How to edit plugin [WPMU Siteweide Tags] to get custom fields?

Is there anyone that knows where to or how to edit this code to get custom field keys and values?

function sitewide_tags_options() {

load_muplugin_textdomain(‘wpmu-sitewide-tags’, MUPLUGINDIR.’/languages’);
if( get_site_option( ‘tags_blog_public’ ) === null )
add_site_option( ‘tags_blog_public’, 1 );

$tags_blog_enable = get_site_option( ‘tags_blog_enable’);
?><h3><?php _e(‘Global Tags’,’wpmu-sitewide-tags’) ?></h3>
<table class=”form-table”>
<tr valign=”top”>
<th scope=”row”><?php _e(‘Tags Blog’,’wpmu-sitewide-tags’) ?></th>
<td>
<label><input name=”tags_blog_enabled” type=”checkbox” id=”tags_blog_enabled” value=”1″ <?php if( get_site_option( ‘tags_blog_enabled’, 0 ) == 1 ) { echo “checked=’checked'”; } ?>” /> <?php _e(“Enabled”,”wpmu-sitewide-tags”); ?></label>
<?php
if( !get_site_option( ‘tags_blog_enabled’ ) ) {
echo “</td></tr></table>”;
return;
}
?>
<p><?php _e( “You can create your post archive in a specific ‘tags’ blog of your choosing, or you can use the main blog of your site. Each has it’s own pros and cons.”,”wpmu-sitewide-tags”); ?></p>

1. <input name=”tags_blog” type=”text” id=”tags_blog” style=”width: 35%” value=”<?php echo attribute_escape( get_site_option( ‘tags_blog’, ‘tags’ ) ); ?>” size=”45″ />
<?php _e(‘Blogname of the blog your global tags and posts will live in. Blog will be created.’,’wpmu-sitewide-tags’) ?>
2. <label><input name=”tags_blog_main_blog” type=”checkbox” id=”tags_blog_main_blog” value=”1″ <?php if( get_site_option( ‘tags_blog_main_blog’, 0 ) == 1 ) { echo “checked=’checked'”; } ?>” /> <?php _e( “Post to main blog”,”wpmu-sitewide-tags” ); ?></label>
<?php _e(‘Create posts in your main blog. All posts will appear on the front page of your site. Remember to to add a post loop to home.php in the theme directory if it exists.’,’wpmu-sitewide-tags’) ?>

</td>
</tr>
<tr valign=”top”>
<th scope=”row”><?php _e(‘Max Posts’,’wpmu-sitewide-tags’) ?></th>
<td>
<input name=”tags_max_posts” type=”text” id=”tags_max_posts” style=”width: 15%” value=”<?php echo intval( get_site_option( ‘tags_max_posts’, 5000 ) ); ?>” size=”5″ />

<?php _e(‘The maximum number of posts stored in the tags blog.’,’wpmu-sitewide-tags’) ?>
</td>
</tr>
<tr valign=”top”>
<th scope=”row”><?php _e(‘Privacy’,’wpmu-sitewide-tags’) ?></th>
<td>
<label><input type=’radio’ name=’tags_blog_public’ value=’1′ <?php echo ( get_site_option( ‘tags_blog_public’ ) == 1 ? ‘checked=”checked”‘ : ” ) ?> /> <?php _e(‘Tags pages can be indexed by search engines.’,’wpmu-sitewide-tags’)?></label>
<label><input type=’radio’ name=’tags_blog_public’ value=’0′ <?php echo ( get_site_option( ‘tags_blog_public’ ) == 0 ? ‘checked=”checked”‘ : ” ) ?> /> <?php _e(‘Tags pages will not be indexed by search engines.’,’wpmu-sitewide-tags’)?></label>

<?php _e(‘Will your tags pages be visible to Google and other search engines?’,’wpmu-sitewide-tags’) ?>
</td>
</tr>
</table>
<?php
}
add_action(‘wpmu_options’, ‘sitewide_tags_options’);

function sitewide_tags_update_options() {
global $wpdb, $current_site, $current_user;
if( !$_POST[ ‘tags_blog_enabled’ ] ) {
if( get_site_option( ‘tags_blog_enabled’ ) != $_POST[ ‘tags_blog_enabled’ ] )
update_site_option( ‘tags_blog_enabled’, 0 );
return;
}
update_site_option( ‘tags_blog_enabled’, 1 );

if( ( isset( $_POST[ ‘tags_blog’ ] ) || isset( $_POST[ ‘tags_blog_main_blog’ ] ) ) && isset( $_POST[ ‘tags_blog_public’ ] ) ) {
if( $_POST[ ‘tags_blog_main_blog’ ] == 1 ) {
$id = $wpdb->get_var( “SELECT blog_id FROM {$wpdb->blogs} WHERE domain = ‘{$current_site->domain}’ AND path = ‘{$current_site->path}'” );
if( $id ) {
update_site_option( ‘tags_blog_id’, $id );
update_site_option( ‘tags_blog_main_blog’, 1 );
} else {
update_site_option( ‘tags_blog_main_blog’, 0 );
}
} else {
update_site_option( ‘tags_blog_main_blog’, 0 );
$tags_blog = $_POST[ ‘tags_blog’ ];
update_site_option( ‘tags_blog’, $tags_blog );
if( constant( ‘VHOST’ ) == ‘yes’ ) {
$domain = $tags_blog . ‘.’ . $current_site->domain;
$path = $current_site->path;
} else {
$domain = $current_site->domain;
$path = trailingslashit( $current_site->path . $tags_blog );
}
$tags_blog_id = $wpdb->get_var( “SELECT blog_id FROM {$wpdb->blogs} WHERE domain = ‘$domain’ AND path = ‘$path'” );
if( $tags_blog_id ) {
update_site_option( ‘tags_blog_id’, $tags_blog_id );
} else {
$wpdb->hide_errors();
$id = wpmu_create_blog( $domain, $path, __( ‘Global Posts’,’wpmu-sitewide-tags’ ), $current_user->id , array( “public” => $_POST[ ‘tags_blog_public’ ] ), $current_site->id);
update_site_option( ‘tags_blog_id’, $id );
$wpdb->show_errors();
}
}
$tags_blog_public = (int)$_POST[ ‘tags_blog_public’ ];
update_site_option( ‘tags_blog_public’, $tags_blog_public );
update_blog_option( $tags_blog_id, ‘blog_public’, $tags_blog_public );
update_blog_status( $tags_blog_id, ‘public’, $tags_blog_public);
}

if( isset( $_POST[ ‘tags_max_posts’ ] ) )
update_site_option( ‘tags_max_posts’, (int)$_POST[ ‘tags_max_posts’ ] );
}
add_action( ‘update_wpmu_options’, ‘sitewide_tags_update_options’ );

function sitewide_tags_post( $post_id, $post ) {
global $wpdb;

if( !get_site_option( ‘tags_blog_enabled’ ) )
return;

// wp_insert_category()
include_once(ABSPATH . ‘wp-admin/includes/admin.php’);

$tags_blog_id = get_site_option( ‘tags_blog_id’ );
if( !$tags_blog_id )
return;

if ( $wpdb->blogid == $tags_blog_id || $post->post_status == ‘inherit’ || $post->post_type != ‘post’ || $post->post_status == ‘revision’ )
return;

$post_blog_id = $wpdb->blogid;
/*
* this will not handle a switch from public to private blog and delete posts in tags-blog
*/
if ( get_blog_status($post_blog_id, “public”) != 1 )
return;

$post->post_category = wp_get_post_categories( $post_id );
foreach( $post->post_category as $c ) {
$cat = get_category( $c );
$cats[] = $cat->name;
}

$post->tags_input = implode( ‘, ‘, wp_get_post_tags( $post_id, array(‘fields’ => ‘names’) ) );
$post->guid = $post_blog_id . ‘.’ . $post_id;

$permalink = get_permalink( $post_id );

switch_to_blog( $tags_blog_id );
if( is_array( $cats ) && !empty( $cats ) ) {
foreach( $cats as $t => $d ) {
wp_insert_category( array(‘cat_name’ => $d, ‘category_parent’ => ”) );
}
}

$global_post = $wpdb->get_row( “SELECT * FROM {$wpdb->posts} WHERE guid = ‘{$post->guid}'” );
if( $post->post_status != ‘publish’ && is_object( $global_post ) ) {
wp_delete_post( $global_post->ID );
} else {
if( $global_post->ID != ” ) {
$post->ID = $global_post->ID; // editing an old post
/* using this kind of update not simple add: fixing permalink-problems */
delete_post_meta( $global_post->ID, “permalink”);
} else {
unset( $post->ID ); // new post
}

$post->ping_status = ‘closed’;
$post->comment_status = ‘closed’;

$p = wp_insert_post( $post );
add_post_meta( $p, “permalink”, $permalink );
}
restore_current_blog();
}
add_action(‘save_post’, ‘sitewide_tags_post’, 10, 2);

function sitewide_tags_post_delete( $post_id ) {
/*
* what should we do if a post will be deleted and the tags blog feature is disabled?
* need an check if we have a post on the tags blog and if so – delete this
*/
global $wpdb;
$tags_blog_id = get_site_option( ‘tags_blog_id’ );
if( null === $tags_blog_id )
return;

if( $wpdb->blogid == $tags_blog_id )
return;

$post_blog_id = $wpdb->blogid;
switch_to_blog( $tags_blog_id );
$global_post_id = $wpdb->get_var( “SELECT ID FROM {$wpdb->posts} WHERE guid = ‘{$post_blog_id}.{$post_id}'” );
if( null !== $global_post_id )
wp_delete_post( $global_post_id );

restore_current_blog();
}
add_action(‘delete_post’, ‘sitewide_tags_post_delete’);

/**
* remove all posts from a given blog ($blog_id != 0)
* – used if a blog is deleted or marked as deactivat, spam, archive, mature
* – also runs if a blog is switched to a none public blog (called by
* sitewide_tags_public_blog_update), more details on sitewide_tags_public_blog_update
* removes some posts if the limit is reached ($blog_id == 0)
* – triggered by other actions but without an given blog_id
* – number of posts to delete in $max_to_del
*
* @param $blog_id
*/
function sitewide_tags_remove_posts($blog_id = 0) {
global $wpdb;
$tags_blog_id = get_site_option( ‘tags_blog_id’ );
$max_to_del = 10;

if( !$tags_blog_id )
return;

/* actions on the tags blog */
if ( ($blog_id == 0) && ($wpdb->blogid == $tags_blog_id) )
return;
if ( $tags_blog_id == $blog_id )
return;

switch_to_blog( $tags_blog_id );

if ( $blog_id != 0 ) {
$posts = $wpdb->get_col( “SELECT ID FROM {$wpdb->posts} WHERE guid LIKE ‘”.$blog_id.”.%'”);
if( is_array( $posts ) && !empty( $posts ) ) {
foreach( $posts as $p_id ) {
wp_delete_post( $p_id );
}
}
} else {
/* delete all posts – not pages – over the max limit */
if( mt_rand( 0, 10 ) ) {
$posts = $wpdb->get_col( “SELECT ID FROM {$wpdb->posts} WHERE post_status=’publish’ AND post_type=’post’ ORDER BY ID DESC limit ” . get_site_option( ‘tags_max_posts’, 5000 ) . “, ” . $max_to_del );
if( is_array( $posts ) && !empty( $posts ) ) {
foreach( $posts as $p_id ) {
wp_delete_post( $p_id );
}
}
}
}
restore_current_blog();
}
/* complete blog actions ($blog_id != 0) */
add_action(‘delete_blog’, ‘sitewide_tags_remove_posts’, 10, 1);
add_action(‘archive_blog’, ‘sitewide_tags_remove_posts’, 10, 1);
add_action(‘deactivate_blog’, ‘sitewide_tags_remove_posts’, 10, 1);
add_action(‘make_spam_blog’, ‘sitewide_tags_remove_posts’, 10, 1);
add_action(‘mature_blog’, ‘sitewide_tags_remove_posts’, 10, 1);
/* single post actions ($blog_id == 0) */
add_action(“transition_post_status”, ‘sitewide_tags_remove_posts’);

/**
* called as an action if the public state for a blog is switched
* – if a blog becomes not public – all posts in the tags blog will be removed
* – bug on 1.5.1: update_option_blog_public is only triggered if the public state
* is changed from the backend – from edit blog as siteadmin the action isn’t
* running and the state in the blogs backend isn’t changed
*
* @param int $old – old public state
* @param int $new – new state, public == 1, not public == 0
*/
function sitewide_tags_public_blog_update($old, $new) {
global $wpdb;
$tags_blog_id = get_site_option( ‘tags_blog_id’ );

if( !$tags_blog_id )
return;

/* the tags blog */
if ( $tags_blog_id == $wpdb->blogid )
return;

if ($new == 0 ) {
sitewide_tags_remove_posts($wpdb->blogid);
}
}
add_action(‘update_option_blog_public’, ‘sitewide_tags_public_blog_update’, 10, 2);

function sitewide_tags_post_link( $link, $post ) {
global $wpdb;
$tags_blog_id = get_site_option( ‘tags_blog_id’ );
if( !$tags_blog_id )
return $link;

if( $wpdb->blogid == $tags_blog_id ) {
$url = get_post_meta( $post->ID, “permalink”, true );
if( $url )
return $url;
}
return $link;
}
add_filter(‘post_link’, ‘sitewide_tags_post_link’, 10, 2);
?>