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|
-module(advanced_event).
-behaviour(gen_server).
-export([start_link/0, start_link/1, notify/2, sync_notify/2,
add_handler/3, delete_handler/3
%, call/3, call/4
]).
-export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, code_change/3]).
-record(handler, {module :: atom(),
id,
state}).
-callback init(InitArgs :: term()) ->
{ok, State :: term()}.
-callback handle_event(Event :: term(), State :: term()) ->
{ok, NewState :: term()} |
{handled, NewState :: term()} |
handled_and_remove |
remove_handler.
-callback handle_call(Request :: term(), State :: term()) ->
{ok, Reply :: term(), NewState :: term()} |
{remove_handler, Reply :: term()}.
-callback handle_info(Info :: term(), State :: term()) ->
{ok, NewState :: term()} |
remove_handler.
-callback terminate(Args :: (term() | {stop, Reason :: term()} |
stop | remove_handler |
{error, {'EXIT', Reason :: term()}} |
{error, term()}),
State :: term()) ->
term().
-callback code_change(OldVsn :: (term() | {down, term()}),
State :: term(), Extra :: term()) ->
{ok, NewState :: term()}.
-type handler() :: atom() | {atom(), term()}.
-type emgr_name() :: {'local', atom()} | {'global', atom()}.
-type emgr_ref() :: atom() | {atom(), atom()} | {'global', atom()} | pid().
-type start_ret() :: {'ok', pid()} | {'error', term()}.
-define(NO_CALLBACK, 'no callback module').
%-spec start_link() -> start_ret().
start_link() ->
gen_server:start_link(?MODULE, [], []).
%-spec start_link(emgr_name()) -> start_ret().
start_link(Name) ->
gen_server:start_link(Name, ?MODULE, [], []).
init(_Args) ->
process_flag(trap_exit, true),
{ok, []}.
-spec add_handler(emgr_ref(), handler(), term()) -> term().
add_handler(Manager, Handler, Args) -> gen_server:call(Manager, {add_handler, Handler, Args}).
-spec delete_handler(emgr_ref(), handler(), term()) -> term().
delete_handler(Manager, Handler, Args) -> gen_server:call(Manager, {delete_handler, Handler, Args}).
-spec notify(emgr_ref(), term()) -> 'ok'.
notify(Manager, Event) -> gen_server:cast(Manager, {notify, Event}).
-spec sync_notify(emgr_ref(), term()) -> 'ok'.
sync_notify(Manager, Event) -> gen_server:call(Manager, {sync_notify, Event}).
%-spec call(emgr_ref(), handler(), term()) -> term().
%call(M, Handler, Query) -> call1(M, Handler, Query).
%-spec call(emgr_ref(), handler(), term(), timeout()) -> term().
%call(M, Handler, Query, Timeout) -> call1(M, Handler, Query, Timeout).
-spec handle_call(term(), {pid(), term()}, list()) -> {reply, term(), list()}.
handle_call({add_handler, Handler, Args}, _From, Handlers) ->
{Module, Id} = case Handler of
{_Mod, _Id} ->
Handler;
Mod ->
{Mod, undefined}
end,
case catch Module:init(Args) of
{ok, State} ->
{reply,ok,[#handler{module=Module,id=Id,state=State}|Handlers]};
Other ->
{reply,Other,Handlers}
end;
handle_call({delete_handler, Handler, Args}, _From, Handlers) ->
{Module, Id} = case Handler of
{_Mod, _Id} ->
Handler;
Mod ->
{Mod, undefined}
end,
case remove_from_list(Module, Id, Handlers) of
error ->
{reply,{error,module_not_found},Handlers};
{H,Hs} ->
case catch (H#handler.module):terminate(Args, (H#handler.state)) of
Result ->
{reply,Result,Hs}
end
end;
handle_call({sync_notify,Event}, _From, Handlers) ->
Handlers1 = call_handlers(Event, Handlers),
{reply,ok,Handlers1}.
handle_cast({notify,Event}, Handlers) ->
Handlers1 = call_handlers(Event, Handlers),
{noreply,Handlers1}.
handle_info(_Msg, Handlers) ->
{noreply,Handlers}.
remove_from_list(Module, Id, [Handler|Handlers]) ->
case Handler of
#handler{module=Module,id=Id} ->
{Handler,Handlers};
_ ->
case remove_from_list(Module, id, Handlers) of
{H,Hs} ->
{H,[Handler|Hs]};
error ->
error
end
end;
remove_from_list(_, _, []) ->
error.
call_handlers(Event, [Handler|Handlers]) ->
case catch (Handler#handler.module):handle_event(Event, Handler#handler.state) of
{ok, State} ->
Rest = call_handlers(Event, Handlers),
[Handler#handler{state=State}|Rest];
{handled, State} ->
[Handler#handler{state=State}|Handlers];
remove_handler ->
(Handler#handler.module):terminate(remove_handler, Handler#handler.state),
call_handlers(Event, Handlers);
handled_and_remove ->
(Handler#handler.module):terminate(remove_handler, Handler#handler.state),
[]
end;
call_handlers(_, []) ->
[].
terminate(Reason, [Handler|Handlers]) ->
(Handler#handler.module):terminate({stop, Reason}, (Handler#handler.state)),
terminate(Reason, Handlers);
terminate(_Reason, []) ->
ok.
code_change(_OldVersion, Config, _Extra) ->
{ok, Config}.
|
