gistfile1.txt

function barley_check_conditions() {
    global $current_user, $post;

    if ( isset($_GET['barley_editor']) && $_GET['barley_editor'] == 'off' )
        return false;
    
    if ( (is_single() || is_page()) && (is_main_query()) && (in_the_loop()) ) {

        if ( current_user_can( 'edit_others_posts' ) || ($post->post_author == $current_user->ID) ) { 
            return true;
        }
    }
return false;
}