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+# Copyright © 2008-2010 Raphaël Hertzog <hertzog@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) = @_;
+ error(g_('%s is not a compression level'), $level)
+ unless compression_is_valid_level($level);
+ $self->{compression_level} = $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 $self = shift;
+ my @prog = (@{compression_get_property($self->{compression}, 'comp_prog')});
+ my $level = '-' . $self->{compression_level};
+ $level = '--' . $self->{compression_level}
+ if $self->{compression_level} !~ m/^[1-9]$/;
+ push @prog, $level;
+ return @prog;
+}
+
+sub get_uncompress_cmdline {
+ my $self = shift;
+ return (@{compression_get_property($self->{compression}, 'decomp_prog')});
+}
+
+sub _sanity_check {
+ 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->_sanity_check(%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->_sanity_check(%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;