4 files changed, 170 insertions, 1 deletions
diff --git a/lib/private/SystemTag/ManagerFactory.php b/lib/private/SystemTag/ManagerFactory.php
index d9acf327f8a..e6938e494bc 100644
--- a/lib/private/SystemTag/ManagerFactory.php
+++ b/lib/private/SystemTag/ManagerFactory.php
@@ -59,6 +59,8 @@ class ManagerFactory implements ISystemTagManagerFactory {
 	public function getManager() {
 		return new SystemTagManager(
 			$this->serverContainer->getDatabaseConnection(),
+			$this->serverContainer->getUserManager(),
+			$this->serverContainer->getGroupManager(),
 			$this->serverContainer->getEventDispatcher()
 		);
 	}
diff --git a/lib/private/SystemTag/SystemTagManager.php b/lib/private/SystemTag/SystemTagManager.php
index 76a60a91328..0e4bdad078e 100644
--- a/lib/private/SystemTag/SystemTagManager.php
+++ b/lib/private/SystemTag/SystemTagManager.php
@@ -30,7 +30,14 @@ use OCP\SystemTag\ManagerEvent;
 use OCP\SystemTag\TagAlreadyExistsException;
 use OCP\SystemTag\TagNotFoundException;
 use Symfony\Component\EventDispatcher\EventDispatcherInterface;
+use OCP\IUserManager;
+use OCP\IGroupManager;
+use OCP\SystemTag\ISystemTag;
+use OCP\UserNotFoundException;
 
+/**
+ * Manager class for system tags
+ */
 class SystemTagManager implements ISystemTagManager {
 
 	const TAG_TABLE = 'systemtag';
@@ -41,6 +48,12 @@ class SystemTagManager implements ISystemTagManager {
 	/** @var EventDispatcherInterface */
 	protected $dispatcher;
 
+	/** @var IUserManager */
+	protected $userManager;
+
+	/** @var IGroupManager */
+	protected $groupManager;
+
 	/**
 	 * Prepared query for selecting tags directly
 	 *
@@ -54,8 +67,15 @@ class SystemTagManager implements ISystemTagManager {
 	 * @param IDBConnection $connection database connection
 	 * @param EventDispatcherInterface $dispatcher
 	 */
-	public function __construct(IDBConnection $connection, EventDispatcherInterface $dispatcher) {
+	public function __construct(
+		IDBConnection $connection,
+		IUserManager $userManager,
+		IGroupManager $groupManager,
+		EventDispatcherInterface $dispatcher
+	) {
 		$this->connection = $connection;
+		$this->userManager = $userManager;
+		$this->groupManager = $groupManager;
 		$this->dispatcher = $dispatcher;
 
 		$query = $this->connection->getQueryBuilder();
@@ -316,6 +336,58 @@ class SystemTagManager implements ISystemTagManager {
 		}
 	}
 
+	/**
+	 * {@inheritdoc}
+	 */
+	public function canUserAssignTag($tag, $userId) {
+		if (!$tag instanceof ISystemTag) {
+			$tags = $this->getTagsByIds([$tag]);
+			/** @var ISystemTag $tag */
+			$tag = current($tags);
+		}
+
+		if ($tag->isUserAssignable()) {
+			return true;
+		}
+
+		$user = $this->userManager->get($userId);
+		if ($user === null) {
+			throw new UserNotFoundException($userId);
+		}
+
+		if ($this->groupManager->isAdmin($userId)) {
+			return true;
+		}
+
+		return false;
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function canUserSeeTag($tag, $userId) {
+		if (!$tag instanceof ISystemTag) {
+			$tags = $this->getTagsByIds([$tag]);
+			/** @var ISystemTag $tag */
+			$tag = current($tags);
+		}
+
+		if ($tag->isUserVisible()) {
+			return true;
+		}
+
+		$user = $this->userManager->get($userId);
+		if ($user === null) {
+			throw new UserNotFoundException($userId);
+		}
+
+		if ($this->groupManager->isAdmin($userId)) {
+			return true;
+		}
+
+		return false;
+	}
+
 	private function createSystemTagFromRow($row) {
 		return new SystemTag((int)$row['id'], $row['name'], (bool)$row['visibility'], (bool)$row['editable']);
 	}
diff --git a/lib/public/SystemTag/ISystemTagManager.php b/lib/public/SystemTag/ISystemTagManager.php
index 983bfd636ce..7fb0c21436c 100644
--- a/lib/public/SystemTag/ISystemTagManager.php
+++ b/lib/public/SystemTag/ISystemTagManager.php
@@ -113,4 +113,37 @@ interface ISystemTagManager {
 	 */
 	public function deleteTags($tagIds);
 
+	/**
+	 * Checks whether the given user is allowed to assign/unassign the tag with the
+	 * given id.
+	 *
+	 * @param string|\OCP\SystemTag\ISystemTag $tag tag id or system tag
+	 * @param string $userId user id
+	 *
+	 * @return true if the user is allowed to assign/unassign the tag, false otherwise
+	 *
+	 * @throws \OCP\SystemTag\TagNotFoundException if tag with the given id does not exist
+	 * @throws \OCP\UserNotFoundException if the given user id does not exist
+	 * @throws \InvalidArgumentException if the tag id is invalid (string instead of integer, etc.)
+	 *
+	 * @since 9.1.0
+	 */
+	public function canUserAssignTag($tag, $userId);
+
+	/**
+	 * Checks whether the given user is allowed to see the tag with the given id.
+	 *
+	 * @param string|\OCP\SystemTag\ISystemTag $tag tag id or system tag
+	 * @param string $userId user id
+	 *
+	 * @return true if the user is allowed to assign/unassign the tag, false otherwise
+	 *
+	 * @throws \OCP\SystemTag\TagNotFoundException if tag with the given id does not exist
+	 * @throws \OCP\UserNotFoundException if the given user id does not exist
+	 * @throws \InvalidArgumentException if the tag id is invalid (string instead of integer, etc.)
+	 *
+	 * @since 9.1.0
+	 */
+	public function canUserSeeTag($tag, $userId);
+
 }
diff --git a/lib/public/UserNotFoundException.php b/lib/public/UserNotFoundException.php
new file mode 100644
index 00000000000..b0f9eea0e8a
--- /dev/null
+++ b/lib/public/UserNotFoundException.php
@@ -0,0 +1,62 @@
+<?php
+/**
+ * @author Vincent Petry <pvince81@owncloud.com>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * 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, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OCP;
+
+/**
+ * Exception when a user was not found
+ *
+ * @since 9.1.0
+ */
+class UserNotFoundException extends \RuntimeException {
+
+	/**
+	 * User id that was not found
+	 *
+	 * @var string
+	 */
+	private $userId;
+
+	/**
+	 * UserNotFoundException constructor.
+	 *
+	 * @param string $message message
+	 * @param int $code error code
+	 * @param \Exception $previous previous exception
+	 * @param string $userId user id
+	 *
+	 * @since 9.1.0
+	 */
+	public function __construct($message = '', $code = 0, \Exception $previous = null, $userId = null) {
+		parent::__construct($message, $code, $previous);
+		$this->userId = $userId;
+	}
+
+	/**
+	 * Returns the user id that was not found
+	 *
+	 * @return string
+	 * @since 9.1.0
+	 */
+	public function getUserId() {
+		return $this->userId;
+	}
+}