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+# Copyright © 1998 Richard Braakman
+# Copyright © 1999 Darren Benham
+# Copyright © 2000 Sean 'Shaleh' Perry
+# Copyright © 2004 Frank Lichtenheld
+# Copyright © 2006 Russ Allbery
+# Copyright © 2007-2009 Raphaël Hertzog <hertzog@debian.org>
+# Copyright © 2008-2009, 2012-2014 Guillem Jover <guillem@debian.org>
+#
+# This program is free software; you may redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+package Dpkg::Deps::OR;
+
+=encoding utf8
+
+=head1 NAME
+
+Dpkg::Deps::OR - list of OR dependencies
+
+=head1 DESCRIPTION
+
+This object represents a list of dependencies of which only one must be met
+for the dependency to be true. It inherits from Dpkg::Deps::Multiple.
+
+=cut
+
+use strict;
+use warnings;
+
+our $VERSION = '1.00';
+
+use parent qw(Dpkg::Deps::Multiple);
+
+=head1 METHODS
+
+=over 4
+
+=item $dep->output([$fh])
+
+The output method uses " | " to join the list of sub-dependencies.
+
+=cut
+
+sub output {
+ my ($self, $fh) = @_;
+
+ my $res = join(' | ', map {
+ $_->output()
+ } grep {
+ not $_->is_empty()
+ } $self->get_deps());
+
+ if (defined $fh) {
+ print { $fh } $res;
+ }
+ return $res;
+}
+
+=item $dep->implies($other_dep)
+
+Returns 1 when $dep implies $other_dep. Returns 0 when $dep implies
+NOT($other_dep). Returns undef when there's no implication. $dep and
+$other_dep do not need to be of the same type.
+
+=cut
+
+sub implies {
+ my ($self, $o) = @_;
+
+ # Special case for AND with a single member, replace it by its member
+ if ($o->isa('Dpkg::Deps::AND')) {
+ my @subdeps = $o->get_deps();
+ if (scalar(@subdeps) == 1) {
+ $o = $subdeps[0];
+ }
+ }
+
+ # In general, an OR dependency can't imply anything except if each
+ # of its member implies a member in the other OR dependency
+ if ($o->isa('Dpkg::Deps::OR')) {
+ my $subset = 1;
+ foreach my $dep ($self->get_deps()) {
+ my $found = 0;
+ foreach my $odep ($o->get_deps()) {
+ $found = 1 if $dep->implies($odep);
+ }
+ $subset = 0 if not $found;
+ }
+ return 1 if $subset;
+ }
+ return;
+}
+
+=item $dep->get_evaluation($facts)
+
+Evaluates the dependency given a list of installed packages and a list of
+virtual packages provided. These lists are part of the Dpkg::Deps::KnownFacts
+object given as parameters.
+
+Returns 1 when it's true, 0 when it's false, undef when some information
+is lacking to conclude.
+
+=cut
+
+sub get_evaluation {
+ my ($self, $facts) = @_;
+
+ # Returns false if all members evaluates to 0
+ # Returns true if at least one member evaluates to true
+ # Returns undef otherwise
+ my $result = 0;
+ foreach my $dep ($self->get_deps()) {
+ my $eval = $dep->get_evaluation($facts);
+ if (not defined $eval) {
+ $result = undef;
+ } elsif ($eval == 1) {
+ $result = 1;
+ last;
+ } elsif ($eval == 0) {
+ # Still possible to have a false evaluation
+ }
+ }
+ return $result;
+}
+
+=item $dep->simplify_deps($facts, @assumed_deps)
+
+Simplifies the dependency as much as possible given the list of facts (see
+object Dpkg::Deps::KnownFacts) and a list of other dependencies that are
+known to be true.
+
+=cut
+
+sub simplify_deps {
+ my ($self, $facts) = @_;
+ my @new;
+
+WHILELOOP:
+ while (@{$self->{list}}) {
+ my $dep = shift @{$self->{list}};
+ my $eval = $dep->get_evaluation($facts);
+ if (defined $eval and $eval == 1) {
+ $self->{list} = [];
+ return;
+ }
+ foreach my $odep (@new, @{$self->{list}}) {
+ next WHILELOOP if $odep->implies($dep);
+ }
+ push @new, $dep;
+ }
+ $self->{list} = [ @new ];
+}
+
+=back
+
+=head1 CHANGES
+
+=head2 Version 1.00 (dpkg 1.15.6)
+
+Mark the module as public.
+
+=cut
+
+1;