%% %% %CopyrightBegin% %% %% Copyright Ericsson AB 1996-2010. All Rights Reserved. %% %% 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 online 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. %% %% %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, 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/5]). -export([behaviour_info/1]). %% System exports -export([system_continue/3, system_terminate/4, system_code_change/4, format_status/2]). %% Internal exports -export([init_it/6]). -import(error_logger, [format/2]). %%%========================================================================= %%% API %%%========================================================================= -spec behaviour_info(atom()) -> 'undefined' | [{atom(), arity()}]. behaviour_info(callbacks) -> [{init,1},{handle_call,3},{handle_cast,2},{handle_info,2}, {terminate,2},{code_change,3}]; behaviour_info(_Other) -> undefined. %%% ----------------------------------------------------------------- %%% 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()} %%% 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). %% ----------------------------------------------------------------- %% 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({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}. %% ----------------------------------------------------------------- %% Asyncronous broadcast, returns nothing, it's just send'n prey %%----------------------------------------------------------------- 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 = {_, _}) -> 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 = get_proc_name(ServerName), Parent = get_parent(), Debug = debug_options(Name, Options), loop(Parent, Name, State, Mod, Timeout, 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 = name(Name0), Debug = debug_options(Name, Options), case catch Mod:init(Args) of {ok, State} -> proc_lib:init_ack(Starter, {ok, self()}), loop(Parent, Name, State, Mod, infinity, Debug); {ok, State, Timeout} -> proc_lib:init_ack(Starter, {ok, self()}), loop(Parent, Name, State, Mod, Timeout, 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.) unregister_name(Name0), proc_lib:init_ack(Starter, {error, Reason}), exit(Reason); ignore -> unregister_name(Name0), proc_lib:init_ack(Starter, ignore), exit(normal); {'EXIT', Reason} -> 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. name({local,Name}) -> Name; name({global,Name}) -> Name; name(Pid) when is_pid(Pid) -> Pid. unregister_name({local,Name}) -> _ = (catch unregister(Name)); unregister_name({global,Name}) -> _ = global:unregister_name(Name); unregister_name(Pid) when is_pid(Pid) -> Pid. %%%======================================================================== %%% Internal functions %%%======================================================================== %%% --------------------------------------------------- %%% The MAIN loop. %%% --------------------------------------------------- loop(Parent, Name, State, Mod, hibernate, Debug) -> proc_lib:hibernate(?MODULE,wake_hib,[Parent, Name, State, Mod, Debug]); loop(Parent, Name, State, Mod, Time, Debug) -> Msg = receive Input -> Input after Time -> timeout end, decode_msg(Msg, Parent, Name, State, Mod, Time, Debug, false). wake_hib(Parent, Name, State, Mod, Debug) -> Msg = receive Input -> Input end, decode_msg(Msg, Parent, Name, State, Mod, hibernate, Debug, true). decode_msg(Msg, Parent, Name, State, Mod, Time, Debug, Hib) -> case Msg of {system, From, Req} -> sys:handle_system_msg(Req, From, Parent, ?MODULE, Debug, [Name, State, Mod, Time], Hib); {'EXIT', Parent, Reason} -> terminate(Reason, Name, Msg, Mod, State, Debug); _Msg when Debug =:= [] -> handle_msg(Msg, Parent, Name, State, Mod); _Msg -> Debug1 = sys:handle_debug(Debug, fun print_event/3, Name, {in, Msg}), handle_msg(Msg, Parent, Name, State, Mod, Debug1) end. %%% --------------------------------------------------- %%% Send/recive 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 !!! unmonitor(R), rec_nodes(Tag, Tail, Name, Badnodes, [{N,Reply}|Replies], Time, TimerId); {timeout, TimerId, _} -> unmonitor(R), %% 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 !!! unmonitor(R), rec_nodes_rest(Tag, Tail, Name, Badnodes, [{N,Reply}|Replies]) after 0 -> unmonitor(R), 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. %% Cancels a monitor started with Ref=erlang:monitor(_, _). unmonitor(Ref) when is_reference(Ref) -> erlang:demonitor(Ref), receive {'DOWN', Ref, _, _, _} -> true after 0 -> true end. %%% --------------------------------------------------- %%% Message handling functions %%% --------------------------------------------------- dispatch({'$gen_cast', Msg}, Mod, State) -> Mod:handle_cast(Msg, State); dispatch(Info, Mod, State) -> Mod:handle_info(Info, State). handle_msg({'$gen_call', From, Msg}, Parent, Name, State, Mod) -> case catch Mod:handle_call(Msg, From, State) of {reply, Reply, NState} -> reply(From, Reply), loop(Parent, Name, NState, Mod, infinity, []); {reply, Reply, NState, Time1} -> reply(From, Reply), loop(Parent, Name, NState, Mod, Time1, []); {noreply, NState} -> loop(Parent, Name, NState, Mod, infinity, []); {noreply, NState, Time1} -> loop(Parent, Name, NState, Mod, Time1, []); {stop, Reason, Reply, NState} -> {'EXIT', R} = (catch terminate(Reason, Name, Msg, Mod, NState, [])), reply(From, Reply), exit(R); Other -> handle_common_reply(Other, Parent, Name, Msg, Mod, State) end; handle_msg(Msg, Parent, Name, State, Mod) -> Reply = (catch dispatch(Msg, Mod, State)), handle_common_reply(Reply, Parent, Name, Msg, Mod, State). handle_msg({'$gen_call', From, Msg}, Parent, Name, State, Mod, Debug) -> case catch Mod:handle_call(Msg, From, State) of {reply, Reply, NState} -> Debug1 = reply(Name, From, Reply, NState, Debug), loop(Parent, Name, NState, Mod, infinity, Debug1); {reply, Reply, NState, Time1} -> Debug1 = reply(Name, From, Reply, NState, Debug), loop(Parent, Name, NState, Mod, Time1, Debug1); {noreply, NState} -> Debug1 = sys:handle_debug(Debug, fun print_event/3, Name, {noreply, NState}), loop(Parent, Name, NState, Mod, infinity, Debug1); {noreply, NState, Time1} -> Debug1 = sys:handle_debug(Debug, fun print_event/3, Name, {noreply, NState}), loop(Parent, Name, NState, Mod, Time1, Debug1); {stop, Reason, Reply, NState} -> {'EXIT', R} = (catch terminate(Reason, Name, Msg, Mod, NState, Debug)), reply(Name, From, Reply, NState, Debug), exit(R); Other -> handle_common_reply(Other, Parent, Name, Msg, Mod, State, Debug) end; handle_msg(Msg, Parent, Name, State, Mod, Debug) -> Reply = (catch dispatch(Msg, Mod, State)), handle_common_reply(Reply, Parent, Name, Msg, Mod, State, Debug). handle_common_reply(Reply, Parent, Name, Msg, Mod, State) -> case Reply of {noreply, NState} -> loop(Parent, Name, NState, Mod, infinity, []); {noreply, NState, Time1} -> loop(Parent, Name, NState, Mod, Time1, []); {stop, Reason, NState} -> terminate(Reason, Name, Msg, Mod, NState, []); {'EXIT', What} -> terminate(What, Name, Msg, Mod, State, []); _ -> terminate({bad_return_value, Reply}, Name, Msg, Mod, State, []) end. handle_common_reply(Reply, Parent, Name, Msg, Mod, State, Debug) -> case Reply of {noreply, NState} -> Debug1 = sys:handle_debug(Debug, fun print_event/3, Name, {noreply, NState}), loop(Parent, Name, NState, Mod, infinity, Debug1); {noreply, NState, Time1} -> Debug1 = sys:handle_debug(Debug, fun print_event/3, Name, {noreply, NState}), loop(Parent, Name, NState, Mod, Time1, Debug1); {stop, Reason, NState} -> terminate(Reason, Name, Msg, Mod, NState, Debug); {'EXIT', What} -> terminate(What, Name, Msg, Mod, State, Debug); _ -> terminate({bad_return_value, Reply}, Name, 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]) -> loop(Parent, Name, State, Mod, Time, Debug). -spec system_terminate(_, _, _, [_]) -> no_return(). system_terminate(Reason, _Parent, Debug, [Name, State, Mod, _Time]) -> terminate(Reason, Name, [], Mod, State, Debug). system_code_change([Name, State, Mod, Time], _Module, OldVsn, Extra) -> case catch Mod:code_change(OldVsn, State, Extra) of {ok, NewState} -> {ok, [Name, NewState, Mod, Time]}; 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) -> 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. %%% --------------------------------------------------- terminate(Reason, Name, Msg, Mod, State, Debug) -> case catch Mod:terminate(Reason, State) of {'EXIT', R} -> error_info(R, Name, Msg, State, Debug), exit(R); _ -> case Reason of normal -> exit(normal); shutdown -> exit(shutdown); {shutdown,_}=Shutdown -> exit(Shutdown); _ -> FmtState = case erlang:function_exported(Mod, format_status, 2) of true -> Args = [get(), State], case catch Mod:format_status(terminate, Args) of {'EXIT', _} -> State; Else -> Else end; _ -> State end, error_info(Reason, Name, Msg, FmtState, Debug), exit(Reason) end end. error_info(_Reason, application_controller, _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, Msg, State, 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, format("** Generic server ~p terminating \n" "** Last message in was ~p~n" "** When Server state == ~p~n" "** Reason for termination == ~n** ~p~n", [Name, Msg, State, Reason1]), sys:print_log(Debug), ok. %%% --------------------------------------------------- %%% Misc. functions. %%% --------------------------------------------------- opt(Op, [{Op, Value}|_]) -> {ok, Value}; opt(Op, [_|Options]) -> opt(Op, Options); opt(_, []) -> false. debug_options(Name, Opts) -> case opt(debug, Opts) of {ok, Options} -> dbg_options(Name, Options); _ -> dbg_options(Name, []) end. dbg_options(Name, []) -> Opts = case init:get_argument(generic_debug) of error -> []; _ -> [log, statistics] end, dbg_opts(Name, Opts); dbg_options(Name, Opts) -> dbg_opts(Name, Opts). dbg_opts(Name, Opts) -> case catch sys:debug_options(Opts) of {'EXIT',_} -> format("~p: ignoring erroneous debug options - ~p~n", [Name, Opts]), []; Dbg -> Dbg end. 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:safe_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:safe_whereis_name(Name) of undefined -> exit(could_not_find_registerd_name); Pid -> Pid end; Pid -> Pid end. %%----------------------------------------------------------------- %% Status information %%----------------------------------------------------------------- format_status(Opt, StatusData) -> [PDict, SysState, Parent, Debug, [Name, State, Mod, _Time]] = StatusData, Header = gen:format_status_header("Status for generic server", Name), Log = sys:get_debug(log, Debug, []), DefaultStatus = [{data, [{"State", State}]}], Specfic = case erlang:function_exported(Mod, format_status, 2) of true -> case catch Mod:format_status(Opt, [PDict, State]) of {'EXIT', _} -> DefaultStatus; StatusList when is_list(StatusList) -> StatusList; Else -> [Else] end; _ -> DefaultStatus end, [{header, Header}, {data, [{"Status", SysState}, {"Parent", Parent}, {"Logged events", Log}]} | Specfic].