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package EPrints::Test::Cycle;

=head1 NAME

EPrints::Test::Cycles - test for memory cycles

=head1 DESCRIPTION

Using this module will add various hooks around EPrints to check for memory cycles, that will cause memory leaks if not correctly cleaned up.

This will slow down EPrints considerably if used.

=head2 What to do if cycles are detected?

Memory cycles can be avoided by using L<Scalar::Util>::weaken.

=cut

use EPrints::Test;

use Devel::Cycle;

BEGIN
{
EPrints::Test::init( __PACKAGE__ );
}

sub EPrints::Session::DESTROY
{
	find_cycle( $_[0], \&report_object_cycle );
}

sub EPrints::MetaField::DESTROY
{
	find_cycle( $_[0], \&report_object_cycle );
}

sub EPrints::DataObj::DESTROY
{
	find_cycle( $_[0], \&report_object_cycle );
}

sub report_object_cycle
{
	my( $cycles ) = @_;

	my( $root, @edges ) = @$cycles;

	print STDERR "Cycle on ".ref($root->[2])." destruction:\n";

	&do_report( \@edges );
}

sub do_report
{
	my( $cycles ) = @_;

	for(@$cycles)
	{
		my( $type, $index, $ref, $value, $is_weak ) = @$_;
		print STDERR sprintf("\t%30s => %-30s\n",($is_weak ? 'w-> ' : '').Devel::Cycle::_format_reference($type,$index,$ref,0),Devel::Cycle::_format_reference(undef,undef,$value,1));
	}
}

1;

=head1 COPYRIGHT

=for COPYRIGHT BEGIN

Copyright 2022 University of Southampton.
EPrints 3.4 is supplied by EPrints Services.

http://www.eprints.org/eprints-3.4/

=for COPYRIGHT END

=for LICENSE BEGIN

This file is part of EPrints 3.4 L<http://www.eprints.org/>.

EPrints 3.4 and this file are released under the terms of the
GNU Lesser General Public License version 3 as published by
the Free Software Foundation unless otherwise stated.

EPrints 3.4 is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with EPrints 3.4.
If not, see L<http://www.gnu.org/licenses/>.

=for LICENSE END