package Sys::CmdMod::Plugin::Ionice;
{
  $Sys::CmdMod::Plugin::Ionice::VERSION = '0.18';
}
BEGIN {
  $Sys::CmdMod::Plugin::Ionice::AUTHORITY = 'cpan:TEX';
}
# ABSTRACT: CmdMod plugin for ionice

use 5.010_000;
use mro 'c3';
use feature ':5.10';

use Moose;
use namespace::autoclean;

# use IO::Handle;
# use autodie;
# use MooseX::Params::Validate;

use Version::Compare;

use Sys::Run;
use File::Blarf;

extends 'Sys::CmdMod::Plugin';

has 'class' => (
    'is'       => 'rw',
    'isa'      => 'Int',
    'default' => 3,
);

sub _init_priority { return 7; }

sub _init_binary {
    my $self = shift;

    return $self->_find_binary('ionice');
}

sub BUILD {
    my $self = shift;

    if ( !-x $self->binary() ) {
        die( 'Could not find executable at ' . $self->binary() );
    }

    # check prio = 0-7
    if ( $self->priority < 0 || $self->priority > 7 ) {
        die('Invalid priority given. Must be 0-7.');
    }

    # check class = 0-3
    if ( $self->class < 0 || $self->class > 3 ) {
        die('Invalid class given. Must be 0-3.');
    }

    # check kernel
    my $kernel = $self->_kernel_version();
    if ( $kernel && Version::Compare::version_compare( $kernel, '2.6.13' ) < 0 ) {
        die( 'Running Kernel version (' . $kernel . ') too old to possibly support ionice.' );
    }

    return 1;
}

sub _kernel_version {
    my $proc_version = '/proc/version';
    if ( -f $proc_version ) {
        my $kernel_version = File::Blarf::slurp( $proc_version, { Chomp => 1, } );
        if ( $kernel_version =~ m/^Linux version (\S+) \(/ ) {
            return $1;
        }
    } ## end if ( -f $proc_version )

    return;
}

sub cmd {
    my $self = shift;
    my $cmd  = shift;

    if ( $self->class() == 1 || $self->class() == 2 ) {
        return $self->binary() . ' -c' . $self->class() . ' -n' . $self->priority() . q{ } . $cmd;
    }
    else {
        return $self->binary() . ' -c' . $self->class() . q{ } . $cmd;
    }
}

no Moose;
__PACKAGE__->meta->make_immutable;

1;

__END__

=pod

=encoding utf-8

=head1 NAME

Sys::CmdMod::Plugin::Ionice - CmdMod plugin for ionice

=head1 METHODS

=head2 BUILD

Initialize this module.

=head2 cmd

Prepend the ionice invocation.

=head1 NAME

Sys::CmdMod::Plugin::Ionice - ionice support

=head1 AUTHOR

Dominik Schulz <dominik.schulz@gauner.org>

=head1 COPYRIGHT AND LICENSE

This software is copyright (c) 2012 by Dominik Schulz.

This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.

=cut