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See Release Notes

  • Bug fixes for general core bugs in 3.10.x will end 8 November 2021 (12 months).
  • Bug fixes for security issues in 3.10.x will end 9 May 2022 (18 months).
  • PHP version: minimum PHP 7.2.0 Note: minimum PHP version has increased since Moodle 3.8. PHP 7.3.x and 7.4.x are supported too.

Differences Between: [Versions 310 and 311] [Versions 310 and 400] [Versions 310 and 401] [Versions 310 and 402] [Versions 310 and 403]

   1  <?php
   2  // This file is part of Moodle - http://moodle.org/
   3  //
   4  // Moodle is free software: you can redistribute it and/or modify
   5  // it under the terms of the GNU General Public License as published by
   6  // the Free Software Foundation, either version 3 of the License, or
   7  // (at your option) any later version.
   8  //
   9  // Moodle is distributed in the hope that it will be useful,
  10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  // GNU General Public License for more details.
  13  //
  14  // You should have received a copy of the GNU General Public License
  15  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16  
  17  /**
  18   * The default questiontype class.
  19   *
  20   * @package    moodlecore
  21   * @subpackage questiontypes
  22   * @copyright  1999 onwards Martin Dougiamas {@link http://moodle.com}
  23   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  24   */
  25  
  26  
  27  defined('MOODLE_INTERNAL') || die();
  28  
  29  require_once($CFG->dirroot . '/question/engine/lib.php');
  30  
  31  
  32  /**
  33   * This is the base class for Moodle question types.
  34   *
  35   * There are detailed comments on each method, explaining what the method is
  36   * for, and the circumstances under which you might need to override it.
  37   *
  38   * Note: the questiontype API should NOT be considered stable yet. Very few
  39   * question types have been produced yet, so we do not yet know all the places
  40   * where the current API is insufficient. I would rather learn from the
  41   * experiences of the first few question type implementors, and improve the
  42   * interface to meet their needs, rather the freeze the API prematurely and
  43   * condem everyone to working round a clunky interface for ever afterwards.
  44   *
  45   * @copyright  1999 onwards Martin Dougiamas {@link http://moodle.com}
  46   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  47   */
  48  class question_type {
  49      protected $fileoptions = array(
  50          'subdirs' => true,
  51          'maxfiles' => -1,
  52          'maxbytes' => 0,
  53      );
  54  
  55      public function __construct() {
  56      }
  57  
  58      /**
  59       * @return string the name of this question type.
  60       */
  61      public function name() {
  62          return substr(get_class($this), 6);
  63      }
  64  
  65      /**
  66       * @return string the full frankenstyle name for this plugin.
  67       */
  68      public function plugin_name() {
  69          return get_class($this);
  70      }
  71  
  72      /**
  73       * @return string the name of this question type in the user's language.
  74       * You should not need to override this method, the default behaviour should be fine.
  75       */
  76      public function local_name() {
  77          return get_string('pluginname', $this->plugin_name());
  78      }
  79  
  80      /**
  81       * The name this question should appear as in the create new question
  82       * dropdown. Override this method to return false if you don't want your
  83       * question type to be createable, for example if it is an abstract base type,
  84       * otherwise, you should not need to override this method.
  85       *
  86       * @return mixed the desired string, or false to hide this question type in the menu.
  87       */
  88      public function menu_name() {
  89          return $this->local_name();
  90      }
  91  
  92      /**
  93       * @return bool override this to return false if this is not really a
  94       *      question type, for example the description question type is not
  95       *      really a question type.
  96       */
  97      public function is_real_question_type() {
  98          return true;
  99      }
 100  
 101      /**
 102       * @return bool true if this question type sometimes requires manual grading.
 103       */
 104      public function is_manual_graded() {
 105          return false;
 106      }
 107  
 108      /**
 109       * @param object $question a question of this type.
 110       * @param string $otherquestionsinuse comma-separate list of other question ids in this attempt.
 111       * @return bool true if a particular instance of this question requires manual grading.
 112       */
 113      public function is_question_manual_graded($question, $otherquestionsinuse) {
 114          return $this->is_manual_graded();
 115      }
 116  
 117      /**
 118       * @return bool true if this question type can be used by the random question type.
 119       */
 120      public function is_usable_by_random() {
 121          return true;
 122      }
 123  
 124      /**
 125       * Whether this question type can perform a frequency analysis of student
 126       * responses.
 127       *
 128       * If this method returns true, you must implement the get_possible_responses
 129       * method, and the question_definition class must implement the
 130       * classify_response method.
 131       *
 132       * @return bool whether this report can analyse all the student responses
 133       * for things like the quiz statistics report.
 134       */
 135      public function can_analyse_responses() {
 136          // This works in most cases.
 137          return !$this->is_manual_graded();
 138      }
 139  
 140      /**
 141       * @return whether the question_answers.answer field needs to have
 142       * restore_decode_content_links_worker called on it.
 143       */
 144      public function has_html_answers() {
 145          return false;
 146      }
 147  
 148      /**
 149       * If your question type has a table that extends the question table, and
 150       * you want the base class to automatically save, backup and restore the extra fields,
 151       * override this method to return an array wherer the first element is the table name,
 152       * and the subsequent entries are the column names (apart from id and questionid).
 153       *
 154       * @return mixed array as above, or null to tell the base class to do nothing.
 155       */
 156      public function extra_question_fields() {
 157          return null;
 158      }
 159  
 160      /**
 161       * If you use extra_question_fields, overload this function to return question id field name
 162       *  in case you table use another name for this column
 163       */
 164      public function questionid_column_name() {
 165          return 'questionid';
 166      }
 167  
 168      /**
 169       * If your question type has a table that extends the question_answers table,
 170       * make this method return an array wherer the first element is the table name,
 171       * and the subsequent entries are the column names (apart from id and answerid).
 172       *
 173       * @return mixed array as above, or null to tell the base class to do nothing.
 174       */
 175      public function extra_answer_fields() {
 176          return null;
 177      }
 178  
 179      /**
 180       * If the quetsion type uses files in responses, then this method should
 181       * return an array of all the response variables that might have corresponding
 182       * files. For example, the essay qtype returns array('attachments', 'answers').
 183       *
 184       * @return array response variable names that may have associated files.
 185       */
 186      public function response_file_areas() {
 187          return array();
 188      }
 189  
 190      /**
 191       * Return an instance of the question editing form definition. This looks for a
 192       * class called edit_{$this->name()}_question_form in the file
 193       * question/type/{$this->name()}/edit_{$this->name()}_question_form.php
 194       * and if it exists returns an instance of it.
 195       *
 196       * @param string $submiturl passed on to the constructor call.
 197       * @return object an instance of the form definition, or null if one could not be found.
 198       */
 199      public function create_editing_form($submiturl, $question, $category,
 200              $contexts, $formeditable) {
 201          global $CFG;
 202          require_once($CFG->dirroot . '/question/type/edit_question_form.php');
 203          $definitionfile = $CFG->dirroot . '/question/type/' . $this->name() .
 204                  '/edit_' . $this->name() . '_form.php';
 205          if (!is_readable($definitionfile) || !is_file($definitionfile)) {
 206              throw new coding_exception($this->plugin_name() .
 207                      ' is missing the definition of its editing formin file ' .
 208                      $definitionfile . '.');
 209          }
 210          require_once($definitionfile);
 211          $classname = $this->plugin_name() . '_edit_form';
 212          if (!class_exists($classname)) {
 213              throw new coding_exception($this->plugin_name() .
 214                      ' does not define the class ' . $this->plugin_name() .
 215                      '_edit_form.');
 216          }
 217          return new $classname($submiturl, $question, $category, $contexts, $formeditable);
 218      }
 219  
 220      /**
 221       * @return string the full path of the folder this plugin's files live in.
 222       */
 223      public function plugin_dir() {
 224          global $CFG;
 225          return $CFG->dirroot . '/question/type/' . $this->name();
 226      }
 227  
 228      /**
 229       * @return string the URL of the folder this plugin's files live in.
 230       */
 231      public function plugin_baseurl() {
 232          global $CFG;
 233          return $CFG->wwwroot . '/question/type/' . $this->name();
 234      }
 235  
 236      /**
 237       * Get extra actions for a question of this type to add to the question bank edit menu.
 238       *
 239       * This method is called if the {@link edit_menu_column} is being used in the
 240       * question bank, which it is by default since Moodle 3.8. If applicable for
 241       * your question type, you can return arn array of {@link action_menu_link}s.
 242       * These will be added at the end of the Edit menu for this question.
 243       *
 244       * The $question object passed in will have a hard-to-predict set of fields,
 245       * because the fields present depend on which columns are included in the
 246       * question bank view. However, you can rely on 'id', 'createdby',
 247       * 'contextid', 'hidden' and 'category' (id) being present, and so you
 248       * can call question_has_capability_on without causing performance problems.
 249       *
 250       * @param stdClass $question the available information about the particular question the action is for.
 251       * @return action_menu_link[] any actions you want to add to the Edit menu for this question.
 252       */
 253      public function get_extra_question_bank_actions(stdClass $question): array {
 254          return [];
 255      }
 256  
 257      /**
 258       * This method should be overriden if you want to include a special heading or some other
 259       * html on a question editing page besides the question editing form.
 260       *
 261       * @param question_edit_form $mform a child of question_edit_form
 262       * @param object $question
 263       * @param string $wizardnow is '' for first page.
 264       */
 265      public function display_question_editing_page($mform, $question, $wizardnow) {
 266          global $OUTPUT;
 267          $heading = $this->get_heading(empty($question->id));
 268          echo $OUTPUT->heading_with_help($heading, 'pluginname', $this->plugin_name());
 269          $mform->display();
 270      }
 271  
 272      /**
 273       * Method called by display_question_editing_page and by question.php to get
 274       * heading for breadcrumbs.
 275       *
 276       * @return string the heading
 277       */
 278      public function get_heading($adding = false) {
 279          if ($adding) {
 280              $string = 'pluginnameadding';
 281          } else {
 282              $string = 'pluginnameediting';
 283          }
 284          return get_string($string, $this->plugin_name());
 285      }
 286  
 287      /**
 288       * Set any missing settings for this question to the default values. This is
 289       * called before displaying the question editing form.
 290       *
 291       * @param object $questiondata the question data, loaded from the databsae,
 292       *      or more likely a newly created question object that is only partially
 293       *      initialised.
 294       */
 295      public function set_default_options($questiondata) {
 296      }
 297  
 298      /**
 299       * Saves (creates or updates) a question.
 300       *
 301       * Given some question info and some data about the answers
 302       * this function parses, organises and saves the question
 303       * It is used by {@link question.php} when saving new data from
 304       * a form, and also by {@link import.php} when importing questions
 305       * This function in turn calls {@link save_question_options}
 306       * to save question-type specific data.
 307       *
 308       * Whether we are saving a new question or updating an existing one can be
 309       * determined by testing !empty($question->id). If it is not empty, we are updating.
 310       *
 311       * The question will be saved in category $form->category.
 312       *
 313       * @param object $question the question object which should be updated. For a
 314       *      new question will be mostly empty.
 315       * @param object $form the object containing the information to save, as if
 316       *      from the question editing form.
 317       * @param object $course not really used any more.
 318       * @return object On success, return the new question object. On failure,
 319       *       return an object as follows. If the error object has an errors field,
 320       *       display that as an error message. Otherwise, the editing form will be
 321       *       redisplayed with validation errors, from validation_errors field, which
 322       *       is itself an object, shown next to the form fields. (I don't think this
 323       *       is accurate any more.)
 324       */
 325      public function save_question($question, $form) {
 326          global $USER, $DB;
 327  
 328          // The actual update/insert done with multiple DB access, so we do it in a transaction.
 329          $transaction = $DB->start_delegated_transaction ();
 330  
 331          list($question->category) = explode(',', $form->category);
 332          $context = $this->get_context_by_category_id($question->category);
 333  
 334          // This default implementation is suitable for most
 335          // question types.
 336  
 337          // First, save the basic question itself.
 338          $question->name = trim($form->name);
 339          $question->parent = isset($form->parent) ? $form->parent : 0;
 340          $question->length = $this->actual_number_of_questions($question);
 341          $question->penalty = isset($form->penalty) ? $form->penalty : 0;
 342  
 343          // The trim call below has the effect of casting any strange values received,
 344          // like null or false, to an appropriate string, so we only need to test for
 345          // missing values. Be careful not to break the value '0' here.
 346          if (!isset($form->questiontext['text'])) {
 347              $question->questiontext = '';
 348          } else {
 349              $question->questiontext = trim($form->questiontext['text']);
 350          }
 351          $question->questiontextformat = !empty($form->questiontext['format']) ?
 352                  $form->questiontext['format'] : 0;
 353  
 354          if (empty($form->generalfeedback['text'])) {
 355              $question->generalfeedback = '';
 356          } else {
 357              $question->generalfeedback = trim($form->generalfeedback['text']);
 358          }
 359          $question->generalfeedbackformat = !empty($form->generalfeedback['format']) ?
 360                  $form->generalfeedback['format'] : 0;
 361  
 362          if ($question->name === '') {
 363              $question->name = shorten_text(strip_tags($form->questiontext['text']), 15);
 364              if ($question->name === '') {
 365                  $question->name = '-';
 366              }
 367          }
 368  
 369          if ($question->penalty > 1 or $question->penalty < 0) {
 370              $question->errors['penalty'] = get_string('invalidpenalty', 'question');
 371          }
 372  
 373          if (isset($form->defaultmark)) {
 374              $question->defaultmark = $form->defaultmark;
 375          }
 376  
 377          if (isset($form->idnumber)) {
 378              if ((string) $form->idnumber === '') {
 379                  $question->idnumber = null;
 380              } else {
 381                  // While this check already exists in the form validation,
 382                  // this is a backstop preventing unnecessary errors.
 383                  // Only set the idnumber if it has changed and will not cause a unique index violation.
 384                  if (strpos($form->category, ',') !== false) {
 385                      list($category, $categorycontextid) = explode(',', $form->category);
 386                  } else {
 387                      $category = $form->category;
 388                  }
 389                  if (!$DB->record_exists('question',
 390                          ['idnumber' => $form->idnumber, 'category' => $category])) {
 391                      $question->idnumber = $form->idnumber;
 392                  }
 393              }
 394          }
 395  
 396          // If the question is new, create it.
 397          $newquestion = false;
 398          if (empty($question->id)) {
 399              // Set the unique code.
 400              $question->stamp = make_unique_id_code();
 401              $question->createdby = $USER->id;
 402              $question->timecreated = time();
 403              $question->id = $DB->insert_record('question', $question);
 404              $newquestion = true;
 405          }
 406  
 407          // Now, whether we are updating a existing question, or creating a new
 408          // one, we have to do the files processing and update the record.
 409          // Question already exists, update.
 410          $question->modifiedby = $USER->id;
 411          $question->timemodified = time();
 412  
 413          if (!empty($question->questiontext) && !empty($form->questiontext['itemid'])) {
 414              $question->questiontext = file_save_draft_area_files($form->questiontext['itemid'],
 415                      $context->id, 'question', 'questiontext', (int)$question->id,
 416                      $this->fileoptions, $question->questiontext);
 417          }
 418          if (!empty($question->generalfeedback) && !empty($form->generalfeedback['itemid'])) {
 419              $question->generalfeedback = file_save_draft_area_files(
 420                      $form->generalfeedback['itemid'], $context->id,
 421                      'question', 'generalfeedback', (int)$question->id,
 422                      $this->fileoptions, $question->generalfeedback);
 423          }
 424          $DB->update_record('question', $question);
 425  
 426          // Now to save all the answers and type-specific options.
 427          $form->id = $question->id;
 428          $form->qtype = $question->qtype;
 429          $form->category = $question->category;
 430          $form->questiontext = $question->questiontext;
 431          $form->questiontextformat = $question->questiontextformat;
 432          // Current context.
 433          $form->context = $context;
 434  
 435          $result = $this->save_question_options($form);
 436  
 437          if (!empty($result->error)) {
 438              print_error($result->error);
 439          }
 440  
 441          if (!empty($result->notice)) {
 442              notice($result->notice, "question.php?id={$question->id}");
 443          }
 444  
 445          if (!empty($result->noticeyesno)) {
 446              throw new coding_exception(
 447                      '$result->noticeyesno no longer supported in save_question.');
 448          }
 449  
 450          // Give the question a unique version stamp determined by question_hash().
 451          $DB->set_field('question', 'version', question_hash($question),
 452                  array('id' => $question->id));
 453  
 454          if ($newquestion) {
 455              // Log the creation of this question.
 456              $event = \core\event\question_created::create_from_question_instance($question, $context);
 457              $event->trigger();
 458          } else {
 459              // Log the update of this question.
 460              $event = \core\event\question_updated::create_from_question_instance($question, $context);
 461              $event->trigger();
 462          }
 463  
 464          $transaction->allow_commit();
 465  
 466          return $question;
 467      }
 468  
 469      /**
 470       * Saves question-type specific options
 471       *
 472       * This is called by {@link save_question()} to save the question-type specific data
 473       * @return object $result->error or $result->notice
 474       * @param object $question  This holds the information from the editing form,
 475       *      it is not a standard question object.
 476       */
 477      public function save_question_options($question) {
 478          global $DB;
 479          $extraquestionfields = $this->extra_question_fields();
 480  
 481          if (is_array($extraquestionfields)) {
 482              $question_extension_table = array_shift($extraquestionfields);
 483  
 484              $function = 'update_record';
 485              $questionidcolname = $this->questionid_column_name();
 486              $options = $DB->get_record($question_extension_table,
 487                      array($questionidcolname => $question->id));
 488              if (!$options) {
 489                  $function = 'insert_record';
 490                  $options = new stdClass();
 491                  $options->$questionidcolname = $question->id;
 492              }
 493              foreach ($extraquestionfields as $field) {
 494                  if (property_exists($question, $field)) {
 495                      $options->$field = $question->$field;
 496                  }
 497              }
 498  
 499              $DB->{$function}($question_extension_table, $options);
 500          }
 501      }
 502  
 503      /**
 504       * Save the answers, with any extra data.
 505       *
 506       * Questions that use answers will call it from {@link save_question_options()}.
 507       * @param object $question  This holds the information from the editing form,
 508       *      it is not a standard question object.
 509       * @return object $result->error or $result->notice
 510       */
 511      public function save_question_answers($question) {
 512          global $DB;
 513  
 514          $context = $question->context;
 515          $oldanswers = $DB->get_records('question_answers',
 516                  array('question' => $question->id), 'id ASC');
 517  
 518          // We need separate arrays for answers and extra answer data, so no JOINS there.
 519          $extraanswerfields = $this->extra_answer_fields();
 520          $isextraanswerfields = is_array($extraanswerfields);
 521          $extraanswertable = '';
 522          $oldanswerextras = array();
 523          if ($isextraanswerfields) {
 524              $extraanswertable = array_shift($extraanswerfields);
 525              if (!empty($oldanswers)) {
 526                  $oldanswerextras = $DB->get_records_sql("SELECT * FROM {{$extraanswertable}} WHERE " .
 527                      'answerid IN (SELECT id FROM {question_answers} WHERE question = ' . $question->id . ')' );
 528              }
 529          }
 530  
 531          // Insert all the new answers.
 532          foreach ($question->answer as $key => $answerdata) {
 533              // Check for, and ignore, completely blank answer from the form.
 534              if ($this->is_answer_empty($question, $key)) {
 535                  continue;
 536              }
 537  
 538              // Update an existing answer if possible.
 539              $answer = array_shift($oldanswers);
 540              if (!$answer) {
 541                  $answer = new stdClass();
 542                  $answer->question = $question->id;
 543                  $answer->answer = '';
 544                  $answer->feedback = '';
 545                  $answer->id = $DB->insert_record('question_answers', $answer);
 546              }
 547  
 548              $answer = $this->fill_answer_fields($answer, $question, $key, $context);
 549              $DB->update_record('question_answers', $answer);
 550  
 551              if ($isextraanswerfields) {
 552                  // Check, if this answer contains some extra field data.
 553                  if ($this->is_extra_answer_fields_empty($question, $key)) {
 554                      continue;
 555                  }
 556  
 557                  $answerextra = array_shift($oldanswerextras);
 558                  if (!$answerextra) {
 559                      $answerextra = new stdClass();
 560                      $answerextra->answerid = $answer->id;
 561                      // Avoid looking for correct default for any possible DB field type
 562                      // by setting real values.
 563                      $answerextra = $this->fill_extra_answer_fields($answerextra, $question, $key, $context, $extraanswerfields);
 564                      $answerextra->id = $DB->insert_record($extraanswertable, $answerextra);
 565                  } else {
 566                      // Update answerid, as record may be reused from another answer.
 567                      $answerextra->answerid = $answer->id;
 568                      $answerextra = $this->fill_extra_answer_fields($answerextra, $question, $key, $context, $extraanswerfields);
 569                      $DB->update_record($extraanswertable, $answerextra);
 570                  }
 571              }
 572          }
 573  
 574          if ($isextraanswerfields) {
 575              // Delete any left over extra answer fields records.
 576              $oldanswerextraids = array();
 577              foreach ($oldanswerextras as $oldextra) {
 578                  $oldanswerextraids[] = $oldextra->id;
 579              }
 580              $DB->delete_records_list($extraanswertable, 'id', $oldanswerextraids);
 581          }
 582  
 583          // Delete any left over old answer records.
 584          $fs = get_file_storage();
 585          foreach ($oldanswers as $oldanswer) {
 586              $fs->delete_area_files($context->id, 'question', 'answerfeedback', $oldanswer->id);
 587              $DB->delete_records('question_answers', array('id' => $oldanswer->id));
 588          }
 589      }
 590  
 591      /**
 592       * Returns true is answer with the $key is empty in the question data and should not be saved in DB.
 593       *
 594       * The questions using question_answers table may want to overload this. Default code will work
 595       * for shortanswer and similar question types.
 596       * @param object $questiondata This holds the information from the question editing form or import.
 597       * @param int $key A key of the answer in question.
 598       * @return bool True if answer shouldn't be saved in DB.
 599       */
 600      protected function is_answer_empty($questiondata, $key) {
 601          return trim($questiondata->answer[$key]) == '' && $questiondata->fraction[$key] == 0 &&
 602                      html_is_blank($questiondata->feedback[$key]['text']);
 603      }
 604  
 605      /**
 606       * Return $answer, filling necessary fields for the question_answers table.
 607       *
 608       * The questions using question_answers table may want to overload this. Default code will work
 609       * for shortanswer and similar question types.
 610       * @param stdClass $answer Object to save data.
 611       * @param object $questiondata This holds the information from the question editing form or import.
 612       * @param int $key A key of the answer in question.
 613       * @param object $context needed for working with files.
 614       * @return $answer answer with filled data.
 615       */
 616      protected function fill_answer_fields($answer, $questiondata, $key, $context) {
 617          $answer->answer   = $questiondata->answer[$key];
 618          $answer->fraction = $questiondata->fraction[$key];
 619          $answer->feedback = $this->import_or_save_files($questiondata->feedback[$key],
 620                  $context, 'question', 'answerfeedback', $answer->id);
 621          $answer->feedbackformat = $questiondata->feedback[$key]['format'];
 622          return $answer;
 623      }
 624  
 625      /**
 626       * Returns true if extra answer fields for answer with the $key is empty
 627       * in the question data and should not be saved in DB.
 628       *
 629       * Questions where extra answer fields are optional will want to overload this.
 630       * @param object $questiondata This holds the information from the question editing form or import.
 631       * @param int $key A key of the answer in question.
 632       * @return bool True if extra answer data shouldn't be saved in DB.
 633       */
 634      protected function is_extra_answer_fields_empty($questiondata, $key) {
 635          // No extra answer data in base class.
 636          return true;
 637      }
 638  
 639      /**
 640       * Return $answerextra, filling necessary fields for the extra answer fields table.
 641       *
 642       * The questions may want to overload it to save files or do other data processing.
 643       * @param stdClass $answerextra Object to save data.
 644       * @param object $questiondata This holds the information from the question editing form or import.
 645       * @param int $key A key of the answer in question.
 646       * @param object $context needed for working with files.
 647       * @param array $extraanswerfields extra answer fields (without table name).
 648       * @return $answer answerextra with filled data.
 649       */
 650      protected function fill_extra_answer_fields($answerextra, $questiondata, $key, $context, $extraanswerfields) {
 651          foreach ($extraanswerfields as $field) {
 652              // The $questiondata->$field[$key] won't work in PHP, break it down to two strings of code.
 653              $fieldarray = $questiondata->$field;
 654              $answerextra->$field = $fieldarray[$key];
 655          }
 656          return $answerextra;
 657      }
 658  
 659      public function save_hints($formdata, $withparts = false) {
 660          global $DB;
 661          $context = $formdata->context;
 662  
 663          $oldhints = $DB->get_records('question_hints',
 664                  array('questionid' => $formdata->id), 'id ASC');
 665  
 666  
 667          $numhints = $this->count_hints_on_form($formdata, $withparts);
 668  
 669          for ($i = 0; $i < $numhints; $i += 1) {
 670              if (html_is_blank($formdata->hint[$i]['text'])) {
 671                  $formdata->hint[$i]['text'] = '';
 672              }
 673  
 674              if ($withparts) {
 675                  $clearwrong = !empty($formdata->hintclearwrong[$i]);
 676                  $shownumcorrect = !empty($formdata->hintshownumcorrect[$i]);
 677              }
 678  
 679              if ($this->is_hint_empty_in_form_data($formdata, $i, $withparts)) {
 680                  continue;
 681              }
 682  
 683              // Update an existing hint if possible.
 684              $hint = array_shift($oldhints);
 685              if (!$hint) {
 686                  $hint = new stdClass();
 687                  $hint->questionid = $formdata->id;
 688                  $hint->hint = '';
 689                  $hint->id = $DB->insert_record('question_hints', $hint);
 690              }
 691  
 692              $hint->hint = $this->import_or_save_files($formdata->hint[$i],
 693                      $context, 'question', 'hint', $hint->id);
 694              $hint->hintformat = $formdata->hint[$i]['format'];
 695              if ($withparts) {
 696                  $hint->clearwrong = $clearwrong;
 697                  $hint->shownumcorrect = $shownumcorrect;
 698              }
 699              $hint->options = $this->save_hint_options($formdata, $i, $withparts);
 700              $DB->update_record('question_hints', $hint);
 701          }
 702  
 703          // Delete any remaining old hints.
 704          $fs = get_file_storage();
 705          foreach ($oldhints as $oldhint) {
 706              $fs->delete_area_files($context->id, 'question', 'hint', $oldhint->id);
 707              $DB->delete_records('question_hints', array('id' => $oldhint->id));
 708          }
 709      }
 710  
 711      /**
 712       * Count number of hints on the form.
 713       * Overload if you use custom hint controls.
 714       * @param object $formdata the data from the form.
 715       * @param bool $withparts whether to take into account clearwrong and shownumcorrect options.
 716       * @return int count of hints on the form.
 717       */
 718      protected function count_hints_on_form($formdata, $withparts) {
 719          if (!empty($formdata->hint)) {
 720              $numhints = max(array_keys($formdata->hint)) + 1;
 721          } else {
 722              $numhints = 0;
 723          }
 724  
 725          if ($withparts) {
 726              if (!empty($formdata->hintclearwrong)) {
 727                  $numclears = max(array_keys($formdata->hintclearwrong)) + 1;
 728              } else {
 729                  $numclears = 0;
 730              }
 731              if (!empty($formdata->hintshownumcorrect)) {
 732                  $numshows = max(array_keys($formdata->hintshownumcorrect)) + 1;
 733              } else {
 734                  $numshows = 0;
 735              }
 736              $numhints = max($numhints, $numclears, $numshows);
 737          }
 738          return $numhints;
 739      }
 740  
 741      /**
 742       * Determine if the hint with specified number is not empty and should be saved.
 743       * Overload if you use custom hint controls.
 744       * @param object $formdata the data from the form.
 745       * @param int $number number of hint under question.
 746       * @param bool $withparts whether to take into account clearwrong and shownumcorrect options.
 747       * @return bool is this particular hint data empty.
 748       */
 749      protected function is_hint_empty_in_form_data($formdata, $number, $withparts) {
 750          if ($withparts) {
 751              return empty($formdata->hint[$number]['text']) && empty($formdata->hintclearwrong[$number]) &&
 752                      empty($formdata->hintshownumcorrect[$number]);
 753          } else {
 754              return  empty($formdata->hint[$number]['text']);
 755          }
 756      }
 757  
 758      /**
 759       * Save additional question type data into the hint optional field.
 760       * Overload if you use custom hint information.
 761       * @param object $formdata the data from the form.
 762       * @param int $number number of hint to get options from.
 763       * @param bool $withparts whether question have parts.
 764       * @return string value to save into the options field of question_hints table.
 765       */
 766      protected function save_hint_options($formdata, $number, $withparts) {
 767          return null;    // By default, options field is unused.
 768      }
 769  
 770      /**
 771       * Can be used to {@link save_question_options()} to transfer the combined
 772       * feedback fields from $formdata to $options.
 773       * @param object $options the $question->options object being built.
 774       * @param object $formdata the data from the form.
 775       * @param object $context the context the quetsion is being saved into.
 776       * @param bool $withparts whether $options->shownumcorrect should be set.
 777       */
 778      protected function save_combined_feedback_helper($options, $formdata,
 779              $context, $withparts = false) {
 780          $options->correctfeedback = $this->import_or_save_files($formdata->correctfeedback,
 781                  $context, 'question', 'correctfeedback', $formdata->id);
 782          $options->correctfeedbackformat = $formdata->correctfeedback['format'];
 783  
 784          $options->partiallycorrectfeedback = $this->import_or_save_files(
 785                  $formdata->partiallycorrectfeedback,
 786                  $context, 'question', 'partiallycorrectfeedback', $formdata->id);
 787          $options->partiallycorrectfeedbackformat = $formdata->partiallycorrectfeedback['format'];
 788  
 789          $options->incorrectfeedback = $this->import_or_save_files($formdata->incorrectfeedback,
 790                  $context, 'question', 'incorrectfeedback', $formdata->id);
 791          $options->incorrectfeedbackformat = $formdata->incorrectfeedback['format'];
 792  
 793          if ($withparts) {
 794              $options->shownumcorrect = !empty($formdata->shownumcorrect);
 795          }
 796  
 797          return $options;
 798      }
 799  
 800      /**
 801       * Loads the question type specific options for the question.
 802       *
 803       * This function loads any question type specific options for the
 804       * question from the database into the question object. This information
 805       * is placed in the $question->options field. A question type is
 806       * free, however, to decide on a internal structure of the options field.
 807       * @return bool            Indicates success or failure.
 808       * @param object $question The question object for the question. This object
 809       *                         should be updated to include the question type
 810       *                         specific information (it is passed by reference).
 811       */
 812      public function get_question_options($question) {
 813          global $CFG, $DB, $OUTPUT;
 814  
 815          if (!isset($question->options)) {
 816              $question->options = new stdClass();
 817          }
 818  
 819          $extraquestionfields = $this->extra_question_fields();
 820          if (is_array($extraquestionfields)) {
 821              $question_extension_table = array_shift($extraquestionfields);
 822              $extra_data = $DB->get_record($question_extension_table,
 823                      array($this->questionid_column_name() => $question->id),
 824                      implode(', ', $extraquestionfields));
 825              if ($extra_data) {
 826                  foreach ($extraquestionfields as $field) {
 827                      $question->options->$field = $extra_data->$field;
 828                  }
 829              } else {
 830                  echo $OUTPUT->notification('Failed to load question options from the table ' .
 831                          $question_extension_table . ' for questionid ' . $question->id);
 832                  return false;
 833              }
 834          }
 835  
 836          $extraanswerfields = $this->extra_answer_fields();
 837          if (is_array($extraanswerfields)) {
 838              $answerextensiontable = array_shift($extraanswerfields);
 839              // Use LEFT JOIN in case not every answer has extra data.
 840              $question->options->answers = $DB->get_records_sql("
 841                      SELECT qa.*, qax." . implode(', qax.', $extraanswerfields) . '
 842                      FROM {question_answers} qa ' . "
 843                      LEFT JOIN {{$answerextensiontable}} qax ON qa.id = qax.answerid
 844                      WHERE qa.question = ?
 845                      ORDER BY qa.id", array($question->id));
 846              if (!$question->options->answers) {
 847                  echo $OUTPUT->notification('Failed to load question answers from the table ' .
 848                          $answerextensiontable . 'for questionid ' . $question->id);
 849                  return false;
 850              }
 851          } else {
 852              // Don't check for success or failure because some question types do
 853              // not use the answers table.
 854              $question->options->answers = $DB->get_records('question_answers',
 855                      array('question' => $question->id), 'id ASC');
 856          }
 857  
 858          $question->hints = $DB->get_records('question_hints',
 859                  array('questionid' => $question->id), 'id ASC');
 860  
 861          return true;
 862      }
 863  
 864      /**
 865       * Create an appropriate question_definition for the question of this type
 866       * using data loaded from the database.
 867       * @param object $questiondata the question data loaded from the database.
 868       * @return question_definition the corresponding question_definition.
 869       */
 870      public function make_question($questiondata) {
 871          $question = $this->make_question_instance($questiondata);
 872          $this->initialise_question_instance($question, $questiondata);
 873          return $question;
 874      }
 875  
 876      /**
 877       * Create an appropriate question_definition for the question of this type
 878       * using data loaded from the database.
 879       * @param object $questiondata the question data loaded from the database.
 880       * @return question_definition an instance of the appropriate question_definition subclass.
 881       *      Still needs to be initialised.
 882       */
 883      protected function make_question_instance($questiondata) {
 884          question_bank::load_question_definition_classes($this->name());
 885          $class = 'qtype_' . $this->name() . '_question';
 886          return new $class();
 887      }
 888  
 889      /**
 890       * Initialise the common question_definition fields.
 891       * @param question_definition $question the question_definition we are creating.
 892       * @param object $questiondata the question data loaded from the database.
 893       */
 894      protected function initialise_question_instance(question_definition $question, $questiondata) {
 895          $question->id = $questiondata->id;
 896          $question->category = $questiondata->category;
 897          $question->contextid = $questiondata->contextid;
 898          $question->parent = $questiondata->parent;
 899          $question->qtype = $this;
 900          $question->name = $questiondata->name;
 901          $question->questiontext = $questiondata->questiontext;
 902          $question->questiontextformat = $questiondata->questiontextformat;
 903          $question->generalfeedback = $questiondata->generalfeedback;
 904          $question->generalfeedbackformat = $questiondata->generalfeedbackformat;
 905          $question->defaultmark = $questiondata->defaultmark + 0;
 906          $question->length = $questiondata->length;
 907          $question->penalty = $questiondata->penalty;
 908          $question->stamp = $questiondata->stamp;
 909          $question->version = $questiondata->version;
 910          $question->hidden = $questiondata->hidden;
 911          $question->idnumber = $questiondata->idnumber;
 912          $question->timecreated = $questiondata->timecreated;
 913          $question->timemodified = $questiondata->timemodified;
 914          $question->createdby = $questiondata->createdby;
 915          $question->modifiedby = $questiondata->modifiedby;
 916  
 917          // Fill extra question fields values.
 918          $extraquestionfields = $this->extra_question_fields();
 919          if (is_array($extraquestionfields)) {
 920              // Omit table name.
 921              array_shift($extraquestionfields);
 922              foreach ($extraquestionfields as $field) {
 923                  $question->$field = $questiondata->options->$field;
 924              }
 925          }
 926  
 927          $this->initialise_question_hints($question, $questiondata);
 928      }
 929  
 930      /**
 931       * Initialise question_definition::hints field.
 932       * @param question_definition $question the question_definition we are creating.
 933       * @param object $questiondata the question data loaded from the database.
 934       */
 935      protected function initialise_question_hints(question_definition $question, $questiondata) {
 936          if (empty($questiondata->hints)) {
 937              return;
 938          }
 939          foreach ($questiondata->hints as $hint) {
 940              $question->hints[] = $this->make_hint($hint);
 941          }
 942      }
 943  
 944      /**
 945       * Create a question_hint, or an appropriate subclass for this question,
 946       * from a row loaded from the database.
 947       * @param object $hint the DB row from the question hints table.
 948       * @return question_hint
 949       */
 950      protected function make_hint($hint) {
 951          return question_hint::load_from_record($hint);
 952      }
 953  
 954      /**
 955       * Initialise the combined feedback fields.
 956       * @param question_definition $question the question_definition we are creating.
 957       * @param object $questiondata the question data loaded from the database.
 958       * @param bool $withparts whether to set the shownumcorrect field.
 959       */
 960      protected function initialise_combined_feedback(question_definition $question,
 961              $questiondata, $withparts = false) {
 962          $question->correctfeedback = $questiondata->options->correctfeedback;
 963          $question->correctfeedbackformat = $questiondata->options->correctfeedbackformat;
 964          $question->partiallycorrectfeedback = $questiondata->options->partiallycorrectfeedback;
 965          $question->partiallycorrectfeedbackformat =
 966                  $questiondata->options->partiallycorrectfeedbackformat;
 967          $question->incorrectfeedback = $questiondata->options->incorrectfeedback;
 968          $question->incorrectfeedbackformat = $questiondata->options->incorrectfeedbackformat;
 969          if ($withparts) {
 970              $question->shownumcorrect = $questiondata->options->shownumcorrect;
 971          }
 972      }
 973  
 974      /**
 975       * Initialise question_definition::answers field.
 976       * @param question_definition $question the question_definition we are creating.
 977       * @param object $questiondata the question data loaded from the database.
 978       * @param bool $forceplaintextanswers most qtypes assume that answers are
 979       *      FORMAT_PLAIN, and dont use the answerformat DB column (it contains
 980       *      the default 0 = FORMAT_MOODLE). Therefore, by default this method
 981       *      ingores answerformat. Pass false here to use answerformat. For example
 982       *      multichoice does this.
 983       */
 984      protected function initialise_question_answers(question_definition $question,
 985              $questiondata, $forceplaintextanswers = true) {
 986          $question->answers = array();
 987          if (empty($questiondata->options->answers)) {
 988              return;
 989          }
 990          foreach ($questiondata->options->answers as $a) {
 991              $question->answers[$a->id] = $this->make_answer($a);
 992              if (!$forceplaintextanswers) {
 993                  $question->answers[$a->id]->answerformat = $a->answerformat;
 994              }
 995          }
 996      }
 997  
 998      /**
 999       * Create a question_answer, or an appropriate subclass for this question,
1000       * from a row loaded from the database.
1001       * @param object $answer the DB row from the question_answers table plus extra answer fields.
1002       * @return question_answer
1003       */
1004      protected function make_answer($answer) {
1005          return new question_answer($answer->id, $answer->answer,
1006                      $answer->fraction, $answer->feedback, $answer->feedbackformat);
1007      }
1008  
1009      /**
1010       * Deletes the question-type specific data when a question is deleted.
1011       * @param int $question the question being deleted.
1012       * @param int $contextid the context this quesiotn belongs to.
1013       */
1014      public function delete_question($questionid, $contextid) {
1015          global $DB;
1016  
1017          $this->delete_files($questionid, $contextid);
1018  
1019          $extraquestionfields = $this->extra_question_fields();
1020          if (is_array($extraquestionfields)) {
1021              $question_extension_table = array_shift($extraquestionfields);
1022              $DB->delete_records($question_extension_table,
1023                      array($this->questionid_column_name() => $questionid));
1024          }
1025  
1026          $extraanswerfields = $this->extra_answer_fields();
1027          if (is_array($extraanswerfields)) {
1028              $answer_extension_table = array_shift($extraanswerfields);
1029              $DB->delete_records_select($answer_extension_table,
1030                      'answerid IN (SELECT qa.id FROM {question_answers} qa WHERE qa.question = ?)',
1031                      array($questionid));
1032          }
1033  
1034          $DB->delete_records('question_answers', array('question' => $questionid));
1035  
1036          $DB->delete_records('question_hints', array('questionid' => $questionid));
1037      }
1038  
1039      /**
1040       * Returns the number of question numbers which are used by the question
1041       *
1042       * This function returns the number of question numbers to be assigned
1043       * to the question. Most question types will have length one; they will be
1044       * assigned one number. The 'description' type, however does not use up a
1045       * number and so has a length of zero. Other question types may wish to
1046       * handle a bundle of questions and hence return a number greater than one.
1047       * @return int         The number of question numbers which should be
1048       *                         assigned to the question.
1049       * @param object $question The question whose length is to be determined.
1050       *                         Question type specific information is included.
1051       */
1052      public function actual_number_of_questions($question) {
1053          // By default, each question is given one number.
1054          return 1;
1055      }
1056  
1057      /**
1058       * Calculate the score a monkey would get on a question by clicking randomly.
1059       *
1060       * Some question types have significant non-zero average expected score
1061       * of the response is just selected randomly. For example 50% for a
1062       * true-false question. It is useful to know what this is. For example
1063       * it gets shown in the quiz statistics report.
1064       *
1065       * For almost any open-ended question type (E.g. shortanswer or numerical)
1066       * this should be 0.
1067       *
1068       * For selective response question types (e.g. multiple choice), you can probably compute this.
1069       *
1070       * For particularly complicated question types the may be impossible or very
1071       * difficult to compute. In this case return null. (Or, if the expected score
1072       * is very tiny even though the exact value is unknown, it may appropriate
1073       * to return 0.)
1074       *
1075       * @param stdClass $questiondata data defining a question, as returned by
1076       *      question_bank::load_question_data().
1077       * @return number|null either a fraction estimating what the student would
1078       *      score by guessing, or null, if it is not possible to estimate.
1079       */
1080      public function get_random_guess_score($questiondata) {
1081          return 0;
1082      }
1083  
1084      /**
1085       * Whether or not to break down question stats and response analysis, for a question defined by $questiondata.
1086       *
1087       * @param object $questiondata The full question definition data.
1088       * @return bool
1089       */
1090      public function break_down_stats_and_response_analysis_by_variant($questiondata) {
1091          return true;
1092      }
1093  
1094      /**
1095       * This method should return all the possible types of response that are
1096       * recognised for this question.
1097       *
1098       * The question is modelled as comprising one or more subparts. For each
1099       * subpart, there are one or more classes that that students response
1100       * might fall into, each of those classes earning a certain score.
1101       *
1102       * For example, in a shortanswer question, there is only one subpart, the
1103       * text entry field. The response the student gave will be classified according
1104       * to which of the possible $question->options->answers it matches.
1105       *
1106       * For the matching question type, there will be one subpart for each
1107       * question stem, and for each stem, each of the possible choices is a class
1108       * of student's response.
1109       *
1110       * A response is an object with two fields, ->responseclass is a string
1111       * presentation of that response, and ->fraction, the credit for a response
1112       * in that class.
1113       *
1114       * Array keys have no specific meaning, but must be unique, and must be
1115       * the same if this function is called repeatedly.
1116       *
1117       * @param object $question the question definition data.
1118       * @return array keys are subquestionid, values are arrays of possible
1119       *      responses to that subquestion.
1120       */
1121      public function get_possible_responses($questiondata) {
1122          return array();
1123      }
1124  
1125      /**
1126       * Utility method used by {@link qtype_renderer::head_code()}. It looks
1127       * for any of the files script.js or script.php that exist in the plugin
1128       * folder and ensures they get included.
1129       */
1130      public function find_standard_scripts() {
1131          global $PAGE;
1132  
1133          $plugindir = $this->plugin_dir();
1134          $plugindirrel = 'question/type/' . $this->name();
1135  
1136          if (file_exists($plugindir . '/script.js')) {
1137              $PAGE->requires->js('/' . $plugindirrel . '/script.js');
1138          }
1139          if (file_exists($plugindir . '/script.php')) {
1140              $PAGE->requires->js('/' . $plugindirrel . '/script.php');
1141          }
1142      }
1143  
1144      /**
1145       * Returns true if the editing wizard is finished, false otherwise.
1146       *
1147       * The default implementation returns true, which is suitable for all question-
1148       * types that only use one editing form. This function is used in
1149       * question.php to decide whether we can regrade any states of the edited
1150       * question and redirect to edit.php.
1151       *
1152       * The dataset dependent question-type, which is extended by the calculated
1153       * question-type, overwrites this method because it uses multiple pages (i.e.
1154       * a wizard) to set up the question and associated datasets.
1155       *
1156       * @param object $form  The data submitted by the previous page.
1157       *
1158       * @return bool      Whether the wizard's last page was submitted or not.
1159       */
1160      public function finished_edit_wizard($form) {
1161          // In the default case there is only one edit page.
1162          return true;
1163      }
1164  
1165      // IMPORT/EXPORT FUNCTIONS --------------------------------- .
1166  
1167      /*
1168       * Imports question from the Moodle XML format
1169       *
1170       * Imports question using information from extra_question_fields function
1171       * If some of you fields contains id's you'll need to reimplement this
1172       */
1173      public function import_from_xml($data, $question, qformat_xml $format, $extra=null) {
1174          $question_type = $data['@']['type'];
1175          if ($question_type != $this->name()) {
1176              return false;
1177          }
1178  
1179          $extraquestionfields = $this->extra_question_fields();
1180          if (!is_array($extraquestionfields)) {
1181              return false;
1182          }
1183  
1184          // Omit table name.
1185          array_shift($extraquestionfields);
1186          $qo = $format->import_headers($data);
1187          $qo->qtype = $question_type;
1188  
1189          foreach ($extraquestionfields as $field) {
1190              $qo->$field = $format->getpath($data, array('#', $field, 0, '#'), '');
1191          }
1192  
1193          // Run through the answers.
1194          $answers = $data['#']['answer'];
1195          $a_count = 0;
1196          $extraanswersfields = $this->extra_answer_fields();
1197          if (is_array($extraanswersfields)) {
1198              array_shift($extraanswersfields);
1199          }
1200          foreach ($answers as $answer) {
1201              $ans = $format->import_answer($answer);
1202              if (!$this->has_html_answers()) {
1203                  $qo->answer[$a_count] = $ans->answer['text'];
1204              } else {
1205                  $qo->answer[$a_count] = $ans->answer;
1206              }
1207              $qo->fraction[$a_count] = $ans->fraction;
1208              $qo->feedback[$a_count] = $ans->feedback;
1209              if (is_array($extraanswersfields)) {
1210                  foreach ($extraanswersfields as $field) {
1211                      $qo->{$field}[$a_count] =
1212                          $format->getpath($answer, array('#', $field, 0, '#'), '');
1213                  }
1214              }
1215              ++$a_count;
1216          }
1217          return $qo;
1218      }
1219  
1220      /*
1221       * Export question to the Moodle XML format
1222       *
1223       * Export question using information from extra_question_fields function
1224       * If some of you fields contains id's you'll need to reimplement this
1225       */
1226      public function export_to_xml($question, qformat_xml $format, $extra=null) {
1227          $extraquestionfields = $this->extra_question_fields();
1228          if (!is_array($extraquestionfields)) {
1229              return false;
1230          }
1231  
1232          // Omit table name.
1233          array_shift($extraquestionfields);
1234          $expout='';
1235          foreach ($extraquestionfields as $field) {
1236              $exportedvalue = $format->xml_escape($question->options->$field);
1237              $expout .= "    <{$field}>{$exportedvalue}</{$field}>\n";
1238          }
1239  
1240          $extraanswersfields = $this->extra_answer_fields();
1241          if (is_array($extraanswersfields)) {
1242              array_shift($extraanswersfields);
1243          }
1244          foreach ($question->options->answers as $answer) {
1245              $extra = '';
1246              if (is_array($extraanswersfields)) {
1247                  foreach ($extraanswersfields as $field) {
1248                      $exportedvalue = $format->xml_escape($answer->$field);
1249                      $extra .= "      <{$field}>{$exportedvalue}</{$field}>\n";
1250                  }
1251              }
1252  
1253              $expout .= $format->write_answer($answer, $extra);
1254          }
1255          return $expout;
1256      }
1257  
1258      /**
1259       * Abstract function implemented by each question type. It runs all the code
1260       * required to set up and save a question of any type for testing purposes.
1261       * Alternate DB table prefix may be used to facilitate data deletion.
1262       */
1263      public function generate_test($name, $courseid=null) {
1264          $form = new stdClass();
1265          $form->name = $name;
1266          $form->questiontextformat = 1;
1267          $form->questiontext = 'test question, generated by script';
1268          $form->defaultmark = 1;
1269          $form->penalty = 0.3333333;
1270          $form->generalfeedback = "Well done";
1271  
1272          $context = context_course::instance($courseid);
1273          $newcategory = question_make_default_categories(array($context));
1274          $form->category = $newcategory->id . ',1';
1275  
1276          $question = new stdClass();
1277          $question->courseid = $courseid;
1278          $question->qtype = $this->qtype;
1279          return array($form, $question);
1280      }
1281  
1282      /**
1283       * Get question context by category id
1284       * @param int $category
1285       * @return object $context
1286       */
1287      protected function get_context_by_category_id($category) {
1288          global $DB;
1289          $contextid = $DB->get_field('question_categories', 'contextid', array('id'=>$category));
1290          $context = context::instance_by_id($contextid, IGNORE_MISSING);
1291          return $context;
1292      }
1293  
1294      /**
1295       * Save the file belonging to one text field.
1296       *
1297       * @param array $field the data from the form (or from import). This will
1298       *      normally have come from the formslib editor element, so it will be an
1299       *      array with keys 'text', 'format' and 'itemid'. However, when we are
1300       *      importing, it will be an array with keys 'text', 'format' and 'files'
1301       * @param object $context the context the question is in.
1302       * @param string $component indentifies the file area question.
1303       * @param string $filearea indentifies the file area questiontext,
1304       *      generalfeedback, answerfeedback, etc.
1305       * @param int $itemid identifies the file area.
1306       *
1307       * @return string the text for this field, after files have been processed.
1308       */
1309      protected function import_or_save_files($field, $context, $component, $filearea, $itemid) {
1310          if (!empty($field['itemid'])) {
1311              // This is the normal case. We are safing the questions editing form.
1312              return file_save_draft_area_files($field['itemid'], $context->id, $component,
1313                      $filearea, $itemid, $this->fileoptions, trim($field['text']));
1314  
1315          } else if (!empty($field['files'])) {
1316              // This is the case when we are doing an import.
1317              foreach ($field['files'] as $file) {
1318                  $this->import_file($context, $component,  $filearea, $itemid, $file);
1319              }
1320          }
1321          return trim($field['text']);
1322      }
1323  
1324      /**
1325       * Move all the files belonging to this question from one context to another.
1326       * @param int $questionid the question being moved.
1327       * @param int $oldcontextid the context it is moving from.
1328       * @param int $newcontextid the context it is moving to.
1329       */
1330      public function move_files($questionid, $oldcontextid, $newcontextid) {
1331          $fs = get_file_storage();
1332          $fs->move_area_files_to_new_context($oldcontextid,
1333                  $newcontextid, 'question', 'questiontext', $questionid);
1334          $fs->move_area_files_to_new_context($oldcontextid,
1335                  $newcontextid, 'question', 'generalfeedback', $questionid);
1336      }
1337  
1338      /**
1339       * Move all the files belonging to this question's answers when the question
1340       * is moved from one context to another.
1341       * @param int $questionid the question being moved.
1342       * @param int $oldcontextid the context it is moving from.
1343       * @param int $newcontextid the context it is moving to.
1344       * @param bool $answerstoo whether there is an 'answer' question area,
1345       *      as well as an 'answerfeedback' one. Default false.
1346       */
1347      protected function move_files_in_answers($questionid, $oldcontextid,
1348              $newcontextid, $answerstoo = false) {
1349          global $DB;
1350          $fs = get_file_storage();
1351  
1352          $answerids = $DB->get_records_menu('question_answers',
1353                  array('question' => $questionid), 'id', 'id,1');
1354          foreach ($answerids as $answerid => $notused) {
1355              if ($answerstoo) {
1356                  $fs->move_area_files_to_new_context($oldcontextid,
1357                          $newcontextid, 'question', 'answer', $answerid);
1358              }
1359              $fs->move_area_files_to_new_context($oldcontextid,
1360                      $newcontextid, 'question', 'answerfeedback', $answerid);
1361          }
1362      }
1363  
1364      /**
1365       * Move all the files belonging to this question's hints when the question
1366       * is moved from one context to another.
1367       * @param int $questionid the question being moved.
1368       * @param int $oldcontextid the context it is moving from.
1369       * @param int $newcontextid the context it is moving to.
1370       * @param bool $answerstoo whether there is an 'answer' question area,
1371       *      as well as an 'answerfeedback' one. Default false.
1372       */
1373      protected function move_files_in_hints($questionid, $oldcontextid, $newcontextid) {
1374          global $DB;
1375          $fs = get_file_storage();
1376  
1377          $hintids = $DB->get_records_menu('question_hints',
1378                  array('questionid' => $questionid), 'id', 'id,1');
1379          foreach ($hintids as $hintid => $notused) {
1380              $fs->move_area_files_to_new_context($oldcontextid,
1381                      $newcontextid, 'question', 'hint', $hintid);
1382          }
1383      }
1384  
1385      /**
1386       * Move all the files belonging to this question's answers when the question
1387       * is moved from one context to another.
1388       * @param int $questionid the question being moved.
1389       * @param int $oldcontextid the context it is moving from.
1390       * @param int $newcontextid the context it is moving to.
1391       * @param bool $answerstoo whether there is an 'answer' question area,
1392       *      as well as an 'answerfeedback' one. Default false.
1393       */
1394      protected function move_files_in_combined_feedback($questionid, $oldcontextid,
1395              $newcontextid) {
1396          global $DB;
1397          $fs = get_file_storage();
1398  
1399          $fs->move_area_files_to_new_context($oldcontextid,
1400                  $newcontextid, 'question', 'correctfeedback', $questionid);
1401          $fs->move_area_files_to_new_context($oldcontextid,
1402                  $newcontextid, 'question', 'partiallycorrectfeedback', $questionid);
1403          $fs->move_area_files_to_new_context($oldcontextid,
1404                  $newcontextid, 'question', 'incorrectfeedback', $questionid);
1405      }
1406  
1407      /**
1408       * Delete all the files belonging to this question.
1409       * @param int $questionid the question being deleted.
1410       * @param int $contextid the context the question is in.
1411       */
1412      protected function delete_files($questionid, $contextid) {
1413          $fs = get_file_storage();
1414          $fs->delete_area_files($contextid, 'question', 'questiontext', $questionid);
1415          $fs->delete_area_files($contextid, 'question', 'generalfeedback', $questionid);
1416      }
1417  
1418      /**
1419       * Delete all the files belonging to this question's answers.
1420       * @param int $questionid the question being deleted.
1421       * @param int $contextid the context the question is in.
1422       * @param bool $answerstoo whether there is an 'answer' question area,
1423       *      as well as an 'answerfeedback' one. Default false.
1424       */
1425      protected function delete_files_in_answers($questionid, $contextid, $answerstoo = false) {
1426          global $DB;
1427          $fs = get_file_storage();
1428  
1429          $answerids = $DB->get_records_menu('question_answers',
1430                  array('question' => $questionid), 'id', 'id,1');
1431          foreach ($answerids as $answerid => $notused) {
1432              if ($answerstoo) {
1433                  $fs->delete_area_files($contextid, 'question', 'answer', $answerid);
1434              }
1435              $fs->delete_area_files($contextid, 'question', 'answerfeedback', $answerid);
1436          }
1437      }
1438  
1439      /**
1440       * Delete all the files belonging to this question's hints.
1441       * @param int $questionid the question being deleted.
1442       * @param int $contextid the context the question is in.
1443       */
1444      protected function delete_files_in_hints($questionid, $contextid) {
1445          global $DB;
1446          $fs = get_file_storage();
1447  
1448          $hintids = $DB->get_records_menu('question_hints',
1449                  array('questionid' => $questionid), 'id', 'id,1');
1450          foreach ($hintids as $hintid => $notused) {
1451              $fs->delete_area_files($contextid, 'question', 'hint', $hintid);
1452          }
1453      }
1454  
1455      /**
1456       * Delete all the files belonging to this question's answers.
1457       * @param int $questionid the question being deleted.
1458       * @param int $contextid the context the question is in.
1459       * @param bool $answerstoo whether there is an 'answer' question area,
1460       *      as well as an 'answerfeedback' one. Default false.
1461       */
1462      protected function delete_files_in_combined_feedback($questionid, $contextid) {
1463          global $DB;
1464          $fs = get_file_storage();
1465  
1466          $fs->delete_area_files($contextid,
1467                  'question', 'correctfeedback', $questionid);
1468          $fs->delete_area_files($contextid,
1469                  'question', 'partiallycorrectfeedback', $questionid);
1470          $fs->delete_area_files($contextid,
1471                  'question', 'incorrectfeedback', $questionid);
1472      }
1473  
1474      public function import_file($context, $component, $filearea, $itemid, $file) {
1475          $fs = get_file_storage();
1476          $record = new stdClass();
1477          if (is_object($context)) {
1478              $record->contextid = $context->id;
1479          } else {
1480              $record->contextid = $context;
1481          }
1482          $record->component = $component;
1483          $record->filearea  = $filearea;
1484          $record->itemid    = $itemid;
1485          $record->filename  = $file->name;
1486          $record->filepath  = '/';
1487          return $fs->create_file_from_string($record, $this->decode_file($file));
1488      }
1489  
1490      protected function decode_file($file) {
1491          switch ($file->encoding) {
1492              case 'base64':
1493              default:
1494                  return base64_decode($file->content);
1495          }
1496      }
1497  }
1498  
1499  
1500  /**
1501   * This class is used in the return value from
1502   * {@link question_type::get_possible_responses()}.
1503   *
1504   * @copyright  2010 The Open University
1505   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1506   */
1507  class question_possible_response {
1508      /**
1509       * @var string the classification of this response the student gave to this
1510       * part of the question. Must match one of the responseclasses returned by
1511       * {@link question_type::get_possible_responses()}.
1512       */
1513      public $responseclass;
1514  
1515      /** @var string the (partial) credit awarded for this responses. */
1516      public $fraction;
1517  
1518      /**
1519       * Constructor, just an easy way to set the fields.
1520       * @param string $responseclassid see the field descriptions above.
1521       * @param string $response see the field descriptions above.
1522       * @param number $fraction see the field descriptions above.
1523       */
1524      public function __construct($responseclass, $fraction) {
1525          $this->responseclass = $responseclass;
1526          $this->fraction = $fraction;
1527      }
1528  
1529      public static function no_response() {
1530          return new question_possible_response(get_string('noresponse', 'question'), 0);
1531      }
1532  }