%% ``The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
%% compliance with the License. You should have received a copy of the
%% Erlang Public License along with this software. If not, it can be
%% retrieved via the world wide web at http://www.erlang.org/.
%%
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and limitations
%% under the License.
%%
%% The Initial Developer of the Original Code is Ericsson Utvecklings AB.
%% Portions created by Ericsson are Copyright 1999, Ericsson Utvecklings
%% AB. All Rights Reserved.''
%%
%% The code has been modified and improved by ProcessOne.
%% Copyright 2007-2013, ProcessOne
%%
%% The change adds the following features:
%% - You can send exit(priority_shutdown) to the p1_fsm process to
%% terminate immediatetly. If the fsm trap_exit process flag has been
%% set to true, the FSM terminate function will called.
%% - You can pass the gen_fsm options to control resource usage.
%% {max_queue, N} will exit the process with priority_shutdown
%% - You can limit the time processing a message (TODO): If the
%% message processing does not return in a given period of time, the
%% process will be terminated.
%% - You might customize the State data before sending it to error_logger
%% in case of a crash (just export the function print_state/1)
%% $Id$
%%
-module(p1_fsm).
%%%-----------------------------------------------------------------
%%%
%%% This state machine is somewhat more pure than state_lib. It is
%%% still based on State dispatching (one function per state), but
%%% allows a function handle_event to take care of events in all states.
%%% It's not that pure anymore :( We also allow synchronized event sending.
%%%
%%% If the Parent process terminates the Module:terminate/2
%%% function is called.
%%%
%%% The user module should export:
%%%
%%% init(Args)
%%% ==> {ok, StateName, StateData}
%%% {ok, StateName, StateData, Timeout}
%%% ignore
%%% {stop, Reason}
%%%
%%% StateName(Msg, StateData)
%%%
%%% ==> {next_state, NewStateName, NewStateData}
%%% {next_state, NewStateName, NewStateData, Timeout}
%%% {stop, Reason, NewStateData}
%%% Reason = normal | shutdown | Term terminate(State) is called
%%%
%%% StateName(Msg, From, StateData)
%%%
%%% ==> {next_state, NewStateName, NewStateData}
%%% {next_state, NewStateName, NewStateData, Timeout}
%%% {reply, Reply, NewStateName, NewStateData}
%%% {reply, Reply, NewStateName, NewStateData, Timeout}
%%% {stop, Reason, NewStateData}
%%% Reason = normal | shutdown | Term terminate(State) is called
%%%
%%% handle_event(Msg, StateName, StateData)
%%%
%%% ==> {next_state, NewStateName, NewStateData}
%%% {next_state, NewStateName, NewStateData, Timeout}
%%% {stop, Reason, Reply, NewStateData}
%%% {stop, Reason, NewStateData}
%%% Reason = normal | shutdown | Term terminate(State) is called
%%%
%%% handle_sync_event(Msg, From, StateName, StateData)
%%%
%%% ==> {next_state, NewStateName, NewStateData}
%%% {next_state, NewStateName, NewStateData, Timeout}
%%% {reply, Reply, NewStateName, NewStateData}
%%% {reply, Reply, NewStateName, NewStateData, Timeout}
%%% {stop, Reason, Reply, NewStateData}
%%% {stop, Reason, NewStateData}
%%% Reason = normal | shutdown | Term terminate(State) is called
%%%
%%% handle_info(Info, StateName) (e.g. {'EXIT', P, R}, {nodedown, N}, ...
%%%
%%% ==> {next_state, NewStateName, NewStateData}
%%% {next_state, NewStateName, NewStateData, Timeout}
%%% {stop, Reason, NewStateData}
%%% Reason = normal | shutdown | Term terminate(State) is called
%%%
%%% terminate(Reason, StateName, StateData) Let the user module clean up
%%% always called when server terminates
%%%
%%% ==> the return value is ignored
%%%
%%%
%%% The work flow (of the fsm) can be described as follows:
%%%
%%% User module fsm
%%% ----------- -------
%%% start -----> start
%%% init <----- .
%%%
%%% loop
%%% StateName <----- .
%%%
%%% handle_event <----- .
%%%
%%% handle__sunc_event <----- .
%%%
%%% handle_info <----- .
%%%
%%% terminate <----- .
%%%
%%%
%%% ---------------------------------------------------
-export([start/3, start/4,
start_link/3, start_link/4,
send_event/2, sync_send_event/2, sync_send_event/3,
send_all_state_event/2,
sync_send_all_state_event/2, sync_send_all_state_event/3,
reply/2,
start_timer/2,send_event_after/2,cancel_timer/1,
enter_loop/4, enter_loop/5, enter_loop/6, wake_hib/7]).
%% Internal exports
-export([init_it/6, print_event/3,
system_continue/3,
system_terminate/4,
system_code_change/4,
format_status/2]).
-import(error_logger , [format/2]).
%%% Internal gen_fsm state
%%% This state is used to defined resource control values:
-record(limits, {max_queue :: non_neg_integer()}).
%%% ---------------------------------------------------
%%% Interface functions.
%%% ---------------------------------------------------
-callback init(Args :: term()) ->
{ok, StateName :: atom(), StateData :: term()} |
{ok, StateName :: atom(), StateData :: term(), timeout() | hibernate} |
{stop, Reason :: term()} | ignore.
-callback handle_event(Event :: term(), StateName :: atom(),
StateData :: term()) ->
{next_state, NextStateName :: atom(), NewStateData :: term()} |
{next_state, NextStateName :: atom(), NewStateData :: term(),
timeout() | hibernate} |
{migrate, NewStateData :: term(),
{Node :: atom(), M :: atom(), F :: atom(), A :: list()},
Timeout :: timeout()} |
{stop, Reason :: term(), NewStateData :: term()}.
-callback handle_sync_event(Event :: term(), From :: {pid(), Tag :: term()},
StateName :: atom(), StateData :: term()) ->
{reply, Reply :: term(), NextStateName :: atom(), NewStateData :: term()} |
{reply, Reply :: term(), NextStateName :: atom(), NewStateData :: term(),
timeout() | hibernate} |
{next_state, NextStateName :: atom(), NewStateData :: term()} |
{next_state, NextStateName :: atom(), NewStateData :: term(),
timeout() | hibernate} |
{migrate, NewStateData :: term(),
{Node :: atom(), M :: atom(), F :: atom(), A :: list()},
Timeout :: timeout()} |
{stop, Reason :: term(), Reply :: term(), NewStateData :: term()} |
{stop, Reason :: term(), NewStateData :: term()}.
-callback handle_info(Info :: term(), StateName :: atom(),
StateData :: term()) ->
{next_state, NextStateName :: atom(), NewStateData :: term()} |
{next_state, NextStateName :: atom(), NewStateData :: term(),
timeout() | hibernate} |
{migrate, NewStateData :: term(),
{Node :: atom(), M :: atom(), F :: atom(), A :: list()},
Timeout :: timeout()} |
{stop, Reason :: normal | term(), NewStateData :: term()}.
-callback terminate(Reason :: normal | shutdown | {shutdown, term()}
| term(), StateName :: atom(), StateData :: term()) ->
term().
-callback code_change(OldVsn :: term() | {down, term()}, StateName :: atom(),
StateData :: term(), Extra :: term()) ->
{ok, NextStateName :: atom(), NewStateData :: term()}.
%%% ---------------------------------------------------
%%% Starts a generic state machine.
%%% start(Mod, Args, Options)
%%% start(Name, Mod, Args, Options)
%%% start_link(Mod, Args, Options)
%%% start_link(Name, Mod, Args, Options) where:
%%% Name ::= {local, atom()} | {global, atom()}
%%% Mod ::= atom(), callback module implementing the 'real' fsm
%%% Args ::= term(), init arguments (to Mod:init/1)
%%% Options ::= [{debug, [Flag]}]
%%% Flag ::= trace | log | {logfile, File} | statistics | debug
%%% (debug == log && statistics)
%%% Returns: {ok, Pid} |
%%% {error, {already_started, Pid}} |
%%% {error, Reason}
%%% ---------------------------------------------------
start(Mod, Args, Options) ->
gen:start(?MODULE, nolink, Mod, Args, Options).
start(Name, Mod, Args, Options) ->
gen:start(?MODULE, nolink, Name, Mod, Args, Options).
start_link(Mod, Args, Options) ->
gen:start(?MODULE, link, Mod, Args, Options).
start_link(Name, Mod, Args, Options) ->
gen:start(?MODULE, link, Name, Mod, Args, Options).
send_event({global, Name}, Event) ->
catch global:send(Name, {'$gen_event', Event}),
ok;
send_event(Name, Event) ->
Name ! {'$gen_event', Event},
ok.
sync_send_event(Name, Event) ->
case catch gen:call(Name, '$gen_sync_event', Event) of
{ok,Res} ->
Res;
{'EXIT',Reason} ->
exit({Reason, {?MODULE, sync_send_event, [Name, Event]}})
end.
sync_send_event(Name, Event, Timeout) ->
case catch gen:call(Name, '$gen_sync_event', Event, Timeout) of
{ok,Res} ->
Res;
{'EXIT',Reason} ->
exit({Reason, {?MODULE, sync_send_event, [Name, Event, Timeout]}})
end.
send_all_state_event({global, Name}, Event) ->
catch global:send(Name, {'$gen_all_state_event', Event}),
ok;
send_all_state_event(Name, Event) ->
Name ! {'$gen_all_state_event', Event},
ok.
sync_send_all_state_event(Name, Event) ->
case catch gen:call(Name, '$gen_sync_all_state_event', Event) of
{ok,Res} ->
Res;
{'EXIT',Reason} ->
exit({Reason, {?MODULE, sync_send_all_state_event, [Name, Event]}})
end.
sync_send_all_state_event(Name, Event, Timeout) ->
case catch gen:call(Name, '$gen_sync_all_state_event', Event, Timeout) of
{ok,Res} ->
Res;
{'EXIT',Reason} ->
exit({Reason, {?MODULE, sync_send_all_state_event,
[Name, Event, Timeout]}})
end.
%% Designed to be only callable within one of the callbacks
%% hence using the self() of this instance of the process.
%% This is to ensure that timers don't go astray in global
%% e.g. when straddling a failover, or turn up in a restarted
%% instance of the process.
%% Returns Ref, sends event {timeout,Ref,Msg} after Time
%% to the (then) current state.
start_timer(Time, Msg) ->
erlang:start_timer(Time, self(), {'$gen_timer', Msg}).
%% Returns Ref, sends Event after Time to the (then) current state.
send_event_after(Time, Event) ->
erlang:start_timer(Time, self(), {'$gen_event', Event}).
%% Returns the remaing time for the timer if Ref referred to
%% an active timer/send_event_after, false otherwise.
cancel_timer(Ref) ->
case erlang:cancel_timer(Ref) of
false ->
receive {timeout, Ref, _} -> 0
after 0 -> false
end;
RemainingTime ->
RemainingTime
end.
%% enter_loop/4,5,6
%% Makes an existing process into a gen_fsm.
%% The calling process will enter the gen_fsm receive loop and become a
%% gen_fsm process.
%% The process *must* have been started using one of the start functions
%% in proc_lib, see proc_lib(3).
%% The user is responsible for any initialization of the process,
%% including registering a name for it.
enter_loop(Mod, Options, StateName, StateData) ->
enter_loop(Mod, Options, StateName, StateData, self(), infinity).
enter_loop(Mod, Options, StateName, StateData, ServerName = {_,_}) ->
enter_loop(Mod, Options, StateName, StateData, ServerName,infinity);
enter_loop(Mod, Options, StateName, StateData, Timeout) ->
enter_loop(Mod, Options, StateName, StateData, self(), Timeout).
enter_loop(Mod, Options, StateName, StateData, ServerName, Timeout) ->
Name = get_proc_name(ServerName),
Parent = get_parent(),
Debug = gen:debug_options(Options),
Limits = limit_options(Options),
Queue = queue:new(),
QueueLen = 0,
loop(Parent, Name, StateName, StateData, Mod, Timeout, Debug,
Limits, Queue, QueueLen).
get_proc_name(Pid) when is_pid(Pid) ->
Pid;
get_proc_name({local, Name}) ->
case process_info(self(), registered_name) of
{registered_name, Name} ->
Name;
{registered_name, _Name} ->
exit(process_not_registered);
[] ->
exit(process_not_registered)
end;
get_proc_name({global, Name}) ->
case global:whereis_name(Name) of
undefined ->
exit(process_not_registered_globally);
Pid when Pid==self() ->
Name;
_Pid ->
exit(process_not_registered_globally)
end.
get_parent() ->
case get('$ancestors') of
[Parent | _] when is_pid(Parent) ->
Parent;
[Parent | _] when is_atom(Parent) ->
name_to_pid(Parent);
_ ->
exit(process_was_not_started_by_proc_lib)
end.
name_to_pid(Name) ->
case whereis(Name) of
undefined ->
case global:whereis_name(Name) of
undefined ->
exit(could_not_find_registerd_name);
Pid ->
Pid
end;
Pid ->
Pid
end.
%%% ---------------------------------------------------
%%% Initiate the new process.
%%% Register the name using the Rfunc function
%%% Calls the Mod:init/Args function.
%%% Finally an acknowledge is sent to Parent and the main
%%% loop is entered.
%%% ---------------------------------------------------
init_it(Starter, self, Name, Mod, Args, Options) ->
init_it(Starter, self(), Name, Mod, Args, Options);
init_it(Starter, Parent, Name0, Mod, Args, Options) ->
Name = name(Name0),
Debug = gen:debug_options(Options),
Limits = limit_options(Options),
Queue = queue:new(),
QueueLen = 0,
case catch Mod:init(Args) of
{ok, StateName, StateData} ->
proc_lib:init_ack(Starter, {ok, self()}),
loop(Parent, Name, StateName, StateData, Mod, infinity, Debug, Limits, Queue, QueueLen);
{ok, StateName, StateData, Timeout} ->
proc_lib:init_ack(Starter, {ok, self()}),
loop(Parent, Name, StateName, StateData, Mod, Timeout, Debug, Limits, Queue, QueueLen);
{stop, Reason} ->
proc_lib:init_ack(Starter, {error, Reason}),
exit(Reason);
ignore ->
proc_lib:init_ack(Starter, ignore),
exit(normal);
{'EXIT', Reason} ->
proc_lib:init_ack(Starter, {error, Reason}),
exit(Reason);
Else ->
Error = {bad_return_value, Else},
proc_lib:init_ack(Starter, {error, Error}),
exit(Error)
end.
name({local,Name}) -> Name;
name({global,Name}) -> Name;
name(Pid) when is_pid(Pid) -> Pid.
%%-----------------------------------------------------------------
%% The MAIN loop
%%-----------------------------------------------------------------
loop(Parent, Name, StateName, StateData, Mod, hibernate, Debug,
Limits, Queue, QueueLen)
when QueueLen > 0 ->
case queue:out(Queue) of
{{value, Msg}, Queue1} ->
decode_msg(Msg, Parent, Name, StateName, StateData, Mod, hibernate,
Debug, Limits, Queue1, QueueLen - 1, false);
{empty, _} ->
Reason = internal_queue_error,
error_info(Mod, Reason, Name, hibernate, StateName, StateData, Debug),
exit(Reason)
end;
loop(Parent, Name, StateName, StateData, Mod, hibernate, Debug,
Limits, _Queue, _QueueLen) ->
proc_lib:hibernate(?MODULE,wake_hib,
[Parent, Name, StateName, StateData, Mod,
Debug, Limits]);
%% First we test if we have reach a defined limit ...
loop(Parent, Name, StateName, StateData, Mod, Time, Debug,
Limits, Queue, QueueLen) ->
try
message_queue_len(Limits, QueueLen)
%% TODO: We can add more limit checking here...
catch
{process_limit, Limit} ->
Reason = {process_limit, Limit},
Msg = {'EXIT', Parent, {error, {process_limit, Limit}}},
terminate(Reason, Name, Msg, Mod, StateName, StateData, Debug)
end,
process_message(Parent, Name, StateName, StateData,
Mod, Time, Debug, Limits, Queue, QueueLen).
%% ... then we can process a new message:
process_message(Parent, Name, StateName, StateData, Mod, Time, Debug,
Limits, Queue, QueueLen) ->
{Msg, Queue1, QueueLen1} = collect_messages(Queue, QueueLen, Time),
decode_msg(Msg,Parent, Name, StateName, StateData, Mod, Time,
Debug, Limits, Queue1, QueueLen1, false).
collect_messages(Queue, QueueLen, Time) ->
receive
Input ->
case Input of
{'EXIT', _Parent, priority_shutdown} ->
{Input, Queue, QueueLen};
_ ->
collect_messages(
queue:in(Input, Queue), QueueLen + 1, Time)
end
after 0 ->
case queue:out(Queue) of
{{value, Msg}, Queue1} ->
{Msg, Queue1, QueueLen - 1};
{empty, _} ->
receive
Input ->
{Input, Queue, QueueLen}
after Time ->
{{'$gen_event', timeout}, Queue, QueueLen}
end
end
end.
wake_hib(Parent, Name, StateName, StateData, Mod, Debug,
Limits) ->
Msg = receive
Input ->
Input
end,
Queue = queue:new(),
QueueLen = 0,
decode_msg(Msg, Parent, Name, StateName, StateData, Mod, hibernate,
Debug, Limits, Queue, QueueLen, true).
decode_msg(Msg,Parent, Name, StateName, StateData, Mod, Time, Debug,
Limits, Queue, QueueLen, Hib) ->
put('$internal_queue_len', QueueLen),
case Msg of
{system, From, Req} ->
sys:handle_system_msg(Req, From, Parent, ?MODULE, Debug,
[Name, StateName, StateData,
Mod, Time, Limits, Queue, QueueLen], Hib);
{'EXIT', Parent, Reason} ->
terminate(Reason, Name, Msg, Mod, StateName, StateData, Debug);
_Msg when Debug == [] ->
handle_msg(Msg, Parent, Name, StateName, StateData,
Mod, Time, Limits, Queue, QueueLen);
_Msg ->
Debug1 = sys:handle_debug(Debug, fun print_event/3,
{Name, StateName}, {in, Msg}),
handle_msg(Msg, Parent, Name, StateName, StateData,
Mod, Time, Debug1, Limits, Queue, QueueLen)
end.
%%-----------------------------------------------------------------
%% Callback functions for system messages handling.
%%-----------------------------------------------------------------
system_continue(Parent, Debug, [Name, StateName, StateData,
Mod, Time, Limits, Queue, QueueLen]) ->
loop(Parent, Name, StateName, StateData, Mod, Time, Debug,
Limits, Queue, QueueLen).
-spec system_terminate(term(), _, _, [term(),...]) -> no_return().
system_terminate(Reason, _Parent, Debug,
[Name, StateName, StateData, Mod, _Time, _Limits]) ->
terminate(Reason, Name, [], Mod, StateName, StateData, Debug).
system_code_change([Name, StateName, StateData, Mod, Time,
Limits, Queue, QueueLen],
_Module, OldVsn, Extra) ->
case catch Mod:code_change(OldVsn, StateName, StateData, Extra) of
{ok, NewStateName, NewStateData} ->
{ok, [Name, NewStateName, NewStateData, Mod, Time,
Limits, Queue, QueueLen]};
Else -> Else
end.
%%-----------------------------------------------------------------
%% Format debug messages. Print them as the call-back module sees
%% them, not as the real erlang messages. Use trace for that.
%%-----------------------------------------------------------------
print_event(Dev, {in, Msg}, {Name, StateName}) ->
case Msg of
{'$gen_event', Event} ->
io:format(Dev, "*DBG* ~p got event ~p in state ~w~n",
[Name, Event, StateName]);
{'$gen_all_state_event', Event} ->
io:format(Dev,
"*DBG* ~p got all_state_event ~p in state ~w~n",
[Name, Event, StateName]);
{timeout, Ref, {'$gen_timer', Message}} ->
io:format(Dev,
"*DBG* ~p got timer ~p in state ~w~n",
[Name, {timeout, Ref, Message}, StateName]);
{timeout, _Ref, {'$gen_event', Event}} ->
io:format(Dev,
"*DBG* ~p got timer ~p in state ~w~n",
[Name, Event, StateName]);
_ ->
io:format(Dev, "*DBG* ~p got ~p in state ~w~n",
[Name, Msg, StateName])
end;
print_event(Dev, {out, Msg, To, StateName}, Name) ->
io:format(Dev, "*DBG* ~p sent ~p to ~w~n"
" and switched to state ~w~n",
[Name, Msg, To, StateName]);
print_event(Dev, return, {Name, StateName}) ->
io:format(Dev, "*DBG* ~p switched to state ~w~n",
[Name, StateName]).
relay_messages(MRef, TRef, Clone, Queue) ->
lists:foreach(
fun(Msg) -> Clone ! Msg end,
queue:to_list(Queue)),
relay_messages(MRef, TRef, Clone).
relay_messages(MRef, TRef, Clone) ->
receive
{'DOWN', MRef, process, Clone, Reason} ->
Reason;
{'EXIT', _Parent, _Reason} ->
{migrated, Clone};
{timeout, TRef, timeout} ->
{migrated, Clone};
Msg ->
Clone ! Msg,
relay_messages(MRef, TRef, Clone)
end.
handle_msg(Msg, Parent, Name, StateName, StateData, Mod, _Time,
Limits, Queue, QueueLen) -> %No debug here
From = from(Msg),
case catch dispatch(Msg, Mod, StateName, StateData) of
{next_state, NStateName, NStateData} ->
loop(Parent, Name, NStateName, NStateData,
Mod, infinity, [], Limits, Queue, QueueLen);
{next_state, NStateName, NStateData, Time1} ->
loop(Parent, Name, NStateName, NStateData, Mod, Time1, [],
Limits, Queue, QueueLen);
{reply, Reply, NStateName, NStateData} when From =/= undefined ->
reply(From, Reply),
loop(Parent, Name, NStateName, NStateData,
Mod, infinity, [], Limits, Queue, QueueLen);
{reply, Reply, NStateName, NStateData, Time1} when From =/= undefined ->
reply(From, Reply),
loop(Parent, Name, NStateName, NStateData, Mod, Time1, [],
Limits, Queue, QueueLen);
{migrate, NStateData, {Node, M, F, A}, Time1} ->
Reason = case catch rpc:call(Node, M, F, A, 5000) of
{badrpc, _} = Err ->
{migration_error, Err};
{'EXIT', _} = Err ->
{migration_error, Err};
{error, _} = Err ->
{migration_error, Err};
{ok, Clone} ->
process_flag(trap_exit, true),
MRef = erlang:monitor(process, Clone),
TRef = erlang:start_timer(Time1, self(), timeout),
relay_messages(MRef, TRef, Clone, Queue);
Reply ->
{migration_error, {bad_reply, Reply}}
end,
terminate(Reason, Name, Msg, Mod, StateName, NStateData, []);
{stop, Reason, NStateData} ->
terminate(Reason, Name, Msg, Mod, StateName, NStateData, []);
{stop, Reason, Reply, NStateData} when From =/= undefined ->
{'EXIT', R} = (catch terminate(Reason, Name, Msg, Mod,
StateName, NStateData, [])),
reply(From, Reply),
exit(R);
{'EXIT', What} ->
terminate(What, Name, Msg, Mod, StateName, StateData, []);
Reply ->
terminate({bad_return_value, Reply},
Name, Msg, Mod, StateName, StateData, [])
end.
handle_msg(Msg, Parent, Name, StateName, StateData,
Mod, _Time, Debug, Limits, Queue, QueueLen) ->
From = from(Msg),
case catch dispatch(Msg, Mod, StateName, StateData) of
{next_state, NStateName, NStateData} ->
Debug1 = sys:handle_debug(Debug, fun print_event/3,
{Name, NStateName}, return),
loop(Parent, Name, NStateName, NStateData,
Mod, infinity, Debug1, Limits, Queue, QueueLen);
{next_state, NStateName, NStateData, Time1} ->
Debug1 = sys:handle_debug(Debug, fun print_event/3,
{Name, NStateName}, return),
loop(Parent, Name, NStateName, NStateData,
Mod, Time1, Debug1, Limits, Queue, QueueLen);
{reply, Reply, NStateName, NStateData} when From =/= undefined ->
Debug1 = reply(Name, From, Reply, Debug, NStateName),
loop(Parent, Name, NStateName, NStateData,
Mod, infinity, Debug1, Limits, Queue, QueueLen);
{reply, Reply, NStateName, NStateData, Time1} when From =/= undefined ->
Debug1 = reply(Name, From, Reply, Debug, NStateName),
loop(Parent, Name, NStateName, NStateData,
Mod, Time1, Debug1, Limits, Queue, QueueLen);
{migrate, NStateData, {Node, M, F, A}, Time1} ->
Reason = case catch rpc:call(Node, M, F, A, Time1) of
{badrpc, R} ->
{migration_error, R};
{'EXIT', R} ->
{migration_error, R};
{error, R} ->
{migration_error, R};
{ok, Clone} ->
process_flag(trap_exit, true),
MRef = erlang:monitor(process, Clone),
TRef = erlang:start_timer(Time1, self(), timeout),
relay_messages(MRef, TRef, Clone, Queue);
Reply ->
{migration_error, {bad_reply, Reply}}
end,
terminate(Reason, Name, Msg, Mod, StateName, NStateData, Debug);
{stop, Reason, NStateData} ->
terminate(Reason, Name, Msg, Mod, StateName, NStateData, Debug);
{stop, Reason, Reply, NStateData} when From =/= undefined ->
{'EXIT', R} = (catch terminate(Reason, Name, Msg, Mod,
StateName, NStateData, Debug)),
reply(Name, From, Reply, Debug, StateName),
exit(R);
{'EXIT', What} ->
terminate(What, Name, Msg, Mod, StateName, StateData, Debug);
Reply ->
terminate({bad_return_value, Reply},
Name, Msg, Mod, StateName, StateData, Debug)
end.
dispatch({'$gen_event', Event}, Mod, StateName, StateData) ->
Mod:StateName(Event, StateData);
dispatch({'$gen_all_state_event', Event}, Mod, StateName, StateData) ->
Mod:handle_event(Event, StateName, StateData);
dispatch({'$gen_sync_event', From, Event}, Mod, StateName, StateData) ->
Mod:StateName(Event, From, StateData);
dispatch({'$gen_sync_all_state_event', From, Event},
Mod, StateName, StateData) ->
Mod:handle_sync_event(Event, From, StateName, StateData);
dispatch({timeout, Ref, {'$gen_timer', Msg}}, Mod, StateName, StateData) ->
Mod:StateName({timeout, Ref, Msg}, StateData);
dispatch({timeout, _Ref, {'$gen_event', Event}}, Mod, StateName, StateData) ->
Mod:StateName(Event, StateData);
dispatch(Info, Mod, StateName, StateData) ->
Mod:handle_info(Info, StateName, StateData).
from({'$gen_sync_event', From, _Event}) -> From;
from({'$gen_sync_all_state_event', From, _Event}) -> From;
from(_) -> undefined.
%% Send a reply to the client.
reply({To, Tag}, Reply) ->
catch To ! {Tag, Reply}.
reply(Name, {To, Tag}, Reply, Debug, StateName) ->
reply({To, Tag}, Reply),
sys:handle_debug(Debug, fun print_event/3, Name,
{out, Reply, To, StateName}).
%%% ---------------------------------------------------
%%% Terminate the server.
%%% ---------------------------------------------------
-spec terminate(term(), _, _, atom(), _, _, _) -> no_return().
terminate(Reason, Name, Msg, Mod, StateName, StateData, Debug) ->
case catch Mod:terminate(Reason, StateName, StateData) of
{'EXIT', R} ->
error_info(Mod, R, Name, Msg, StateName, StateData, Debug),
exit(R);
_ ->
case Reason of
normal ->
exit(normal);
shutdown ->
exit(shutdown);
priority_shutdown ->
%% Priority shutdown should be considered as
%% shutdown by SASL
exit(shutdown);
{process_limit, _Limit} ->
exit(Reason);
{migrated, _Clone} ->
exit(normal);
_ ->
error_info(Mod, Reason, Name, Msg, StateName, StateData, Debug),
exit(Reason)
end
end.
error_info(Mod, Reason, Name, Msg, StateName, StateData, Debug) ->
Reason1 =
case Reason of
{undef,[{M,F,A}|MFAs]} ->
case code:is_loaded(M) of
false ->
{'module could not be loaded',[{M,F,A}|MFAs]};
_ ->
case erlang:function_exported(M, F, length(A)) of
true ->
Reason;
false ->
{'function not exported',[{M,F,A}|MFAs]}
end
end;
_ ->
Reason
end,
StateToPrint = case erlang:function_exported(Mod, print_state, 1) of
true -> (catch Mod:print_state(StateData));
false -> StateData
end,
Str = "** State machine ~p terminating \n" ++
get_msg_str(Msg) ++
"** When State == ~p~n"
"** Data == ~p~n"
"** Reason for termination = ~n** ~p~n",
format(Str, [Name, get_msg(Msg), StateName, StateToPrint, Reason1]),
sys:print_log(Debug),
ok.
get_msg_str({'$gen_event', _Event}) ->
"** Last event in was ~p~n";
get_msg_str({'$gen_sync_event', _Event}) ->
"** Last sync event in was ~p~n";
get_msg_str({'$gen_all_state_event', _Event}) ->
"** Last event in was ~p (for all states)~n";
get_msg_str({'$gen_sync_all_state_event', _Event}) ->
"** Last sync event in was ~p (for all states)~n";
get_msg_str({timeout, _Ref, {'$gen_timer', _Msg}}) ->
"** Last timer event in was ~p~n";
get_msg_str({timeout, _Ref, {'$gen_event', _Msg}}) ->
"** Last timer event in was ~p~n";
get_msg_str(_Msg) ->
"** Last message in was ~p~n".
get_msg({'$gen_event', Event}) -> Event;
get_msg({'$gen_sync_event', Event}) -> Event;
get_msg({'$gen_all_state_event', Event}) -> Event;
get_msg({'$gen_sync_all_state_event', Event}) -> Event;
get_msg({timeout, Ref, {'$gen_timer', Msg}}) -> {timeout, Ref, Msg};
get_msg({timeout, _Ref, {'$gen_event', Event}}) -> Event;
get_msg(Msg) -> Msg.
%%-----------------------------------------------------------------
%% Status information
%%-----------------------------------------------------------------
format_status(Opt, StatusData) ->
[PDict, SysState, Parent, Debug, [Name, StateName, StateData, Mod, _Time, _Limits, _Queue, _QueueLen]] =
StatusData,
NameTag = if is_pid(Name) ->
pid_to_list(Name);
is_atom(Name) ->
Name
end,
Header = lists:concat(["Status for state machine ", NameTag]),
Log = sys:get_debug(log, Debug, []),
Specfic =
case erlang:function_exported(Mod, format_status, 2) of
true ->
case catch Mod:format_status(Opt,[PDict,StateData]) of
{'EXIT', _} -> [{data, [{"StateData", StateData}]}];
Else -> Else
end;
_ ->
[{data, [{"StateData", StateData}]}]
end,
[{header, Header},
{data, [{"Status", SysState},
{"Parent", Parent},
{"Logged events", Log},
{"StateName", StateName}]} |
Specfic].
%%-----------------------------------------------------------------
%% Resources limit management
%%-----------------------------------------------------------------
%% Extract know limit options
limit_options(Options) ->
limit_options(Options, #limits{}).
limit_options([], Limits) ->
Limits;
%% Maximum number of messages allowed in the process message queue
limit_options([{max_queue,N}|Options], Limits)
when is_integer(N) ->
NewLimits = Limits#limits{max_queue=N},
limit_options(Options, NewLimits);
limit_options([_|Options], Limits) ->
limit_options(Options, Limits).
%% Throw max_queue if we have reach the max queue size
%% Returns ok otherwise
message_queue_len(#limits{max_queue = undefined}, _QueueLen) ->
ok;
message_queue_len(#limits{max_queue = MaxQueue}, QueueLen) ->
Pid = self(),
case process_info(Pid, message_queue_len) of
{message_queue_len, N} when N + QueueLen > MaxQueue ->
throw({process_limit, {max_queue, N + QueueLen}});
_ ->
ok
end.
