Proyectos de Subversion Moodle

<?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/>.

/**

 * This file defines the question attempt step class, and a few related classes.

 *

 * @package    moodlecore

 * @subpackage questionengine

 * @copyright  2009 The Open University

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

defined('MOODLE_INTERNAL') || die();

/**

 * Stores one step in a {@see question_attempt}.

 *

 * The most important attributes of a step are the state, which is one of the

 * {@see question_state} constants, the fraction, which may be null, or a

 * number bewteen the attempt's minfraction and maxfraction, and the array of submitted

 * data, about which more later.

 *

 * A step also tracks the time it was created, and the user responsible for

 * creating it.

 *

 * The submitted data is basically just an array of name => value pairs, with

 * certain conventions about the to divide the variables into five = 2 x 2 + 1 categories.

 *

 * Variables may either belong to the behaviour, in which case the

 * name starts with a '-', or they may belong to the question type in which case

 * they name does not start with a '-'.

 *

 * Second, variables may either be ones that came form the original request, in

 * which case the name does not start with an _, or they are cached values that

 * were created during processing, in which case the name does start with an _.

 *

 * In addition, we can store 'metadata', typically only in the first step of a

 * question attempt. These are stored with the initial characters ':_'.

 *

 * That is, each name will start with one of '', '_', '-', '-_' or ':_'. The remainder

 * of the name was supposed to match the regex [a-z][a-z0-9]* - but this has never

 * been enforced. Question types exist which break this rule. E.g. qtype_combined.

 * Perhpas now, an accurate regex would be [a-z][a-z0-9_:]*.

 *

 * These variables can be accessed with {@see get_behaviour_var()} and {@see get_qt_var()},

 * - to be clear, ->get_behaviour_var('x') gets the variable with name '-x' -

 * and values whose names start with '_' can be set using {@see set_behaviour_var()}

 * and {@see set_qt_var()}. There are some other methods like {@see has_behaviour_var()}

 * to check wether a varaible with a particular name is set, and {@see get_behaviour_data()}

 * to get all the behaviour data as an associative array. There are also

 * {@see get_metadata_var()}, {@see set_metadata_var()} and {@see has_metadata_var()},

 *

 * @copyright  2009 The Open University

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

class question_attempt_step {

    /**

     * @var int Indicates that timecreated will be set the first time the attempt is rendered

     */

    const TIMECREATED_ON_FIRST_RENDER = -1;

    /**

     * @var integer if this attempts is stored in the question_attempts table,

     * the id of that row.

     */

    private $id = null;

    /**

     * @var question_state one of the {@see question_state} constants.

     * The state after this step.

     */

    private $state;

    /**

     * @var null|number the fraction (grade on a scale of

     * minfraction .. maxfraction, normally 0..1) or null.

     */

    private $fraction = null;

    /** @var int the timestamp when this step was created. */

    private $timecreated;

    /** @var int the id of the user responsible for creating this step. */

    private $userid;

    /** @var array name => value pairs. The submitted data. */

    private $data;

    /** @var array name => array of {@see stored_file}s. Caches the contents of file areas. */

    private $files = array();

    /** @var stdClass|null User information. */

    private $user = null;

    /**

     * You should not need to call this constructor in your own code. Steps are

     * normally created by {@see question_attempt} methods like

     * {@see question_attempt::process_action()}.

     * @param array $data the submitted data that defines this step.

     * @param int|null $timecreated the time to record for the action. If null, use now. If

     *     {@see self::TIMECREATED_ON_FIRST_RENDER}, the time will be set the first time the attempt is rendered.

     * @param int|null $userid the user to attribute the aciton to. (If not given, use the current user.)

     * @param int|null $existingstepid if this step is going to replace an existing step

     *      (for example, during a regrade) this is the id of the previous step we are replacing.

     */

    public function __construct($data = [], $timecreated = null, $userid = null,

            $existingstepid = null) {

        global $USER;

        if (!is_array($data)) {

            throw new coding_exception('$data must be an array when constructing a question_attempt_step.');

        }

        $this->state = question_state::$unprocessed;

        $this->data = $data;

        if (is_null($timecreated)) {

            $this->timecreated = time();

        } else {

            $this->timecreated = $timecreated;

        }

        if (is_null($userid)) {

            $this->userid = $USER->id;

        } else {

            $this->userid = $userid;

        }

        if (!is_null($existingstepid)) {

            $this->id = $existingstepid;

        }

    }

    /**

     * @return int|null The id of this step in the database. null if this step

     * is not stored in the database.

     */

    public function get_id() {

        return $this->id;

    }

    /** @return question_state The state after this step. */

    public function get_state() {

        return $this->state;

    }

    /**

     * Set the state. Normally only called by behaviours.

     * @param question_state $state one of the {@see question_state} constants.

     */

    public function set_state($state) {

        $this->state = $state;

    }

    /**

     * @return null|number the fraction (grade on a scale of

     * minfraction .. maxfraction, normally 0..1),

     * or null if this step has not been marked.

     */

    public function get_fraction() {

        return $this->fraction;

    }

    /**

     * Set the fraction. Normally only called by behaviours.

     * @param null|number $fraction the fraction to set.

     */

    public function set_fraction($fraction) {

        $this->fraction = $fraction;

    }

    /** @return int the id of the user resonsible for creating this step. */

    public function get_user_id() {

        return $this->userid;

    }

    /**

     * Update full user information for step.

     *

     * @param stdClass $user Full user object.

     * @throws coding_exception

     */

    public function add_full_user_object(stdClass $user): void {

        if ($user->id != $this->userid) {

            throw new coding_exception('Wrong user passed to add_full_user_object');

        }

        $this->user = $user;

    }

    /**

     * Return the full user object.

     *

     * @return null|stdClass Get full user object.

     */

    public function get_user(): ?stdClass {

        if ($this->user === null) {

            debugging('Attempt to access the step user before it was initialised. ' .

                'Did you forget to call question_usage_by_activity::preload_all_step_users() or similar?', DEBUG_DEVELOPER);

        }

        return $this->user;

    }

    /**

     * Get full name of user who did action.

     *

     * @return string full name of user.

     */

    public function get_user_fullname(): string {

        return fullname($this->get_user());

    }

    /** @return int the timestamp when this step was created. */

    public function get_timecreated() {

        return $this->timecreated;

    }

    /**

     * Setter for $this->timecreated.

     *

     * @param int $timecreated

     * @return void

     */

    public function set_timecreated(int $timecreated): void {

        $this->timecreated = $timecreated;

    }

    /**

     * @param string $name the name of a question type variable to look for in the submitted data.

     * @return bool whether a variable with this name exists in the question type data.

     */

    public function has_qt_var($name) {

        return array_key_exists($name, $this->data);

    }

    /**

     * @param string $name the name of a question type variable to look for in the submitted data.

     * @return string the requested variable, or null if the variable is not set.

     */

    public function get_qt_var($name) {

        if (!$this->has_qt_var($name)) {

            return null;

        }

        return $this->data[$name];

    }

    /**

     * Set a cached question type variable.

     * @param string $name the name of the variable to set. Must match _[a-z][a-z0-9]*.

     * @param string $value the value to set.

     */

    public function set_qt_var($name, $value) {

        if ($name[0] != '_') {

            throw new coding_exception('Cannot set question type data ' . $name .

                    ' on an attempt step. You can only set variables with names begining with _.');

        }

        $this->data[$name] = $value;

    }

    /**

     * Get the latest set of files for a particular question type variable of

     * type question_attempt::PARAM_FILES.

     *

     * @param string $name the name of the associated variable.

     * @param int $contextid contextid of the question attempt

     * @return array of {@see stored_files}.

     */

    public function get_qt_files($name, $contextid) {

        if (array_key_exists($name, $this->files)) {

            return $this->files[$name];

        }

        if (!$this->has_qt_var($name)) {

            $this->files[$name] = array();

            return array();

        }

        $fs = get_file_storage();

        $filearea = question_file_saver::clean_file_area_name('response_' . $name);

        $this->files[$name] = $fs->get_area_files($contextid, 'question',

                $filearea, $this->id, 'sortorder', false);

        return $this->files[$name];

    }

    /**

     * Prepare a draft file are for the files belonging the a response variable

     * of this step.

     *

     * @param string $name the variable name the files belong to.

     * @param int $contextid the id of the context the quba belongs to.

     * @return int the draft itemid.

     */

    public function prepare_response_files_draft_itemid($name, $contextid) {

        list($draftid, $notused) = $this->prepare_response_files_draft_itemid_with_text(

                $name, $contextid, null);

        return $draftid;

    }

    /**

     * Prepare a draft file are for the files belonging the a response variable

     * of this step, while rewriting the URLs in some text.

     *

     * @param string $name the variable name the files belong to.

     * @param int $contextid the id of the context the quba belongs to.

     * @param string|null $text the text to update the URLs in.

     * @return array(int, string) the draft itemid and the text with URLs rewritten.

     */

    public function prepare_response_files_draft_itemid_with_text($name, $contextid, $text) {

        $filearea = question_file_saver::clean_file_area_name('response_' . $name);

        $draftid = 0; // Will be filled in by file_prepare_draft_area.

        $newtext = file_prepare_draft_area($draftid, $contextid, 'question',

                $filearea, $this->id, null, $text);

        return array($draftid, $newtext);

    }

    /**

     * Rewrite the @@PLUGINFILE@@ tokens in a response variable from this step

     * that contains links to file. Normally you should probably call

     * {@see question_attempt::rewrite_response_pluginfile_urls()} instead of

     * calling this method directly.

     *

     * @param string $text the text to update the URLs in.

     * @param int $contextid the id of the context the quba belongs to.

     * @param string $name the variable name the files belong to.

     * @param array $extras extra file path components.

     * @return string the rewritten text.

     */

    public function rewrite_response_pluginfile_urls($text, $contextid, $name, $extras) {

        $filearea = question_file_saver::clean_file_area_name('response_' . $name);

        return question_rewrite_question_urls($text, 'pluginfile.php', $contextid,

                'question', $filearea, $extras, $this->id);

    }

    /**

     * Get all the question type variables.

     * @param array name => value pairs.

     */

    public function get_qt_data() {

        $result = array();

        foreach ($this->data as $name => $value) {

            if ($name[0] != '-' && $name[0] != ':') {

                $result[$name] = $value;

            }

        }

        return $result;

    }

    /**

     * @param string $name the name of a behaviour variable to look for in the submitted data.

     * @return bool whether a variable with this name exists in the question type data.

     */

    public function has_behaviour_var($name) {

        return array_key_exists('-' . $name, $this->data);

    }

    /**

     * @param string $name the name of a behaviour variable to look for in the submitted data.

     * @return string the requested variable, or null if the variable is not set.

     */

    public function get_behaviour_var($name) {

        if (!$this->has_behaviour_var($name)) {

            return null;

        }

        return $this->data['-' . $name];

    }

    /**

     * Set a cached behaviour variable.

     * @param string $name the name of the variable to set. Must match _[a-z][a-z0-9]*.

     * @param string $value the value to set.

     */

    public function set_behaviour_var($name, $value) {

        if ($name[0] != '_') {

            throw new coding_exception('Cannot set question type data ' . $name .

                    ' on an attempt step. You can only set variables with names begining with _.');

        }

        return $this->data['-' . $name] = $value;

    }

    /**

     * Get all the behaviour variables.

     *

     * @return array name => value pairs. NOTE! the name has the leading - stripped off.

     *      (If you don't understand the note, read the comment at the top of this class :-))

     */

    public function get_behaviour_data() {

        $result = array();

        foreach ($this->data as $name => $value) {

            if ($name[0] == '-') {

                $result[substr($name, 1)] = $value;

            }

        }

        return $result;

    }

    /**

     * Get all the submitted data, but not the cached data. behaviour

     * variables have the - at the start of their name. This is only really

     * intended for use by {@see question_attempt::regrade()}, it should not

     * be considered part of the public API.

     * @param array name => value pairs.

     */

    public function get_submitted_data() {

        $result = array();

        foreach ($this->data as $name => $value) {

            if ($name[0] == '_' || ($name[0] == '-' && $name[1] == '_')) {

                continue;

            }

            $result[$name] = $value;

        }

        return $result;

    }

    /**

     * Get all the data. behaviour variables have the - at the start of

     * their name. This is only intended for internal use, for example by

     * {@see question_engine_data_mapper::insert_question_attempt_step()},

     * however, it can occasionally be useful in test code. It should not be

     * considered part of the public API of this class.

     * @param array name => value pairs.

     */

    public function get_all_data() {

        return $this->data;

    }

    /**

     * Set a metadata variable.

     *

     * Do not call this method directly from  your code. It is for internal

     * use only. You should call {@see question_usage::set_question_attempt_metadata()}.

     *

     * @param string $name the name of the variable to set. [a-z][a-z0-9]*.

     * @param string $value the value to set.

     */

    public function set_metadata_var($name, $value) {

        $this->data[':_' . $name] = $value;

    }

    /**

     * Whether this step has a metadata variable.

     *

     * Do not call this method directly from  your code. It is for internal

     * use only. You should call {@see question_usage::get_question_attempt_metadata()}.

     *

     * @param string $name the name of the variable to set. [a-z][a-z0-9]*.

     * @return bool the value to set previously, or null if this variable was never set.

     */

    public function has_metadata_var($name) {

        return isset($this->data[':_' . $name]);

    }

    /**

     * Get a metadata variable.

     *

     * Do not call this method directly from  your code. It is for internal

     * use only. You should call {@see question_usage::get_question_attempt_metadata()}.

     *

     * @param string $name the name of the variable to set. [a-z][a-z0-9]*.

     * @return string the value to set previously, or null if this variable was never set.

     */

    public function get_metadata_var($name) {

        if (!$this->has_metadata_var($name)) {

            return null;

        }

        return $this->data[':_' . $name];

    }

    /**

     * Create a question_attempt_step from records loaded from the database.

     * @param Iterator $records Raw records loaded from the database.

     * @param int $stepid The id of the records to extract.

     * @param string $qtype The question type of which this is an attempt.

     *      If not given, each record must include a qtype field.

     * @return question_attempt_step The newly constructed question_attempt_step.

     */

    public static function load_from_records($records, $attemptstepid, $qtype = null) {

        $currentrec = $records->current();

        while ($currentrec->attemptstepid != $attemptstepid) {

            $records->next();

            if (!$records->valid()) {

                throw new coding_exception('Question attempt step ' . $attemptstepid .

                        ' not found in the database.');

            }

            $currentrec = $records->current();

        }

        $record = $currentrec;

        $contextid = null;

        $data = array();

        while ($currentrec && $currentrec->attemptstepid == $attemptstepid) {

            if (!is_null($currentrec->name)) {

                $data[$currentrec->name] = $currentrec->value;

            }

            $records->next();

            if ($records->valid()) {

                $currentrec = $records->current();

            } else {

                $currentrec = false;

            }

        }

        $step = new question_attempt_step_read_only($data, $record->timecreated, $record->userid);

        $step->state = question_state::get($record->state);

        $step->id = $record->attemptstepid;

        if (!is_null($record->fraction)) {

            $step->fraction = $record->fraction + 0;

        }

        // This next chunk of code requires getting $contextid and $qtype here.

        // Somehow, we need to get that information to this point by modifying

        // all the paths by which this method can be called.

        // Can we only return files when it's possible? Should there be some kind of warning?

        if (is_null($qtype)) {

            $qtype = $record->qtype;

        }

        foreach (question_bank::get_qtype($qtype)->response_file_areas() as $area) {

            if (empty($step->data[$area])) {

                continue;

            }

            $step->data[$area] = new question_file_loader($step, $area, $step->data[$area], $record->contextid);

        }

        return $step;

    }

}

/**

 * A subclass of {@see question_attempt_step} used when processing a new submission.

 *

 * When we are processing some new submitted data, which may or may not lead to

 * a new step being added to the {@see question_usage_by_activity} we create an

 * instance of this class. which is then passed to the question behaviour and question

 * type for processing. At the end of processing we then may, or may not, keep it.

 *

 * @copyright  2010 The Open University

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

class question_attempt_pending_step extends question_attempt_step {

    /** @var string the new response summary, if there is one. */

    protected $newresponsesummary = null;

    /** @var int the new variant number, if there is one. */

    protected $newvariant = null;

    /**

     * If as a result of processing this step, the response summary for the

     * question attempt should changed, you should call this method to set the

     * new summary.

     * @param string $responsesummary the new response summary.

     */

    public function set_new_response_summary($responsesummary) {

        $this->newresponsesummary = $responsesummary;

    }

    /**

     * Get the new response summary, if there is one.

     * @return string the new response summary, or null if it has not changed.

     */

    public function get_new_response_summary() {

        return $this->newresponsesummary;

    }

    /**

     * Whether this processing this step has changed the response summary.

     * @return bool true if there is a new response summary.

     */

    public function response_summary_changed() {

        return !is_null($this->newresponsesummary);

    }

    /**

     * If as a result of processing this step, you identify that this variant of the

     * question is actually identical to the another one, you may change the

     * variant number recorded, in order to give better statistics. For an example

     * see qbehaviour_opaque.

     * @param int $variant the new variant number.

     */

    public function set_new_variant_number($variant) {

        $this->newvariant = $variant;

    }

    /**

     * Get the new variant number, if there is one.

     * @return int the new variant number, or null if it has not changed.

     */

    public function get_new_variant_number() {

        return $this->newvariant;

    }

    /**

     * Whether this processing this step has changed the variant number.

     * @return bool true if there is a new variant number.

     */

    public function variant_number_changed() {

        return !is_null($this->newvariant);

    }

}

/**

 * A subclass of {@see question_attempt_step} that cannot be modified.

 *

 * @copyright  2009 The Open University

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

class question_attempt_step_read_only extends question_attempt_step {

    public function set_state($state) {

        throw new coding_exception('Cannot modify a question_attempt_step_read_only.');

    }

    public function set_fraction($fraction) {

        throw new coding_exception('Cannot modify a question_attempt_step_read_only.');

    }

    public function set_qt_var($name, $value) {

        throw new coding_exception('Cannot modify a question_attempt_step_read_only.');

    }

    public function set_behaviour_var($name, $value) {

        throw new coding_exception('Cannot modify a question_attempt_step_read_only.');

    }

}

/**

 * A null {@see question_attempt_step} returned from

 * {@see question_attempt::get_last_step()} etc. when a an attempt has just been

 * created and there is no actual step.

 *

 * @copyright  2009 The Open University

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

class question_null_step {

    public function get_state() {

        return question_state::$notstarted;

    }

    public function set_state($state) {

        throw new coding_exception('This question has not been started.');

    }

    public function get_fraction() {

        return null;

    }

}

/**

 * This is an adapter class that wraps a {@see question_attempt_step} and

 * modifies the get/set_*_data methods so that they operate only on the parts

 * that belong to a particular subquestion, as indicated by an extra prefix.

 *

 * @copyright  2010 The Open University

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

class question_attempt_step_subquestion_adapter extends question_attempt_step {

    /** @var question_attempt_step the step we are wrapping. */

    protected $realstep;

    /** @var string the exta prefix on fields we work with. */

    protected $extraprefix;

    /**

     * Constructor.

     * @param question_attempt_step $realstep the step to wrap. (Can be null if you

     *      just want to call add/remove.prefix.)

     * @param string $extraprefix the extra prefix that is used for date fields.

     */

    public function __construct($realstep, $extraprefix) {

        $this->realstep = $realstep;

        $this->extraprefix = $extraprefix;

    }

    /**

     * Add the extra prefix to a field name.

     * @param string $field the plain field name.

     * @return string the field name with the extra bit of prefix added.

     */

    public function add_prefix($field) {

        if (substr($field, 0, 2) === '-_') {

            return '-_' . $this->extraprefix . substr($field, 2);

        } else if (substr($field, 0, 1) === '-') {

            return '-' . $this->extraprefix . substr($field, 1);

        } else if (substr($field, 0, 1) === '_') {

            return '_' . $this->extraprefix . substr($field, 1);

        } else {

            return $this->extraprefix . $field;

        }

    }

    /**

     * Remove the extra prefix from a field name if it is present.

     * @param string $field the extended field name.

     * @return string the field name with the extra bit of prefix removed, or

     * null if the extre prefix was not present.

     */

    public function remove_prefix($field) {

        if (preg_match('~^(-?_?)' . preg_quote($this->extraprefix, '~') . '(.*)$~', $field, $matches)) {

            return $matches[1] . $matches[2];

        } else {

            return null;

        }

    }

    /**

     * Filter some data to keep only those entries where the key contains

     * extraprefix, and remove the extra prefix from the reutrned arrary.

     * @param array $data some of the data stored in this step.

     * @return array the data with the keys ajusted using {@see remove_prefix()}.

     */

    public function filter_array($data) {

        $result = array();

        foreach ($data as $fullname => $value) {

            if ($name = $this->remove_prefix($fullname)) {

                $result[$name] = $value;

            }

        }

        return $result;

    }

    public function get_state() {

        return $this->realstep->get_state();

    }

    public function set_state($state) {

        throw new coding_exception('Cannot modify a question_attempt_step_subquestion_adapter.');

    }

    public function get_fraction() {

        return $this->realstep->get_fraction();

    }

    public function set_fraction($fraction) {

        throw new coding_exception('Cannot modify a question_attempt_step_subquestion_adapter.');

    }

    public function get_user_id() {

        return $this->realstep->get_user_id();

    }

    public function get_timecreated() {

        return $this->realstep->get_timecreated();

    }

    public function has_qt_var($name) {

        return $this->realstep->has_qt_var($this->add_prefix($name));

    }

    public function get_qt_var($name) {

        return $this->realstep->get_qt_var($this->add_prefix($name));

    }

    public function set_qt_var($name, $value) {

        $this->realstep->set_qt_var($this->add_prefix($name), $value);

    }

    public function get_qt_data() {

        return $this->filter_array($this->realstep->get_qt_data());

    }

    public function has_behaviour_var($name) {

        return $this->realstep->has_behaviour_var($this->add_prefix($name));

    }

    public function get_behaviour_var($name) {

        return $this->realstep->get_behaviour_var($this->add_prefix($name));

    }

    public function set_behaviour_var($name, $value) {

        return $this->realstep->set_behaviour_var($this->add_prefix($name), $value);

    }

    public function get_behaviour_data() {

        return $this->filter_array($this->realstep->get_behaviour_data());

    }

    public function get_submitted_data() {

        return $this->filter_array($this->realstep->get_submitted_data());

    }

    public function get_all_data() {

        return $this->filter_array($this->realstep->get_all_data());

    }

    public function get_qt_files($name, $contextid) {

        throw new coding_exception('No attempt has yet been made to implement files support in ' .

                'question_attempt_step_subquestion_adapter.');

    }

    public function prepare_response_files_draft_itemid($name, $contextid) {

        throw new coding_exception('No attempt has yet been made to implement files support in ' .

                'question_attempt_step_subquestion_adapter.');

    }

    public function prepare_response_files_draft_itemid_with_text($name, $contextid, $text) {

        throw new coding_exception('No attempt has yet been made to implement files support in ' .

                'question_attempt_step_subquestion_adapter.');

    }

    public function rewrite_response_pluginfile_urls($text, $contextid, $name, $extras) {

        throw new coding_exception('No attempt has yet been made to implement files support in ' .

                'question_attempt_step_subquestion_adapter.');

    }

}