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Diffstat (limited to 'lib/stdlib/src/gen_server.erl')
| -rw-r--r-- | lib/stdlib/src/gen_server.erl | 853 |
1 files changed, 853 insertions, 0 deletions
diff --git a/lib/stdlib/src/gen_server.erl b/lib/stdlib/src/gen_server.erl new file mode 100644 index 0000000000..f1a9a31c63 --- /dev/null +++ b/lib/stdlib/src/gen_server.erl @@ -0,0 +1,853 @@ +%% +%% %CopyrightBegin% +%% +%% Copyright Ericsson AB 1996-2009. 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, print_event/3]). + +-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, <ServerName>, <TimeOut>) ->_ +%% +%% 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, {?MODULE, print_event}, + 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, {?MODULE, print_event}, Name, + {noreply, NState}), + loop(Parent, Name, NState, Mod, infinity, Debug1); + {noreply, NState, Time1} -> + Debug1 = sys:handle_debug(Debug, {?MODULE, print_event}, 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, {?MODULE, print_event}, Name, + {noreply, NState}), + loop(Parent, Name, NState, Mod, infinity, Debug1); + {noreply, NState, Time1} -> + Debug1 = sys:handle_debug(Debug, {?MODULE, print_event}, 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, {?MODULE, print_event}, 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); + _ -> + error_info(Reason, Name, Msg, State, 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, + NameTag = if is_pid(Name) -> + pid_to_list(Name); + is_atom(Name) -> + Name + end, + Header = lists:concat(["Status for generic server ", 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, State]) of + {'EXIT', _} -> [{data, [{"State", State}]}]; + Else -> Else + end; + _ -> + [{data, [{"State", State}]}] + end, + [{header, Header}, + {data, [{"Status", SysState}, + {"Parent", Parent}, + {"Logged events", Log}]} | + Specfic]. |