%% %% %CopyrightBegin% %% %% Copyright Ericsson AB 1996-2017. All Rights Reserved. %% %% Licensed under the Apache License, Version 2.0 (the "License"); %% you may not use this file except in compliance with the License. %% You may obtain a copy of the License at %% %% http://www.apache.org/licenses/LICENSE-2.0 %% %% Unless required by applicable law or agreed to in writing, software %% distributed under the License is distributed on an "AS IS" BASIS, %% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. %% See the License for the specific language governing permissions and %% limitations under the License. %% %% %CopyrightEnd% %% -module(gen_server). %%% --------------------------------------------------- %%% %%% The idea behind THIS server is that the user module %%% provides (different) functions to handle different %%% kind of inputs. %%% If the Parent process terminates the Module:terminate/2 %%% function is called. %%% %%% The user module should export: %%% %%% init(Args) %%% ==> {ok, State} %%% {ok, State, Timeout} %%% ignore %%% {stop, Reason} %%% %%% handle_call(Msg, {From, Tag}, State) %%% %%% ==> {reply, Reply, State} %%% {reply, Reply, State, Timeout} %%% {noreply, State} %%% {noreply, State, Timeout} %%% {stop, Reason, Reply, State} %%% Reason = normal | shutdown | Term terminate(State) is called %%% %%% handle_cast(Msg, State) %%% %%% ==> {noreply, State} %%% {noreply, State, Timeout} %%% {stop, Reason, State} %%% Reason = normal | shutdown | Term terminate(State) is called %%% %%% handle_info(Info, State) Info is e.g. {'EXIT', P, R}, {nodedown, N}, ... %%% %%% ==> {noreply, State} %%% {noreply, State, Timeout} %%% {stop, Reason, State} %%% Reason = normal | shutdown | Term, terminate(State) is called %%% %%% terminate(Reason, State) Let the user module clean up %%% always called when server terminates %%% %%% ==> ok %%% %%% %%% The work flow (of the server) can be described as follows: %%% %%% User module Generic %%% ----------- ------- %%% start -----> start %%% init <----- . %%% %%% loop %%% handle_call <----- . %%% -----> reply %%% %%% handle_cast <----- . %%% %%% handle_info <----- . %%% %%% terminate <----- . %%% %%% -----> reply %%% %%% %%% --------------------------------------------------- %% API -export([start/3, start/4, start_link/3, start_link/4, stop/1, stop/3, call/2, call/3, cast/2, reply/2, abcast/2, abcast/3, multi_call/2, multi_call/3, multi_call/4, enter_loop/3, enter_loop/4, enter_loop/5, wake_hib/6]). %% System exports -export([system_continue/3, system_terminate/4, system_code_change/4, system_get_state/1, system_replace_state/2, format_status/2]). %% Internal exports -export([init_it/6]). %%%========================================================================= %%% API %%%========================================================================= -callback init(Args :: term()) -> {ok, State :: term()} | {ok, State :: term(), timeout() | hibernate} | {stop, Reason :: term()} | ignore. -callback handle_call(Request :: term(), From :: {pid(), Tag :: term()}, State :: term()) -> {reply, Reply :: term(), NewState :: term()} | {reply, Reply :: term(), NewState :: term(), timeout() | hibernate} | {noreply, NewState :: term()} | {noreply, NewState :: term(), timeout() | hibernate} | {stop, Reason :: term(), Reply :: term(), NewState :: term()} | {stop, Reason :: term(), NewState :: term()}. -callback handle_cast(Request :: term(), State :: term()) -> {noreply, NewState :: term()} | {noreply, NewState :: term(), timeout() | hibernate} | {stop, Reason :: term(), NewState :: term()}. -callback handle_info(Info :: timeout | term(), State :: term()) -> {noreply, NewState :: term()} | {noreply, NewState :: term(), timeout() | hibernate} | {stop, Reason :: term(), NewState :: term()}. -callback terminate(Reason :: (normal | shutdown | {shutdown, term()} | term()), State :: term()) -> term(). -callback code_change(OldVsn :: (term() | {down, term()}), State :: term(), Extra :: term()) -> {ok, NewState :: term()} | {error, Reason :: term()}. -callback format_status(Opt, StatusData) -> Status when Opt :: 'normal' | 'terminate', StatusData :: [PDict | State], PDict :: [{Key :: term(), Value :: term()}], State :: term(), Status :: term(). -optional_callbacks( [handle_info/2, terminate/2, code_change/3, format_status/2]). %%% ----------------------------------------------------------------- %%% Starts a generic server. %%% 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()} | {via, atom(), term()} %%% Mod ::= atom(), callback module implementing the 'real' server %%% Args ::= term(), init arguments (to Mod:init/1) %%% Options ::= [{timeout, Timeout} | {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). %% ----------------------------------------------------------------- %% Stop a generic server and wait for it to terminate. %% If the server is located at another node, that node will %% be monitored. %% ----------------------------------------------------------------- stop(Name) -> gen:stop(Name). stop(Name, Reason, Timeout) -> gen:stop(Name, Reason, Timeout). %% ----------------------------------------------------------------- %% Make a call to a generic server. %% If the server is located at another node, that node will %% be monitored. %% If the client is trapping exits and is linked server termination %% is handled here (? Shall we do that here (or rely on timeouts) ?). %% ----------------------------------------------------------------- call(Name, Request) -> case catch gen:call(Name, '$gen_call', Request) of {ok,Res} -> Res; {'EXIT',Reason} -> exit({Reason, {?MODULE, call, [Name, Request]}}) end. call(Name, Request, Timeout) -> case catch gen:call(Name, '$gen_call', Request, Timeout) of {ok,Res} -> Res; {'EXIT',Reason} -> exit({Reason, {?MODULE, call, [Name, Request, Timeout]}}) end. %% ----------------------------------------------------------------- %% Make a cast to a generic server. %% ----------------------------------------------------------------- cast({global,Name}, Request) -> catch global:send(Name, cast_msg(Request)), ok; cast({via, Mod, Name}, Request) -> catch Mod:send(Name, cast_msg(Request)), ok; cast({Name,Node}=Dest, Request) when is_atom(Name), is_atom(Node) -> do_cast(Dest, Request); cast(Dest, Request) when is_atom(Dest) -> do_cast(Dest, Request); cast(Dest, Request) when is_pid(Dest) -> do_cast(Dest, Request). do_cast(Dest, Request) -> do_send(Dest, cast_msg(Request)), ok. cast_msg(Request) -> {'$gen_cast',Request}. %% ----------------------------------------------------------------- %% Send a reply to the client. %% ----------------------------------------------------------------- reply({To, Tag}, Reply) -> catch To ! {Tag, Reply}. %% ----------------------------------------------------------------- %% Asynchronous broadcast, returns nothing, it's just send 'n' pray %%----------------------------------------------------------------- abcast(Name, Request) when is_atom(Name) -> do_abcast([node() | nodes()], Name, cast_msg(Request)). abcast(Nodes, Name, Request) when is_list(Nodes), is_atom(Name) -> do_abcast(Nodes, Name, cast_msg(Request)). do_abcast([Node|Nodes], Name, Msg) when is_atom(Node) -> do_send({Name,Node},Msg), do_abcast(Nodes, Name, Msg); do_abcast([], _,_) -> abcast. %%% ----------------------------------------------------------------- %%% Make a call to servers at several nodes. %%% Returns: {[Replies],[BadNodes]} %%% A Timeout can be given %%% %%% A middleman process is used in case late answers arrives after %%% the timeout. If they would be allowed to glog the callers message %%% queue, it would probably become confused. Late answers will %%% now arrive to the terminated middleman and so be discarded. %%% ----------------------------------------------------------------- multi_call(Name, Req) when is_atom(Name) -> do_multi_call([node() | nodes()], Name, Req, infinity). multi_call(Nodes, Name, Req) when is_list(Nodes), is_atom(Name) -> do_multi_call(Nodes, Name, Req, infinity). multi_call(Nodes, Name, Req, infinity) -> do_multi_call(Nodes, Name, Req, infinity); multi_call(Nodes, Name, Req, Timeout) when is_list(Nodes), is_atom(Name), is_integer(Timeout), Timeout >= 0 -> do_multi_call(Nodes, Name, Req, Timeout). %%----------------------------------------------------------------- %% enter_loop(Mod, Options, State, , ) ->_ %% %% Description: Makes an existing process into a gen_server. %% The calling process will enter the gen_server receive %% loop and become a gen_server 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, State) -> enter_loop(Mod, Options, State, self(), infinity). enter_loop(Mod, Options, State, ServerName = {Scope, _}) when Scope == local; Scope == global -> enter_loop(Mod, Options, State, ServerName, infinity); enter_loop(Mod, Options, State, ServerName = {via, _, _}) -> enter_loop(Mod, Options, State, ServerName, infinity); enter_loop(Mod, Options, State, Timeout) -> enter_loop(Mod, Options, State, self(), Timeout). enter_loop(Mod, Options, State, ServerName, Timeout) -> Name = gen:get_proc_name(ServerName), Parent = gen:get_parent(), Debug = gen:debug_options(Name, Options), HibernateAfterTimeout = gen:hibernate_after(Options), loop(Parent, Name, State, Mod, Timeout, HibernateAfterTimeout, Debug). %%%======================================================================== %%% Gen-callback functions %%%======================================================================== %%% --------------------------------------------------- %%% 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 = gen:name(Name0), Debug = gen:debug_options(Name, Options), HibernateAfterTimeout = gen:hibernate_after(Options), case catch Mod:init(Args) of {ok, State} -> proc_lib:init_ack(Starter, {ok, self()}), loop(Parent, Name, State, Mod, infinity, HibernateAfterTimeout, Debug); {ok, State, Timeout} -> proc_lib:init_ack(Starter, {ok, self()}), loop(Parent, Name, State, Mod, Timeout, HibernateAfterTimeout, Debug); {stop, Reason} -> %% For consistency, we must make sure that the %% registered name (if any) is unregistered before %% the parent process is notified about the failure. %% (Otherwise, the parent process could get %% an 'already_started' error if it immediately %% tried starting the process again.) gen:unregister_name(Name0), proc_lib:init_ack(Starter, {error, Reason}), exit(Reason); ignore -> gen:unregister_name(Name0), proc_lib:init_ack(Starter, ignore), exit(normal); {'EXIT', Reason} -> gen:unregister_name(Name0), 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. %%%======================================================================== %%% Internal functions %%%======================================================================== %%% --------------------------------------------------- %%% The MAIN loop. %%% --------------------------------------------------- loop(Parent, Name, State, Mod, hibernate, HibernateAfterTimeout, Debug) -> proc_lib:hibernate(?MODULE,wake_hib,[Parent, Name, State, Mod, HibernateAfterTimeout, Debug]); loop(Parent, Name, State, Mod, infinity, HibernateAfterTimeout, Debug) -> receive Msg -> decode_msg(Msg, Parent, Name, State, Mod, infinity, HibernateAfterTimeout, Debug, false) after HibernateAfterTimeout -> loop(Parent, Name, State, Mod, hibernate, HibernateAfterTimeout, Debug) end; loop(Parent, Name, State, Mod, Time, HibernateAfterTimeout, Debug) -> Msg = receive Input -> Input after Time -> timeout end, decode_msg(Msg, Parent, Name, State, Mod, Time, HibernateAfterTimeout, Debug, false). wake_hib(Parent, Name, State, Mod, HibernateAfterTimeout, Debug) -> Msg = receive Input -> Input end, decode_msg(Msg, Parent, Name, State, Mod, hibernate, HibernateAfterTimeout, Debug, true). decode_msg(Msg, Parent, Name, State, Mod, Time, HibernateAfterTimeout, Debug, Hib) -> case Msg of {system, From, Req} -> sys:handle_system_msg(Req, From, Parent, ?MODULE, Debug, [Name, State, Mod, Time, HibernateAfterTimeout], Hib); {'EXIT', Parent, Reason} -> terminate(Reason, Name, undefined, Msg, Mod, State, Debug); _Msg when Debug =:= [] -> handle_msg(Msg, Parent, Name, State, Mod, HibernateAfterTimeout); _Msg -> Debug1 = sys:handle_debug(Debug, fun print_event/3, Name, {in, Msg}), handle_msg(Msg, Parent, Name, State, Mod, HibernateAfterTimeout, Debug1) end. %%% --------------------------------------------------- %%% Send/receive functions %%% --------------------------------------------------- do_send(Dest, Msg) -> case catch erlang:send(Dest, Msg, [noconnect]) of noconnect -> spawn(erlang, send, [Dest,Msg]); Other -> Other end. do_multi_call(Nodes, Name, Req, infinity) -> Tag = make_ref(), Monitors = send_nodes(Nodes, Name, Tag, Req), rec_nodes(Tag, Monitors, Name, undefined); do_multi_call(Nodes, Name, Req, Timeout) -> Tag = make_ref(), Caller = self(), Receiver = spawn( fun() -> %% Middleman process. Should be unsensitive to regular %% exit signals. The sychronization is needed in case %% the receiver would exit before the caller started %% the monitor. process_flag(trap_exit, true), Mref = erlang:monitor(process, Caller), receive {Caller,Tag} -> Monitors = send_nodes(Nodes, Name, Tag, Req), TimerId = erlang:start_timer(Timeout, self(), ok), Result = rec_nodes(Tag, Monitors, Name, TimerId), exit({self(),Tag,Result}); {'DOWN',Mref,_,_,_} -> %% Caller died before sending us the go-ahead. %% Give up silently. exit(normal) end end), Mref = erlang:monitor(process, Receiver), Receiver ! {self(),Tag}, receive {'DOWN',Mref,_,_,{Receiver,Tag,Result}} -> Result; {'DOWN',Mref,_,_,Reason} -> %% The middleman code failed. Or someone did %% exit(_, kill) on the middleman process => Reason==killed exit(Reason) end. send_nodes(Nodes, Name, Tag, Req) -> send_nodes(Nodes, Name, Tag, Req, []). send_nodes([Node|Tail], Name, Tag, Req, Monitors) when is_atom(Node) -> Monitor = start_monitor(Node, Name), %% Handle non-existing names in rec_nodes. catch {Name, Node} ! {'$gen_call', {self(), {Tag, Node}}, Req}, send_nodes(Tail, Name, Tag, Req, [Monitor | Monitors]); send_nodes([_Node|Tail], Name, Tag, Req, Monitors) -> %% Skip non-atom Node send_nodes(Tail, Name, Tag, Req, Monitors); send_nodes([], _Name, _Tag, _Req, Monitors) -> Monitors. %% Against old nodes: %% If no reply has been delivered within 2 secs. (per node) check that %% the server really exists and wait for ever for the answer. %% %% Against contemporary nodes: %% Wait for reply, server 'DOWN', or timeout from TimerId. rec_nodes(Tag, Nodes, Name, TimerId) -> rec_nodes(Tag, Nodes, Name, [], [], 2000, TimerId). rec_nodes(Tag, [{N,R}|Tail], Name, Badnodes, Replies, Time, TimerId ) -> receive {'DOWN', R, _, _, _} -> rec_nodes(Tag, Tail, Name, [N|Badnodes], Replies, Time, TimerId); {{Tag, N}, Reply} -> %% Tag is bound !!! erlang:demonitor(R, [flush]), rec_nodes(Tag, Tail, Name, Badnodes, [{N,Reply}|Replies], Time, TimerId); {timeout, TimerId, _} -> erlang:demonitor(R, [flush]), %% Collect all replies that already have arrived rec_nodes_rest(Tag, Tail, Name, [N|Badnodes], Replies) end; rec_nodes(Tag, [N|Tail], Name, Badnodes, Replies, Time, TimerId) -> %% R6 node receive {nodedown, N} -> monitor_node(N, false), rec_nodes(Tag, Tail, Name, [N|Badnodes], Replies, 2000, TimerId); {{Tag, N}, Reply} -> %% Tag is bound !!! receive {nodedown, N} -> ok after 0 -> ok end, monitor_node(N, false), rec_nodes(Tag, Tail, Name, Badnodes, [{N,Reply}|Replies], 2000, TimerId); {timeout, TimerId, _} -> receive {nodedown, N} -> ok after 0 -> ok end, monitor_node(N, false), %% Collect all replies that already have arrived rec_nodes_rest(Tag, Tail, Name, [N | Badnodes], Replies) after Time -> case rpc:call(N, erlang, whereis, [Name]) of Pid when is_pid(Pid) -> % It exists try again. rec_nodes(Tag, [N|Tail], Name, Badnodes, Replies, infinity, TimerId); _ -> % badnode receive {nodedown, N} -> ok after 0 -> ok end, monitor_node(N, false), rec_nodes(Tag, Tail, Name, [N|Badnodes], Replies, 2000, TimerId) end end; rec_nodes(_, [], _, Badnodes, Replies, _, TimerId) -> case catch erlang:cancel_timer(TimerId) of false -> % It has already sent it's message receive {timeout, TimerId, _} -> ok after 0 -> ok end; _ -> % Timer was cancelled, or TimerId was 'undefined' ok end, {Replies, Badnodes}. %% Collect all replies that already have arrived rec_nodes_rest(Tag, [{N,R}|Tail], Name, Badnodes, Replies) -> receive {'DOWN', R, _, _, _} -> rec_nodes_rest(Tag, Tail, Name, [N|Badnodes], Replies); {{Tag, N}, Reply} -> %% Tag is bound !!! erlang:demonitor(R, [flush]), rec_nodes_rest(Tag, Tail, Name, Badnodes, [{N,Reply}|Replies]) after 0 -> erlang:demonitor(R, [flush]), rec_nodes_rest(Tag, Tail, Name, [N|Badnodes], Replies) end; rec_nodes_rest(Tag, [N|Tail], Name, Badnodes, Replies) -> %% R6 node receive {nodedown, N} -> monitor_node(N, false), rec_nodes_rest(Tag, Tail, Name, [N|Badnodes], Replies); {{Tag, N}, Reply} -> %% Tag is bound !!! receive {nodedown, N} -> ok after 0 -> ok end, monitor_node(N, false), rec_nodes_rest(Tag, Tail, Name, Badnodes, [{N,Reply}|Replies]) after 0 -> receive {nodedown, N} -> ok after 0 -> ok end, monitor_node(N, false), rec_nodes_rest(Tag, Tail, Name, [N|Badnodes], Replies) end; rec_nodes_rest(_Tag, [], _Name, Badnodes, Replies) -> {Replies, Badnodes}. %%% --------------------------------------------------- %%% Monitor functions %%% --------------------------------------------------- start_monitor(Node, Name) when is_atom(Node), is_atom(Name) -> if node() =:= nonode@nohost, Node =/= nonode@nohost -> Ref = make_ref(), self() ! {'DOWN', Ref, process, {Name, Node}, noconnection}, {Node, Ref}; true -> case catch erlang:monitor(process, {Name, Node}) of {'EXIT', _} -> %% Remote node is R6 monitor_node(Node, true), Node; Ref when is_reference(Ref) -> {Node, Ref} end end. %% --------------------------------------------------- %% Helper functions for try-catch of callbacks. %% Returns the return value of the callback, or %% {'EXIT', ExitReason, ReportReason} (if an exception occurs) %% %% ExitReason is the reason that shall be used when the process %% terminates. %% %% ReportReason is the reason that shall be printed in the error %% report. %% %% These functions are introduced in order to add the stack trace in %% the error report produced when a callback is terminated with %% erlang:exit/1 (OTP-12263). %% --------------------------------------------------- try_dispatch({'$gen_cast', Msg}, Mod, State) -> try_dispatch(Mod, handle_cast, Msg, State); try_dispatch(Info, Mod, State) -> try_dispatch(Mod, handle_info, Info, State). try_dispatch(Mod, Func, Msg, State) -> try {ok, Mod:Func(Msg, State)} catch throw:R -> {ok, R}; error:undef = R when Func == handle_info -> case erlang:function_exported(Mod, handle_info, 2) of false -> error_logger:warning_msg("** Undefined handle_info in ~p~n" "** Unhandled message: ~p~n", [Mod, Msg]), {ok, {noreply, State}}; true -> Stacktrace = erlang:get_stacktrace(), {'EXIT', {R, Stacktrace}, {R, Stacktrace}} end; error:R -> Stacktrace = erlang:get_stacktrace(), {'EXIT', {R, Stacktrace}, {R, Stacktrace}}; exit:R -> Stacktrace = erlang:get_stacktrace(), {'EXIT', R, {R, Stacktrace}} end. try_handle_call(Mod, Msg, From, State) -> try {ok, Mod:handle_call(Msg, From, State)} catch throw:R -> {ok, R}; error:R -> Stacktrace = erlang:get_stacktrace(), {'EXIT', {R, Stacktrace}, {R, Stacktrace}}; exit:R -> Stacktrace = erlang:get_stacktrace(), {'EXIT', R, {R, Stacktrace}} end. try_terminate(Mod, Reason, State) -> case erlang:function_exported(Mod, terminate, 2) of true -> try {ok, Mod:terminate(Reason, State)} catch throw:R -> {ok, R}; error:R -> Stacktrace = erlang:get_stacktrace(), {'EXIT', {R, Stacktrace}, {R, Stacktrace}}; exit:R -> Stacktrace = erlang:get_stacktrace(), {'EXIT', R, {R, Stacktrace}} end; false -> {ok, ok} end. %%% --------------------------------------------------- %%% Message handling functions %%% --------------------------------------------------- handle_msg({'$gen_call', From, Msg}, Parent, Name, State, Mod, HibernateAfterTimeout) -> Result = try_handle_call(Mod, Msg, From, State), case Result of {ok, {reply, Reply, NState}} -> reply(From, Reply), loop(Parent, Name, NState, Mod, infinity, HibernateAfterTimeout, []); {ok, {reply, Reply, NState, Time1}} -> reply(From, Reply), loop(Parent, Name, NState, Mod, Time1, HibernateAfterTimeout, []); {ok, {noreply, NState}} -> loop(Parent, Name, NState, Mod, infinity, HibernateAfterTimeout, []); {ok, {noreply, NState, Time1}} -> loop(Parent, Name, NState, Mod, Time1, HibernateAfterTimeout, []); {ok, {stop, Reason, Reply, NState}} -> {'EXIT', R} = (catch terminate(Reason, Name, From, Msg, Mod, NState, [])), reply(From, Reply), exit(R); Other -> handle_common_reply(Other, Parent, Name, From, Msg, Mod, HibernateAfterTimeout, State) end; handle_msg(Msg, Parent, Name, State, Mod, HibernateAfterTimeout) -> Reply = try_dispatch(Msg, Mod, State), handle_common_reply(Reply, Parent, Name, undefined, Msg, Mod, HibernateAfterTimeout, State). handle_msg({'$gen_call', From, Msg}, Parent, Name, State, Mod, HibernateAfterTimeout, Debug) -> Result = try_handle_call(Mod, Msg, From, State), case Result of {ok, {reply, Reply, NState}} -> Debug1 = reply(Name, From, Reply, NState, Debug), loop(Parent, Name, NState, Mod, infinity, HibernateAfterTimeout, Debug1); {ok, {reply, Reply, NState, Time1}} -> Debug1 = reply(Name, From, Reply, NState, Debug), loop(Parent, Name, NState, Mod, Time1, HibernateAfterTimeout, Debug1); {ok, {noreply, NState}} -> Debug1 = sys:handle_debug(Debug, fun print_event/3, Name, {noreply, NState}), loop(Parent, Name, NState, Mod, infinity, HibernateAfterTimeout, Debug1); {ok, {noreply, NState, Time1}} -> Debug1 = sys:handle_debug(Debug, fun print_event/3, Name, {noreply, NState}), loop(Parent, Name, NState, Mod, Time1, HibernateAfterTimeout, Debug1); {ok, {stop, Reason, Reply, NState}} -> {'EXIT', R} = (catch terminate(Reason, Name, From, Msg, Mod, NState, Debug)), _ = reply(Name, From, Reply, NState, Debug), exit(R); Other -> handle_common_reply(Other, Parent, Name, From, Msg, Mod, HibernateAfterTimeout, State, Debug) end; handle_msg(Msg, Parent, Name, State, Mod, HibernateAfterTimeout, Debug) -> Reply = try_dispatch(Msg, Mod, State), handle_common_reply(Reply, Parent, Name, undefined, Msg, Mod, HibernateAfterTimeout, State, Debug). handle_common_reply(Reply, Parent, Name, From, Msg, Mod, HibernateAfterTimeout, State) -> case Reply of {ok, {noreply, NState}} -> loop(Parent, Name, NState, Mod, infinity, HibernateAfterTimeout, []); {ok, {noreply, NState, Time1}} -> loop(Parent, Name, NState, Mod, Time1, HibernateAfterTimeout, []); {ok, {stop, Reason, NState}} -> terminate(Reason, Name, From, Msg, Mod, NState, []); {'EXIT', ExitReason, ReportReason} -> terminate(ExitReason, ReportReason, Name, From, Msg, Mod, State, []); {ok, BadReply} -> terminate({bad_return_value, BadReply}, Name, From, Msg, Mod, State, []) end. handle_common_reply(Reply, Parent, Name, From, Msg, Mod, HibernateAfterTimeout, State, Debug) -> case Reply of {ok, {noreply, NState}} -> Debug1 = sys:handle_debug(Debug, fun print_event/3, Name, {noreply, NState}), loop(Parent, Name, NState, Mod, infinity, HibernateAfterTimeout, Debug1); {ok, {noreply, NState, Time1}} -> Debug1 = sys:handle_debug(Debug, fun print_event/3, Name, {noreply, NState}), loop(Parent, Name, NState, Mod, Time1, HibernateAfterTimeout, Debug1); {ok, {stop, Reason, NState}} -> terminate(Reason, Name, From, Msg, Mod, NState, Debug); {'EXIT', ExitReason, ReportReason} -> terminate(ExitReason, ReportReason, Name, From, Msg, Mod, State, Debug); {ok, BadReply} -> terminate({bad_return_value, BadReply}, Name, From, Msg, Mod, State, Debug) end. reply(Name, {To, Tag}, Reply, State, Debug) -> reply({To, Tag}, Reply), sys:handle_debug(Debug, fun print_event/3, Name, {out, Reply, To, State} ). %%----------------------------------------------------------------- %% Callback functions for system messages handling. %%----------------------------------------------------------------- system_continue(Parent, Debug, [Name, State, Mod, Time, HibernateAfterTimeout]) -> loop(Parent, Name, State, Mod, Time, HibernateAfterTimeout, Debug). -spec system_terminate(_, _, _, [_]) -> no_return(). system_terminate(Reason, _Parent, Debug, [Name, State, Mod, _Time, _HibernateAfterTimeout]) -> terminate(Reason, Name, undefined, [], Mod, State, Debug). system_code_change([Name, State, Mod, Time, HibernateAfterTimeout], _Module, OldVsn, Extra) -> case catch Mod:code_change(OldVsn, State, Extra) of {ok, NewState} -> {ok, [Name, NewState, Mod, Time, HibernateAfterTimeout]}; Else -> Else end. system_get_state([_Name, State, _Mod, _Time, _HibernateAfterTimeout]) -> {ok, State}. system_replace_state(StateFun, [Name, State, Mod, Time, HibernateAfterTimeout]) -> NState = StateFun(State), {ok, NState, [Name, NState, Mod, Time, HibernateAfterTimeout]}. %%----------------------------------------------------------------- %% 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) -> case Msg of {'$gen_call', {From, _Tag}, Call} -> io:format(Dev, "*DBG* ~p got call ~p from ~w~n", [Name, Call, From]); {'$gen_cast', Cast} -> io:format(Dev, "*DBG* ~p got cast ~p~n", [Name, Cast]); _ -> io:format(Dev, "*DBG* ~p got ~p~n", [Name, Msg]) end; print_event(Dev, {out, Msg, To, State}, Name) -> io:format(Dev, "*DBG* ~p sent ~p to ~w, new state ~w~n", [Name, Msg, To, State]); print_event(Dev, {noreply, State}, Name) -> io:format(Dev, "*DBG* ~p new state ~w~n", [Name, State]); print_event(Dev, Event, Name) -> io:format(Dev, "*DBG* ~p dbg ~p~n", [Name, Event]). %%% --------------------------------------------------- %%% Terminate the server. %%% --------------------------------------------------- -spec terminate(_, _, _, _, _, _, _) -> no_return(). terminate(Reason, Name, From, Msg, Mod, State, Debug) -> terminate(Reason, Reason, Name, From, Msg, Mod, State, Debug). -spec terminate(_, _, _, _, _, _, _, _) -> no_return(). terminate(ExitReason, ReportReason, Name, From, Msg, Mod, State, Debug) -> Reply = try_terminate(Mod, ExitReason, State), case Reply of {'EXIT', ExitReason1, ReportReason1} -> FmtState = format_status(terminate, Mod, get(), State), error_info(ReportReason1, Name, From, Msg, FmtState, Debug), exit(ExitReason1); _ -> case ExitReason of normal -> exit(normal); shutdown -> exit(shutdown); {shutdown,_}=Shutdown -> exit(Shutdown); _ -> FmtState = format_status(terminate, Mod, get(), State), error_info(ReportReason, Name, From, Msg, FmtState, Debug), exit(ExitReason) end end. error_info(_Reason, application_controller, _From, _Msg, _State, _Debug) -> %% OTP-5811 Don't send an error report if it's the system process %% application_controller which is terminating - let init take care %% of it instead ok; error_info(Reason, Name, From, Msg, State, Debug) -> Reason1 = case Reason of {undef,[{M,F,A,L}|MFAs]} -> case code:is_loaded(M) of false -> {'module could not be loaded',[{M,F,A,L}|MFAs]}; _ -> case erlang:function_exported(M, F, length(A)) of true -> Reason; false -> {'function not exported',[{M,F,A,L}|MFAs]} end end; _ -> Reason end, {ClientFmt, ClientArgs} = client_stacktrace(From), LimitedState = error_logger:limit_term(State), error_logger:format("** Generic server ~p terminating \n" "** Last message in was ~p~n" "** When Server state == ~p~n" "** Reason for termination == ~n** ~p~n" ++ ClientFmt, [Name, Msg, LimitedState, Reason1] ++ ClientArgs), sys:print_log(Debug), ok. client_stacktrace(undefined) -> {"", []}; client_stacktrace({From, _Tag}) -> client_stacktrace(From); client_stacktrace(From) when is_pid(From), node(From) =:= node() -> case process_info(From, [current_stacktrace, registered_name]) of undefined -> {"** Client ~p is dead~n", [From]}; [{current_stacktrace, Stacktrace}, {registered_name, []}] -> {"** Client ~p stacktrace~n" "** ~p~n", [From, Stacktrace]}; [{current_stacktrace, Stacktrace}, {registered_name, Name}] -> {"** Client ~p stacktrace~n" "** ~p~n", [Name, Stacktrace]} end; client_stacktrace(From) when is_pid(From) -> {"** Client ~p is remote on node ~p~n", [From, node(From)]}. %%----------------------------------------------------------------- %% Status information %%----------------------------------------------------------------- format_status(Opt, StatusData) -> [PDict, SysState, Parent, Debug, [Name, State, Mod, _Time, _HibernateAfterTimeout]] = StatusData, Header = gen:format_status_header("Status for generic server", Name), Log = sys:get_debug(log, Debug, []), Specfic = case format_status(Opt, Mod, PDict, State) of S when is_list(S) -> S; S -> [S] end, [{header, Header}, {data, [{"Status", SysState}, {"Parent", Parent}, {"Logged events", Log}]} | Specfic]. format_status(Opt, Mod, PDict, State) -> DefStatus = case Opt of terminate -> State; _ -> [{data, [{"State", State}]}] end, case erlang:function_exported(Mod, format_status, 2) of true -> case catch Mod:format_status(Opt, [PDict, State]) of {'EXIT', _} -> DefStatus; Else -> Else end; _ -> DefStatus end.