summaryrefslogtreecommitdiffstats
path: root/scripts/Dpkg/Deps/AND.pm
blob: 7b403c237ae672d7bd1b19f65330b9bdb9976294 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
# 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::AND;

=encoding utf8

=head1 NAME

Dpkg::Deps::AND - list of AND dependencies

=head1 DESCRIPTION

This class represents a list of dependencies that must be met at the same
time. 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) = @_;

    # If any individual member can imply $o or NOT $o, we're fine
    foreach my $dep ($self->get_deps()) {
        my $implication = $dep->implies($o);
        return 1 if defined $implication and $implication == 1;
        return 0 if defined $implication and $implication == 0;
    }

    # If o is an AND, we might have an implication, if we find an
    # implication within us for each predicate in o
    if ($o->isa('Dpkg::Deps::AND')) {
        my $subset = 1;
        foreach my $odep ($o->get_deps()) {
            my $found = 0;
            foreach my $dep ($self->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) = @_;

    # Return 1 only if all members evaluates to true
    # Return 0 if at least one member evaluates to false
    # Return undef otherwise
    my $result = 1;
    foreach my $dep ($self->get_deps()) {
        my $eval = $dep->get_evaluation($facts);
        if (not defined $eval) {
            $result = undef;
        } elsif ($eval == 0) {
            $result = 0;
            last;
        } elsif ($eval == 1) {
            # Still possible
        }
    }
    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, @knowndeps) = @_;
    my @new;

WHILELOOP:
    while (@{$self->{list}}) {
        my $dep = shift @{$self->{list}};
        my $eval = $dep->get_evaluation($facts);
        next if defined $eval and $eval == 1;
        foreach my $odep (@knowndeps, @new) {
            next WHILELOOP if $odep->implies($dep);
        }
        # When a dependency is implied by another dependency that
        # follows, then invert them
        # "a | b, c, a"  becomes "a, c" and not "c, a"
        my $i = 0;
        foreach my $odep (@{$self->{list}}) {
            if (defined $odep and $odep->implies($dep)) {
                splice @{$self->{list}}, $i, 1;
                unshift @{$self->{list}}, $odep;
                next WHILELOOP;
            }
            $i++;
        }
        push @new, $dep;
    }
    $self->{list} = [ @new ];
}

=back

=head1 CHANGES

=head2 Version 1.00 (dpkg 1.15.6)

Mark the module as public.

=cut

1;