micmania1 / silverstripe-config

    {

        $filtered = [];

        foreach($documents as $key => $document) {

            if(isset($document['header'][self::ONLY_FLAG])) {

                // If not all rules match, then we exclude this document

                if(!$this->testRules($document['header'], self::ONLY_FLAG)) {

                    continue;

                }

            }

            if(isset($document['header'][self::EXCEPT_FLAG])) {

                // If all rules pass, then we exclude this document

                }

            }

            if(isset($document['header'][self::EXCEPT_FLAG])) {

                // If all rules pass, then we exclude this document

                if($this->testRules($document['header'], self::EXCEPT_FLAG)) {

                    continue;

                }

            }

            $filtered[$key] = $document;

        }