class RulesPHPEvaluator

class RulesPHPEvaluator extends RulesDataInputEvaluator {
    
    /**
     * Overrides RulesDataProcessor::editAccess().
     */
    public function editAccess() {
        return parent::editAccess() && (user_access('use PHP for settings') || drupal_is_cli());
    }
    
    /**
     * Helper function to find variables in PHP code.
     *
     * @param string $text
     *   The PHP code.
     * @param array $var_info
     *   Array with variable names as keys.
     */
    public static function getUsedVars($text, $var_info) {
        if (strpos($text, '<?') !== FALSE) {
            $used_vars = array();
            foreach ($var_info as $name => $info) {
                if (strpos($text, '$' . $name) !== FALSE) {
                    $used_vars[] = $name;
                }
            }
            return $used_vars;
        }
    }
    
    /**
     * Overrides RulesDataInputEvaluator::prepare().
     */
    public function prepare($text, $var_info) {
        // A returned NULL skips the evaluator.
        $this->setting = self::getUsedVars($text, $var_info);
    }
    
    /**
     * Evaluates PHP code contained in $text.
     *
     * This method doesn't apply $options, thus the PHP code is responsible for
     * behaving appropriately.
     */
    public function evaluate($text, $options, RulesState $state) {
        $vars['eval_options'] = $options;
        foreach ($this->setting as $key => $var_name) {
            $vars[$var_name] = $state->get($var_name);
        }
        return rules_php_eval($text, rules_unwrap_data($vars));
    }
    
    /**
     * Overrides RulesDataInputEvaluator::help().
     */
    public static function help($var_info) {
        module_load_include('inc', 'rules', 'rules/modules/php.rules');
        $render = array(
            '#type' => 'fieldset',
            '#title' => t('PHP Evaluation'),
            '#collapsible' => TRUE,
            '#collapsed' => TRUE,
        ) + rules_php_evaluator_help($var_info);
        return $render;
    }

}