nextcloud/lib/private/Activity/EventMerger.php

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<?php
/**
* @copyright Copyright (c) 2016 Joas Schilling <coding@schilljs.com>
*
* @author Joas Schilling <coding@schilljs.com>
*
* @license GNU AGPL version 3 or any later version
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
namespace OC\Activity;
use OCP\Activity\IEvent;
use OCP\Activity\IEventMerger;
use OCP\IL10N;
class EventMerger implements IEventMerger {
/** @var IL10N */
protected $l10n;
/**
* @param IL10N $l10n
*/
public function __construct(IL10N $l10n) {
$this->l10n = $l10n;
}
/**
* Combines two events when possible to have grouping:
*
* Example1: Two events with subject '{user} created {file}' and
* $mergeParameter file with different file and same user will be merged
* to '{user} created {file1} and {file2}' and the childEvent on the return
* will be set, if the events have been merged.
*
* Example2: Two events with subject '{user} created {file}' and
* $mergeParameter file with same file and same user will be merged to
* '{user} created {file1}' and the childEvent on the return will be set, if
* the events have been merged.
*
* The following requirements have to be met, in order to be merged:
* - Both events need to have the same `getApp()`
* - Both events must not have a message `getMessage()`
* - Both events need to have the same subject `getSubject()`
* - Both events need to have the same object type `getObjectType()`
* - The time difference between both events must not be bigger then 3 hours
* - Only up to 5 events can be merged.
* - All parameters apart from such starting with $mergeParameter must be
* the same for both events.
*
* @param string $mergeParameter
* @param IEvent $event
* @param IEvent|null $previousEvent
* @return IEvent
*/
public function mergeEvents($mergeParameter, IEvent $event, IEvent $previousEvent = null) {
// No second event => can not combine
if (!$previousEvent instanceof IEvent) {
return $event;
}
// Different app => can not combine
if ($event->getApp() !== $previousEvent->getApp()) {
return $event;
}
// Message is set => can not combine
if ($event->getMessage() !== '' || $previousEvent->getMessage() !== '') {
return $event;
}
// Different subject => can not combine
if ($event->getSubject() !== $previousEvent->getSubject()) {
return $event;
}
// Different object type => can not combine
if ($event->getObjectType() !== $previousEvent->getObjectType()) {
return $event;
}
// More than 3 hours difference => can not combine
if (abs($event->getTimestamp() - $previousEvent->getTimestamp()) > 3 * 60 * 60) {
return $event;
}
// Other parameters are not the same => can not combine
try {
list($combined, $parameters) = $this->combineParameters($mergeParameter, $event, $previousEvent);
} catch (\UnexpectedValueException $e) {
return $event;
}
try {
$newSubject = $this->getExtendedSubject($event->getRichSubject(), $mergeParameter, $combined);
$parsedSubject = $this->generateParsedSubject($newSubject, $parameters);
$event->setRichSubject($newSubject, $parameters)
->setParsedSubject($parsedSubject)
->setChildEvent($previousEvent)
->setTimestamp(max($event->getTimestamp(), $previousEvent->getTimestamp()));
} catch (\UnexpectedValueException $e) {
return $event;
}
return $event;
}
/**
* @param string $mergeParameter
* @param IEvent $event
* @param IEvent $previousEvent
* @return array
* @throws \UnexpectedValueException
*/
protected function combineParameters($mergeParameter, IEvent $event, IEvent $previousEvent) {
$params1 = $event->getRichSubjectParameters();
$params2 = $previousEvent->getRichSubjectParameters();
$params = [];
$combined = 0;
// Check that all parameters from $event exist in $previousEvent
foreach ($params1 as $key => $parameter) {
if (preg_match('/^' . $mergeParameter . '(\d+)?$/', $key)) {
if (!$this->checkParameterAlreadyExits($params, $mergeParameter, $parameter)) {
$combined++;
$params[$mergeParameter . $combined] = $parameter;
}
continue;
}
if (!isset($params2[$key]) || $params2[$key] !== $parameter) {
// Parameter missing on $previousEvent or different => can not combine
throw new \UnexpectedValueException();
}
$params[$key] = $parameter;
}
// Check that all parameters from $previousEvent exist in $event
foreach ($params2 as $key => $parameter) {
if (preg_match('/^' . $mergeParameter . '(\d+)?$/', $key)) {
if (!$this->checkParameterAlreadyExits($params, $mergeParameter, $parameter)) {
$combined++;
$params[$mergeParameter . $combined] = $parameter;
}
continue;
}
if (!isset($params1[$key]) || $params1[$key] !== $parameter) {
// Parameter missing on $event or different => can not combine
throw new \UnexpectedValueException();
}
$params[$key] = $parameter;
}
return [$combined, $params];
}
/**
* @param array[] $parameters
* @param string $mergeParameter
* @param array $parameter
* @return bool
*/
protected function checkParameterAlreadyExits($parameters, $mergeParameter, $parameter) {
foreach ($parameters as $key => $param) {
if (preg_match('/^' . $mergeParameter . '(\d+)?$/', $key)) {
if ($param === $parameter) {
return true;
}
}
}
return false;
}
/**
* @param string $subject
* @param string $parameter
* @param int $counter
* @return mixed
*/
protected function getExtendedSubject($subject, $parameter, $counter) {
switch ($counter) {
case 1:
$replacement = '{' . $parameter . '1}';
break;
case 2:
$replacement = $this->l10n->t(
'%1$s and %2$s',
['{' . $parameter . '2}', '{' . $parameter . '1}']
);
break;
case 3:
$replacement = $this->l10n->t(
'%1$s, %2$s and %3$s',
['{' . $parameter . '3}', '{' . $parameter . '2}', '{' . $parameter . '1}']
);
break;
case 4:
$replacement = $this->l10n->t(
'%1$s, %2$s, %3$s and %4$s',
['{' . $parameter . '4}', '{' . $parameter . '3}', '{' . $parameter . '2}', '{' . $parameter . '1}']
);
break;
case 5:
$replacement = $this->l10n->t(
'%1$s, %2$s, %3$s, %4$s and %5$s',
['{' . $parameter . '5}', '{' . $parameter . '4}', '{' . $parameter . '3}', '{' . $parameter . '2}', '{' . $parameter . '1}']
);
break;
default:
throw new \UnexpectedValueException();
}
return str_replace(
'{' . $parameter . '}',
$replacement,
$subject
);
}
/**
* @param string $subject
* @param array[] $parameters
* @return string
*/
protected function generateParsedSubject($subject, $parameters) {
$placeholders = $replacements = [];
foreach ($parameters as $placeholder => $parameter) {
$placeholders[] = '{' . $placeholder . '}';
if ($parameter['type'] === 'file') {
$replacements[] = trim($parameter['path'], '/');
} else if (isset($parameter['name'])) {
$replacements[] = $parameter['name'];
} else {
$replacements[] = $parameter['id'];
}
}
return str_replace($placeholders, $replacements, $subject);
}
}