func> <func> <name>Module:init(Args) -> Result</name> - <fsummary>Initialize process and internal state.</fsummary> + <fsummary> + Optional function for initializing process and internal state. + </fsummary> <type> <v>Args = term()</v> - <v>Result = {CallbackMode,State,Data}</v> - <v> | {CallbackMode,State,Data,Actions}</v> + <v>Result = {ok,State,Data}</v> + <v> | {ok,State,Data,Actions}</v> <v> | {stop,Reason} | ignore</v> - <v> - CallbackMode = - <seealso marker="#type-callback_mode">callback_mode()</seealso> - </v> <v>State = <seealso marker="#type-state">state()</seealso></v> <v> Data = <seealso marker="#type-data">data()</seealso> @@ -1372,7 +1396,7 @@ handle_event(_, _, State, Data) -> <seealso marker="#start_link/3"><c>start_link/3,4</c></seealso> or <seealso marker="#start/3"><c>start/3,4</c></seealso>, - this function is called by the new process to initialize + this optional function is called by the new process to initialize the implementation state and server data. </p> <p> @@ -1381,11 +1405,8 @@ handle_event(_, _, State, Data) -> </p> <p> If the initialization is successful, the function is to - return <c>{CallbackMode,State,Data}</c> or - <c>{CallbackMode,State,Data,Actions}</c>. - <c>CallbackMode</c> selects the - <seealso marker="#type-callback_mode"><em>callback mode</em></seealso> - of the <c>gen_statem</c>. + return <c>{ok,State,Data}</c> or + <c>{ok,State,Data,Actions}</c>. <c>State</c> is the initial <seealso marker="#type-state"><c>state()</c></seealso> and <c>Data</c> the initial server @@ -1403,11 +1424,16 @@ handle_event(_, _, State, Data) -> or <c>ignore</c>; see <seealso marker="#start_link/3"><c>start_link/3,4</c></seealso>. </p> - <p> - This function can use - <seealso marker="erts:erlang#throw/1"><c>erlang:throw/1</c></seealso> - to return <c>Result</c>. - </p> + <note> + <p> + This callback is optional, so a callback module does not need + to export it, but most do. If this function is not exported, + the <c>gen_statem</c> should be started through + <seealso marker="proc_lib"><c>proc_lib</c></seealso> + and + <seealso marker="#enter_loop/4"><c>enter_loop/4-6</c></seealso>. + </p> + </note> </desc> </func> @@ -1438,10 +1464,14 @@ handle_event(_, _, State, Data) -> This callback is optional, so a callback module does not need to export it. The <c>gen_statem</c> module provides a default implementation of this function that returns - <c>{State,Data}</c>. If this callback fails, the default - function returns <c>{State,Info}</c>, - where <c>Info</c> informs of the crash but no details, - to hide possibly sensitive data. + <c>{State,Data}</c>. + </p> + <p> + If this callback is exported but fails, + to hide possibly sensitive data, + the default function will instead return <c>{State,Info}</c>, + where <c>Info</c> says nothing but the fact that + <c>format_status/2</c> has crashed. </p> </note> <p>This function is called by a <c>gen_statem</c> process when @@ -1502,11 +1532,6 @@ handle_event(_, _, State, Data) -> printed in log files. Another use is to hide sensitive data from being written to the error log. </p> - <p> - This function can use - <seealso marker="erts:erlang#throw/1"><c>erlang:throw/1</c></seealso> - to return <c>Status</c>. - </p> </desc> </func> @@ -1581,9 +1606,12 @@ handle_event(_, _, State, Data) -> see <seealso marker="#type-action"><c>action()</c></seealso>. </p> <p> - These functions can use - <seealso marker="erts:erlang#throw/1"><c>erlang:throw/1</c></seealso>, - to return the result. + Note the fact that you can use + <seealso marker="erts:erlang#throw/1"><c>throw</c></seealso> + to return the result, which can be useful. + For example to bail out with <c>throw(keep_state_and_data)</c> + from deep within complex code that is in no position to + return <c>{next_state,State,Data}</c>. </p> </desc> </func> @@ -1656,11 +1684,6 @@ handle_event(_, _, State, Data) -> and an error report is issued using <seealso marker="kernel:error_logger#format/2"><c>error_logger:format/2</c></seealso>. </p> - <p> - This function can use - <seealso marker="erts:erlang#throw/1"><c>erlang:throw/1</c></seealso> - to return <c>Ignored</c>, which is ignored anyway. - </p> </desc> </func> </funcs> diff --git a/lib/stdlib/src/gen_statem.erl b/lib/stdlib/src/gen_statem.erl index c02e6a1a19..3b3477b282 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 @@ -559,9 +557,15 @@ init_it(Starter, Parent, ServerRef, Module, Args, Opts) -> Result -> init_result(Starter, Parent, ServerRef, Module, Result, Opts); Class:Reason -> + Stacktrace = erlang:get_stacktrace(), + Name = gen:get_proc_name(ServerRef), gen:unregister_name(ServerRef), proc_lib:init_ack(Starter, {error,Reason}), - erlang:raise(Class, Reason, erlang:get_stacktrace()) + error_info( + Class, Reason, Stacktrace, + #{name => Name, callback_mode => undefined}, + [], [], undefined), + erlang:raise(Class, Reason, Stacktrace) end. %%--------------------------------------------------------------------------- @@ -569,30 +573,12 @@ 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}), @@ -602,8 +588,14 @@ init_result(Starter, Parent, ServerRef, Module, Result, Opts) -> proc_lib:init_ack(Starter, ignore), exit(normal); _ -> - Error = {bad_return_value,Result}, + Name = gen:get_proc_name(ServerRef), + gen:unregister_name(ServerRef), + Error = {bad_return_from_init,Result}, proc_lib:init_ack(Starter, {error,Error}), + error_info( + error, Error, ?STACKTRACE(), + #{name => Name, callback_mode => undefined}, + [], [], undefined), exit(Error) end. @@ -631,11 +623,9 @@ 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 -> @@ -676,14 +666,14 @@ format_status( %% them, not as the real erlang messages. Use trace for that. %%--------------------------------------------------------------------------- -print_event(Dev, {in,Event}, {Name,_}) -> +print_event(Dev, {in,Event}, {Name,State}) -> io:format( - Dev, "*DBG* ~p received ~s~n", - [Name,event_string(Event)]); -print_event(Dev, {out,Reply,{To,_Tag}}, {Name,_}) -> + Dev, "*DBG* ~p receive ~s in state ~p~n", + [Name,event_string(Event),State]); +print_event(Dev, {out,Reply,{To,_Tag}}, {Name,State}) -> io:format( - Dev, "*DBG* ~p sent ~p to ~p~n", - [Name,Reply,To]); + Dev, "*DBG* ~p send ~p to ~p from state ~p~n", + [Name,Reply,To,State]); print_event(Dev, {Tag,Event,NextState}, {Name,State}) -> StateString = case NextState of @@ -875,22 +865,36 @@ loop_event( %% try case CallbackMode of + undefined -> + Module:callback_mode(); state_functions -> - Module:State(Type, Content, Data); + erlang:apply(Module, State, [Type,Content,Data]); handle_event_function -> Module:handle_event(Type, Content, State, Data) - end of + 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) 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); - error:badarg when CallbackMode =:= state_functions -> + error:badarg -> case erlang:get_stacktrace() of - [{erlang,apply,[Module,State,_],_}|Stacktrace] -> - Args = [Type,Content,Data], + [{erlang,apply, + [Module,State,[Type,Content,Data]=Args], + _} + |Stacktrace] + 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}}, @@ -902,24 +906,29 @@ loop_event( Debug, S, [Event|Events], State, Data, P) end; error:undef -> - %% Process an undef to check for the simple mistake + %% 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,State, - [Type,Content,Data]=Args, - _} + [{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 -> + when CallbackMode =:= state_functions -> terminate( error, {undef_state_function,{Module,State,Args}}, Stacktrace, Debug, S, [Event|Events], State, Data, P); - [{Module,handle_event, - [Type,Content,State,Data]=Args, - _} + [{Module,handle_event,[Type,Content,State,Data]=Args,_} |Stacktrace] - when CallbackMode =:= handle_event_function -> + when CallbackMode =:= handle_event_function -> terminate( error, {undef_state_function,{Module,handle_event,Args}}, @@ -937,6 +946,25 @@ loop_event( Debug, S, [Event|Events], State, Data, P) 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 -> + terminate( + error, + {bad_return_from_callback_mode,CallbackMode}, + ?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) -> @@ -989,7 +1017,9 @@ loop_event_result( State, Data, P, Event, State, Actions); _ -> terminate( - error, {bad_return_value,Result}, ?STACKTRACE(), + error, + {bad_return_from_state_function,Result}, + ?STACKTRACE(), Debug, S, [Event|Events], State, Data, P) end. @@ -1026,20 +1056,26 @@ loop_event_actions( Postpone, Hibernate, Timeout, NextEvents); false -> terminate( - error, {bad_action,Action}, ?STACKTRACE(), + 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, Debug, S, Events, + Parent, NewDebug, S, Events, State, NewData, P, Event, NextState, Actions, Postpone, Hibernate, Timeout, [{Type,Content}|NextEvents]); false -> terminate( - error, {bad_action,Action}, ?STACKTRACE(), + error, + {bad_action_from_state_function,Action}, + ?STACKTRACE(), Debug, S, [Event|Events], State, NewData, P) end; %% Actions that set options @@ -1050,7 +1086,9 @@ loop_event_actions( NewPostpone, Hibernate, Timeout, NextEvents); {postpone,_} -> terminate( - error, {bad_action,Action}, ?STACKTRACE(), + error, + {bad_action_from_state_function,Action}, + ?STACKTRACE(), Debug, S, [Event|Events], State, NewData, P); postpone -> loop_event_actions( @@ -1064,7 +1102,9 @@ loop_event_actions( Postpone, NewHibernate, Timeout, NextEvents); {hibernate,_} -> terminate( - error, {bad_action,Action}, ?STACKTRACE(), + error, + {bad_action_from_state_function,Action}, + ?STACKTRACE(), Debug, S, [Event|Events], State, NewData, P); hibernate -> loop_event_actions( @@ -1083,7 +1123,9 @@ loop_event_actions( Postpone, Hibernate, NewTimeout, NextEvents); {timeout,_,_} -> terminate( - error, {bad_action,Action}, ?STACKTRACE(), + error, + {bad_action_from_state_function,Action}, + ?STACKTRACE(), Debug, S, [Event|Events], State, NewData, P); infinity -> % Clear timer - it will never trigger loop_event_actions( @@ -1098,7 +1140,9 @@ loop_event_actions( Postpone, Hibernate, NewTimeout, NextEvents); _ -> terminate( - error, {bad_action,Action}, ?STACKTRACE(), + error, + {bad_action_from_state_function,Action}, + ?STACKTRACE(), Debug, S, [Event|Events], State, NewData, P) end; %% @@ -1170,7 +1214,9 @@ do_reply_then_terminate( NewDebug, S, Q, State, Data, P, Rs); _ -> terminate( - error, {bad_action,R}, ?STACKTRACE(), + error, + {bad_reply_action_from_state_function,R}, + ?STACKTRACE(), Debug, S, Q, State, Data, P) end. @@ -1189,8 +1235,9 @@ terminate( C:R -> ST = erlang:get_stacktrace(), error_info( - C, R, ST, Debug, S, Q, P, + C, R, ST, S, Q, P, format_status(terminate, get(), S, State, Data)), + sys:print_log(Debug), erlang:raise(C, R, ST) end, case Reason of @@ -1199,8 +1246,9 @@ terminate( {shutdown,_} -> ok; _ -> error_info( - Class, Reason, Stacktrace, Debug, S, Q, P, - format_status(terminate, get(), S, State, Data)) + Class, Reason, Stacktrace, S, Q, P, + format_status(terminate, get(), S, State, Data)), + sys:print_log(Debug) end, case Stacktrace of [] -> @@ -1210,7 +1258,7 @@ terminate( end. error_info( - Class, Reason, Stacktrace, Debug, + Class, Reason, Stacktrace, #{name := Name, callback_mode := CallbackMode}, Q, P, FmtData) -> {FixedReason,FixedStacktrace} = @@ -1277,9 +1325,7 @@ error_info( case FixedStacktrace of [] -> []; _ -> [FixedStacktrace] - end), - sys:print_log(Debug), - ok. + end). %% Call Module:format_status/2 or return a default value @@ -1292,7 +1338,7 @@ format_status(Opt, PDict, #{module := Module}, State, Data) -> _:_ -> format_status_default( Opt, State, - "Module:format_status/2 crashed") + atom_to_list(Module) ++ ":format_status/2 crashed") end; false -> format_status_default(Opt, State, Data) @@ -1300,10 +1346,10 @@ format_status(Opt, PDict, #{module := Module}, State, Data) -> %% The default Module:format_status/2 format_status_default(Opt, State, Data) -> - SSD = {State,Data}, + StateData = {State,Data}, case Opt of terminate -> - SSD; + StateData; _ -> - [{data,[{"State",SSD}]}] + [{data,[{"State",StateData}]}] end. diff --git a/lib/stdlib/test/gen_statem_SUITE.erl b/lib/stdlib/test/gen_statem_SUITE.erl index 364314f91b..1d1417c2e6 100644 --- a/lib/stdlib/test/gen_statem_SUITE.erl +++ b/lib/stdlib/test/gen_statem_SUITE.erl @@ -37,33 +37,32 @@ all() -> {group, stop_handle_event}, {group, abnormal}, {group, abnormal_handle_event}, - shutdown, stop_and_reply, event_order, + shutdown, stop_and_reply, event_order, code_change, {group, sys}, hibernate, enter_loop]. groups() -> - [{start, [], - [start1, start2, start3, start4, start5, start6, start7, - start8, start9, start10, start11, start12, next_events]}, - {start_handle_event, [], - [start1, start2, start3, start4, start5, start6, start7, - start8, start9, start10, start11, start12, next_events]}, - {stop, [], - [stop1, stop2, stop3, stop4, stop5, stop6, stop7, stop8, stop9, stop10]}, - {stop_handle_event, [], - [stop1, stop2, stop3, stop4, stop5, stop6, stop7, stop8, stop9, stop10]}, - {abnormal, [], [abnormal1, abnormal2]}, - {abnormal_handle_event, [], [abnormal1, abnormal2]}, - {sys, [], - [sys1, code_change, - call_format_status, - error_format_status, terminate_crash_format, - get_state, replace_state]}, - {sys_handle_event, [], - [sys1, - call_format_status, - error_format_status, terminate_crash_format, - get_state, replace_state]}]. + [{start, [], tcs(start)}, + {start_handle_event, [], tcs(start)}, + {stop, [], tcs(stop)}, + {stop_handle_event, [], tcs(stop)}, + {abnormal, [], tcs(abnormal)}, + {abnormal_handle_event, [], tcs(abnormal)}, + {sys, [], tcs(sys)}, + {sys_handle_event, [], tcs(sys)}]. + +tcs(start) -> + [start1, start2, start3, start4, start5, start6, start7, + start8, start9, start10, start11, start12, next_events]; +tcs(stop) -> + [stop1, stop2, stop3, stop4, stop5, stop6, stop7, stop8, stop9, stop10]; +tcs(abnormal) -> + [abnormal1, abnormal2]; +tcs(sys) -> + [sys1, call_format_status, + error_format_status, terminate_crash_format, + get_state, replace_state]. + init_per_suite(Config) -> Config. @@ -461,10 +460,10 @@ abnormal2(Config) -> {ok,Pid} = gen_statem:start_link(?MODULE, start_arg(Config, []), []), %% bad return value in the gen_statem loop - {{bad_return_value,badreturn},_} = + {{bad_return_from_state_function,badreturn},_} = ?EXPECT_FAILURE(gen_statem:call(Pid, badreturn), Reason), receive - {'EXIT',Pid,{bad_return_value,badreturn}} -> ok + {'EXIT',Pid,{bad_return_from_state_function,badreturn}} -> ok after 5000 -> ct:fail(gen_statem_did_not_die) end, @@ -633,11 +632,13 @@ sys1(Config) -> sys:resume(Pid), stop_it(Pid). -code_change(Config) -> - Mode = handle_event_function, - {ok,Pid} = gen_statem:start(?MODULE, start_arg(Config, []), []), +code_change(_Config) -> + {ok,Pid} = + gen_statem:start( + ?MODULE, {callback_mode,state_functions,[]}, []), {idle,data} = sys:get_state(Pid), sys:suspend(Pid), + Mode = handle_event_function, sys:change_code(Pid, ?MODULE, old_vsn, Mode), sys:resume(Pid), {idle,{old_vsn,data,Mode}} = sys:get_state(Pid), @@ -708,7 +709,7 @@ error_format_status(Config) -> gen_statem:start( ?MODULE, start_arg(Config, {data,Data}), []), %% bad return value in the gen_statem loop - {{bad_return_value,badreturn},_} = + {{bad_return_from_state_function,badreturn},_} = ?EXPECT_FAILURE(gen_statem:call(Pid, badreturn), Reason), receive {error,_, @@ -716,7 +717,7 @@ error_format_status(Config) -> "** State machine"++_, [Pid,{{call,_},badreturn}, {formatted,idle,Data}, - error,{bad_return_value,badreturn}|_]}} -> + error,{bad_return_from_state_function,badreturn}|_]}} -> ok; Other when is_tuple(Other), element(1, Other) =:= error -> error_logger_forwarder:unregister(), @@ -1029,11 +1030,7 @@ enter_loop(_Config) -> end, %% Process not started using proc_lib - CallbackMode = state_functions, - Pid4 = - spawn_link( - gen_statem, enter_loop, - [?MODULE,[],CallbackMode,state0,[]]), + Pid4 = spawn_link(gen_statem, enter_loop, [?MODULE,[],state0,[]]), receive {'EXIT',Pid4,process_was_not_started_by_proc_lib} -> ok @@ -1107,21 +1104,18 @@ enter_loop(Reg1, Reg2) -> anon -> ignore end, proc_lib:init_ack({ok, self()}), - CallbackMode = state_functions, case Reg2 of local -> gen_statem:enter_loop( - ?MODULE, [], CallbackMode, state0, [], {local,armitage}); + ?MODULE, [], state0, [], {local,armitage}); global -> gen_statem:enter_loop( - ?MODULE, [], CallbackMode, state0, [], {global,armitage}); + ?MODULE, [], state0, [], {global,armitage}); via -> gen_statem:enter_loop( - ?MODULE, [], CallbackMode, state0, [], - {via, dummy_via, armitage}); + ?MODULE, [], state0, [], {via, dummy_via, armitage}); anon -> - gen_statem:enter_loop( - ?MODULE, [], CallbackMode, state0, []) + gen_statem:enter_loop(?MODULE, [], state0, []) end. @@ -1266,33 +1260,39 @@ init(stop_shutdown) -> {stop,shutdown}; init(sleep) -> ?t:sleep(1000), - {state_functions,idle,data}; + {ok,idle,data}; init(hiber) -> - {state_functions,hiber_idle,[]}; + {ok,hiber_idle,[]}; init(hiber_now) -> - {state_functions,hiber_idle,[],[hibernate]}; + {ok,hiber_idle,[],[hibernate]}; init({data, Data}) -> - {state_functions,idle,Data}; + {ok,idle,Data}; init({callback_mode,CallbackMode,Arg}) -> - case init(Arg) of - {_,State,Data,Ops} -> - {CallbackMode,State,Data,Ops}; - {_,State,Data} -> - {CallbackMode,State,Data}; - Other -> - Other - end; + ets:new(?MODULE, [named_table,private]), + ets:insert(?MODULE, {callback_mode,CallbackMode}), + init(Arg); init({map_statem,#{init := Init}=Machine}) -> + ets:new(?MODULE, [named_table,private]), + ets:insert(?MODULE, {callback_mode,handle_event_function}), case Init() of {ok,State,Data,Ops} -> - {handle_event_function,State,[Data|Machine],Ops}; + {ok,State,[Data|Machine],Ops}; {ok,State,Data} -> - {handle_event_function,State,[Data|Machine]}; + {ok,State,[Data|Machine]}; Other -> Other end; init([]) -> - {state_functions,idle,data}. + {ok,idle,data}. + +callback_mode() -> + try ets:lookup(?MODULE, callback_mode) of + [{callback_mode,CallbackMode}] -> + CallbackMode + catch + error:badarg -> + state_functions + end. terminate(_, _State, crash_terminate) -> exit({crash,terminate}); @@ -1568,7 +1568,12 @@ wrap_result(Result) -> code_change(OldVsn, State, Data, CallbackMode) -> - {CallbackMode,State,{OldVsn,Data,CallbackMode}}. + io:format( + "code_change(~p, ~p, ~p, ~p)~n", [OldVsn,State,Data,CallbackMode]), + ets:insert(?MODULE, {callback_mode,CallbackMode}), + io:format( + "code_change(~p, ~p, ~p, ~p)~n", [OldVsn,State,Data,CallbackMode]), + {ok,State,{OldVsn,Data,CallbackMode}}. format_status(terminate, [_Pdict,State,Data]) -> {formatted,State,Data}; |