diff options
Diffstat (limited to 'system/doc/design_principles/statem.xml')
| -rw-r--r-- | system/doc/design_principles/statem.xml | 550 |
1 files changed, 332 insertions, 218 deletions
diff --git a/system/doc/design_principles/statem.xml b/system/doc/design_principles/statem.xml index 16f6ce8348..5269d23487 100644 --- a/system/doc/design_principles/statem.xml +++ b/system/doc/design_principles/statem.xml @@ -356,8 +356,8 @@ State(S) x Event(E) -> Actions(A), State(S')</pre> </p> </item> <tag> - <c>{stop_and_reply, Reason, NewData, Actions}</c><br /> - <c>{stop_and_reply, Reason, Actions}</c> + <c>{stop_and_reply, Reason, NewData, ReplyActions}</c><br /> + <c>{stop_and_reply, Reason, ReplyActions}</c> </tag> <item> <p> @@ -377,7 +377,7 @@ State(S) x Event(E) -> Actions(A), State(S')</pre> </seealso> callback function is called before any <seealso marker="#Event Handler">event handler</seealso> - is called. This function behaves exactly as an event handler + is called. This function behaves like an event handler function, but gets its only argument <c>Args</c> from the <c>gen_statem</c> <seealso marker="stdlib:gen_statem#start/3"> @@ -678,13 +678,14 @@ StateName(EventType, EventContent, Data) -> A door with a code lock can be seen as a state machine. Initially, the door is locked. When someone presses a button, an event is generated. - Depending on what buttons have been pressed before, - the sequence so far can be correct, incomplete, or wrong. + The pressed buttons are collected, up to the number of buttons + in the correct code. If correct, the door is unlocked for 10 seconds (10,000 milliseconds). - If incomplete, we wait for another button to be pressed. If - wrong, we start all over, waiting for a new button sequence. + If not correct, we wait for a new button to be pressed. </p> - <image file="../design_principles/code_lock.png"> + <!-- The image is edited with dia in a .dia file, + then exported to Scalable Vector Graphics. --> + <image file="../design_principles/code_lock.svg" width="80%"> <icaption>Code Lock State Diagram</icaption> </image> <p> @@ -698,37 +699,44 @@ StateName(EventType, EventContent, Data) -> -export([start_link/1]). -export([button/1]). --export([init/1,callback_mode/0,terminate/3,code_change/4]). +-export([init/1,callback_mode/0,terminate/3]). -export([locked/3,open/3]). start_link(Code) -> gen_statem:start_link({local,?NAME}, ?MODULE, Code, []). -button(Digit) -> - gen_statem:cast(?NAME, {button,Digit}). +button(Button) -> + gen_statem:cast(?NAME, {button,Button}). init(Code) -> do_lock(), - Data = #{code => Code, remaining => Code}, + Data = #{code => Code, length => length(Code), buttons => []}, {ok, locked, Data}. callback_mode() -> state_functions. - + ]]></code> + <code type="erl"><![CDATA[ locked( - cast, {button,Digit}, - #{code := Code, remaining := Remaining} = Data) -> - case Remaining of - [Digit] -> + cast, {button,Button}, + #{code := Code, length := Length, buttons := Buttons} = Data) -> + NewButtons = + if + length(Buttons) < Length -> + Buttons; + true -> + tl(Buttons) + end ++ [Button], + if + NewButtons =:= Code -> % Correct do_unlock(), - {next_state, open, Data#{remaining := Code}, + {next_state, open, Data#{buttons := []}, [{state_timeout,10000,lock}]}; - [Digit|Rest] -> % Incomplete - {next_state, locked, Data#{remaining := Rest}}; - _Wrong -> - {next_state, locked, Data#{remaining := Code}} + true -> % Incomplete | Incorrect + {next_state, locked, Data#{buttons := NewButtons}} end. - + ]]></code> + <code type="erl"><![CDATA[ open(state_timeout, lock, Data) -> do_lock(), {next_state, locked, Data}; @@ -743,8 +751,6 @@ do_unlock() -> terminate(_Reason, State, _Data) -> State =/= locked andalso do_lock(), ok. -code_change(_Vsn, State, Data, _Extra) -> - {ok, State, Data}. ]]></code> <p>The code is explained in the next sections.</p> </section> @@ -820,17 +826,17 @@ start_link(Code) -> in this case <c>locked</c>; assuming that the door is locked to begin with. <c>Data</c> is the internal server data of the <c>gen_statem</c>. Here the server data is a <seealso marker="stdlib:maps">map</seealso> - with key <c>code</c> that stores - the correct button sequence, and key <c>remaining</c> - that stores the remaining correct button sequence - (the same as the <c>code</c> to begin with). + with key <c>code</c> that stores the correct button sequence, + key <c>length</c> store its length, + and key <c>buttons</c> that stores the collected buttons + up to the same length. </p> <code type="erl"><![CDATA[ init(Code) -> do_lock(), - Data = #{code => Code, remaining => Code}, - {ok,locked,Data}. + Data = #{code => Code, length => length(Code), buttons => []}, + {ok, locked, Data}. ]]></code> <p>Function <seealso marker="stdlib:gen_statem#start_link/3"><c>gen_statem:start_link</c></seealso> @@ -848,10 +854,6 @@ init(Code) -> a <c>gen_statem</c> that is not part of a supervision tree. </p> - <code type="erl"><![CDATA[ -callback_mode() -> - state_functions. - ]]></code> <p> Function <seealso marker="stdlib:gen_statem#Module:callback_mode/0"><c>Module:callback_mode/0</c></seealso> @@ -859,8 +861,12 @@ callback_mode() -> <seealso marker="#Callback Modes"><c>CallbackMode</c></seealso> for the callback module, in this case <seealso marker="stdlib:gen_statem#type-callback_mode"><c>state_functions</c></seealso>. - That is, each state has got its own handler function. + That is, each state has got its own handler function: </p> + <code type="erl"><![CDATA[ +callback_mode() -> + state_functions. + ]]></code> </section> @@ -884,7 +890,7 @@ button(Digit) -> <c>{button,Digit}</c> is the event content. </p> <p> - The event is made into a message and sent to the <c>gen_statem</c>. + The event is sent to the <c>gen_statem</c>. When the event is received, the <c>gen_statem</c> calls <c>StateName(cast, Event, Data)</c>, which is expected to return a tuple <c>{next_state, NewStateName, NewData}</c>, @@ -893,44 +899,48 @@ button(Digit) -> <c>NewStateName</c> is the name of the next state to go to. <c>NewData</c> is a new value for the server data of the <c>gen_statem</c>, and <c>Actions</c> is a list of - actions on the <c>gen_statem</c> engine. + actions to be performed by the <c>gen_statem</c> engine. </p> + <code type="erl"><![CDATA[ locked( - cast, {button,Digit}, - #{code := Code, remaining := Remaining} = Data) -> - case Remaining of - [Digit] -> % Complete + cast, {button,Button}, + #{code := Code, length := Length, buttons := Buttons} = Data) -> + NewButtons = + if + length(Buttons) < Length -> + Buttons; + true -> + tl(Buttons) + end ++ [Button], + if + NewButtons =:= Code -> % Correct do_unlock(), - {next_state, open, Data#{remaining := Code}, + {next_state, open, Data#{buttons := []}, [{state_timeout,10000,lock}]}; - [Digit|Rest] -> % Incomplete - {next_state, locked, Data#{remaining := Rest}}; - [_|_] -> % Wrong - {next_state, locked, Data#{remaining := Code}} + true -> % Incomplete | Incorrect + {next_state, locked, Data#{buttons := NewButtons}} end. - -open(state_timeout, lock, Data) -> - do_lock(), - {next_state, locked, Data}; -open(cast, {button,_}, Data) -> - {next_state, open, Data}. ]]></code> <p> - If the door is locked and a button is pressed, the pressed - button is compared with the next correct button. + In state <c>locked</c>, when a button is pressed, + it is collected with the last pressed buttons + up to the length of the correct dode, + and compared with the correct code. Depending on the result, the door is either unlocked and the <c>gen_statem</c> goes to state <c>open</c>, or the door remains in state <c>locked</c>. </p> <p> - If the pressed button is incorrect, the server data - restarts from the start of the code sequence. - </p> - <p> - If the whole code is correct, the server changes states - to <c>open</c>. + When changing to state <c>open</c>, the collected + buttons are reset, the lock unlocked, and a state timer + for 10 s is started. </p> + + <code type="erl"><![CDATA[ +open(cast, {button,_}, Data) -> + {next_state, open, Data}. + ]]></code> <p> In state <c>open</c>, a button event is ignored by staying in the same state. This can also be done @@ -948,7 +958,7 @@ open(cast, {button,_}, Data) -> the following tuple is returned from <c>locked/2</c>: </p> <code type="erl"><![CDATA[ -{next_state, open, Data#{remaining := Code}, +{next_state, open, Data#{buttons := []}, [{state_timeout,10000,lock}]}; ]]></code> <p> @@ -986,9 +996,9 @@ open(state_timeout, lock, Data) -> <p> Consider a <c>code_length/0</c> function that returns the length of the correct code - (that should not be sensitive to reveal). + (that should not be too sensitive to reveal). We dispatch all events that are not state-specific - to the common function <c>handle_event/3</c>: + to the common function <c>handle_common/3</c>: </p> <code type="erl"><![CDATA[ ... @@ -1001,16 +1011,44 @@ code_length() -> ... locked(...) -> ... ; locked(EventType, EventContent, Data) -> - handle_event(EventType, EventContent, Data). + handle_common(EventType, EventContent, Data). ... open(...) -> ... ; open(EventType, EventContent, Data) -> - handle_event(EventType, EventContent, Data). + handle_common(EventType, EventContent, Data). -handle_event({call,From}, code_length, #{code := Code} = Data) -> +handle_common({call,From}, code_length, #{code := Code} = Data) -> {keep_state, Data, [{reply,From,length(Code)}]}. ]]></code> + + <p> + Another way to do it is through a convenience macro + <c>?HANDLE_COMMON/3</c>: + </p> + <code type="erl"><![CDATA[ +... +-export([button/1,code_length/0]). +... + +code_length() -> + gen_statem:call(?NAME, code_length). + +-define(HANDLE_COMMON(T, C, D), + ?FUNCTION_NAME(T, C, D) -> handle_common((T), (C), (D))). +%% +handle_common({call,From}, code_length, #{code := Code} = Data) -> + {keep_state, Data, [{reply,From,length(Code)}]}. + +... +locked(...) -> ... ; +?HANDLE_COMMON. + +... +open(...) -> ... ; +?HANDLE_COMMON. + ]]></code> + <p> This example uses <seealso marker="stdlib:gen_statem#call/2"><c>gen_statem:call/2</c></seealso>, @@ -1047,16 +1085,22 @@ callback_mode() -> handle_event(cast, {button,Digit}, State, #{code := Code} = Data) -> case State of locked -> - case maps:get(remaining, Data) of - [Digit] -> % Complete - do_unlock(), - {next_state, open, Data#{remaining := Code}, + #{length := Length, buttons := Buttons} = Data, + NewButtons = + if + length(Buttons) < Length -> + Buttons; + true -> + tl(Buttons) + end ++ [Button], + if + NewButtons =:= Code -> % Correct + do_unlock(), + {next_state, open, Data#{buttons := []}, [{state_timeout,10000,lock}]}; - [Digit|Rest] -> % Incomplete - {keep_state, Data#{remaining := Rest}}; - [_|_] -> % Wrong - {keep_state, Data#{remaining := Code}} - end; + true -> % Incomplete | Incorrect + {keep_state, Data#{buttons := NewButtons}} + end; open -> keep_state_and_data end; @@ -1165,16 +1209,15 @@ stop() -> <code type="erl"><![CDATA[ ... -locked( - timeout, _, - #{code := Code, remaining := Remaining} = Data) -> - {next_state, locked, Data#{remaining := Code}}; +locked(timeout, _, Data) -> + {next_state, locked, Data#{buttons := []}}; locked( cast, {button,Digit}, - #{code := Code, remaining := Remaining} = Data) -> + #{code := Code, length := Length, buttons := Buttons} = Data) -> ... - [Digit|Rest] -> % Incomplete - {next_state, locked, Data#{remaining := Rest}, 30000}; + true -> % Incomplete | Incorrect + {next_state, locked, Data#{buttons := NewButtons}, + 30000} ... ]]></code> <p> @@ -1189,6 +1232,13 @@ locked( Whatever event you act on has already cancelled the event time-out... </p> + <p> + Note that an event time-out does not work well with + when you have for example a status call as in + <seealso marker="#All State Events">All State Events</seealso>, + or handle unknown events, since all kinds of events + will cancel the event time-out. + </p> </section> <!-- =================================================================== --> @@ -1222,12 +1272,13 @@ locked( ... locked( cast, {button,Digit}, - #{code := Code, remaining := Remaining} = Data) -> - case Remaining of - [Digit] -> + #{code := Code, length := Length, buttons := Buttons} = Data) -> +... + if + NewButtons =:= Code -> % Correct do_unlock(), - {next_state, open, Data#{remaining := Code}, - [{{timeout,open_tm},10000,lock}]}; + {next_state, open, Data#{buttons := []}, + [{{timeout,open_tm},10000,lock}]}; ... open({timeout,open_tm}, lock, Data) -> @@ -1273,12 +1324,13 @@ open(cast, {button,_}, Data) -> ... locked( cast, {button,Digit}, - #{code := Code, remaining := Remaining} = Data) -> - case Remaining of - [Digit] -> + #{code := Code, length := Length, buttons := Buttons} = Data) -> +... + if + NewButtons =:= Code -> % Correct do_unlock(), Tref = erlang:start_timer(10000, self(), lock), - {next_state, open, Data#{remaining := Code, timer => Tref}}; + {next_state, open, Data#{buttons := [], timer => Tref}}; ... open(info, {timeout,Tref,lock}, #{timer := Tref} = Data) -> @@ -1398,28 +1450,38 @@ start_link(Code) -> fun () -> true = register(?NAME, self()), do_lock(), - locked(Code, Code) + locked(Code, length(Code), []) end). -button(Digit) -> - ?NAME ! {button,Digit}. - -locked(Code, [Digit|Remaining]) -> +button(Button) -> + ?NAME ! {button,Button}. + ]]></code> + <code type="erl"><![CDATA[ +locked(Code, Length, Buttons) -> receive - {button,Digit} when Remaining =:= [] -> - do_unlock(), - open(Code); - {button,Digit} -> - locked(Code, Remaining); - {button,_} -> - locked(Code, Code) + {button,Button} -> + NewButtons = + if + length(Buttons) < Length -> + Buttons; + true -> + tl(Buttons) + end ++ [Button], + if + NewButtons =:= Code -> % Correct + do_unlock(), + open(Code, Length); + true -> % Incomplete | Incorrect + locked(Code, Length, NewButtons) + end end. - -open(Code) -> + ]]></code> + <code type="erl"><![CDATA[ +open(Code, Length) -> receive after 10000 -> do_lock(), - locked(Code, Code) + locked(Code, Length, []) end. do_lock() -> @@ -1483,7 +1545,7 @@ do_unlock() -> ... init(Code) -> process_flag(trap_exit, true), - Data = #{code => Code}, + Data = #{code => Code, length = length(Code)}, {ok, locked, Data}. callback_mode() -> @@ -1491,13 +1553,14 @@ callback_mode() -> locked(enter, _OldState, Data) -> do_lock(), - {keep_state,Data#{remaining => Code}}; + {keep_state,Data#{buttons => []}}; locked( cast, {button,Digit}, - #{code := Code, remaining := Remaining} = Data) -> - case Remaining of - [Digit] -> - {next_state, open, Data}; + #{code := Code, length := Length, buttons := Buttons} = Data) -> +... + if + NewButtons =:= Code -> % Correct + {next_state, open, Data}; ... open(enter, _OldState, _Data) -> @@ -1557,48 +1620,50 @@ open(state_timeout, lock, Data) -> to synchronize the state machines. </p> <p> - The following example uses an input model where you give the lock - characters with <c>put_chars(Chars)</c> and then call - <c>enter()</c> to finish the input. + The following example uses an input model where the buttons + generate up/down events and the lock responds to an up + event after the corresponding down event. </p> <code type="erl"><![CDATA[ ... --export(put_chars/1, enter/0). +-export(down/1, up/1). ... -put_chars(Chars) when is_binary(Chars) -> - gen_statem:call(?NAME, {chars,Chars}). +down(button) -> + gen_statem:cast(?NAME, {down,Button}). -enter() -> - gen_statem:call(?NAME, enter). +up(button) -> + gen_statem:cast(?NAME, {up,Button}). ... locked(enter, _OldState, Data) -> do_lock(), {keep_state,Data#{remaining => Code, buf => []}}; +locked( + internal, {button,Digit}, + #{code := Code, length := Length, buttons := Buttons} = Data) -> ... - -handle_event({call,From}, {chars,Chars}, #{buf := Buf} = Data) -> - {keep_state, Data#{buf := [Chars|Buf], - [{reply,From,ok}]}; -handle_event({call,From}, enter, #{buf := Buf} = Data) -> - Chars = unicode:characters_to_binary(lists:reverse(Buf)), - try binary_to_integer(Chars) of - Digit -> - {keep_state, Data#{buf := []}, - [{reply,From,ok}, - {next_event,internal,{button,Chars}}]} - catch - error:badarg -> - {keep_state, Data#{buf := []}, - [{reply,From,{error,not_an_integer}}]} + ]]></code> + <code type="erl"><![CDATA[ +handle_common(cast, {down,Button}, Data) -> + {keep_state, Data#{button := Button}; +handle_common(cast, {up,Button}, Data) -> + case Data of + #{button := Button} -> + {keep_state,maps:remove(button, Data), + [{next_event,internal,{button,Button}}]}; + #{} -> + keep_state_and_data end; ... + +open(internal, {button,_}, Data) -> + {keep_state,Data,[postpone]}; +... ]]></code> <p> If you start this program with <c>code_lock:start([17])</c> - you can unlock with <c>code_lock:put_chars(<<"001">>), - code_lock:put_chars(<<"7">>), code_lock:enter()</c>. + you can unlock with <c>code_lock:down(17), code_lock:up(17).</c> </p> </section> @@ -1612,13 +1677,15 @@ handle_event({call,From}, enter, #{buf := Buf} = Data) -> modifications and some more using state enter calls, which deserves a new state diagram: </p> - <image file="../design_principles/code_lock_2.png"> + <!-- The image is edited with dia in a .dia file, + then exported to Scalable Vector Graphics. --> + <image file="../design_principles/code_lock_2.svg" width="80%"> <icaption>Code Lock State Diagram Revisited</icaption> </image> <p> Notice that this state diagram does not specify how to handle a button event in the state <c>open</c>. So, you need to - read somewhere else that unspecified events + read here that unspecified events must be ignored as in not consumed but handled in some other state. Also, the state diagram does not show that the <c>code_length/0</c> call must be handled in every state. @@ -1636,8 +1703,8 @@ handle_event({call,From}, enter, #{buf := Buf} = Data) -> -define(NAME, code_lock_2). -export([start_link/1,stop/0]). --export([button/1,code_length/0]). --export([init/1,callback_mode/0,terminate/3,code_change/4]). +-export([down/1,up/1,code_length/0]). +-export([init/1,callback_mode/0,terminate/3]). -export([locked/3,open/3]). start_link(Code) -> @@ -1645,52 +1712,74 @@ start_link(Code) -> stop() -> gen_statem:stop(?NAME). -button(Digit) -> - gen_statem:cast(?NAME, {button,Digit}). +down(Digit) -> + gen_statem:cast(?NAME, {down,Digit}). +up(Digit) -> + gen_statem:cast(?NAME, {up,Digit}). code_length() -> gen_statem:call(?NAME, code_length). - + ]]></code> + <code type="erl"><![CDATA[ init(Code) -> process_flag(trap_exit, true), - Data = #{code => Code}, + Data = #{code => Code, length => Length, buttons => []}, {ok, locked, Data}. callback_mode() -> [state_functions,state_enter]. -locked(enter, _OldState, #{code := Code} = Data) -> +-define(HANDLE_COMMON, + ?FUNCTION_NAME(T, C, D) -> handle_common((T), (C), (D))). +%% +handle_common(cast, {down,Button}, Data) -> + {keep_state, Data#{button => Button}}; +handle_common(cast, {up,Button}, Data) -> + case Data of + #{button := Button} -> + {keep_state, maps:remove(button, Data), + [{next_event,internal,{button,Data}}]}; + #{} -> + keep_state_and_data + end; +handle_common({call,From}, code_length, #{code := Code}) -> + {keep_state_and_data, [{reply,From,length(Code)}]}. + ]]></code> + <code type="erl"><![CDATA[ +locked(enter, _OldState, Data) -> do_lock(), - {keep_state, Data#{remaining => Code}}; -locked( - timeout, _, - #{code := Code, remaining := Remaining} = Data) -> - {keep_state, Data#{remaining := Code}}; + {keep_state, Data#{buttons := []}}; +locked(state_timeout, button, Data) -> + {keep_state, Data#{buttons := []}}; locked( - cast, {button,Digit}, - #{code := Code, remaining := Remaining} = Data) -> - case Remaining of - [Digit] -> % Complete - {next_state, open, Data}; - [Digit|Rest] -> % Incomplete - {keep_state, Data#{remaining := Rest}, 30000}; - [_|_] -> % Wrong - {keep_state, Data#{remaining := Code}} + internal, {button,Digit}, + #{code := Code, length := Length, buttons := Buttons} = Data) -> + NewButtons = + if + length(Buttons) < Length -> + Buttons; + true -> + tl(Buttons) + end ++ [Button], + if + NewButtons =:= Code -> % Correct + do_unlock(), + {next_state, open, Data, + [{state_timeout,10000,lock}]}; + true -> % Incomplete | Incorrect + {keep_state, Data#{buttons := NewButtons}, + [{state_timeout,30000,button}]} end; -locked(EventType, EventContent, Data) -> - handle_event(EventType, EventContent, Data). - +?HANDLE_COMMON. + ]]></code> + <code type="erl"><![CDATA[ open(enter, _OldState, _Data) -> do_unlock(), {keep_state_and_data, [{state_timeout,10000,lock}]}; open(state_timeout, lock, Data) -> {next_state, locked, Data}; -open(cast, {button,_}, _) -> +open(internal, {button,_}, _) -> {keep_state_and_data, [postpone]}; -open(EventType, EventContent, Data) -> - handle_event(EventType, EventContent, Data). - -handle_event({call,From}, code_length, #{code := Code}) -> - {keep_state_and_data, [{reply,From,length(Code)}]}. +?HANDLE_COMMON. do_lock() -> io:format("Locked~n", []). @@ -1700,8 +1789,6 @@ do_unlock() -> terminate(_Reason, State, _Data) -> State =/= locked andalso do_lock(), ok. -code_change(_Vsn, State, Data, _Extra) -> - {ok,State,Data}. ]]></code> </section> @@ -1724,26 +1811,32 @@ callback_mode() -> [handle_event_function,state_enter]. %% State: locked -handle_event( - enter, _OldState, locked, - #{code := Code} = Data) -> +handle_event(enter, _OldState, locked, Data) -> do_lock(), - {keep_state, Data#{remaining => Code}}; + {keep_state, Data#{buttons := []}}; +handle_event(state_timeout, button, locked, Data) -> + {keep_state, Data#{buttons := []}}; handle_event( - timeout, _, locked, - #{code := Code, remaining := Remaining} = Data) -> - {keep_state, Data#{remaining := Code}}; -handle_event( - cast, {button,Digit}, locked, - #{code := Code, remaining := Remaining} = Data) -> - case Remaining of - [Digit] -> % Complete - {next_state, open, Data}; - [Digit|Rest] -> % Incomplete - {keep_state, Data#{remaining := Rest}, 30000}; - [_|_] -> % Wrong - {keep_state, Data#{remaining := Code}} + internal, {button,Digit}, locked, + #{code := Code, length := Length, buttons := Buttons} = Data) -> + NewButtons = + if + length(Buttons) < Length -> + Buttons; + true -> + tl(Buttons) + end ++ [Button], + if + NewButtons =:= Code -> % Correct + do_unlock(), + {next_state, open, Data, + [{state_timeout,10000,lock}]}; + true -> % Incomplete | Incorrect + {keep_state, Data#{buttons := NewButtons}, + [{state_timeout,30000,button}]} end; + ]]></code> + <code type="erl"><![CDATA[ %% %% State: open handle_event(enter, _OldState, open, _Data) -> @@ -1753,10 +1846,22 @@ handle_event(state_timeout, lock, open, Data) -> {next_state, locked, Data}; handle_event(cast, {button,_}, open, _) -> {keep_state_and_data,[postpone]}; + ]]></code> + <code type="erl"><![CDATA[ %% %% Any state -handle_event({call,From}, code_length, _State, #{code := Code}) -> - {keep_state_and_data, [{reply,From,length(Code)}]}. +handle_event(cast, {down,Button}, _State, Data) -> + {keep_state, Data#{button => Button}}; +handle_event(cast, {up,Button}, _State, Data) -> + case Data of + #{button := Button} -> + {keep_state, maps:remove(button, Data), + [{state_timeout,30000,button}]}; + #{} -> + keep_state_and_data + end; +handle_event({call,From}, code_length, _State, #{length := Length}) -> + {keep_state_and_data, [{reply,From,Length}]}. ... ]]></code> @@ -1800,7 +1905,7 @@ handle_event({call,From}, code_length, _State, #{code := Code}) -> </p> <code type="erl"><![CDATA[ ... --export([init/1,terminate/3,code_change/4,format_status/2]). +-export([init/1,terminate/3,format_status/2]). ... format_status(Opt, [_PDict,State,Data]) -> @@ -1808,7 +1913,6 @@ format_status(Opt, [_PDict,State,Data]) -> {State, maps:filter( fun (code, _) -> false; - (remaining, _) -> false; (_, _) -> true end, Data)}, @@ -1896,7 +2000,7 @@ format_status(Opt, [_PDict,State,Data]) -> -export([start_link/2,stop/0]). -export([button/1,code_length/0,set_lock_button/1]). --export([init/1,callback_mode/0,terminate/3,code_change/4,format_status/2]). +-export([init/1,callback_mode/0,terminate/3,format_status/2]). -export([handle_event/4]). start_link(Code, LockButton) -> @@ -1911,10 +2015,11 @@ code_length() -> gen_statem:call(?NAME, code_length). set_lock_button(LockButton) -> gen_statem:call(?NAME, {set_lock_button,LockButton}). - + ]]></code> + <code type="erl"><![CDATA[ init({Code,LockButton}) -> process_flag(trap_exit, true), - Data = #{code => Code, remaining => undefined}, + Data = #{code => Code, length => length(Code), buttons => []}, {ok, {locked,LockButton}, Data}. callback_mode() -> @@ -1927,33 +2032,41 @@ handle_event( [{reply,From,OldLockButton}]}; handle_event( {call,From}, code_length, - {_StateName,_LockButton}, #{code := Code}) -> + {_StateName,_LockButton}, #{length := Length}) -> {keep_state_and_data, - [{reply,From,length(Code)}]}; + [{reply,From,Length}]}; + ]]></code> + <code type="erl"><![CDATA[ %% %% State: locked -handle_event( - EventType, EventContent, - {locked,LockButton}, #{code := Code, remaining := Remaining} = Data) -> +handle_event(EventType, EventContent, {locked,LockButton}, Data) -> case {EventType, EventContent} of {enter, _OldState} -> do_lock(), - {keep_state, Data#{remaining := Code}}; - {timeout, _} -> - {keep_state, Data#{remaining := Code}}; + {keep_state, Data#{buttons := []}}; + {state_timeout, button} -> + {keep_state, Data#{buttons := []}}; {{call,From}, {button,Digit}} -> - case Remaining of - [Digit] -> % Complete + #{length := Length, buttons := Buttons} = Data, + NewButtons = + if + length(Buttons) < Length -> + Buttons; + true -> + tl(Buttons) + end ++ [Button], + case Data of + #{code := NewButtons} -> {next_state, {open,LockButton}, Data, [{reply,From,ok}]}; - [Digit|Rest] -> % Incomplete - {keep_state, Data#{remaining := Rest}, - [{reply,From,ok}, 30000]}; - [_|_] -> % Wrong - {keep_state, Data#{remaining := Code}, - [{reply,From,ok}]} - end + #{} -> + {keep_state, Data#{buttons := NewButtons}, + [{reply,From,ok}, + {state_timeout,30000,button}]} + end end; + ]]></code> + <code type="erl"><![CDATA[ %% %% State: open handle_event( @@ -1962,7 +2075,8 @@ handle_event( case {EventType, EventContent} of {enter, _OldState} -> do_unlock(), - {keep_state_and_data, [{state_timeout,10000,lock}]}; + {keep_state_and_data, + [{state_timeout,10000,lock}]}; {state_timeout, lock} -> {next_state, {locked,LockButton}, Data}; {{call,From}, {button,Digit}} -> @@ -1975,7 +2089,8 @@ handle_event( [postpone]} end end. - + ]]></code> + <code type="erl"><![CDATA[ do_lock() -> io:format("Locked~n", []). do_unlock() -> @@ -1984,8 +2099,6 @@ do_unlock() -> terminate(_Reason, State, _Data) -> State =/= locked andalso do_lock(), ok. -code_change(_Vsn, State, Data, _Extra) -> - {ok,State,Data}. format_status(Opt, [_PDict,State,Data]) -> StateData = {State, @@ -2046,7 +2159,8 @@ handle_event( {enter, _OldState} -> do_unlock(), {keep_state_and_data, - [{state_timeout,10000,lock},hibernate]}; + [{state_timeout,10000,lock}, + hibernate]}; ... ]]></code> <p> |