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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/>.
/**
* More object oriented wrappers around parts of the Moodle question bank.
*
* In due course, I expect that the question bank will be converted to a
* fully object oriented structure, at which point this file can be a
* starting point.
*
* @package moodlecore
* @subpackage questionbank
* @copyright 2009 The Open University
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
defined('MOODLE_INTERNAL') || die();
require_once(__DIR__ . '/../type/questiontypebase.php');
/**
* This static class provides access to the other question bank.
*
* It provides functions for managing question types and question definitions.
*
* @copyright 2009 The Open University
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
abstract class question_bank {
// TODO: This limit can be deleted if someday we move all TEXTS to BIG ones. MDL-19603
const MAX_SUMMARY_LENGTH = 32000;
/** @var array question type name => question_type subclass. */
private static $questiontypes = array();
/** @var array question type name => 1. Records which question definitions have been loaded. */
private static $loadedqdefs = array();
/** @var boolean nasty hack to allow unit tests to call {@link load_question()}. */
private static $testmode = false;
private static $testdata = array();
private static $questionconfig = null;
/**
* @var array string => string The standard set of grade options (fractions)
* to use when editing questions, in the range 0 to 1 inclusive. Array keys
* are string becuase: a) we want grades to exactly 7 d.p., and b. you can't
* have float array keys in PHP.
* Initialised by {@link ensure_grade_options_initialised()}.
*/
private static $fractionoptions = null;
/** @var array string => string The full standard set of (fractions) -1 to 1 inclusive. */
private static $fractionoptionsfull = null;
/**
* @param string $qtypename a question type name, e.g. 'multichoice'.
* @return bool whether that question type is installed in this Moodle.
*/
public static function is_qtype_installed($qtypename) {
$plugindir = core_component::get_plugin_directory('qtype', $qtypename);
return $plugindir && is_readable($plugindir . '/questiontype.php');
}
/**
* Get the question type class for a particular question type.
* @param string $qtypename the question type name. For example 'multichoice' or 'shortanswer'.
* @param bool $mustexist if false, the missing question type is returned when
* the requested question type is not installed.
* @return question_type the corresponding question type class.
*/
public static function get_qtype($qtypename, $mustexist = true) {
global $CFG;
if (isset(self::$questiontypes[$qtypename])) {
return self::$questiontypes[$qtypename];
}
$file = core_component::get_plugin_directory('qtype', $qtypename) . '/questiontype.php';
if (!is_readable($file)) {
if ($mustexist || $qtypename == 'missingtype') {
throw new coding_exception('Unknown question type ' . $qtypename);
} else {
return self::get_qtype('missingtype');
}
}
include_once($file);
$class = 'qtype_' . $qtypename;
if (!class_exists($class)) {
throw new coding_exception("Class {$class} must be defined in {$file}.");
}
self::$questiontypes[$qtypename] = new $class();
return self::$questiontypes[$qtypename];
}
/**
* Load the question configuration data from config_plugins.
* @return object get_config('question') with caching.
*/
public static function get_config() {
if (is_null(self::$questionconfig)) {
self::$questionconfig = get_config('question');
}
return self::$questionconfig;
}
/**
* @param string $qtypename the internal name of a question type. For example multichoice.
* @return bool whether users are allowed to create questions of this type.
*/
public static function qtype_enabled($qtypename) {
$config = self::get_config();
$enabledvar = $qtypename . '_disabled';
return self::qtype_exists($qtypename) && empty($config->$enabledvar) &&
self::get_qtype($qtypename)->menu_name() != '';
}
/**
* @param string $qtypename the internal name of a question type. For example multichoice.
* @return bool whether this question type exists.
*/
public static function qtype_exists($qtypename) {
return array_key_exists($qtypename, core_component::get_plugin_list('qtype'));
}
/**
* @param $qtypename the internal name of a question type, for example multichoice.
* @return string the human_readable name of this question type, from the language pack.
*/
public static function get_qtype_name($qtypename) {
return self::get_qtype($qtypename)->local_name();
}
/**
* @return array all the installed question types.
*/
public static function get_all_qtypes() {
$qtypes = array();
foreach (core_component::get_plugin_list('qtype') as $plugin => $notused) {
try {
$qtypes[$plugin] = self::get_qtype($plugin);
} catch (coding_exception $e) {
// Catching coding_exceptions here means that incompatible
// question types do not cause the rest of Moodle to break.
}
}
return $qtypes;
}
/**
* Sort an array of question types according to the order the admin set up,
* and then alphabetically for the rest.
* @param array qtype->name() => qtype->local_name().
* @return array sorted array.
*/
public static function sort_qtype_array($qtypes, $config = null) {
if (is_null($config)) {
$config = self::get_config();
}
$sortorder = array();
$otherqtypes = array();
foreach ($qtypes as $name => $localname) {
$sortvar = $name . '_sortorder';
if (isset($config->$sortvar)) {
$sortorder[$config->$sortvar] = $name;
} else {
$otherqtypes[$name] = $localname;
}
}
ksort($sortorder);
core_collator::asort($otherqtypes);
$sortedqtypes = array();
foreach ($sortorder as $name) {
$sortedqtypes[$name] = $qtypes[$name];
}
foreach ($otherqtypes as $name => $notused) {
$sortedqtypes[$name] = $qtypes[$name];
}
return $sortedqtypes;
}
/**
* @return array all the question types that users are allowed to create,
* sorted into the preferred order set on the admin screen.
*/
public static function get_creatable_qtypes() {
$config = self::get_config();
$allqtypes = self::get_all_qtypes();
$qtypenames = array();
foreach ($allqtypes as $name => $qtype) {
if (self::qtype_enabled($name)) {
$qtypenames[$name] = $qtype->local_name();
}
}
$qtypenames = self::sort_qtype_array($qtypenames);
$creatableqtypes = array();
foreach ($qtypenames as $name => $notused) {
$creatableqtypes[$name] = $allqtypes[$name];
}
return $creatableqtypes;
}
/**
* Load the question definition class(es) belonging to a question type. That is,
* include_once('/question/type/' . $qtypename . '/question.php'), with a bit
* of checking.
* @param string $qtypename the question type name. For example 'multichoice' or 'shortanswer'.
*/
public static function load_question_definition_classes($qtypename) {
global $CFG;
if (isset(self::$loadedqdefs[$qtypename])) {
return;
}
$file = $CFG->dirroot . '/question/type/' . $qtypename . '/question.php';
if (!is_readable($file)) {
throw new coding_exception('Unknown question type (no definition) ' . $qtypename);
}
include_once($file);
self::$loadedqdefs[$qtypename] = 1;
}
/**
* This method needs to be called whenever a question is edited.
*/
public static function notify_question_edited($questionid) {
question_finder::get_instance()->uncache_question($questionid);
}
/**
* Load a question definition data from the database. The data will be
* returned as a plain stdClass object.
* @param int $questionid the id of the question to load.
* @return object question definition loaded from the database.
*/
public static function load_question_data($questionid) {
return question_finder::get_instance()->load_question_data($questionid);
}
/**
* Load a question definition from the database. The object returned
* will actually be of an appropriate {@link question_definition} subclass.
* @param int $questionid the id of the question to load.
* @param bool $allowshuffle if false, then any shuffle option on the selected
* quetsion is disabled.
* @return question_definition loaded from the database.
*/
public static function load_question($questionid, $allowshuffle = true) {
if (self::$testmode) {
// Evil, test code in production, but no way round it.
return self::return_test_question_data($questionid);
}
$questiondata = self::load_question_data($questionid);
if (!$allowshuffle) {
$questiondata->options->shuffleanswers = false;
}
return self::make_question($questiondata);
}
/**
* Convert the question information loaded with {@link get_question_options()}
* to a question_definintion object.
* @param object $questiondata raw data loaded from the database.
* @return question_definition loaded from the database.
*/
public static function make_question($questiondata) {
return self::get_qtype($questiondata->qtype, false)->make_question($questiondata, false);
}
/**
* @return question_finder a question finder.
*/
public static function get_finder() {
return question_finder::get_instance();
}
/**
* Only to be called from unit tests. Allows {@link load_test_data()} to be used.
*/
public static function start_unit_test() {
self::$testmode = true;
}
/**
* Only to be called from unit tests. Allows {@link load_test_data()} to be used.
*/
public static function end_unit_test() {
self::$testmode = false;
self::$testdata = array();
}
private static function return_test_question_data($questionid) {
if (!isset(self::$testdata[$questionid])) {
throw new coding_exception('question_bank::return_test_data(' . $questionid .
') called, but no matching question has been loaded by load_test_data.');
}
return self::$testdata[$questionid];
}
/**
* To be used for unit testing only. Will throw an exception if
* {@link start_unit_test()} has not been called first.
* @param object $questiondata a question data object to put in the test data store.
*/
public static function load_test_question_data(question_definition $question) {
if (!self::$testmode) {
throw new coding_exception('question_bank::load_test_data called when ' .
'not in test mode.');
}
self::$testdata[$question->id] = $question;
}
protected static function ensure_fraction_options_initialised() {
if (!is_null(self::$fractionoptions)) {
return;
}
// define basic array of grades. This list comprises all fractions of the form:
// a. p/q for q <= 6, 0 <= p <= q
// b. p/10 for 0 <= p <= 10
// c. 1/q for 1 <= q <= 10
// d. 1/20
$rawfractions = array(
0.9000000,
0.8333333,
0.8000000,
0.7500000,
0.7000000,
0.6666667,
0.6000000,
0.5000000,
0.4000000,
0.3333333,
0.3000000,
0.2500000,
0.2000000,
0.1666667,
0.1428571,
0.1250000,
0.1111111,
0.1000000,
0.0500000,
);
// Put the None option at the top.
self::$fractionoptions = array(
'0.0' => get_string('none'),
'1.0' => '100%',
);
self::$fractionoptionsfull = array(
'0.0' => get_string('none'),
'1.0' => '100%',
);
// The the positive grades in descending order.
foreach ($rawfractions as $fraction) {
$percentage = format_float(100 * $fraction, 5, true, true) . '%';
self::$fractionoptions["{$fraction}"] = $percentage;
self::$fractionoptionsfull["{$fraction}"] = $percentage;
}
// The the negative grades in descending order.
foreach (array_reverse($rawfractions) as $fraction) {
self::$fractionoptionsfull['' . (-$fraction)] =
format_float(-100 * $fraction, 5, true, true) . '%';
}
self::$fractionoptionsfull['-1.0'] = '-100%';
}
/**
* @return array string => string The standard set of grade options (fractions)
* to use when editing questions, in the range 0 to 1 inclusive. Array keys
* are string becuase: a) we want grades to exactly 7 d.p., and b. you can't
* have float array keys in PHP.
* Initialised by {@link ensure_grade_options_initialised()}.
*/
public static function fraction_options() {
self::ensure_fraction_options_initialised();
return self::$fractionoptions;
}
/** @return array string => string The full standard set of (fractions) -1 to 1 inclusive. */
public static function fraction_options_full() {
self::ensure_fraction_options_initialised();
return self::$fractionoptionsfull;
}
/**
* Return a list of the different question types present in the given categories.
*
* @param array $categories a list of category ids
* @return array the list of question types in the categories
* @since Moodle 3.1
*/
public static function get_all_question_types_in_categories($categories) {
global $DB;
list($categorysql, $params) = $DB->get_in_or_equal($categories);
$sql = "SELECT DISTINCT q.qtype
FROM {question} q
WHERE q.category $categorysql";
$qtypes = $DB->get_fieldset_sql($sql, $params);
return $qtypes;
}
}
/**
* Class for loading questions according to various criteria.
*
* @copyright 2009 The Open University
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class question_finder implements cache_data_source {
/** @var question_finder the singleton instance of this class. */
protected static $questionfinder = null;
/**
* @return question_finder a question finder.
*/
public static function get_instance() {
if (is_null(self::$questionfinder)) {
self::$questionfinder = new question_finder();
}
return self::$questionfinder;
}
/* See cache_data_source::get_instance_for_cache. */
public static function get_instance_for_cache(cache_definition $definition) {
return self::get_instance();
}
/**
* @return get the question definition cache we are using.
*/
protected function get_data_cache() {
// Do not double cache here because it may break cache resetting.
return cache::make('core', 'questiondata');
}
/**
* This method needs to be called whenever a question is edited.
*/
public function uncache_question($questionid) {
$this->get_data_cache()->delete($questionid);
}
/**
* Load a question definition data from the database. The data will be
* returned as a plain stdClass object.
* @param int $questionid the id of the question to load.
* @return object question definition loaded from the database.
*/
public function load_question_data($questionid) {
return $this->get_data_cache()->get($questionid);
}
/**
* Get the ids of all the questions in a list of categories.
* @param array $categoryids either a categoryid, or a comma-separated list
* category ids, or an array of them.
* @param string $extraconditions extra conditions to AND with the rest of
* the where clause. Must use named parameters.
* @param array $extraparams any parameters used by $extraconditions.
* @return array questionid => questionid.
*/
public function get_questions_from_categories($categoryids, $extraconditions,
$extraparams = array()) {
global $DB;
list($qcsql, $qcparams) = $DB->get_in_or_equal($categoryids, SQL_PARAMS_NAMED, 'qc');
if ($extraconditions) {
$extraconditions = ' AND (' . $extraconditions . ')';
}
return $DB->get_records_select_menu('question',
"category {$qcsql}
AND parent = 0
AND hidden = 0
{$extraconditions}", $qcparams + $extraparams, '', 'id,id AS id2');
}
/**
* Get the ids of all the questions in a list of categories, with the number
* of times they have already been used in a given set of usages.
*
* The result array is returned in order of increasing (count previous uses).
*
* @param array $categoryids an array question_category ids.
* @param qubaid_condition $qubaids which question_usages to count previous uses from.
* @param string $extraconditions extra conditions to AND with the rest of
* the where clause. Must use named parameters.
* @param array $extraparams any parameters used by $extraconditions.
* @return array questionid => count of number of previous uses.
*/
public function get_questions_from_categories_with_usage_counts($categoryids,
qubaid_condition $qubaids, $extraconditions = '', $extraparams = array()) {
return $this->get_questions_from_categories_and_tags_with_usage_counts(
$categoryids, $qubaids, $extraconditions, $extraparams);
}
/**
* Get the ids of all the questions in a list of categories that have ALL the provided tags,
* with the number of times they have already been used in a given set of usages.
*
* The result array is returned in order of increasing (count previous uses).
*
* @param array $categoryids an array of question_category ids.
* @param qubaid_condition $qubaids which question_usages to count previous uses from.
* @param string $extraconditions extra conditions to AND with the rest of
* the where clause. Must use named parameters.
* @param array $extraparams any parameters used by $extraconditions.
* @param array $tagids an array of tag ids
* @return array questionid => count of number of previous uses.
*/
public function get_questions_from_categories_and_tags_with_usage_counts($categoryids,
qubaid_condition $qubaids, $extraconditions = '', $extraparams = array(), $tagids = array()) {
global $DB;
list($qcsql, $qcparams) = $DB->get_in_or_equal($categoryids, SQL_PARAMS_NAMED, 'qc');
$select = "q.id, (SELECT COUNT(1)
FROM " . $qubaids->from_question_attempts('qa') . "
WHERE qa.questionid = q.id AND " . $qubaids->where() . "
) AS previous_attempts";
$from = "{question} q";
$where = "q.category {$qcsql}
AND q.parent = 0
AND q.hidden = 0";
$params = $qcparams;
if (!empty($tagids)) {
// We treat each additional tag as an AND condition rather than
// an OR condition.
//
// For example, if the user filters by the tags "foo" and "bar" then
// we reduce the question list to questions that are tagged with both
// "foo" AND "bar". Any question that does not have ALL of the specified
// tags will be omitted.
list($tagsql, $tagparams) = $DB->get_in_or_equal($tagids, SQL_PARAMS_NAMED, 'ti');
$tagparams['tagcount'] = count($tagids);
$tagparams['questionitemtype'] = 'question';
$tagparams['questioncomponent'] = 'core_question';
$where .= " AND q.id IN (SELECT ti.itemid
FROM {tag_instance} ti
WHERE ti.itemtype = :questionitemtype
AND ti.component = :questioncomponent
AND ti.tagid {$tagsql}
GROUP BY ti.itemid
HAVING COUNT(itemid) = :tagcount)";
$params += $tagparams;
}
if ($extraconditions) {
$extraconditions = ' AND (' . $extraconditions . ')';
}
return $DB->get_records_sql_menu("SELECT $select
FROM $from
WHERE $where $extraconditions
ORDER BY previous_attempts",
$qubaids->from_where_params() + $params + $extraparams);
}
/* See cache_data_source::load_for_cache. */
public function load_for_cache($questionid) {
global $DB;
$questiondata = $DB->get_record_sql('
SELECT q.*, qc.contextid
FROM {question} q
JOIN {question_categories} qc ON q.category = qc.id
WHERE q.id = :id', array('id' => $questionid), MUST_EXIST);
get_question_options($questiondata);
return $questiondata;
}
/* See cache_data_source::load_many_for_cache. */
public function load_many_for_cache(array $questionids) {
global $DB;
list($idcondition, $params) = $DB->get_in_or_equal($questionids);
$questiondata = $DB->get_records_sql('
SELECT q.*, qc.contextid
FROM {question} q
JOIN {question_categories} qc ON q.category = qc.id
WHERE q.id ' . $idcondition, $params);
foreach ($questionids as $id) {
if (!array_key_exists($id, $questiondata)) {
throw new dml_missing_record_exception('question', '', array('id' => $id));
}
get_question_options($questiondata[$id]);
}
return $questiondata;
}
}