File Coverage

blib/lib/Dpkg/Compression/Process.pm

Criterion	Covered	Total	%
statement	72	72	100.0
branch	14	22	63.6
condition	5	12	41.6
subroutine	16	16	100.0
pod	8	8	100.0
total	115	130	88.4

# Copyright © 2008-2010 Raphaël Hertzog
#
# 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 .

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 (of
B).

=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 (of
B).

=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, 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 and one parameter
C as accepted by B.

You must call C 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 and one parameter
C as accepted by B.

You must call C 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 to wait until the sub-process has exited
and verify its return code. Any given option will be forwarded to
the C function. Most notably you can use the "nocheck" option
to verify the return code yourself instead of letting C 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;