Net::SSH::AuthorizedKey::Base - Virtual Base Class for ssh keys

    # Documentation to understand methods shared
    # by all parsers. Not for direct use.

###########################################
package Net::SSH::AuthorizedKey::Base;
###########################################
use strict;
use warnings;
use Log::Log4perl qw(:easy);
use Text::ParseWords;
use Digest::MD5 qw(md5_hex);

  # Accessors common for both ssh1 and ssh2 keys
our @accessors = qw(key type error email comment);
__PACKAGE__->make_accessor( $_ ) for @accessors;

  # Some functions must be implemented in the subclass
do {
    no strict qw(refs);

    *{__PACKAGE__ . "::$_"} = sub {
        die "Whoa! '$_' in the virtual base class has to be ",
            " implemented by a real subclass.";
    };

} for qw(option_type as_string);

  # Options accepted by all keys
our %VALID_OPTIONS = (
    "no-port-forwarding"  => 1,
    "no-agent-forwarding" => 1,
    "no-x11-forwarding"   => 1,
    "no-pty"              => 1,
    "no-user-rc"          => 1,
    command               => "s",
    environment           => "s",
    from                  => "s",
    permitopen            => "s",
    tunnel                => "s",
);

###########################################
sub new {
###########################################
    my($class, %options) = @_;

    my $self = {
        error        => "(no error)",
        option_order => [],
        %options,
    };

    bless $self, $class;
    return $self;
}

###########################################
sub option_type_global {
###########################################
    my($self, $key) = @_;

    if(exists $VALID_OPTIONS{ $key }) {
        return $VALID_OPTIONS{ $key };
    }

      # Maybe the subclass knows about it
    return $self->option_type($key);
}

###########################################
sub options {
###########################################
    my($self) = @_;

    return {
        map { $_ => $self->option( $_ ) } 
            keys %{ $self->{ options } } 
    };
}

###########################################
sub option {
###########################################
    my($self, $key, $value, $append) = @_;

    $key = lc $key;

    my $option_type = $self->option_type_global($key);

    if(! defined $option_type) {
        LOGWARN "Illegal option '$key'";
        return undef;
    }

    if(defined $value) {

        if( $append ) {
            if( $self->{options}->{$key} and
                ref($self->{options}->{$key}) ne "ARRAY" ) {
                $self->{options}->{$key} = [ $self->{options}->{$key} ];
            }
        } else {
            $self->option_delete( $key );
        }

        if($option_type eq "s") {
            if( $self->{options}->{$key} and
                ref($self->{options}->{$key}) eq "ARRAY" ) {
                DEBUG "Adding option $key to $value";
                push @{ $self->{options}->{$key} }, $value;
            } else {
                DEBUG "Setting option $key to $value";
                $self->{options}->{$key} = $value;
            }
        } else {
            $self->{options}->{$key} = undef;
        }
        push @{ $self->{option_order} }, $key;
    }

    if( "$option_type" eq "1" ) {
        return exists $self->{options}->{$key};
    }

    return $self->{options}->{$key};
}

###########################################
sub option_delete {
###########################################
    my($self, $key) = @_;

    $key = lc $key;

    @{ $self->{option_order} } = 
        grep { $_ ne $key } @{ $self->{option_order} };

    delete $self->{options}->{$key};
}

###########################################
sub options_as_string {
###########################################
    my($self) = @_;

    my $string = "";
    my @parts  = ();

    for my $option ( @{ $self->{option_order} } ) {
        if(defined $self->{options}->{$option}) {
            if(ref($self->{options}->{$option}) eq "ARRAY") {
                for (@{ $self->{options}->{$option} }) {
                    push @parts, option_quote($option, $_);
                }
            } else {
                push @parts, option_quote($option, $self->{options}->{$option});
            }
        } else {
            push @parts, $option;
        }
    }
    return join(',', @parts);
}

###########################################
sub option_quote {
###########################################
    my($option, $text) = @_;

    $text =~ s/([\\"])/\\$1/g;
    return "$option=\"" . $text . "\"";
}

###########################################
sub parse {
###########################################
    my($class, $string) = @_;

    DEBUG "Parsing line '$string'";

    # Clean up leading whitespace
    $string =~ s/^\s+//;
    $string =~ s/^#.*//;
 
    if(! length $string) {
        DEBUG "Nothing to parse";
        return;
    }

    if(my $key = $class->key_read( $string ) ) {
          # We found a key without options
        $key->{options} = {};
        DEBUG "Found ", $key->type(), " key: ", $key->as_string();
        return $key;
    }

    # No key found. Probably there are options in front of the key.
    # By the way: the openssh-5.x parser doesn't allow escaped 
    # backslashes (\\), so we don't either.
    my $rc = (
        (my $key_string = $string) =~ 
                      s/^((?:
                                                      (?:"(?:\\"|.)*?)"|
                                                      \S
                                                    )+
                                                  )
                                              //x );
    my $options_string = ($rc ? $1 : "");
    $key_string        =~ s/^\s+//;

    DEBUG "Trying line with options stripped: [$key_string]";

    if(my $key = $class->key_read( $key_string ) ) {
          # We found a key with options
        $key->{options} = {};
        $key->options_parse( $options_string );
        DEBUG "Found ", $key->type(), " key: ", $key->as_string();
        return $key;
    }

    DEBUG "$class cannot parse line: $string";

    return undef;
}

###########################################
sub options_parse {
###########################################
    my($self, $string) = @_;

    DEBUG "Parsing options: [$string]";
    my @options = parse_line(qr/\s*,\s*/, 0, $string);

      # delete empty/undefined fields
    @options = grep { defined $_ and length $_ } @options;

    DEBUG "Parsed options: ", join(' ', map { "[$_]" } @options);

    for my $option (@options) {
        my($key, $value) = split /=/, $option, 2;
        $value = 1 unless defined $value;
        $value =~ s/^"(.*)"$/$1/; # remove quotes

        $self->option($key, $value, 1);
    }
}

###########################################
sub fingerprint {
###########################################
    my($self) = @_;

    my $data = $self->options();

    my $string = join '', map { $_ => $data->{$_} } sort keys %$data;
    $string .= $self->key();

    return md5_hex($string);
}

##################################################
# Poor man's Class::Struct
##################################################
sub make_accessor {
##################################################
    my($package, $name) = @_;

    no strict qw(refs);

    my $code = <<EOT;
        *{"$package\\::$name"} = sub {
            my(\$self, \$value) = \@_;

            if(defined \$value) {
                \$self->{$name} = \$value;
            }
            if(exists \$self->{$name}) {
                return (\$self->{$name});
            } else {
                return "";
            }
        }
EOT
    if(! defined *{"$package\::$name"}) {
        eval $code or die "$@";
    }
}

1;

__END__