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<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
/**
* Privacy class for requesting user data.
*
* @package core_calendar
* @copyright 2018 Zig Tan <zig@moodle.com>
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
namespace core_calendar\privacy;
defined('MOODLE_INTERNAL') || die();
use \core_privacy\local\metadata\collection;
use \core_privacy\local\request\approved_contextlist;
use \core_privacy\local\request\context;
use \core_privacy\local\request\contextlist;
use \core_privacy\local\request\transform;
use \core_privacy\local\request\writer;
use \core_privacy\local\request\userlist;
use \core_privacy\local\request\approved_userlist;
/**
* Privacy Subsystem for core_calendar implementing metadata, plugin, and user_preference providers.
*
* @package core_calendar
* @copyright 2018 Zig Tan <zig@moodle.com>
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class provider implements
\core_privacy\local\metadata\provider,
\core_privacy\local\request\plugin\provider,
\core_privacy\local\request\core_userlist_provider,
\core_privacy\local\request\user_preference_provider
{
/**
* Provides meta data that is stored about a user with core_calendar.
*
* @param collection $collection A collection of meta data items to be added to.
* @return collection Returns the collection of metadata.
*/
public static function get_metadata(collection $collection) : collection {
// The calendar 'event' table contains user data.
$collection->add_database_table(
'event',
[
'name' => 'privacy:metadata:calendar:event:name',
'description' => 'privacy:metadata:calendar:event:description',
'eventtype' => 'privacy:metadata:calendar:event:eventtype',
'timestart' => 'privacy:metadata:calendar:event:timestart',
'timeduration' => 'privacy:metadata:calendar:event:timeduration',
],
'privacy:metadata:calendar:event'
);
// The calendar 'event_subscriptions' table contains user data.
$collection->add_database_table(
'event_subscriptions',
[
'name' => 'privacy:metadata:calendar:event_subscriptions:name',
'url' => 'privacy:metadata:calendar:event_subscriptions:url',
'eventtype' => 'privacy:metadata:calendar:event_subscriptions:eventtype',
],
'privacy:metadata:calendar:event_subscriptions'
);
// The calendar user preference setting 'calendar_savedflt'.
$collection->add_user_preference(
'calendar_savedflt',
'privacy:metadata:calendar:preferences:calendar_savedflt'
);
return $collection;
}
/**
* Get the list of contexts that contain calendar user information for the specified user.
*
* @param int $userid The user to search.
* @return contextlist $contextlist The contextlist containing the list of contexts used in this plugin.
*/
public static function get_contexts_for_userid(int $userid) : contextlist {
$contextlist = new contextlist();
// Calendar Events can exist at Site, Course Category, Course, Course Group, User, or Course Modules contexts.
$params = [
'sitecontext' => CONTEXT_SYSTEM,
'categorycontext' => CONTEXT_COURSECAT,
'coursecontext' => CONTEXT_COURSE,
'groupcontext' => CONTEXT_COURSE,
'usercontext' => CONTEXT_USER,
'cuserid' => $userid,
'modulecontext' => CONTEXT_MODULE,
'muserid' => $userid
];
// Get contexts of Calendar Events for the owner.
$sql = "SELECT ctx.id
FROM {context} ctx
JOIN {event} e ON
(e.eventtype = 'site' AND ctx.contextlevel = :sitecontext) OR
(e.categoryid = ctx.instanceid AND e.eventtype = 'category' AND ctx.contextlevel = :categorycontext) OR
(e.courseid = ctx.instanceid AND e.eventtype = 'course' AND ctx.contextlevel = :coursecontext) OR
(e.courseid = ctx.instanceid AND e.eventtype = 'group' AND ctx.contextlevel = :groupcontext) OR
(e.userid = ctx.instanceid AND e.eventtype = 'user' AND ctx.contextlevel = :usercontext)
WHERE e.userid = :cuserid
UNION
SELECT ctx.id
FROM {context} ctx
JOIN {course_modules} cm ON cm.id = ctx.instanceid AND ctx.contextlevel = :modulecontext
JOIN {modules} m ON m.id = cm.module
JOIN {event} e ON e.modulename = m.name AND e.courseid = cm.course AND e.instance = cm.instance
WHERE e.userid = :muserid";
$contextlist->add_from_sql($sql, $params);
// Calendar Subscriptions can exist at Site, Course Category, Course, Course Group, or User contexts.
$params = [
'sitecontext' => CONTEXT_SYSTEM,
'categorycontext' => CONTEXT_COURSECAT,
'coursecontext' => CONTEXT_COURSE,
'groupcontext' => CONTEXT_COURSE,
'usercontext' => CONTEXT_USER,
'userid' => $userid
];
// Get contexts for Calendar Subscriptions for the owner.
$sql = "SELECT ctx.id
FROM {context} ctx
JOIN {event_subscriptions} s ON
(s.eventtype = 'site' AND ctx.contextlevel = :sitecontext) OR
(s.categoryid = ctx.instanceid AND s.eventtype = 'category' AND ctx.contextlevel = :categorycontext) OR
(s.courseid = ctx.instanceid AND s.eventtype = 'course' AND ctx.contextlevel = :coursecontext) OR
(s.courseid = ctx.instanceid AND s.eventtype = 'group' AND ctx.contextlevel = :groupcontext) OR
(s.userid = ctx.instanceid AND s.eventtype = 'user' AND ctx.contextlevel = :usercontext)
WHERE s.userid = :userid";
$contextlist->add_from_sql($sql, $params);
// Return combined contextlist for Calendar Events & Calendar Subscriptions.
return $contextlist;
}
/**
* Get the list of users within a specific context.
*
* @param userlist $userlist The userlist containing the list of users who have data in this context/plugin combination.
*/
public static function get_users_in_context(userlist $userlist) {
global $DB;
$context = $userlist->get_context();
// Calendar Events can exist at Site (CONTEXT_SYSTEM), Course Category (CONTEXT_COURSECAT),
// Course and Course Group (CONTEXT_COURSE), User (CONTEXT_USER), or Course Modules (CONTEXT_MODULE) contexts.
if ($context->contextlevel == CONTEXT_MODULE) {
$params = ['cmid' => $context->instanceid];
$sql = "SELECT e.userid
FROM {course_modules} cm
JOIN {modules} m ON m.id = cm.module
JOIN {event} e ON e.modulename = m.name AND e.courseid = cm.course AND e.instance = cm.instance
WHERE cm.id = :cmid";
$userlist->add_from_sql('userid', $sql, $params);
} else if ($context->contextlevel == CONTEXT_SYSTEM) {
// Get contexts of Calendar Events for the owner.
$sql = "SELECT userid FROM {event} WHERE eventtype = 'site'";
$userlist->add_from_sql('userid', $sql, []);
// Get contexts for Calendar Subscriptions for the owner.
$sql = "SELECT userid FROM {event_subscriptions} WHERE eventtype = 'site'";
$userlist->add_from_sql('userid', $sql, []);
} else if (in_array($context->contextlevel, [CONTEXT_COURSECAT, CONTEXT_COURSE, CONTEXT_USER])) {
$eventfields = [
CONTEXT_COURSECAT => 'categoryid',
CONTEXT_COURSE => 'courseid',
CONTEXT_USER => 'userid'
];
$eventfield = $eventfields[$context->contextlevel];
$eventtypes = [
CONTEXT_COURSECAT => 'category',
CONTEXT_COURSE => ['course' , 'group'],
CONTEXT_USER => 'user'
];
list($eventtypesql, $eventtypeparams) = $DB->get_in_or_equal($eventtypes[$context->contextlevel], SQL_PARAMS_NAMED);
$params = $eventtypeparams + ['instanceid' => $context->instanceid];
// Get contexts of Calendar Events for the owner.
$sql = "SELECT userid
FROM {event}
WHERE eventtype $eventtypesql
AND $eventfield = :instanceid";
$userlist->add_from_sql('userid', $sql, $params);
// Get contexts for Calendar Subscriptions for the owner.
$sql = "SELECT userid
FROM {event_subscriptions}
WHERE eventtype $eventtypesql
AND $eventfield = :instanceid";
$userlist->add_from_sql('userid', $sql, $params);
}
}
/**
* Export all user data for the specified user, in the specified contexts.
*
* @param approved_contextlist $contextlist The approved contexts to export information for.
*/
public static function export_user_data(approved_contextlist $contextlist) {
if (empty($contextlist)) {
return;
}
self::export_user_calendar_event_data($contextlist);
self::export_user_calendar_subscription_data($contextlist);
}
/**
* Export all user preferences for the plugin.
*
* @param int $userid The userid of the user whose data is to be exported.
*/
public static function export_user_preferences(int $userid) {
$calendarsavedflt = get_user_preferences('calendar_savedflt', null, $userid);
if (null !== $calendarsavedflt) {
writer::export_user_preference(
'core_calendar',
'calendarsavedflt',
$calendarsavedflt,
get_string('privacy:metadata:calendar:preferences:calendar_savedflt', 'core_calendar')
);
}
}
/**
* Delete all Calendar Event and Calendar Subscription data for all users in the specified context.
*
* @param context $context Transform the specific context to delete data for.
*/
public static function delete_data_for_all_users_in_context(\context $context) {
// Delete all Calendar Events in the specified context in batches.
if ($eventids = array_keys(self::get_calendar_event_ids_by_context($context))) {
self::delete_batch_records('event', 'id', $eventids);
}
// Delete all Calendar Subscriptions in the specified context in batches.
if ($subscriptionids = array_keys(self::get_calendar_subscription_ids_by_context($context))) {
self::delete_batch_records('event_subscriptions', 'id', $subscriptionids);
}
}
/**
* Delete multiple users within a single context.
*
* @param approved_userlist $userlist The approved context and user information to delete information for.
*/
public static function delete_data_for_users(approved_userlist $userlist) {
$context = $userlist->get_context();
$userids = $userlist->get_userids();
$allowedcontexts = [
CONTEXT_SYSTEM,
CONTEXT_COURSECAT,
CONTEXT_COURSE,
CONTEXT_MODULE,
CONTEXT_USER
];
if (!in_array($context->contextlevel, $allowedcontexts)) {
return;
}
if (empty($userids)) {
return;
}
// Delete all Calendar Events in the specified context in batches.
if ($eventids = array_keys(self::get_calendar_event_ids_by_context($context, $userids))) {
self::delete_batch_records('event', 'id', $eventids);
}
// Delete all Calendar Subscriptions in the specified context in batches.
if ($subscriptionids = array_keys(self::get_calendar_subscription_ids_by_context($context, $userids))) {
self::delete_batch_records('event_subscriptions', 'id', $subscriptionids);
}
}
/**
* Delete all user data for the specified user, in the specified contexts.
*
* @param approved_contextlist $contextlist The approved contexts and user information to delete information for.
*/
public static function delete_data_for_user(approved_contextlist $contextlist) {
if (empty($contextlist)) {
return;
}
// Delete all Calendar Events for the owner and specified contexts in batches.
$eventdetails = self::get_calendar_event_details_by_contextlist($contextlist);
$eventids = [];
foreach ($eventdetails as $eventdetail) {
$eventids[] = $eventdetail->eventid;
}
$eventdetails->close();
self::delete_batch_records('event', 'id', $eventids);
// Delete all Calendar Subscriptions for the owner and specified contexts in batches.
$subscriptiondetails = self::get_calendar_subscription_details_by_contextlist($contextlist);
$subscriptionids = [];
foreach ($subscriptiondetails as $subscriptiondetail) {
$subscriptionids[] = $subscriptiondetail->subscriptionid;
}
$subscriptiondetails->close();
self::delete_batch_records('event_subscriptions', 'id', $subscriptionids);
}
/**
* Helper function to export Calendar Events data by a User's contextlist.
*
* @param approved_contextlist $contextlist
* @throws \coding_exception
*/
protected static function export_user_calendar_event_data(approved_contextlist $contextlist) {
// Calendar Events can exist at Site, Course Category, Course, Course Group, User, or Course Modules contexts.
$eventdetails = self::get_calendar_event_details_by_contextlist($contextlist);
// Multiple Calendar Events of the same eventtype and time can exist for a context, so collate them for export.
$eventrecords = [];
foreach ($eventdetails as $eventdetail) {
// Create an array key based on the contextid, eventtype, and time.
$key = $eventdetail->contextid . $eventdetail->eventtype . $eventdetail->timestart;
if (array_key_exists($key, $eventrecords) === false) {
$eventrecords[$key] = [ $eventdetail ];
} else {
$eventrecords[$key] = array_merge($eventrecords[$key], [$eventdetail]);
}
}
$eventdetails->close();
// Export Calendar Event data.
foreach ($eventrecords as $eventrecord) {
$index = (count($eventrecord) > 1) ? 1 : 0;
foreach ($eventrecord as $event) {
// Export the events using the structure Calendar/Events/{datetime}/{eventtype}-event.json.
$subcontexts = [
get_string('calendar', 'calendar'),
get_string('events', 'calendar'),
date('c', $event->timestart)
];
$name = $event->eventtype . '-event';
// Use name {eventtype}-event-{index}.json if multiple eventtypes and time exists at the same context.
if ($index != 0) {
$name .= '-' . $index;
$index++;
}
$eventdetails = (object) [
'name' => $event->name,
'description' => $event->description,
'location' => $event->location,
'eventtype' => $event->eventtype,
'timestart' => transform::datetime($event->timestart),
'timeduration' => $event->timeduration
];
$context = \context::instance_by_id($event->contextid);
writer::with_context($context)->export_related_data($subcontexts, $name, $eventdetails);
}
}
}
/**
* Helper function to export Calendar Subscriptions data by a User's contextlist.
*
* @param approved_contextlist $contextlist
* @throws \coding_exception
*/
protected static function export_user_calendar_subscription_data(approved_contextlist $contextlist) {
// Calendar Subscriptions can exist at Site, Course Category, Course, Course Group, or User contexts.
$subscriptiondetails = self::get_calendar_subscription_details_by_contextlist($contextlist);
// Multiple Calendar Subscriptions of the same eventtype can exist for a context, so collate them for export.
$subscriptionrecords = [];
foreach ($subscriptiondetails as $subscriptiondetail) {
// Create an array key based on the contextid and eventtype.
$key = $subscriptiondetail->contextid . $subscriptiondetail->eventtype;
if (array_key_exists($key, $subscriptionrecords) === false) {
$subscriptionrecords[$key] = [ $subscriptiondetail ];
} else {
$subscriptionrecords[$key] = array_merge($subscriptionrecords[$key], [$subscriptiondetail]);
}
}
$subscriptiondetails->close();
// Export Calendar Subscription data.
foreach ($subscriptionrecords as $subscriptionrecord) {
$index = (count($subscriptionrecord) > 1) ? 1 : 0;
foreach ($subscriptionrecord as $subscription) {
// Export the events using the structure Calendar/Subscriptions/{eventtype}-subscription.json.
$subcontexts = [
get_string('calendar', 'calendar'),
get_string('subscriptions', 'calendar')
];
$name = $subscription->eventtype . '-subscription';
// Use name {eventtype}-subscription-{index}.json if multiple eventtypes exists at the same context.
if ($index != 0) {
$name .= '-' . $index;
$index++;
}
$context = \context::instance_by_id($subscription->contextid);
writer::with_context($context)->export_related_data($subcontexts, $name, $subscription);
}
}
}
/**
* Helper function to return all Calendar Event id results for a specified context and optionally
* included user list.
*
* @param \context $context
* @param array $userids
* @return array|null
* @throws \dml_exception
*/
protected static function get_calendar_event_ids_by_context(\context $context, $userids = array()) {
global $DB;
// Calendar Events can exist at Site (CONTEXT_SYSTEM), Course Category (CONTEXT_COURSECAT),
// Course and Course Group (CONTEXT_COURSE), User (CONTEXT_USER), or Course Modules (CONTEXT_MODULE) contexts.
if (!in_array($context->contextlevel, [CONTEXT_SYSTEM, CONTEXT_COURSECAT, CONTEXT_COURSE, CONTEXT_USER, CONTEXT_MODULE])) {
return [];
}
$whereusersql = '';
$userparams = array();
if (!empty($userids)) {
list($usersql, $userparams) = $DB->get_in_or_equal($userids, SQL_PARAMS_NAMED);
$whereusersql = "AND e.userid {$usersql}";
}
if ($context->contextlevel == CONTEXT_MODULE) { // Course Module events.
$params = ['cmid' => $context->instanceid];
// Get Calendar Events for the specified Course Module context.
$sql = "SELECT DISTINCT e.id AS eventid
FROM {course_modules} cm
JOIN {modules} m ON m.id = cm.module
JOIN {event} e ON e.modulename = m.name AND e.courseid = cm.course AND e.instance = cm.instance
WHERE cm.id = :cmid
$whereusersql";
} else if ($context->contextlevel == CONTEXT_SYSTEM) { // Site events.
$params = [];
$sql = "SELECT DISTINCT e.id AS eventid
FROM {event} e
WHERE e.eventtype = 'site'
$whereusersql";
} else { // The rest.
$eventfields = [
CONTEXT_COURSECAT => 'categoryid',
CONTEXT_COURSE => 'courseid',
CONTEXT_USER => 'userid'
];
$eventfield = $eventfields[$context->contextlevel];
$eventtypes = [
CONTEXT_COURSECAT => 'category',
CONTEXT_COURSE => ['course' , 'group'],
CONTEXT_USER => 'user'
];
list($eventtypesql, $eventtypeparams) = $DB->get_in_or_equal($eventtypes[$context->contextlevel], SQL_PARAMS_NAMED);
$params = $eventtypeparams + ['instanceid' => $context->instanceid];
// Get Calendar Events for the specified Moodle context.
$sql = "SELECT DISTINCT e.id AS eventid
FROM {event} e
WHERE e.eventtype $eventtypesql
AND e.{$eventfield} = :instanceid
$whereusersql";
}
$params += $userparams;
return $DB->get_records_sql($sql, $params);
}
/**
* Helper function to return all Calendar Subscription id results for a specified context and optionally
* included user list.
*
* @param \context $context
* @param array $userids
* @return array
* @throws \dml_exception
*/
protected static function get_calendar_subscription_ids_by_context(\context $context, $userids = array()) {
global $DB;
// Calendar Subscriptions can exist at Site (CONTEXT_SYSTEM), Course Category (CONTEXT_COURSECAT),
// Course and Course Group (CONTEXT_COURSE), or User (CONTEXT_USER) contexts.
if (!in_array($context->contextlevel, [CONTEXT_SYSTEM, CONTEXT_COURSECAT, CONTEXT_COURSE, CONTEXT_USER])) {
return [];
}
$whereusersql = '';
$userparams = array();
if (!empty($userids)) {
list($usersql, $userparams) = $DB->get_in_or_equal($userids, SQL_PARAMS_NAMED);
$whereusersql = "AND s.userid {$usersql}";
}
if ($context->contextlevel == CONTEXT_SYSTEM) {
$params = [];
// Get Calendar Subscriptions for the system context.
$sql = "SELECT DISTINCT s.id AS subscriptionid
FROM {event_subscriptions} s
WHERE s.eventtype = 'site'
$whereusersql";
} else {
$eventfields = [
CONTEXT_COURSECAT => 'categoryid',
CONTEXT_COURSE => 'courseid',
CONTEXT_USER => 'userid'
];
$eventfield = $eventfields[$context->contextlevel];
$eventtypes = [
CONTEXT_COURSECAT => 'category',
CONTEXT_COURSE => ['course' , 'group'],
CONTEXT_USER => 'user'
];
list($eventtypesql, $eventtypeparams) = $DB->get_in_or_equal($eventtypes[$context->contextlevel], SQL_PARAMS_NAMED);
$params = $eventtypeparams + ['instanceid' => $context->instanceid];
// Get Calendar Subscriptions for the specified context.
$sql = "SELECT DISTINCT s.id AS subscriptionid
FROM {event_subscriptions} s
WHERE s.eventtype $eventtypesql
AND s.{$eventfield} = :instanceid
$whereusersql";
}
$params += $userparams;
return $DB->get_records_sql($sql, $params);
}
/**
* Helper function to return the Calendar Events for a given user and context list.
*
* @param approved_contextlist $contextlist
* @return array
* @throws \coding_exception
* @throws \dml_exception
*/
protected static function get_calendar_event_details_by_contextlist(approved_contextlist $contextlist) {
global $DB;
$userid = $contextlist->get_user()->id;
list($contextsql1, $contextparams1) = $DB->get_in_or_equal($contextlist->get_contextids(), SQL_PARAMS_NAMED);
list($contextsql2, $contextparams2) = $DB->get_in_or_equal($contextlist->get_contextids(), SQL_PARAMS_NAMED);
// Calendar Events can exist at Site, Course Category, Course, Course Group, User, or Course Modules contexts.
$params = [
'sitecontext' => CONTEXT_SYSTEM,
'categorycontext' => CONTEXT_COURSECAT,
'coursecontext' => CONTEXT_COURSE,
'groupcontext' => CONTEXT_COURSE,
'usercontext' => CONTEXT_USER,
'cuserid' => $userid,
'modulecontext' => CONTEXT_MODULE,
'muserid' => $userid
];
$params += $contextparams1;
$params += $contextparams2;
// Get Calendar Events details for the approved contexts and the owner.
$sql = "SELECT ctxid as contextid,
details.id as eventid,
details.name as name,
details.description as description,
details.location as location,
details.eventtype as eventtype,
details.timestart as timestart,
details.timeduration as timeduration
FROM (
SELECT e.id AS id,
ctx.id AS ctxid
FROM {context} ctx
INNER JOIN {event} e ON
(e.eventtype = 'site' AND ctx.contextlevel = :sitecontext) OR
(e.categoryid = ctx.instanceid AND e.eventtype = 'category' AND ctx.contextlevel = :categorycontext) OR
(e.courseid = ctx.instanceid AND e.eventtype = 'course' AND ctx.contextlevel = :coursecontext) OR
(e.courseid = ctx.instanceid AND e.eventtype = 'group' AND ctx.contextlevel = :groupcontext) OR
(e.userid = ctx.instanceid AND e.eventtype = 'user' AND ctx.contextlevel = :usercontext)
WHERE e.userid = :cuserid
AND ctx.id {$contextsql1}
UNION
SELECT e.id AS id,
ctx.id AS ctxid
FROM {context} ctx
INNER JOIN {course_modules} cm ON cm.id = ctx.instanceid AND ctx.contextlevel = :modulecontext
INNER JOIN {modules} m ON m.id = cm.module
INNER JOIN {event} e ON e.modulename = m.name AND e.courseid = cm.course AND e.instance = cm.instance
WHERE e.userid = :muserid
AND ctx.id {$contextsql2}
) ids
JOIN {event} details ON details.id = ids.id
ORDER BY ids.id";
return $DB->get_recordset_sql($sql, $params);
}
/**
* Helper function to return the Calendar Subscriptions for a given user and context list.
*
* @param approved_contextlist $contextlist
* @return array
* @throws \coding_exception
* @throws \dml_exception
*/
protected static function get_calendar_subscription_details_by_contextlist(approved_contextlist $contextlist) {
global $DB;
$user = $contextlist->get_user();
list($contextsql, $contextparams) = $DB->get_in_or_equal($contextlist->get_contextids(), SQL_PARAMS_NAMED);
$params = [
'sitecontext' => CONTEXT_SYSTEM,
'categorycontext' => CONTEXT_COURSECAT,
'coursecontext' => CONTEXT_COURSE,
'groupcontext' => CONTEXT_COURSE,
'usercontext' => CONTEXT_USER,
'userid' => $user->id
];
$params += $contextparams;
// Get Calendar Subscriptions for the approved contexts and the owner.
$sql = "SELECT DISTINCT
c.id as contextid,
s.id as subscriptionid,
s.name as name,
s.url as url,
s.eventtype as eventtype
FROM {context} c
INNER JOIN {event_subscriptions} s ON
(s.eventtype = 'site' AND c.contextlevel = :sitecontext) OR
(s.categoryid = c.instanceid AND s.eventtype = 'category' AND c.contextlevel = :categorycontext) OR
(s.courseid = c.instanceid AND s.eventtype = 'course' AND c.contextlevel = :coursecontext) OR
(s.courseid = c.instanceid AND s.eventtype = 'group' AND c.contextlevel = :groupcontext) OR
(s.userid = c.instanceid AND s.eventtype = 'user' AND c.contextlevel = :usercontext)
WHERE s.userid = :userid
AND c.id {$contextsql}";
return $DB->get_recordset_sql($sql, $params);
}
/**
* Helper function to delete records in batches in order to minimise amount of deletion queries.
*
* @param string $tablename The table name to delete from.
* @param string $field The table column field name to delete records by.
* @param array $values The table column field values to delete records by.
* @throws \dml_exception
*/
protected static function delete_batch_records($tablename, $field, $values) {
global $DB;
// Batch deletion with an upper limit of 2000 records to minimise the number of deletion queries.
$batchrecords = array_chunk($values, 2000);
foreach ($batchrecords as $batchrecord) {
$DB->delete_records_list($tablename, $field, $batchrecord);
}
}
}