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# You may distribute under the terms of either the GNU General Public License
# or the Artistic License (the same terms as Perl itself)
#
# (C) Paul Evans, 2009 -- leonerd@leonerd.org.uk
package IO::Async::Signal;
use strict;
use warnings;
use base qw( IO::Async::Notifier );
our $VERSION = '0.29';
use Carp;
=head1 NAME
C<IO::Async::Signal> - event callback on receipt of a POSIX signal
=head1 SYNOPSIS
use IO::Async::Signal;
use IO::Async::Loop;
my $loop = IO::Async::Loop->new();
my $signal = IO::Async::Signal->new(
name => "HUP",
on_receipt => sub {
print "I caught SIGHUP\n";
},
);
$loop->add( $signal );
$loop->loop_forever;
=head1 DESCRIPTION
This module provides a class of C<IO::Async::Notifier> which invokes its
callback when a particular POSIX signal is received.
Multiple objects can be added to a C<Loop> that all watch for the same signal.
The callback functions will all be invoked, in no particular order.
This object may be used in one of two ways; with a callback function, or as a
base class.
=over 4
=item Callbacks
If the C<on_receipt> key is supplied to the constructor, it should contain a
CODE reference to a callback function to be invoked when the signal is received.
$on_receipt->( $self )
=item Base Class
If a subclass is built, then it can override the C<on_receipt> method.
$self->on_receipt()
=back
=cut
=head1 PARAMETERS
The following named parameters may be passed to C<new> or C<configure>:
=over 8
=item name => STRING
The name of the signal to watch. This should be a bare name like C<TERM>. Can
only be given at construction time.
=item on_receipt => CODE
CODE reference to callback to invoke when the signal is received. If not
supplied, the subclass method will be called instead.
=back
Once constructed, the C<Signal> will need to be added to the C<Loop> before it
will work.
=cut
sub _init
{
my $self = shift;
my ( $params ) = @_;
my $name = delete $params->{name} or croak "Expected 'name'";
$name =~ s/^SIG//; # Trim a leading "SIG"
$self->{name} = $name;
$self->SUPER::_init( $params );
}
sub configure
{
my $self = shift;
my %params = @_;
if( exists $params{on_receipt} ) {
$self->{on_receipt} = delete $params{on_receipt};
undef $self->{cb}; # Will be lazily constructed when needed
if( my $loop = $self->get_loop ) {
$self->_remove_from_loop( $loop );
$self->_add_to_loop( $loop );
}
}
if( !$self->{on_receipt} and !$self->can( 'on_receipt' ) ) {
croak 'Expected either a on_receipt callback or an ->on_receipt method';
}
$self->SUPER::configure( %params );
}
sub _add_to_loop
{
my $self = shift;
my ( $loop ) = @_;
if( !$self->{cb} ) {
if( $self->{on_receipt} ) {
$self->{cb} = $self->_capture_weakself( $self->{on_receipt} );
}
else {
$self->{cb} = $self->_capture_weakself( 'on_receipt' );
}
}
$self->{id} = $loop->attach_signal( $self->{name}, $self->{cb} );
}
sub _remove_from_loop
{
my $self = shift;
my ( $loop ) = @_;
$loop->detach_signal( $self->{name}, $self->{id} );
undef $self->{id};
}
# Keep perl happy; keep Britain tidy
1;
__END__
=head1 AUTHOR
Paul Evans <leonerd@leonerd.org.uk>
|
