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# Copyright © 2008-2010 Raphaël Hertzog <hertzog@debian.org>
# Copyright © 2008-2022 Guillem Jover <guillem@debian.org>
#
# This program is free software; you can 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 program 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::Compression::Process;
use strict;
use warnings;
our $VERSION = '1.00';
use Carp;
use Dpkg::Compression;
use Dpkg::ErrorHandling;
use Dpkg::Gettext;
use Dpkg::IPC;
=encoding utf8
=head1 NAME
Dpkg::Compression::Process - run compression/decompression processes
=head1 DESCRIPTION
This module provides an object oriented interface to run and manage
compression/decompression processes.
=head1 METHODS
=over 4
=item $proc = Dpkg::Compression::Process->new(%opts)
Create a new instance of the object. Supported options are "compression"
and "compression_level" (see corresponding set_* functions).
=cut
sub new {
my ($this, %args) = @_;
my $class = ref($this) || $this;
my $self = {};
bless $self, $class;
$self->set_compression($args{compression} || compression_get_default());
$self->set_compression_level($args{compression_level} ||
compression_get_default_level());
return $self;
}
=item $proc->set_compression($comp)
Select the compression method to use. It errors out if the method is not
supported according to C<compression_is_supported> (of
B<Dpkg::Compression>).
=cut
sub set_compression {
my ($self, $method) = @_;
error(g_('%s is not a supported compression method'), $method)
unless compression_is_supported($method);
$self->{compression} = $method;
}
=item $proc->set_compression_level($level)
Select the compression level to use. It errors out if the level is not
valid according to C<compression_is_valid_level> (of
B<Dpkg::Compression>).
=cut
sub set_compression_level {
my ($self, $level) = @_;
compression_set_level($self->{compression}, $level);
}
=item @exec = $proc->get_compress_cmdline()
=item @exec = $proc->get_uncompress_cmdline()
Returns a list ready to be passed to C<exec>, its first element is the
program name (either for compression or decompression) and the following
elements are parameters for the program.
When executed the program acts as a filter between its standard input
and its standard output.
=cut
sub get_compress_cmdline {
my $self = shift;
return compression_get_cmdline_compress($self->{compression});
}
sub get_uncompress_cmdline {
my $self = shift;
return compression_get_cmdline_decompress($self->{compression});
}
sub _check_opts {
my ($self, %opts) = @_;
# Check for proper cleaning before new start
error(g_('Dpkg::Compression::Process can only start one subprocess at a time'))
if $self->{pid};
# Check options
my $to = my $from = 0;
foreach my $thing (qw(file handle string pipe)) {
$to++ if $opts{"to_$thing"};
$from++ if $opts{"from_$thing"};
}
croak 'exactly one to_* parameter is needed' if $to != 1;
croak 'exactly one from_* parameter is needed' if $from != 1;
return %opts;
}
=item $proc->compress(%opts)
Starts a compressor program. You must indicate where it will read its
uncompressed data from and where it will write its compressed data to.
This is accomplished by passing one parameter C<to_*> and one parameter
C<from_*> as accepted by B<Dpkg::IPC::spawn>.
You must call C<wait_end_process> after having called this method to
properly close the sub-process (and verify that it exited without error).
=cut
sub compress {
my ($self, %opts) = @_;
$self->_check_opts(%opts);
my @prog = $self->get_compress_cmdline();
$opts{exec} = \@prog;
$self->{cmdline} = "@prog";
$self->{pid} = spawn(%opts);
delete $self->{pid} if $opts{to_string}; # wait_child already done
}
=item $proc->uncompress(%opts)
Starts a decompressor program. You must indicate where it will read its
compressed data from and where it will write its uncompressed data to.
This is accomplished by passing one parameter C<to_*> and one parameter
C<from_*> as accepted by B<Dpkg::IPC::spawn>.
You must call C<wait_end_process> after having called this method to
properly close the sub-process (and verify that it exited without error).
=cut
sub uncompress {
my ($self, %opts) = @_;
$self->_check_opts(%opts);
my @prog = $self->get_uncompress_cmdline();
$opts{exec} = \@prog;
$self->{cmdline} = "@prog";
$self->{pid} = spawn(%opts);
delete $self->{pid} if $opts{to_string}; # wait_child already done
}
=item $proc->wait_end_process(%opts)
Call B<Dpkg::IPC::wait_child> to wait until the sub-process has exited
and verify its return code. Any given option will be forwarded to
the C<wait_child> function. Most notably you can use the "nocheck" option
to verify the return code yourself instead of letting C<wait_child> do
it for you.
=cut
sub wait_end_process {
my ($self, %opts) = @_;
$opts{cmdline} //= $self->{cmdline};
wait_child($self->{pid}, %opts) if $self->{pid};
delete $self->{pid};
delete $self->{cmdline};
}
=back
=head1 CHANGES
=head2 Version 1.00 (dpkg 1.15.6)
Mark the module as public.
=cut
1;
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