diff options
Diffstat (limited to 'src/gen_server2.erl')
| -rw-r--r-- | src/gen_server2.erl | 121 |
1 files changed, 75 insertions, 46 deletions
diff --git a/src/gen_server2.erl b/src/gen_server2.erl index a637dddd..35258139 100644 --- a/src/gen_server2.erl +++ b/src/gen_server2.erl @@ -58,6 +58,20 @@ %% hibernate the process immediately, as it would if backoff wasn't %% being used. Instead it'll wait for the current timeout as described %% above. +%% +%% 7) The callback module can return from any of the handle_* +%% functions, a {become, Module, State} triple, or a {become, Module, +%% State, Timeout} quadruple. This allows the gen_server to +%% dynamically change the callback module. The State is the new state +%% which will be passed into any of the callback functions in the new +%% module. Note there is no form also encompassing a reply, thus if +%% you wish to reply in handle_call/3 and change the callback module, +%% you need to use gen_server2:reply/2 to issue the reply manually. +%% +%% 8) The callback module can optionally implement +%% format_message_queue/2 which is the equivalent of format_status/2 +%% but where the second argument is specifically the priority_queue +%% which contains the prioritised message_queue. %% All modifications are (C) 2009-2011 VMware, Inc. @@ -444,8 +458,8 @@ unregister_name({global,Name}) -> _ = global:unregister_name(Name); unregister_name(Pid) when is_pid(Pid) -> Pid; -% Under R12 let's just ignore it, as we have a single term as Name. -% On R13 it will never get here, as we get tuple with 'local/global' atom. +%% Under R12 let's just ignore it, as we have a single term as Name. +%% On R13 it will never get here, as we get tuple with 'local/global' atom. unregister_name(_Name) -> ok. extend_backoff(undefined) -> @@ -584,41 +598,35 @@ adjust_timeout_state(SleptAt, AwokeAt, {backoff, CurrentTO, MinimumTO, CurrentTO1 = Base + Extra, {backoff, CurrentTO1, MinimumTO, DesiredHibPeriod, RandomState1}. -in({'$gen_cast', Msg}, GS2State = #gs2_state { prioritise_cast = PC, - queue = Queue }) -> - GS2State #gs2_state { queue = priority_queue:in( - {'$gen_cast', Msg}, - PC(Msg, GS2State), Queue) }; -in({'$gen_call', From, Msg}, GS2State = #gs2_state { prioritise_call = PC, - queue = Queue }) -> - GS2State #gs2_state { queue = priority_queue:in( - {'$gen_call', From, Msg}, - PC(Msg, From, GS2State), Queue) }; -in(Input, GS2State = #gs2_state { prioritise_info = PI, queue = Queue }) -> - GS2State #gs2_state { queue = priority_queue:in( - Input, PI(Input, GS2State), Queue) }. - -process_msg(Msg, - GS2State = #gs2_state { parent = Parent, - name = Name, - debug = Debug }) -> - case Msg of - {system, From, Req} -> - sys:handle_system_msg( - Req, From, Parent, ?MODULE, Debug, - GS2State); - %% gen_server puts Hib on the end as the 7th arg, but that - %% version of the function seems not to be documented so - %% leaving out for now. - {'EXIT', Parent, Reason} -> - terminate(Reason, Msg, GS2State); - _Msg when Debug =:= [] -> - handle_msg(Msg, GS2State); - _Msg -> - Debug1 = sys:handle_debug(Debug, fun print_event/3, - Name, {in, Msg}), - handle_msg(Msg, GS2State #gs2_state { debug = Debug1 }) - end. +in({'$gen_cast', Msg} = Input, + GS2State = #gs2_state { prioritise_cast = PC }) -> + in(Input, PC(Msg, GS2State), GS2State); +in({'$gen_call', From, Msg} = Input, + GS2State = #gs2_state { prioritise_call = PC }) -> + in(Input, PC(Msg, From, GS2State), GS2State); +in({'EXIT', Parent, _R} = Input, GS2State = #gs2_state { parent = Parent }) -> + in(Input, infinity, GS2State); +in({system, _From, _Req} = Input, GS2State) -> + in(Input, infinity, GS2State); +in(Input, GS2State = #gs2_state { prioritise_info = PI }) -> + in(Input, PI(Input, GS2State), GS2State). + +in(Input, Priority, GS2State = #gs2_state { queue = Queue }) -> + GS2State # gs2_state { queue = priority_queue:in(Input, Priority, Queue) }. + +process_msg({system, From, Req}, + GS2State = #gs2_state { parent = Parent, debug = Debug }) -> + sys:handle_system_msg(Req, From, Parent, ?MODULE, Debug, GS2State); +process_msg({'EXIT', Parent, Reason} = Msg, + GS2State = #gs2_state { parent = Parent }) -> + %% gen_server puts Hib on the end as the 7th arg, but that version + %% of the fun seems not to be documented so leaving out for now. + terminate(Reason, Msg, GS2State); +process_msg(Msg, GS2State = #gs2_state { debug = [] }) -> + handle_msg(Msg, GS2State); +process_msg(Msg, GS2State = #gs2_state { name = Name, debug = Debug }) -> + Debug1 = sys:handle_debug(Debug, fun print_event/3, Name, {in, Msg}), + handle_msg(Msg, GS2State #gs2_state { debug = Debug1 }). %%% --------------------------------------------------- %%% Send/recive functions @@ -880,6 +888,22 @@ handle_common_reply(Reply, Msg, GS2State = #gs2_state { name = Name, loop(GS2State #gs2_state { state = NState, time = Time1, debug = Debug1 }); + {become, Mod, NState} -> + Debug1 = common_debug(Debug, fun print_event/3, Name, + {become, Mod, NState}), + loop(find_prioritisers( + GS2State #gs2_state { mod = Mod, + state = NState, + time = infinity, + debug = Debug1 })); + {become, Mod, NState, Time1} -> + Debug1 = common_debug(Debug, fun print_event/3, Name, + {become, Mod, NState}), + loop(find_prioritisers( + GS2State #gs2_state { mod = Mod, + state = NState, + time = Time1, + debug = Debug1 })); _ -> handle_common_termination(Reply, Msg, GS2State) end. @@ -1136,17 +1160,22 @@ format_status(Opt, StatusData) -> 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, + Specfic = callback(Mod, format_status, [Opt, [PDict, State]], + fun () -> [{data, [{"State", State}]}] end), + Messages = callback(Mod, format_message_queue, [Opt, Queue], + fun () -> priority_queue:to_list(Queue) end), [{header, Header}, {data, [{"Status", SysState}, {"Parent", Parent}, {"Logged events", Log}, - {"Queued messages", priority_queue:to_list(Queue)}]} | + {"Queued messages", Messages}]} | Specfic]. + +callback(Mod, FunName, Args, DefaultThunk) -> + case erlang:function_exported(Mod, FunName, length(Args)) of + true -> case catch apply(Mod, FunName, Args) of + {'EXIT', _} -> DefaultThunk(); + Success -> Success + end; + false -> DefaultThunk() + end. |