Proyectos de Subversion Moodle

<?php

// This file is part of Moodle - https://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 <https://www.gnu.org/licenses/>.

namespace core\context;

use core\context;

use stdClass;

use coding_exception, moodle_url;

/**

 * System context class

 *

 * @package   core_access

 * @category  access

 * @copyright Petr Skoda

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

 * @since     Moodle 4.2

 */

class system extends context {

    /** @var int numeric context level value matching legacy CONTEXT_SYSTEM */

    public const LEVEL = 10;

    /**

     * Please use \core\context\system::instance() if you need the instance of context.

     *

     * @param stdClass $record

     */

    protected function __construct(stdClass $record) {

        parent::__construct($record);

        if ($record->contextlevel != self::LEVEL) {

            throw new coding_exception('Invalid $record->contextlevel in core\context\system constructor.');

        }

    }

    /**

     * Returns short context name.

     *

     * @since Moodle 4.2

     *

     * @return string

     */

    public static function get_short_name(): string {

        return 'system';

    }

    /**

     * Returns human readable context level name.

     *

     * @return string the human readable context level name.

     */

    public static function get_level_name() {

        return get_string('coresystem');

    }

    /**

     * Returns human readable context identifier.

     *

     * @param boolean $withprefix does not apply to system context

     * @param boolean $short does not apply to system context

     * @param boolean $escape does not apply to system context

     * @return string the human readable context name.

     */

    public function get_context_name($withprefix = true, $short = false, $escape = true) {

        return self::get_level_name();

    }

    /**

     * Returns the most relevant URL for this context.

     *

     * @return moodle_url

     */

    public function get_url() {

        return new moodle_url('/');

    }

    /**

     * Returns list of all role archetypes that are compatible

     * with role assignments in context level.

     * @since Moodle 4.2

     *

     * @return int[]

     */

    protected static function get_compatible_role_archetypes(): array {

        return ['manager', 'coursecreator'];

    }

    /**

     * Returns list of all possible parent context levels.

     * @since Moodle 4.2

     *

     * @return int[]

     */

    public static function get_possible_parent_levels(): array {

        return [];

    }

    /**

     * Returns array of relevant context capability records.

     *

     * @param string $sort

     * @return array

     */

    public function get_capabilities(string $sort = self::DEFAULT_CAPABILITY_SORT) {

        global $DB;

        return $DB->get_records('capabilities', [], $sort);

    }

    /**

     * Create missing context instances at system context

     */

    protected static function create_level_instances() {

        // Nothing to do here, the system context is created automatically in installer.

        self::instance(0);

    }

    /**

     * Returns system context instance.

     *

     * @param int $instanceid should be 0

     * @param int $strictness

     * @param bool $cache

     * @return system context instance

     */

    public static function instance($instanceid = 0, $strictness = MUST_EXIST, $cache = true) {

        global $DB;

        if ($instanceid != 0) {

            debugging('context_system::instance(): invalid $id parameter detected, should be 0');

        }

        // SYSCONTEXTID is cached in local cache to eliminate 1 query per page.

        if (defined('SYSCONTEXTID') && $cache) {

            if (!isset(context::$systemcontext)) {

                $record = new stdClass();

                $record->id = SYSCONTEXTID;

                $record->contextlevel = self::LEVEL;

                $record->instanceid = 0;

                $record->path = '/'.SYSCONTEXTID;

                $record->depth = 1;

                $record->locked = 0;

                context::$systemcontext = new system($record);

            }

            return context::$systemcontext;

        }

        try {

            // We ignore the strictness completely because system context must exist except during install.

            $record = $DB->get_record('context', array('contextlevel' => self::LEVEL), '*', MUST_EXIST);

        } catch (\dml_exception $e) {

            // Table or record does not exist.

            if (!during_initial_install()) {

                // Do not mess with system context after install, it simply must exist.

                throw $e;

            }

            $record = null;

        }

        if (!$record) {

            $record = new stdClass();

            $record->contextlevel = self::LEVEL;

            $record->instanceid = 0;

            $record->depth = 1;

            $record->path = null; // Not known before insert.

            $record->locked = 0;

            try {

                if ($DB->count_records('context')) {

                    // Contexts already exist, this is very weird, system must be first!!!

                    return null;

                }

                if (defined('SYSCONTEXTID')) {

                    // This would happen only in unittest on sites that went through weird 1.7 upgrade.

                    $record->id = SYSCONTEXTID;

                    $DB->import_record('context', $record);

                    $DB->get_manager()->reset_sequence('context');

                } else {

                    $record->id = $DB->insert_record('context', $record);

                }

            } catch (\dml_exception $e) {

                // Can not create context - table does not exist yet, sorry.

                return null;

            }

        }

        if ($record->instanceid != 0) {

            // This is very weird, somebody must be messing with context table.

            debugging('Invalid system context detected');

        }

        if ($record->depth != 1 || $record->path != '/'.$record->id) {

            // Fix path if necessary, initial install or path reset.

            $record->depth = 1;

            $record->path = '/'.$record->id;

            $DB->update_record('context', $record);

        }

        if (empty($record->locked)) {

            $record->locked = 0;

        }

        if (!defined('SYSCONTEXTID')) {

            define('SYSCONTEXTID', $record->id);

        }

        context::$systemcontext = new system($record);

        return context::$systemcontext;

    }

    /**

     * Returns all site contexts except the system context, DO NOT call on production servers!!

     *

     * Contexts are not cached.

     *

     * @return array

     */

    public function get_child_contexts() {

        global $DB;

        debugging('Fetching of system context child courses is strongly discouraged'

            . ' on production servers (it may eat all available memory)!');

        // Just get all the contexts except for system level

        // and hope we don't OOM in the process - don't cache.

        $sql = "SELECT c.*

                  FROM {context} c

                 WHERE contextlevel > " . self::LEVEL;

        $records = $DB->get_records_sql($sql);

        $result = array();

        foreach ($records as $record) {

            $result[$record->id] = context::create_instance_from_record($record);

        }

        return $result;

    }

    /**

     * Returns sql necessary for purging of stale context instances.

     *

     * @return string cleanup SQL

     */

    protected static function get_cleanup_sql() {

        $sql = "

                  SELECT c.*

                    FROM {context} c

                   WHERE 1=2

               ";

        return $sql;

    }

    /**

     * Rebuild context paths and depths at system context level.

     *

     * @param bool $force

     */

    protected static function build_paths($force) {

        global $DB;

        /* note: ignore $force here, we always do full test of system context */

        // Exactly one record must exist.

        $record = $DB->get_record('context', array('contextlevel' => self::LEVEL), '*', MUST_EXIST);

        if ($record->instanceid != 0) {

            debugging('Invalid system context detected');

        }

        if (defined('SYSCONTEXTID') && $record->id != SYSCONTEXTID) {

            debugging('Invalid SYSCONTEXTID detected');

        }

        if ($record->depth != 1 || $record->path != '/'.$record->id) {

            // Fix path if necessary, initial install or path reset.

            $record->depth = 1;

            $record->path = '/'.$record->id;

            $DB->update_record('context', $record);

        }

    }

    /**

     * Set whether this context has been locked or not.

     *

     * @param   bool    $locked

     * @return  $this

     */

    public function set_locked(bool $locked) {

        if ($locked) {

            throw new \coding_exception('It is not possible to lock the system context');

        }

        return parent::set_locked($locked);

    }

}