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pbot/PBot/EventDispatcher.pm
2021-07-04 23:26:54 -07:00

106 lines
3.0 KiB
Perl

# File: EventDispatcher.pm
#
# Purpose: Registers event handlers and dispatches events to them.
#
# Note: PBot::EventDispatcher has no relation to PBot::EventQueue.
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.
package PBot::EventDispatcher;
use parent 'PBot::Class';
use PBot::Imports;
sub initialize {
my ($self, %conf) = @_;
# hash table of event handlers
$self->{handlers} = {};
}
# add an event handler
sub register_handler {
my ($self, $event_name, $subref) = @_;
# get the package of the calling subroutine
my ($package) = caller(0);
# internal identifier to find calling package's event handler
my $handler_id = "$package-$event_name";
# add the event handler
$self->{handlers}->{$event_name}->{$handler_id} = $subref;
# debugging
if ($self->{pbot}->{registry}->get_value('eventdispatcher', 'debug')) {
$self->{pbot}->{logger}->log("EventDispatcher: Add handler: $handler_id\n");
}
}
# remove an event handler
sub remove_handler {
my ($self, $event_name) = @_;
# get the package of the calling subroutine
my ($package) = caller(0);
# internal identifier to find calling package's event handler
my $handler_id = "$package-$event_name";
# remove the event handler
if (exists $self->{handlers}->{$event_name}) {
delete $self->{handlers}->{$event_name}->{$handler_id};
# remove root event-name key if it has no more handlers
if (not keys %{$self->{handlers}->{$event_name}}) {
delete $self->{handlers}->{$event_name};
}
}
# debugging
if ($self->{pbot}->{registry}->get_value('eventdispatcher', 'debug')) {
$self->{pbot}->{logger}->log("EventDispatcher: Remove handler: $handler_id\n");
}
}
# send an event to its handlers
sub dispatch_event {
my ($self, $event_name, $event_data) = @_;
# debugging flag
my $debug = $self->{pbot}->{registry}->get_value('eventdispatcher', 'debug') // 0;
# event handler return value
my $ret = undef;
# if the event-name has handlers
if (exists $self->{handlers}->{$event_name}) {
# then dispatch the event to each one
foreach my $handler_id (keys %{$self->{handlers}->{$event_name}}) {
# event handler subref
my $subref = $self->{handlers}->{$event_name}->{$handler_id};
# debugging
if ($debug) {
$self->{pbot}->{logger}->log("Dispatching $event_name to handler $handler_id\n");
}
# invoke event handler
eval { $ret = $subref->($event_name, $event_data) };
# check for error
if (my $error = $@) {
chomp $error;
$self->{pbot}->{logger}->log("Error in event handler: $error\n");
}
}
}
# return event handler result
return $ret;
}
1;