Add an event merger and use it for the files activities

Signed-off-by: Joas Schilling <coding@schilljs.com>

4 files changed, 328 insertions, 0 deletions

diff --git a/lib/private/Activity/EventMerger.php b/lib/private/Activity/EventMerger.php
new file mode 100644
index 00000000000..91e79068665
--- /dev/null
+++ b/lib/private/Activity/EventMerger.php
@@ -0,0 +1,256 @@
+<?php
+/**
+ * @copyright Copyright (c) 2016 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);
+		} 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 . '1}', '{' . $parameter . '2}']
+				);
+				break;
+			case 3:
+				$replacement = $this->l10n->t(
+					'%1$s, %2$s and %3$s',
+					['{' . $parameter . '1}', '{' . $parameter . '2}', '{' . $parameter . '3}']
+				);
+				break;
+			case 4:
+				$replacement = $this->l10n->t(
+					'%1$s, %2$s, %3$s and %4$s',
+					['{' . $parameter . '1}', '{' . $parameter . '2}', '{' . $parameter . '3}', '{' . $parameter . '4}']
+				);
+				break;
+			case 5:
+				$replacement = $this->l10n->t(
+					'%1$s, %2$s, %3$s, %4$s and %5$s',
+					['{' . $parameter . '1}', '{' . $parameter . '2}', '{' . $parameter . '3}', '{' . $parameter . '4}', '{' . $parameter . '5}']
+				);
+				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);
+	}
+}
diff --git a/lib/private/AppFramework/DependencyInjection/DIContainer.php b/lib/private/AppFramework/DependencyInjection/DIContainer.php
index 48c9b6f4589..148a15172ac 100644
--- a/lib/private/AppFramework/DependencyInjection/DIContainer.php
+++ b/lib/private/AppFramework/DependencyInjection/DIContainer.php
@@ -98,6 +98,9 @@ class DIContainer extends SimpleContainer implements IAppContainer {
 		$this->registerService('OCP\\Activity\\IManager', function($c) {
 			return $this->getServer()->getActivityManager();
 		});
+		$this->registerService(\OCP\Activity\IEventMerger::class, function($c) {
+			return $this->getServer()->query(\OCP\Activity\IEventMerger::class);
+		});
 
 		$this->registerService('OCP\\ICache', function($c) {
 			return $this->getServer()->getCache();
diff --git a/lib/private/Server.php b/lib/private/Server.php
index 1d3d588e9fc..797b7a4b823 100644
--- a/lib/private/Server.php
+++ b/lib/private/Server.php
@@ -401,6 +401,11 @@ class Server extends ServerContainer implements IServerContainer {
 				$c->query(IValidator::class)
 			);
 		});
+		$this->registerService(\OCP\Activity\IEventMerger::class, function (Server $c) {
+			return new \OC\Activity\EventMerger(
+				$c->getL10N('lib')
+			);
+		});
 		$this->registerAlias(IValidator::class, Validator::class);
 		$this->registerService('AvatarManager', function (Server $c) {
 			return new AvatarManager(
diff --git a/lib/public/Activity/IEventMerger.php b/lib/public/Activity/IEventMerger.php
new file mode 100644
index 00000000000..8bd8e540770
--- /dev/null
+++ b/lib/public/Activity/IEventMerger.php
@@ -0,0 +1,64 @@
+<?php
+/**
+ * @copyright Copyright (c) 2016 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 OCP\Activity;
+
+
+/**
+ * Interface EventMerger
+ *
+ * @package OCP\Activity
+ * @since 11.0
+ */
+interface IEventMerger {
+
+	/**
+	 * 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 $previousEvent
+	 * @return IEvent
+	 * @since 11.0
+	 */
+	public function mergeEvents($mergeParameter, IEvent $event, IEvent $previousEvent = null);
+
+}