redis_finder.php

        $intersections = false;
        $filters = false;
        
        // If any follows, followed_by, or tags are specified, attempt to narrow the search.
        
        foreach ($this->follows as $cond)
        {
            $filters = true;
            $keys = $this->database->set_members(Stalkr::get_type_table($this->type) . ':fing:' . $cond);
            if (!$keys) continue;
            $intersections = ($intersections === false) ? $keys : array_intersect($intersections, $keys);
        }
        
        foreach ($this->followed_by as $cond)
        {
            $filters = true;
            $keys = $this->database->set_members(Stalkr::get_type_table($this->type) . ':fer:' . $cond);
            if (!$keys) continue;
            $intersections = ($intersections === false) ? $keys : array_intersect($intersections, $keys);
        }
        
        foreach ($this->tags as $tag)
        {
            $filters = true;
            $tag = ctype_alnum($tag) ? $tag : base64_encode($tag);
            $keys = $this->database->set_members(Stalkr::get_type_table($this->type) . ':tag:' . $tag);
            if (!$keys) continue;
            $intersections = ($intersections === false) ? $keys : array_intersect($intersections, $keys);
        }
        
        // Initialize the result set.
        
        $this->result = array();

        // Check for conditions and no results
        
        if(($intersections === false) && ($filters === true)) {
            return array();
        }