File Coverage

File:Dpkg/Interface/Storable.pm
Coverage:79.6%

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1# Copyright © 2010 Raphaël Hertzog <hertzog@debian.org>
2#
3# This program is free software; you can redistribute it and/or modify
4# it under the terms of the GNU General Public License as published by
5# the Free Software Foundation; either version 2 of the License, or
6# (at your option) any later version.
7#
8# This program is distributed in the hope that it will be useful,
9# but WITHOUT ANY WARRANTY; without even the implied warranty of
10# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11# GNU General Public License for more details.
12#
13# You should have received a copy of the GNU General Public License
14# along with this program.  If not, see <https://www.gnu.org/licenses/>.
15
16package Dpkg::Interface::Storable;
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use strict;
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use warnings;
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21our $VERSION = '1.01';
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use Carp;
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use Dpkg::Gettext;
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use Dpkg::ErrorHandling;
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28use overload
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    '""' => \&_stringify,
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    'fallback' => 1;
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32=encoding utf8
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=head1 NAME

Dpkg::Interface::Storable - common methods related to object serialization

=head1 DESCRIPTION

Dpkg::Interface::Storable is only meant to be used as parent
class for other classes. It provides common methods that are
all implemented on top of two basic methods parse() and output().

=head1 BASE METHODS

Those methods must be provided by the class that wish to inherit
from Dpkg::Interface::Storable so that the methods provided can work.

=over 4

=item $obj->parse($fh[, $desc])

This methods initialize the object with the data stored in the
filehandle. $desc is optional and is a textual description of
the filehandle used in error messages.

=item $string = $obj->output([$fh])

This method returns a string representation of the object in $string
and it writes the same string to $fh (if it's defined).

=back

=head1 PROVIDED METHODS

=over 4

=item $obj->load($filename, %opts)

Initialize the object with the data stored in the file. The file can be
compressed, it will be decompressed on the fly by using a
Dpkg::Compression::FileHandle object. If $opts{compression} is false the
decompression support will be disabled. If $filename is "-", then the
standard input is read (no compression is allowed in that case).

=cut
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78sub load {
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    my ($self, $file, %opts) = @_;
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    $opts{compression} //= 1;
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    unless ($self->can('parse')) {
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        croak ref($self) . ' cannot be loaded, it lacks the parse method';
83    }
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    my ($desc, $fh) = ($file, undef);
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    if ($file eq '-') {
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        $fh = \*STDIN;
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        $desc = g_('<standard input>');
88    } else {
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        if ($opts{compression}) {
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            require Dpkg::Compression::FileHandle;
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            $fh = Dpkg::Compression::FileHandle->new();
92        }
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        open($fh, '<', $file) or syserr(g_('cannot read %s'), $file);
94    }
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    my $res = $self->parse($fh, $desc, %opts);
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    if ($file ne '-') {
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        close($fh) or syserr(g_('cannot close %s'), $file);
98    }
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    return $res;
100}
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=item $obj->save($filename, %opts)

Store the object in the file. If the filename ends with a known
compression extension, it will be compressed on the fly by using a
Dpkg::Compression::FileHandle object. If $opts{compression} is false the
compression support will be disabled. If $filename is "-", then the
standard output is used (data are written uncompressed in that case).

=cut
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112sub save {
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    my ($self, $file, %opts) = @_;
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    $opts{compression} //= 1;
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    unless ($self->can('output')) {
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        croak ref($self) . ' cannot be saved, it lacks the output method';
117    }
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    my $fh;
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    if ($file eq '-') {
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        $fh = \*STDOUT;
121    } else {
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        if ($opts{compression}) {
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            require Dpkg::Compression::FileHandle;
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            $fh = Dpkg::Compression::FileHandle->new();
125        }
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        open($fh, '>', $file) or syserr(g_('cannot write %s'), $file);
127    }
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    $self->output($fh, %opts);
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    if ($file ne '-') {
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        close($fh) or syserr(g_('cannot close %s'), $file);
131    }
132}
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=item "$obj"

Return a string representation of the object.

=cut
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140sub _stringify {
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    my $self = shift;
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    unless ($self->can('output')) {
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        croak ref($self) . ' cannot be stringified, it lacks the output method';
144    }
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    return $self->output();
146}
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148=back
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=head1 CHANGES

=head2 Version 1.01 (dpkg 1.19.0)

New options: The $obj->load() and $obj->save() methods support a new
compression option.

=head2 Version 1.00 (dpkg 1.15.6)

Mark the module as public.

=cut
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1631;