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<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
/**
* Base class for rules that restrict the ability to attempt a quiz.
*
* @package mod_quiz
* @copyright 2011 The Open University
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
defined('MOODLE_INTERNAL') || die();
require_once($CFG->dirroot . '/mod/quiz/locallib.php');
/**
* A base class that defines the interface for the various quiz access rules.
* Most of the methods are defined in a slightly unnatural way because we either
* want to say that access is allowed, or explain the reason why it is block.
* Therefore instead of is_access_allowed(...) we have prevent_access(...) that
* return false if access is permitted, or a string explanation (which is treated
* as true) if access should be blocked. Slighly unnatural, but actually the easiest
* way to implement this.
*
* @copyright 2009 Tim Hunt
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
* @since Moodle 2.2
*/
abstract class quiz_access_rule_base {
/** @var stdClass the quiz settings. */
protected $quiz;
/** @var quiz the quiz object. */
protected $quizobj;
/** @var int the time to use as 'now'. */
protected $timenow;
/**
* Create an instance of this rule for a particular quiz.
* @param quiz $quizobj information about the quiz in question.
* @param int $timenow the time that should be considered as 'now'.
*/
public function __construct($quizobj, $timenow) {
$this->quizobj = $quizobj;
$this->quiz = $quizobj->get_quiz();
$this->timenow = $timenow;
}
/**
* Return an appropriately configured instance of this rule, if it is applicable
* to the given quiz, otherwise return null.
* @param quiz $quizobj information about the quiz in question.
* @param int $timenow the time that should be considered as 'now'.
* @param bool $canignoretimelimits whether the current user is exempt from
* time limits by the mod/quiz:ignoretimelimits capability.
* @return quiz_access_rule_base|null the rule, if applicable, else null.
*/
public static function make(quiz $quizobj, $timenow, $canignoretimelimits) {
return null;
}
/**
* Whether or not a user should be allowed to start a new attempt at this quiz now.
* @param int $numattempts the number of previous attempts this user has made.
* @param object $lastattempt information about the user's last completed attempt.
* @return string false if access should be allowed, a message explaining the
* reason if access should be prevented.
*/
public function prevent_new_attempt($numprevattempts, $lastattempt) {
return false;
}
/**
* Whether the user should be blocked from starting a new attempt or continuing
* an attempt now.
* @return string false if access should be allowed, a message explaining the
* reason if access should be prevented.
*/
public function prevent_access() {
return false;
}
/**
* @param int|null $attemptid the id of the current attempt, if there is one,
* otherwise null.
* @return bool whether a check is required before the user starts/continues
* their attempt.
*/
public function is_preflight_check_required($attemptid) {
return false;
}
/**
* Add any field you want to pre-flight check form. You should only do
* something here if {@link is_preflight_check_required()} returned true.
*
* @param mod_quiz_preflight_check_form $quizform the form being built.
* @param MoodleQuickForm $mform The wrapped MoodleQuickForm.
* @param int|null $attemptid the id of the current attempt, if there is one,
* otherwise null.
*/
public function add_preflight_check_form_fields(mod_quiz_preflight_check_form $quizform,
MoodleQuickForm $mform, $attemptid) {
// Do nothing by default.
}
/**
* Validate the pre-flight check form submission. You should only do
* something here if {@link is_preflight_check_required()} returned true.
*
* If the form validates, the user will be allowed to continue.
*
* @param array $data the submitted form data.
* @param array $files any files in the submission.
* @param array $errors the list of validation errors that is being built up.
* @param int|null $attemptid the id of the current attempt, if there is one,
* otherwise null.
* @return array the update $errors array;
*/
public function validate_preflight_check($data, $files, $errors, $attemptid) {
return $errors;
}
/**
* The pre-flight check has passed. This is a chance to record that fact in
* some way.
* @param int|null $attemptid the id of the current attempt, if there is one,
* otherwise null.
*/
public function notify_preflight_check_passed($attemptid) {
// Do nothing by default.
}
/**
* This is called when the current attempt at the quiz is finished. This is
* used, for example by the password rule, to clear the flag in the session.
*/
public function current_attempt_finished() {
// Do nothing by default.
}
/**
* Information, such as might be shown on the quiz view page, relating to this restriction.
* There is no obligation to return anything. If it is not appropriate to tell students
* about this rule, then just return ''.
* @return mixed a message, or array of messages, explaining the restriction
* (may be '' if no message is appropriate).
*/
public function description() {
return '';
}
/**
* If this rule can determine that this user will never be allowed another attempt at
* this quiz, then return true. This is used so we can know whether to display a
* final grade on the view page. This will only be called if there is not a currently
* active attempt for this user.
* @param int $numattempts the number of previous attempts this user has made.
* @param object $lastattempt information about the user's last completed attempt.
* @return bool true if this rule means that this user will never be allowed another
* attempt at this quiz.
*/
public function is_finished($numprevattempts, $lastattempt) {
return false;
}
/**
* If, because of this rule, the user has to finish their attempt by a certain time,
* you should override this method to return the attempt end time.
* @param object $attempt the current attempt
* @return mixed the attempt close time, or false if there is no close time.
*/
public function end_time($attempt) {
return false;
}
/**
* If the user should be shown a different amount of time than $timenow - $this->end_time(), then
* override this method. This is useful if the time remaining is large enough to be omitted.
* @param object $attempt the current attempt
* @param int $timenow the time now. We don't use $this->timenow, so we can
* give the user a more accurate indication of how much time is left.
* @return mixed the time left in seconds (can be negative) or false if there is no limit.
*/
public function time_left_display($attempt, $timenow) {
$endtime = $this->end_time($attempt);
if ($endtime === false) {
return false;
}
return $endtime - $timenow;
}
/**
* @return boolean whether this rule requires that the attemp (and review)
* pages must be displayed in a pop-up window.
*/
public function attempt_must_be_in_popup() {
return false;
}
/**
* @return array any options that are required for showing the attempt page
* in a popup window.
*/
public function get_popup_options() {
return array();
}
/**
* Sets up the attempt (review or summary) page with any special extra
* properties required by this rule. securewindow rule is an example of where
* this is used.
*
* @param moodle_page $page the page object to initialise.
*/
public function setup_attempt_page($page) {
// Do nothing by default.
}
/**
* It is possible for one rule to override other rules.
*
* The aim is that third-party rules should be able to replace sandard rules
* if they want. See, for example MDL-13592.
*
* @return array plugin names of other rules that this one replaces.
* For example array('ipaddress', 'password').
*/
public function get_superceded_rules() {
return array();
}
/**
* Add any fields that this rule requires to the quiz settings form. This
* method is called from {@link mod_quiz_mod_form::definition()}, while the
* security seciton is being built.
* @param mod_quiz_mod_form $quizform the quiz settings form that is being built.
* @param MoodleQuickForm $mform the wrapped MoodleQuickForm.
*/
public static function add_settings_form_fields(
mod_quiz_mod_form $quizform, MoodleQuickForm $mform) {
// By default do nothing.
}
/**
* Validate the data from any form fields added using {@link add_settings_form_fields()}.
* @param array $errors the errors found so far.
* @param array $data the submitted form data.
* @param array $files information about any uploaded files.
* @param mod_quiz_mod_form $quizform the quiz form object.
* @return array $errors the updated $errors array.
*/
public static function validate_settings_form_fields(array $errors,
array $data, $files, mod_quiz_mod_form $quizform) {
return $errors;
}
/**
* @return array key => lang string any choices to add to the quiz Browser
* security settings menu.
*/
public static function get_browser_security_choices() {
return array();
}
/**
* Save any submitted settings when the quiz settings form is submitted. This
* is called from {@link quiz_after_add_or_update()} in lib.php.
* @param object $quiz the data from the quiz form, including $quiz->id
* which is the id of the quiz being saved.
*/
public static function save_settings($quiz) {
// By default do nothing.
}
/**
* Delete any rule-specific settings when the quiz is deleted. This is called
* from {@link quiz_delete_instance()} in lib.php.
* @param object $quiz the data from the database, including $quiz->id
* which is the id of the quiz being deleted.
* @since Moodle 2.7.1, 2.6.4, 2.5.7
*/
public static function delete_settings($quiz) {
// By default do nothing.
}
/**
* Return the bits of SQL needed to load all the settings from all the access
* plugins in one DB query. The easiest way to understand what you need to do
* here is probalby to read the code of {@link quiz_access_manager::load_settings()}.
*
* If you have some settings that cannot be loaded in this way, then you can
* use the {@link get_extra_settings()} method instead, but that has
* performance implications.
*
* @param int $quizid the id of the quiz we are loading settings for. This
* can also be accessed as quiz.id in the SQL. (quiz is a table alisas for {quiz}.)
* @return array with three elements:
* 1. fields: any fields to add to the select list. These should be alised
* if neccessary so that the field name starts the name of the plugin.
* 2. joins: any joins (should probably be LEFT JOINS) with other tables that
* are needed.
* 3. params: array of placeholder values that are needed by the SQL. You must
* used named placeholders, and the placeholder names should start with the
* plugin name, to avoid collisions.
*/
public static function get_settings_sql($quizid) {
return array('', '', array());
}
/**
* You can use this method to load any extra settings your plugin has that
* cannot be loaded efficiently with get_settings_sql().
* @param int $quizid the quiz id.
* @return array setting value name => value. The value names should all
* start with the name of your plugin to avoid collisions.
*/
public static function get_extra_settings($quizid) {
return array();
}
}