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% 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.
-module(couch_event_listener_mfa).
-behavior(couch_event_listener).
-export([
start_link/4,
enter_loop/4,
stop/1
]).
-export([
init/1,
terminate/2,
handle_event/3,
handle_cast/2,
handle_info/2
]).
-record(st, {
mod,
func,
state,
parent
}).
start_link(Mod, Func, State, Options) ->
Parent =
case proplists:get_value(parent, Options) of
P when is_pid(P) -> P;
_ -> self()
end,
Arg = {Parent, Mod, Func, State},
couch_event_listener:start_link(?MODULE, Arg, Options).
enter_loop(Mod, Func, State, Options) ->
Parent =
case proplists:get_value(parent, Options) of
P when is_pid(P) ->
erlang:monitor(process, P),
P;
_ ->
undefined
end,
St = #st{
mod = Mod,
func = Func,
state = State,
parent = Parent
},
couch_event_listener:enter_loop(?MODULE, St, Options).
stop(Pid) ->
couch_event_listener:cast(Pid, shutdown).
init({Parent, Mod, Func, State}) ->
erlang:monitor(process, Parent),
{ok, #st{
mod = Mod,
func = Func,
state = State,
parent = Parent
}}.
terminate(_Reason, _MFA) ->
ok.
handle_event(DbName, Event, #st{mod = Mod, func = Func, state = State} = St) ->
try
case Mod:Func(DbName, Event, State) of
{ok, NewState} ->
{ok, St#st{state = NewState}};
stop ->
{stop, normal, St};
Else ->
couch_log:error("~p: else in handle_event for db ~p, event ~p, else ~p", [?MODULE, DbName, Event, Else]),
erlang:error(Else)
end
catch
error:Reason:Stack ->
couch_log:error("~p: error in handle_event for db ~p, event ~p, reason ~p, stack ~p", [?MODULE, DbName, Event, Reason, Stack]),
erlang:error(Reason);
exit:Reason:Stack ->
couch_log:error("~p: exit in handle_event for db ~p, event ~p, reason ~p, stack ~p", [?MODULE, DbName, Event, Reason, Stack]),
erlang:exit(Reason);
throw:Reason:Stack ->
couch_log:error("~p: throw in handle_event for db ~p, event ~p, reason ~p, stack ~p", [?MODULE, DbName, Event, Reason, Stack]),
erlang:throw(Reason)
end.
handle_cast(shutdown, St) ->
{stop, normal, St};
handle_cast(_Msg, St) ->
{ok, St}.
handle_info({'DOWN', _Ref, process, Parent, _Reason}, #st{parent = Parent} = St) ->
{stop, normal, St};
handle_info(_Msg, St) ->
{ok, St}.
|
