<?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);
}
}