owncloud/core

View on GitHub
lib/private/Share/Share.php

Summary

Maintainability
F
1 mo
Test Coverage
<?php
/**
 * @author Arthur Schiwon <blizzz@arthur-schiwon.de>
 * @author Bart Visscher <bartv@thisnet.nl>
 * @author Bernhard Reiter <ockham@raz.or.at>
 * @author Björn Schießle <bjoern@schiessle.org>
 * @author Christopher Schäpers <kondou@ts.unde.re>
 * @author Christoph Wurst <christoph@owncloud.com>
 * @author Daniel Hansson <enoch85@gmail.com>
 * @author Joas Schilling <coding@schilljs.com>
 * @author Jörn Friedrich Dreyer <jfd@butonic.de>
 * @author Lukas Reschke <lukas@statuscode.ch>
 * @author Michael Kuhn <suraia@ikkoku.de>
 * @author Morris Jobke <hey@morrisjobke.de>
 * @author Robin Appelman <icewind@owncloud.com>
 * @author Robin McCorkell <robin@mccorkell.me.uk>
 * @author Roeland Jago Douma <rullzer@owncloud.com>
 * @author Sebastian Döll <sebastian.doell@libasys.de>
 * @author Stefan Weil <sw@weilnetz.de>
 * @author Thomas Müller <thomas.mueller@tmit.eu>
 * @author Torben Dannhauer <torben@dannhauer.de>
 * @author Vincent Petry <pvince81@owncloud.com>
 * @author Volkan Gezer <volkangezer@gmail.com>
 *
 * @copyright Copyright (c) 2018, ownCloud GmbH
 * @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 OC\Share;

use Doctrine\DBAL\Connection;
use OC\Files\Filesystem;
use OC\Group\Group;
use OCA\FederatedFileSharing\DiscoveryManager;
use OCP\DB\QueryBuilder\IQueryBuilder;
use OCP\IUser;
use OCP\IUserSession;
use OCP\IDBConnection;
use OCP\IConfig;
use Symfony\Component\EventDispatcher\GenericEvent;

/**
 * This class provides the ability for apps to share their content between users.
 * Apps must create a backend class that implements OCP\Share_Backend and register it with this class.
 *
 * It provides the following hooks:
 *  - post_shared
 */
class Share extends Constants {
    /** CRUDS permissions (Create, Read, Update, Delete, Share) using a bitmask
     * Construct permissions for share() and setPermissions with Or (|) e.g.
     * Give user read and update permissions: PERMISSION_READ | PERMISSION_UPDATE
     *
     * Check if permission is granted with And (&) e.g. Check if delete is
     * granted: if ($permissions & PERMISSION_DELETE)
     *
     * Remove permissions with And (&) and Not (~) e.g. Remove the update
     * permission: $permissions &= ~PERMISSION_UPDATE
     *
     * Apps are required to handle permissions on their own, this class only
     * stores and manages the permissions of shares
     * @see lib/public/constants.php
     */

    /**
     * Register a sharing backend class that implements OCP\Share_Backend for an item type
     * @param string $itemType Item type
     * @param string $class Backend class
     * @param string $collectionOf (optional) Depends on item type
     * @param array $supportedFileExtensions (optional) List of supported file extensions if this item type depends on files
     * @return boolean true if backend is registered or false if error
     */
    public static function registerBackend($itemType, $class, $collectionOf = null, $supportedFileExtensions = null) {
        if (self::isEnabled()) {
            if (!isset(self::$backendTypes[$itemType])) {
                self::$backendTypes[$itemType] = [
                    'class' => $class,
                    'collectionOf' => $collectionOf,
                    'supportedFileExtensions' => $supportedFileExtensions
                ];
                if (\count(self::$backendTypes) === 1) {
                    \OC_Util::addScript('core', 'shareconfigmodel');
                    \OC_Util::addScript('core', 'sharemodel');
                    \OC_Util::addScript('core', 'sharescollection');
                    \OC_Util::addScript('core', 'shareitemmodel');
                    \OC_Util::addScript('core', 'sharedialogresharerinfoview');
                    \OC_Util::addScript('core', 'sharedialoglinklistview');
                    \OC_Util::addScript('core', 'sharedialoglinkshareview');
                    \OC_Util::addScript('core', 'sharedialogmailview');
                    \OC_Util::addScript('core', 'sharedialoglinksocialview');
                    \OC_Util::addScript('core', 'sharedialoglinkexpirationview');
                    \OC_Util::addScript('core', 'sharedialogshareelistview');
                    \OC_Util::addScript('core', 'sharedialogview');
                    \OC_Util::addScript('core', 'share');
                    \OC_Util::addStyle('core', 'share');
                    \OC_Util::addScript('core', 'user');
                }
                return true;
            }
            \OCP\Util::writeLog(
                'OCP\Share',
                'Sharing backend '.$class.' not registered, '.self::$backendTypes[$itemType]['class']
                .' is already registered for '.$itemType,
                \OCP\Util::WARN
            );
        }
        return false;
    }

    /**
     * Check if the Share API is enabled
     * @return boolean true if enabled or false
     *
     * The Share API is enabled by default if not configured
     */
    public static function isEnabled() {
        if (\OC::$server->getAppConfig()->getValue('core', 'shareapi_enabled', 'yes') == 'yes') {
            return true;
        }
        return false;
    }

    /**
     * Find which users can access a shared item
     * @param string $path to the file
     * @param string $ownerUser owner of the file
     * @param boolean $includeOwner include owner to the list of users with access to the file
     * @param boolean $returnUserPaths Return an array with the user => path map
     * @param boolean $recursive take all parent folders into account (default true)
     * @return array
     * @note $path needs to be relative to user data dir, e.g. 'file.txt'
     *       not '/admin/data/file.txt'
     */
    public static function getUsersSharingFile($path, $ownerUser, $includeOwner = false, $returnUserPaths = false, $recursive = true) {
        $userManager = \OC::$server->getUserManager();
        $userObject = $userManager->get($ownerUser);

        if ($userObject === null) {
            $msg = "Backends provided no user object for $ownerUser";
            \OC::$server->getLogger()->error($msg, ['app' => __CLASS__]);
            throw new \OC\User\NoUserException($msg);
        }

        $ownerUser = $userObject->getUID();

        Filesystem::initMountPoints($ownerUser);
        $shares = $sharePaths = $fileTargets = [];
        $publicShare = false;
        $remoteShare = false;
        $source = -1;
        $cache = $mountPath = false;

        $view = new \OC\Files\View('/' . $ownerUser . '/files');
        $meta = $view->getFileInfo($path);
        if ($meta) {
            $path = \substr($meta->getPath(), \strlen('/' . $ownerUser . '/files'));
        } else {
            // if the file doesn't exists yet we start with the parent folder
            $meta = $view->getFileInfo(\dirname($path));
        }

        if ($meta !== false) {
            $source = $meta['fileid'];
            $cache = new \OC\Files\Cache\Cache($meta['storage']);

            $mountPath = $meta->getMountPoint()->getMountPoint();
            if ($mountPath !== false) {
                $mountPath = \substr($mountPath, \strlen('/' . $ownerUser . '/files'));
            }
        }

        $connection = \OC::$server->getDatabaseConnection();

        $paths = [];
        $rejected = [];
        # TODO: performance consideration - build list of all parent folders up front - don't loop
        while ($source !== -1) {
            // Fetch all shares with another user
            if (!$returnUserPaths) {
                $query = \OC_DB::prepare(
                    'SELECT `parent`, `share_with`, `file_source`, `file_target`, `accepted`
                    FROM
                    `*PREFIX*share`
                    WHERE
                    `item_source` = ? AND `share_type` = ? AND `item_type` IN (\'file\', \'folder\')'
                );
                $result = $query->execute([$source, self::SHARE_TYPE_USER]);
            } else {
                $query = \OC_DB::prepare(
                    'SELECT `parent`, `share_with`, `file_source`, `file_target`, `accepted`
                FROM
                `*PREFIX*share`
                WHERE
                `item_source` = ? AND `share_type` IN (?, ?) AND `item_type` IN (\'file\', \'folder\')'
                );
                $result = $query->execute([$source, self::SHARE_TYPE_USER, self::$shareTypeGroupUserUnique]);
            }

            if (\OCP\DB::isError($result)) {
                \OCP\Util::writeLog('OCP\Share', \OC_DB::getErrorMessage(), \OCP\Util::ERROR);
            } else {
                while ($row = $result->fetchRow()) {
                    if ((int)($row['accepted']) === Constants::STATE_REJECTED) {
                        $rejected[]= $row['parent'];
                        continue;
                    }
                    $shares[] = $row['share_with'];
                    if ($returnUserPaths) {
                        $fileTargets[(int) $row['file_source']][$row['share_with']] = $row;
                    }
                }
            }

            // We also need to take group shares into account
            $qb = $connection->getQueryBuilder();
            $qb->select('share_with', 'file_source', 'file_target')
                ->from('share')
                ->where($qb->expr()->eq('item_source', $qb->createNamedParameter($source)))
                ->andWhere($qb->expr()->eq('share_type', $qb->createNamedParameter(self::SHARE_TYPE_GROUP)))
                ->andWhere($qb->expr()->in('item_type', $qb->createNamedParameter(['file', 'folder'], Connection::PARAM_STR_ARRAY)));

            if (!empty($rejected)) {
                $qb->andWhere($qb->expr()->notIn('id', $qb->createNamedParameter($rejected, Connection::PARAM_INT_ARRAY)));
            }
            $result = $qb->execute();

            while ($row = $result->fetch()) {
                $usersInGroup = self::usersInGroup($row['share_with']);
                $shares = \array_merge($shares, $usersInGroup);
                if ($returnUserPaths) {
                    foreach ($usersInGroup as $user) {
                        if (!isset($fileTargets[(int) $row['file_source']][$user])) {
                            // When the user already has an entry for this file source
                            // the file is either shared directly with him as well, or
                            // he has an exception entry (because of naming conflict).
                            $fileTargets[(int) $row['file_source']][$user] = $row;
                        }
                    }
                }
            }

            //check for public link shares
            if (!$publicShare) {
                $query = \OC_DB::prepare(
                    '
                    SELECT `share_with`
                    FROM `*PREFIX*share`
                    WHERE `item_source` = ? AND `share_type` = ? AND `item_type` IN (\'file\', \'folder\')',
                    1
                );

                $result = $query->execute([$source, self::SHARE_TYPE_LINK]);

                if (\OCP\DB::isError($result)) {
                    \OCP\Util::writeLog('OCP\Share', \OC_DB::getErrorMessage(), \OCP\Util::ERROR);
                } else {
                    if ($result->fetchRow()) {
                        $publicShare = true;
                    }
                }
            }

            //check for remote share
            if (!$remoteShare) {
                $query = \OC_DB::prepare(
                    '
                    SELECT `share_with`
                    FROM `*PREFIX*share`
                    WHERE `item_source` = ? AND `share_type` = ? AND `item_type` IN (\'file\', \'folder\')',
                    1
                );

                $result = $query->execute([$source, self::SHARE_TYPE_REMOTE]);

                if (\OCP\DB::isError($result)) {
                    \OCP\Util::writeLog('OCP\Share', \OC_DB::getErrorMessage(), \OCP\Util::ERROR);
                } else {
                    if ($result->fetchRow()) {
                        $remoteShare = true;
                    }
                }
            }

            // let's get the parent for the next round
            $meta = $cache->get((int)$source);
            if ($recursive === true && $meta !== false) {
                $paths[$source] = $meta['path'];
                $source = (int)$meta['parent'];
            } else {
                $source = -1;
            }
        }

        // Include owner in list of users, if requested
        if ($includeOwner) {
            $shares[] = $ownerUser;
        }

        if ($returnUserPaths) {
            $fileTargetIDs = \array_keys($fileTargets);
            $fileTargetIDs = \array_unique($fileTargetIDs);

            if (!empty($fileTargetIDs)) {
                $query = \OC_DB::prepare(
                    'SELECT `fileid`, `path`
                    FROM `*PREFIX*filecache`
                    WHERE `fileid` IN (' . \implode(',', $fileTargetIDs) . ')'
                );
                $result = $query->execute();

                if (\OCP\DB::isError($result)) {
                    \OCP\Util::writeLog('OCP\Share', \OC_DB::getErrorMessage(), \OCP\Util::ERROR);
                } else {
                    while ($row = $result->fetchRow()) {
                        foreach ($fileTargets[$row['fileid']] as $uid => $shareData) {
                            if ($mountPath !== false) {
                                $sharedPath = $shareData['file_target'];
                                $sharedPath .= \substr($path, \strlen($mountPath) + \strlen($paths[$row['fileid']]));
                                $sharePaths[$uid] = $sharedPath;
                            } else {
                                $sharedPath = $shareData['file_target'];
                                $sharedPath .= \substr($path, \strlen($row['path']) -5);
                                $sharePaths[$uid] = $sharedPath;
                            }
                        }
                    }
                }
            }

            if ($includeOwner) {
                $sharePaths[$ownerUser] = $path;
            } else {
                unset($sharePaths[$ownerUser]);
            }

            return $sharePaths;
        }

        return ['users' => \array_unique($shares), 'public' => $publicShare, 'remote' => $remoteShare];
    }

    /**
     * Get the items of item type shared with the current user
     * @param string $itemType
     * @param int $format (optional) Format type must be defined by the backend
     * @param mixed $parameters (optional)
     * @param int $limit Number of items to return (optional) Returns all by default
     * @param boolean $includeCollections (optional)
     * @return mixed Return depends on format
     */
    public static function getItemsSharedWith(
        $itemType,
        $format = self::FORMAT_NONE,
        $parameters = null,
        $limit = -1,
        $includeCollections = false
    ) {
        return self::getItems(
            $itemType,
            null,
            self::$shareTypeUserAndGroups,
            \OC_User::getUser(),
            null,
            $format,
            $parameters,
            $limit,
            $includeCollections
        );
    }

    /**
     * Get the items of item type shared with a user
     * @param string $itemType
     * @param string $user id for which user we want the shares
     * @param int $format (optional) Format type must be defined by the backend
     * @param mixed $parameters (optional)
     * @param int $limit Number of items to return (optional) Returns all by default
     * @param boolean $includeCollections (optional)
     * @return mixed Return depends on format
     */
    public static function getItemsSharedWithUser(
        $itemType,
        $user,
        $format = self::FORMAT_NONE,
        $parameters = null,
        $limit = -1,
        $includeCollections = false
    ) {
        return self::getItems(
            $itemType,
            null,
            self::$shareTypeUserAndGroups,
            $user,
            null,
            $format,
            $parameters,
            $limit,
            $includeCollections
        );
    }

    /**
     * Get the item of item type shared with the current user
     * @param string $itemType
     * @param string $itemTarget
     * @param int $format (optional) Format type must be defined by the backend
     * @param mixed $parameters (optional)
     * @param boolean $includeCollections (optional)
     * @return mixed Return depends on format
     */
    public static function getItemSharedWith(
        $itemType,
        $itemTarget,
        $format = self::FORMAT_NONE,
        $parameters = null,
        $includeCollections = false
    ) {
        return self::getItems(
            $itemType,
            $itemTarget,
            self::$shareTypeUserAndGroups,
            \OC_User::getUser(),
            null,
            $format,
            $parameters,
            1,
            $includeCollections
        );
    }

    /**
     * Get the item of item type shared with a given user by source
     * @param string $itemType
     * @param string $itemSource
     * @param string $user User to whom the item was shared
     * @param string $owner Owner of the share
     * @param int $shareType only look for a specific share type
     * @return array Return list of items with file_target, permissions and expiration
     */
    public static function getItemSharedWithUser($itemType, $itemSource, $user, $owner = null, $shareType = null) {
        $shares = [];
        $fileDependent = false;

        $where = 'WHERE';
        $fileDependentWhere = '';
        if ($itemType === 'file' || $itemType === 'folder') {
            $fileDependent = true;
            $column = 'file_source';
            $fileDependentWhere = 'INNER JOIN `*PREFIX*filecache` ON `file_source` = `*PREFIX*filecache`.`fileid` ';
            $fileDependentWhere .= 'INNER JOIN `*PREFIX*storages` ON `numeric_id` = `*PREFIX*filecache`.`storage` ';
        } else {
            $column = 'item_source';
        }

        $select = self::createSelectStatement(self::FORMAT_NONE, $fileDependent);

        $where .= ' `' . $column . '` = ? AND `item_type` = ? ';
        $arguments = [$itemSource, $itemType];
        // for link shares $user === null
        if ($user !== null) {
            $where .= ' AND `share_with` = ? ';
            $arguments[] = $user;
        }

        if ($shareType !== null) {
            $where .= ' AND `share_type` = ? ';
            $arguments[] = $shareType;
        }

        if ($owner !== null) {
            $where .= ' AND `uid_owner` = ? ';
            $arguments[] = $owner;
        }

        $query = \OC_DB::prepare('SELECT ' . $select . ' FROM `*PREFIX*share` '. $fileDependentWhere . $where);

        $result = \OC_DB::executeAudited($query, $arguments);

        while ($row = $result->fetchRow()) {
            if ($fileDependent && !self::isFileReachable($row['path'], $row['storage_id'])) {
                continue;
            }
            if ($fileDependent && (int)$row['file_parent'] === -1) {
                // if it is a mount point we need to get the path from the mount manager
                $mountManager = \OC\Files\Filesystem::getMountManager();
                $mountPoint = $mountManager->findByStorageId($row['storage_id']);
                if (!empty($mountPoint)) {
                    $path = $mountPoint[0]->getMountPoint();
                    $path = \trim($path, '/');
                    $path = \substr($path, \strlen($owner) + 1); //normalize path to 'files/foo.txt`
                    $row['path'] = $path;
                } else {
                    \OC::$server->getLogger()->warning(
                        'Could not resolve mount point for ' . $row['storage_id'],
                        ['app' => 'OCP\Share']
                    );
                }
            }
            $shares[] = $row;
        }

        //if didn't found a result than let's look for a group share.
        if (empty($shares) && $user !== null) {
            $groups = self::getGroupsForUser($user);

            if (!empty($groups)) {
                $where = $fileDependentWhere . ' WHERE `' . $column . '` = ? AND `item_type` = ? AND `share_with` in (?)';
                $arguments = [$itemSource, $itemType, $groups];
                $types = [null, null, IQueryBuilder::PARAM_STR_ARRAY];

                if ($owner !== null) {
                    $where .= ' AND `uid_owner` = ?';
                    $arguments[] = $owner;
                    $types[] = null;
                }

                // TODO: inject connection, hopefully one day in the future when this
                // class isn't static anymore...
                $conn = \OC::$server->getDatabaseConnection();
                $result = $conn->executeQuery(
                    'SELECT ' . $select . ' FROM `*PREFIX*share` ' . $where,
                    $arguments,
                    $types
                );

                while ($row = $result->fetch()) {
                    $shares[] = $row;
                }
            }
        }

        return $shares;
    }

    /**
     * Get the item of item type shared with the current user by source
     * @param string $itemType
     * @param string $itemSource
     * @param int $format (optional) Format type must be defined by the backend
     * @param mixed $parameters
     * @param boolean $includeCollections
     * @param string $shareWith (optional) define against which user should be checked, default: current user
     * @return array
     */
    public static function getItemSharedWithBySource(
        $itemType,
        $itemSource,
        $format = self::FORMAT_NONE,
        $parameters = null,
        $includeCollections = false,
        $shareWith = null
    ) {
        $shareWith = ($shareWith === null) ? \OC_User::getUser() : $shareWith;
        return self::getItems(
            $itemType,
            $itemSource,
            self::$shareTypeUserAndGroups,
            $shareWith,
            null,
            $format,
            $parameters,
            1,
            $includeCollections,
            true
        );
    }

    /**
     * Get the item of item type shared by a link
     * @param string $itemType
     * @param string $itemSource
     * @param string $uidOwner Owner of link
     * @return array
     */
    public static function getItemSharedWithByLink($itemType, $itemSource, $uidOwner) {
        return self::getItems(
            $itemType,
            $itemSource,
            self::SHARE_TYPE_LINK,
            null,
            $uidOwner,
            self::FORMAT_NONE,
            null,
            1
        );
    }

    /**
     * Based on the given token the share information will be returned - password protected shares will be verified
     * @param string $token
     * @param bool $checkPasswordProtection
     * @return array|boolean false will be returned in case the token is unknown or unauthorized
     */
    public static function getShareByToken($token, $checkPasswordProtection = true) {
        $query = \OC_DB::prepare('SELECT * FROM `*PREFIX*share` WHERE `token` = ?', 1);
        $result = $query->execute([$token]);
        if ($result === false) {
            \OCP\Util::writeLog('OCP\Share', \OC_DB::getErrorMessage() . ', token=' . $token, \OCP\Util::ERROR);
        }
        $row = $result->fetchRow();
        if ($row === false) {
            return false;
        }
        if (\is_array($row) and self::expireItem($row)) {
            return false;
        }

        // password protected shares need to be authenticated
        if ($checkPasswordProtection && !\OCP\Share::checkPasswordProtectedShare($row)) {
            return false;
        }

        return $row;
    }

    /**
     * resolves reshares down to the last real share
     * @param array $linkItem
     * @return array file owner
     */
    public static function resolveReShare($linkItem) {
        if (isset($linkItem['parent'])) {
            $parent = $linkItem['parent'];
            while (isset($parent)) {
                $query = \OC_DB::prepare('SELECT * FROM `*PREFIX*share` WHERE `id` = ?', 1);
                $item = $query->execute([$parent])->fetchRow();
                if (isset($item['parent'])) {
                    $parent = $item['parent'];
                } else {
                    return $item;
                }
            }
        }
        return $linkItem;
    }

    /**
     * Get the shared items of item type owned by the current user
     * @param string $itemType
     * @param int $format (optional) Format type must be defined by the backend
     * @param mixed $parameters
     * @param int $limit Number of items to return (optional) Returns all by default
     * @param boolean $includeCollections
     * @return mixed Return depends on format
     */
    public static function getItemsShared(
        $itemType,
        $format = self::FORMAT_NONE,
        $parameters = null,
        $limit = -1,
        $includeCollections = false
    ) {
        return self::getItems(
            $itemType,
            null,
            null,
            null,
            \OC_User::getUser(),
            $format,
            $parameters,
            $limit,
            $includeCollections
        );
    }

    /**
     * Get the shared item of item type owned by the current user
     * @param string $itemType
     * @param string $itemSource
     * @param int $format (optional) Format type must be defined by the backend
     * @param mixed $parameters
     * @param boolean $includeCollections
     * @return mixed Return depends on format
     */
    public static function getItemShared(
        $itemType,
        $itemSource,
        $format = self::FORMAT_NONE,
        $parameters = null,
        $includeCollections = false
    ) {
        return self::getItems(
            $itemType,
            $itemSource,
            null,
            null,
            \OC_User::getUser(),
            $format,
            $parameters,
            -1,
            $includeCollections
        );
    }

    /**
     * Get all users an item is shared with
     * @param string $itemType
     * @param string $itemSource
     * @param string $uidOwner
     * @param boolean $includeCollections
     * @param boolean $checkExpireDate
     * @return array Return array of users
     */
    public static function getUsersItemShared($itemType, $itemSource, $uidOwner, $includeCollections = false, $checkExpireDate = true) {
        $users = [];
        $items = self::getItems($itemType, $itemSource, null, null, $uidOwner, self::FORMAT_NONE, null, -1, $includeCollections, false, $checkExpireDate);
        if ($items) {
            foreach ($items as $item) {
                if ((int)$item['share_type'] === self::SHARE_TYPE_USER) {
                    $users[] = $item['share_with'];
                } elseif ((int)$item['share_type'] === self::SHARE_TYPE_GROUP) {
                    $users = \array_merge($users, self::usersInGroup($item['share_with']));
                }
            }
        }
        return $users;
    }

    /**
     * Share an item with a user, group, or via private link
     * @param string $itemType
     * @param string $itemSource
     * @param int $shareType SHARE_TYPE_USER, SHARE_TYPE_GROUP, or SHARE_TYPE_LINK
     * @param string $shareWith User or group the item is being shared with
     * @param int $permissions CRUDS
     * @param string $itemSourceName
     * @param \DateTime $expirationDate
     * @param bool $passwordChanged
     * @return boolean|string Returns true on success or false on failure, Returns token on success for links
     * @throws \OC\HintException when the share type is remote and the shareWith is invalid
     * @throws \Exception
     */
    public static function shareItem($itemType, $itemSource, $shareType, $shareWith, $permissions, $itemSourceName = null, \DateTime $expirationDate = null, $passwordChanged = null) {
        $backend = self::getBackend($itemType);
        $l = \OC::$server->getL10N('lib');

        if ($backend->isShareTypeAllowed($shareType) === false) {
            $message = 'Sharing %s failed, because the backend does not allow shares from type %d';
            $message_t = $l->t('Sharing %s failed, because the backend does not allow shares from type %d', [$itemSourceName, $shareType]);
            \OCP\Util::writeLog('OCP\Share', \sprintf($message, $itemSourceName, $shareType), \OCP\Util::DEBUG);
            throw new \Exception($message_t);
        }

        $uidOwner = \OC_User::getUser();
        $shareWithinGroupOnly = self::shareWithGroupMembersOnly();
        $shareWithMembershipGroupOnly = self::shareWithMembershipGroupOnly();

        if ($itemSourceName === null) {
            $itemSourceName = $itemSource;
        }
        $itemName = $itemSourceName;

        // check if file can be shared
        if ($itemType === 'file' or $itemType === 'folder') {
            $path = \OC\Files\Filesystem::getPath($itemSource);
            $itemName = $path;

            // verify that the file exists before we try to share it
            if (!$path) {
                $message = 'Sharing %s failed, because the file does not exist';
                $message_t = $l->t('Sharing %s failed, because the file does not exist', [$itemSourceName]);
                \OCP\Util::writeLog('OCP\Share', \sprintf($message, $itemSourceName), \OCP\Util::DEBUG);
                throw new \Exception($message_t);
            }
            // verify that the user has share permission
            if (!\OC\Files\Filesystem::isSharable($path) || \OCP\Util::isSharingDisabledForUser()) {
                $message = 'You are not allowed to share %s';
                $message_t = $l->t('You are not allowed to share %s', [$path]);
                \OCP\Util::writeLog('OCP\Share', \sprintf($message, $path), \OCP\Util::DEBUG);
                throw new \Exception($message_t);
            }
        }

        //verify that we don't share a folder which already contains a share mount point
        if ($itemType === 'folder') {
            $path = '/' . $uidOwner . '/files' . \OC\Files\Filesystem::getPath($itemSource) . '/';
            $mountManager = \OC\Files\Filesystem::getMountManager();
            $mounts = $mountManager->findIn($path);
            foreach ($mounts as $mount) {
                if ($mount->getStorage()->instanceOfStorage('\OCA\Files_Sharing\ISharedStorage')) {
                    $message = 'Sharing "' . $itemSourceName . '" failed, because it contains files shared with you!';
                    \OCP\Util::writeLog('OCP\Share', $message, \OCP\Util::DEBUG);
                    throw new \Exception($message);
                }
            }
        }

        // single file shares should never have delete permissions
        if ($itemType === 'file') {
            $permissions = (int)$permissions & ~\OCP\Constants::PERMISSION_DELETE;
        }

        //Validate expirationDate
        if ($expirationDate !== null) {
            try {
                /*
                 * Reuse the validateExpireDate.
                 * We have to pass time() since the second arg is the time
                 * the file was shared, since it is not shared yet we just use
                 * the current time.
                 */
                $expirationDate = self::validateExpireDate($expirationDate->format('Y-m-d'), \time(), $itemType, $itemSource);
            } catch (\Exception $e) {
                throw new \OC\HintException($e->getMessage(), $e->getMessage(), 404);
            }
        }

        // Verify share type and sharing conditions are met
        if ($shareType === self::SHARE_TYPE_USER) {
            if ($shareWith == $uidOwner) {
                $message = 'Sharing %s failed, because you can not share with yourself';
                $message_t = $l->t('Sharing %s failed, because you can not share with yourself', [$itemName]);
                \OCP\Util::writeLog('OCP\Share', \sprintf($message, $itemSourceName), \OCP\Util::DEBUG);
                throw new \Exception($message_t);
            }
            if (!\OC_User::userExists($shareWith)) {
                $message = 'Sharing %s failed, because the user %s does not exist';
                $message_t = $l->t('Sharing %s failed, because the user %s does not exist', [$itemSourceName, $shareWith]);
                \OCP\Util::writeLog('OCP\Share', \sprintf($message, $itemSourceName, $shareWith), \OCP\Util::DEBUG);
                throw new \Exception($message_t);
            }
            if ($shareWithinGroupOnly) {
                $inGroup = \array_intersect(self::getGroupsForUser($uidOwner), self::getGroupsForUser($shareWith));
                if (empty($inGroup)) {
                    $message = 'Sharing %s failed, because the user '
                        .'%s is not a member of any groups that %s is a member of';
                    $message_t = $l->t('Sharing %s failed, because the user %s is not a member of any groups that %s is a member of', [$itemName, $shareWith, $uidOwner]);
                    \OCP\Util::writeLog('OCP\Share', \sprintf($message, $itemName, $shareWith, $uidOwner), \OCP\Util::DEBUG);
                    throw new \Exception($message_t);
                }
            }
            // Check if the item source is already shared with the user, either from the same owner or a different user
            if ($checkExists = self::getItems(
                $itemType,
                $itemSource,
                self::$shareTypeUserAndGroups,
                $shareWith,
                null,
                self::FORMAT_NONE,
                null,
                1,
                true,
                true
            )) {
                // Only allow the same share to occur again if it is the same
                // owner and is not a user share, this use case is for increasing
                // permissions for a specific user
                if ($checkExists['uid_owner'] != $uidOwner || $checkExists['share_type'] == $shareType) {
                    $message = 'Sharing %s failed, because this item is already shared with %s';
                    $message_t = $l->t('Sharing %s failed, because this item is already shared with %s', [$itemSourceName, $shareWith]);
                    \OCP\Util::writeLog('OCP\Share', \sprintf($message, $itemSourceName, $shareWith), \OCP\Util::DEBUG);
                    throw new \Exception($message_t);
                }
            }
            if ($checkExists = self::getItems(
                $itemType,
                $itemSource,
                self::SHARE_TYPE_USER,
                $shareWith,
                null,
                self::FORMAT_NONE,
                null,
                1,
                true,
                true
            )) {
                // Only allow the same share to occur again if it is the same
                // owner and is not a user share, this use case is for increasing
                // permissions for a specific user
                if ($checkExists['uid_owner'] != $uidOwner || $checkExists['share_type'] == $shareType) {
                    $message = 'Sharing %s failed, because this item is already shared with user %s';
                    $message_t = $l->t('Sharing %s failed, because this item is already shared with user %s', [$itemSourceName, $shareWith]);
                    \OCP\Util::writeLog('OCP\Share', \sprintf($message, $itemSourceName, $shareWith), \OCP\Util::ERROR);
                    throw new \Exception($message_t);
                }
            }
        } elseif ($shareType === self::SHARE_TYPE_GROUP) {
            if (!\OC::$server->getGroupManager()->groupExists($shareWith)) {
                $message = 'Sharing %s failed, because the group %s does not exist';
                $message_t = $l->t('Sharing %s failed, because the group %s does not exist', [$itemSourceName, $shareWith]);
                \OCP\Util::writeLog('OCP\Share', \sprintf($message, $itemSourceName, $shareWith), \OCP\Util::DEBUG);
                throw new \Exception($message_t);
            }
            if ($shareWithMembershipGroupOnly && !\OC::$server->getGroupManager()->inGroup($uidOwner, $shareWith)) {
                $message = 'Sharing %s failed, because '
                    .'%s is not a member of the group %s';
                $message_t = $l->t('Sharing %s failed, because %s is not a member of the group %s', [$itemSourceName, $uidOwner, $shareWith]);
                \OCP\Util::writeLog('OCP\Share', \sprintf($message, $itemSourceName, $uidOwner, $shareWith), \OCP\Util::DEBUG);
                throw new \Exception($message_t);
            }
            // Check if the item source is already shared with the group, either from the same owner or a different user
            // The check for each user in the group is done inside the put() function
            if ($checkExists = self::getItems(
                $itemType,
                $itemSource,
                self::SHARE_TYPE_GROUP,
                $shareWith,
                null,
                self::FORMAT_NONE,
                null,
                1,
                true,
                true
            )) {
                if ($checkExists['share_with'] === $shareWith && $checkExists['share_type'] === \OCP\Share::SHARE_TYPE_GROUP) {
                    $message = 'Sharing %s failed, because this item is already shared with %s';
                    $message_t = $l->t('Sharing %s failed, because this item is already shared with %s', [$itemSourceName, $shareWith]);
                    \OCP\Util::writeLog('OCP\Share', \sprintf($message, $itemSourceName, $shareWith), \OCP\Util::DEBUG);
                    throw new \Exception($message_t);
                }
            }
            // Convert share with into an array with the keys group and users
            $group = $shareWith;
            $usersInGroup = \OC::$server->getGroupManager()->get($group)->getUsers();
            $usersInGroup = \array_values(\array_map(function (IUser $u) {
                return $u->getUID();
            }, $usersInGroup));
            $shareWith = [];
            $shareWith['group'] = $group;
            $shareWith['users'] = \array_diff($usersInGroup, [$uidOwner]);
        } elseif ($shareType === self::SHARE_TYPE_LINK) {
            $updateExistingShare = false;
            if (\OC::$server->getAppConfig()->getValue('core', 'shareapi_allow_links', 'yes') == 'yes') {
                // IF the password is changed via the old ajax endpoint verify it before deleting the old share
                if ($passwordChanged === true) {
                    self::verifyPassword($shareWith);
                }

                // when updating a link share
                // FIXME Don't delete link if we update it
                if ($checkExists = self::getItems(
                    $itemType,
                    $itemSource,
                    self::SHARE_TYPE_LINK,
                    null,
                    $uidOwner,
                    self::FORMAT_NONE,
                    null,
                    1
                )) {
                    // remember old token
                    $oldToken = $checkExists['token'];
                    $oldPermissions = $checkExists['permissions'];
                    //delete the old share
                    Helper::delete($checkExists['id']);
                    $updateExistingShare = true;
                }

                if ($passwordChanged === null) {
                    // Generate hash of password - same method as user passwords
                    if (\is_string($shareWith) && $shareWith !== '') {
                        self::verifyPassword($shareWith);
                        $shareWith = \OC::$server->getHasher()->hash($shareWith);
                    } else {
                        // reuse the already set password, but only if we change permissions
                        // otherwise the user disabled the password protection
                        if ($checkExists && (int)$permissions !== (int)$oldPermissions) {
                            $shareWith = $checkExists['share_with'];
                        }
                    }
                } else {
                    if ($passwordChanged === true) {
                        if (\is_string($shareWith) && $shareWith !== '') {
                            self::verifyPassword($shareWith);
                            $shareWith = \OC::$server->getHasher()->hash($shareWith);
                        }
                    } elseif ($updateExistingShare) {
                        $shareWith = $checkExists['share_with'];
                    }
                }

                if (\OCP\Util::isPublicLinkPasswordRequired() && empty($shareWith)) {
                    $message = 'You need to provide a password to create a public link, only protected links are allowed';
                    $message_t = $l->t('You need to provide a password to create a public link, only protected links are allowed');
                    \OCP\Util::writeLog('OCP\Share', $message, \OCP\Util::DEBUG);
                    throw new \Exception($message_t);
                }

                if ($updateExistingShare === false &&
                    self::isDefaultExpireDateEnabled() &&
                    empty($expirationDate)) {
                    $expirationDate = Helper::calcExpireDate();
                }

                // Generate token
                if (isset($oldToken)) {
                    $token = $oldToken;
                } else {
                    $token = \OC::$server->getSecureRandom()->generate(
                        self::TOKEN_LENGTH,
                        \OCP\Security\ISecureRandom::CHAR_LOWER.\OCP\Security\ISecureRandom::CHAR_UPPER.
                        \OCP\Security\ISecureRandom::CHAR_DIGITS
                    );
                }
                $result = self::put(
                    $itemType,
                    $itemSource,
                    $shareType,
                    $shareWith,
                    $uidOwner,
                    $permissions,
                    null,
                    $token,
                    $itemSourceName,
                    $expirationDate
                );
                if ($result) {
                    return $token;
                } else {
                    return false;
                }
            }
            $message = 'Sharing %s failed, because sharing with links is not allowed';
            $message_t = $l->t('Sharing %s failed, because sharing with links is not allowed', [$itemSourceName]);
            \OCP\Util::writeLog('OCP\Share', \sprintf($message, $itemSourceName), \OCP\Util::DEBUG);
            throw new \Exception($message_t);
        } elseif ($shareType === self::SHARE_TYPE_REMOTE) {
            /*
             * Check if file is not already shared with the remote user
             */
            if ($checkExists = self::getItems(
                $itemType,
                $itemSource,
                self::SHARE_TYPE_REMOTE,
                $shareWith,
                $uidOwner,
                self::FORMAT_NONE,
                null,
                1,
                true,
                true
            )) {
                $message = 'Sharing %s failed, because this item is already shared with %s';
                $message_t = $l->t('Sharing %s failed, because this item is already shared with %s', [$itemSourceName, $shareWith]);
                \OCP\Util::writeLog('OCP\Share', \sprintf($message, $itemSourceName, $shareWith), \OCP\Util::DEBUG);
                throw new \Exception($message_t);
            }

            // don't allow federated shares if source and target server are the same
            list($user, $remote) = Helper::splitUserRemote($shareWith);
            $currentServer = self::removeProtocolFromUrl(\OC::$server->getURLGenerator()->getAbsoluteURL('/'));
            $currentUser = \OC::$server->getUserSession()->getUser()->getUID();
            if (Helper::isSameUserOnSameServer($user, $remote, $currentUser, $currentServer)) {
                $message = 'Not allowed to create a federated share with the same user.';
                $message_t = $l->t('Not allowed to create a federated share with the same user');
                \OCP\Util::writeLog('OCP\Share', $message, \OCP\Util::DEBUG);
                throw new \Exception($message_t);
            }

            $token = \OC::$server->getSecureRandom()->generate(self::TOKEN_LENGTH, \OCP\Security\ISecureRandom::CHAR_LOWER . \OCP\Security\ISecureRandom::CHAR_UPPER .
                \OCP\Security\ISecureRandom::CHAR_DIGITS);

            $shareWith = $user . '@' . $remote;
            $shareId = self::put($itemType, $itemSource, $shareType, $shareWith, $uidOwner, $permissions, null, $token, $itemSourceName);

            $send = false;
            if ($shareId) {
                $send = self::sendRemoteShare($token, $shareWith, $itemSourceName, $shareId, $uidOwner);
            }

            if ($send === false) {
                $currentUser = \OC::$server->getUserSession()->getUser()->getUID();
                self::unshare($itemType, $itemSource, $shareType, $shareWith, $currentUser);
                $message_t = $l->t('Sharing %s failed, could not find %s, check spelling and server availability.', [$itemSourceName, $shareWith]);
                throw new \Exception($message_t);
            }

            return $send;
        } else {
            // Future share types need to include their own conditions
            $message = 'Share type %s is not valid for %s';
            $message_t = $l->t('Share type %s is not valid for %s', [$shareType, $itemSource]);
            \OCP\Util::writeLog('OCP\Share', \sprintf($message, $shareType, $itemSource), \OCP\Util::DEBUG);
            throw new \Exception($message_t);
        }

        // Put the item into the database
        $result = self::put($itemType, $itemSource, $shareType, $shareWith, $uidOwner, $permissions, null, null, $itemSourceName, $expirationDate);

        return $result ? true : false;
    }

    /**
     * Unshare an item from a user, group, or delete a private link
     * @param string $itemType
     * @param string $itemSource
     * @param int $shareType SHARE_TYPE_USER, SHARE_TYPE_GROUP, or SHARE_TYPE_LINK
     * @param string $shareWith User or group the item is being shared with
     * @param string $owner owner of the share, if null the current user is used
     * @return boolean true on success or false on failure
     */
    public static function unshare($itemType, $itemSource, $shareType, $shareWith, $owner = null) {
        // check if it is a valid itemType
        self::getBackend($itemType);

        $items = self::getItemSharedWithUser($itemType, $itemSource, $shareWith, $owner, $shareType);

        $toDelete = [];
        $newParent = null;
        $currentUser = $owner ? $owner : \OC_User::getUser();
        foreach ($items as $item) {
            // delete the item with the expected share_type and owner
            if ((int)$item['share_type'] === (int)$shareType && $item['uid_owner'] === $currentUser) {
                $toDelete = $item;
                // if there is more then one result we don't have to delete the children
                // but update their parent. For group shares the new parent should always be
                // the original group share and not the db entry with the unique name
            } elseif ((int)$item['share_type'] === self::$shareTypeGroupUserUnique) {
                $newParent = $item['parent'];
            } else {
                $newParent = $item['id'];
            }
        }

        if (!empty($toDelete)) {
            self::unshareItem($toDelete, $newParent);
            return true;
        }
        return false;
    }

    /**
     * Unshare an item from all users, groups, and remove all links
     * @param string $itemType
     * @param string $itemSource
     * @return boolean true on success or false on failure
     */
    public static function unshareAll($itemType, $itemSource) {
        // Get all of the owners of shares of this item.
        $query = \OC_DB::prepare('SELECT `uid_owner` from `*PREFIX*share` WHERE `item_type`=? AND `item_source`=?');
        $result = $query->execute([$itemType, $itemSource]);
        $shares = [];
        // Add each owner's shares to the array of all shares for this item.
        while ($row = $result->fetchRow()) {
            $shares = \array_merge($shares, self::getItems($itemType, $itemSource, null, null, $row['uid_owner']));
        }
        if (!empty($shares)) {
            // Pass all the vars we have for now, they may be useful
            $hookParams = [
                'itemType' => $itemType,
                'itemSource' => $itemSource,
                'shares' => $shares,
            ];
            \OC_Hook::emit('OCP\Share', 'pre_unshareAll', $hookParams);
            foreach ($shares as $share) {
                self::unshareItem($share);
            }
            \OC_Hook::emit('OCP\Share', 'post_unshareAll', $hookParams);
            return true;
        }
        return false;
    }

    /**
     * Unshare an item shared with the current user
     * @param string $itemType
     * @param string $itemOrigin Item target or source
     * @param boolean $originIsSource true if $itemOrigin is the source, false if $itemOrigin is the target (optional)
     * @return boolean true on success or false on failure
     *
     * Unsharing from self is not allowed for items inside collections
     */
    public static function unshareFromSelf($itemType, $itemOrigin, $originIsSource = false) {
        $originType = ($originIsSource) ? 'source' : 'target';
        $uid = \OCP\User::getUser();

        if ($itemType === 'file' || $itemType === 'folder') {
            $statement = 'SELECT * FROM `*PREFIX*share` WHERE `item_type` = ? and `file_' . $originType . '` = ?';
        } else {
            $statement = 'SELECT * FROM `*PREFIX*share` WHERE `item_type` = ? and `item_' . $originType . '` = ?';
        }

        $query = \OCP\DB::prepare($statement);
        $result = $query->execute([$itemType, $itemOrigin]);

        $shares = $result->fetchAll();

        $listOfUnsharedItems = [];

        $itemUnshared = false;
        foreach ($shares as $share) {
            if ((int)$share['share_type'] === \OCP\Share::SHARE_TYPE_USER &&
                $share['share_with'] === $uid) {
                $deletedShares = Helper::delete($share['id']);
                $shareTmp = [
                    'id' => $share['id'],
                    'shareWith' => $share['share_with'],
                    'itemTarget' => $share['item_target'],
                    'itemType' => $share['item_type'],
                    'shareType' => (int)$share['share_type'],
                ];
                if (isset($share['file_target'])) {
                    $shareTmp['fileTarget'] = $share['file_target'];
                }
                $listOfUnsharedItems = \array_merge($listOfUnsharedItems, $deletedShares, [$shareTmp]);
                $itemUnshared = true;
                break;
            } elseif ((int)$share['share_type'] === \OCP\Share::SHARE_TYPE_GROUP) {
                if (\OC::$server->getGroupManager()->inGroup($uid, $share['share_with'])) {
                    $groupShare = $share;
                }
            } elseif ((int)$share['share_type'] === self::$shareTypeGroupUserUnique &&
                $share['share_with'] === $uid) {
                $uniqueGroupShare = $share;
            }
        }

        if (!$itemUnshared && isset($groupShare) && !isset($uniqueGroupShare)) {
            $query = \OC_DB::prepare('INSERT INTO `*PREFIX*share`'
                .' (`item_type`, `item_source`, `item_target`, `parent`, `share_type`,'
                .' `share_with`, `uid_owner`, `permissions`, `stime`, `file_source`, `file_target`)'
                .' VALUES (?,?,?,?,?,?,?,?,?,?,?)');
            $query->execute([$groupShare['item_type'], $groupShare['item_source'], $groupShare['item_target'],
                $groupShare['id'], self::$shareTypeGroupUserUnique,
                \OC_User::getUser(), $groupShare['uid_owner'], 0, $groupShare['stime'], $groupShare['file_source'],
                $groupShare['file_target']]);
            $shareTmp = [
                'id' => $groupShare['id'],
                'shareWith' => $groupShare['share_with'],
                'itemTarget' => $groupShare['item_target'],
                'itemType' => $groupShare['item_type'],
                'shareType' => (int)$groupShare['share_type'],
            ];
            if (isset($groupShare['file_target'])) {
                $shareTmp['fileTarget'] = $groupShare['file_target'];
            }
            $listOfUnsharedItems = \array_merge($listOfUnsharedItems, [$shareTmp]);
            $itemUnshared = true;
        } elseif (!$itemUnshared && isset($uniqueGroupShare)) {
            $query = \OC_DB::prepare('UPDATE `*PREFIX*share` SET `permissions` = ? WHERE `id` = ?');
            $query->execute([0, $uniqueGroupShare['id']]);
            $shareTmp = [
                'id' => $uniqueGroupShare['id'],
                'shareWith' => $uniqueGroupShare['share_with'],
                'itemTarget' => $uniqueGroupShare['item_target'],
                'itemType' => $uniqueGroupShare['item_type'],
                'shareType' => (int)$uniqueGroupShare['share_type'],
            ];
            if (isset($uniqueGroupShare['file_target'])) {
                $shareTmp['fileTarget'] = $uniqueGroupShare['file_target'];
            }
            $listOfUnsharedItems = \array_merge($listOfUnsharedItems, [$shareTmp]);
            $itemUnshared = true;
        }

        if ($itemUnshared) {
            \OC_Hook::emit(
                'OCP\Share',
                'post_unshareFromSelf',
                ['unsharedItems' => $listOfUnsharedItems, 'itemType' => $itemType]
            );
        }

        return $itemUnshared;
    }

    /**
     * sent status if users got informed by mail about share
     * @param string $itemType
     * @param string $itemSource
     * @param int $shareType SHARE_TYPE_USER, SHARE_TYPE_GROUP, or SHARE_TYPE_LINK
     * @param string $recipient with whom was the file shared
     * @param boolean $status
     */
    public static function setSendMailStatus($itemType, $itemSource, $shareType, $recipient, $status) {
        $status = $status ? 1 : 0;
        $query = \OC_DB::prepare(
            'UPDATE `*PREFIX*share`
                    SET `mail_send` = ?
                    WHERE `item_type` = ? AND `item_source` = ? AND `share_type` = ? AND `share_with` = ?'
        );

        $result = $query->execute([$status, $itemType, $itemSource, $shareType, $recipient]);

        if ($result === false) {
            \OCP\Util::writeLog('OCP\Share', 'Couldn\'t set send mail status', \OCP\Util::ERROR);
        }
    }

    /**
     * Set the permissions of an item for a specific user or group
     * @param string $itemType
     * @param string $itemSource
     * @param int $shareType SHARE_TYPE_USER, SHARE_TYPE_GROUP, or SHARE_TYPE_LINK
     * @param string $shareWith User or group the item is being shared with
     * @param int $permissions CRUDS permissions
     * @return boolean true on success or false on failure
     * @throws \Exception when trying to grant more permissions then the user has himself
     */
    public static function setPermissions($itemType, $itemSource, $shareType, $shareWith, $permissions) {
        $l = \OC::$server->getL10N('lib');
        $connection = \OC::$server->getDatabaseConnection();

        $intArrayToLiteralArray = function ($intArray, $eb) {
            return \array_map(function ($int) use ($eb) {
                return $eb->literal((int)$int, 'integer');
            }, $intArray);
        };
        $sanitizeItem = function ($item) {
            $item['id'] = (int)$item['id'];
            $item['permissions'] = (int)$item['permissions'];
            return $item;
        };

        if ($rootItem = self::getItems(
            $itemType,
            $itemSource,
            $shareType,
            $shareWith,
            \OC_User::getUser(),
            self::FORMAT_NONE,
            null,
            1,
            false
        )) {
            // Check if this item is a reshare and verify that the permissions
            // granted don't exceed the parent shared item
            if (isset($rootItem['parent'])) {
                $qb = $connection->getQueryBuilder();
                $qb->select('permissions')
                    ->from('share')
                    ->where($qb->expr()->eq('id', $qb->createParameter('id')))
                    ->setParameter(':id', $rootItem['parent']);
                $dbresult = $qb->execute();

                $result = $dbresult->fetch();
                $dbresult->closeCursor();
                if (~(int)$result['permissions'] & $permissions) {
                    $message = 'Setting permissions for %s failed,'
                        .' because the permissions exceed permissions granted to %s';
                    $message_t = $l->t('Setting permissions for %s failed, because the permissions exceed permissions granted to %s', [$itemSource, \OC_User::getUser()]);
                    \OCP\Util::writeLog('OCP\Share', \sprintf($message, $itemSource, \OC_User::getUser()), \OCP\Util::DEBUG);
                    throw new \Exception($message_t);
                }
            }
            $qb = $connection->getQueryBuilder();
            $qb->update('share')
                ->set('permissions', $qb->createParameter('permissions'))
                ->where($qb->expr()->eq('id', $qb->createParameter('id')))
                ->setParameter(':id', $rootItem['id'])
                ->setParameter(':permissions', $permissions);
            $qb->execute();
            if ($itemType === 'file' || $itemType === 'folder') {
                \OC_Hook::emit('OCP\Share', 'post_update_permissions', [
                    'itemType' => $itemType,
                    'itemSource' => $itemSource,
                    'shareType' => $shareType,
                    'shareWith' => $shareWith,
                    'uidOwner' => \OC_User::getUser(),
                    'permissions' => $permissions,
                    'path' => $rootItem['path'],
                    'share' => $rootItem
                ]);
            }

            // Share id's to update with the new permissions
            $ids = [];
            $items = [];

            // Check if permissions were removed
            if ((int)$rootItem['permissions'] & ~$permissions) {
                // If share permission is removed all reshares must be deleted
                if (($rootItem['permissions'] & \OCP\Constants::PERMISSION_SHARE) && (~$permissions & \OCP\Constants::PERMISSION_SHARE)) {
                    // delete all shares, keep parent and group children
                    Helper::delete($rootItem['id'], true, null, null, true);
                }

                // Remove permission from all children
                $parents = [$rootItem['id']];
                while (!empty($parents)) {
                    $parents = $intArrayToLiteralArray($parents, $qb->expr());
                    $qb = $connection->getQueryBuilder();
                    $qb->select('id', 'permissions', 'item_type')
                        ->from('share')
                        ->where($qb->expr()->in('parent', $parents));
                    $result = $qb->execute();
                    // Reset parents array, only go through loop again if
                    // items are found that need permissions removed
                    $parents = [];
                    while ($item = $result->fetch()) {
                        $item = $sanitizeItem($item);

                        $items[] = $item;
                        // Check if permissions need to be removed
                        if ($item['permissions'] & ~$permissions) {
                            // Add to list of items that need permissions removed
                            $ids[] = $item['id'];
                            $parents[] = $item['id'];
                        }
                    }
                    $result->closeCursor();
                }

                // Remove the permissions for all reshares of this item
                if (!empty($ids)) {
                    $ids = "'".\implode("','", $ids)."'";
                    // TODO this should be done with Doctrine platform objects
                    if (\OC::$server->getConfig()->getSystemValue("dbtype") === 'oci') {
                        $andOp = 'BITAND(`permissions`, ?)';
                    } else {
                        $andOp = '`permissions` & ?';
                    }
                    $query = \OC_DB::prepare('UPDATE `*PREFIX*share` SET `permissions` = '.$andOp
                        .' WHERE `id` IN ('.$ids.')');
                    $query->execute([$permissions]);
                }
            }

            /*
             * Permissions were added
             * Update all USERGROUP shares. (So group shares where the user moved their mountpoint).
             */
            if ($permissions & ~(int)$rootItem['permissions']) {
                $qb = $connection->getQueryBuilder();
                $qb->select('id', 'permissions', 'item_type')
                    ->from('share')
                    ->where($qb->expr()->eq('parent', $qb->createParameter('parent')))
                    ->andWhere($qb->expr()->eq('share_type', $qb->createParameter('share_type')))
                    ->andWhere($qb->expr()->neq('permissions', $qb->createParameter('shareDeleted')))
                    ->setParameter(':parent', (int)$rootItem['id'])
                    ->setParameter(':share_type', 2)
                    ->setParameter(':shareDeleted', 0);
                $result = $qb->execute();

                $ids = [];
                while ($item = $result->fetch()) {
                    $item = $sanitizeItem($item);
                    $items[] = $item;
                    $ids[] = $item['id'];
                }
                $result->closeCursor();

                // Add permissions for all USERGROUP shares of this item
                if (!empty($ids)) {
                    $ids = $intArrayToLiteralArray($ids, $qb->expr());

                    $qb = $connection->getQueryBuilder();
                    $qb->update('share')
                        ->set('permissions', $qb->createParameter('permissions'))
                        ->where($qb->expr()->in('id', $ids))
                        ->setParameter(':permissions', $permissions);
                    $qb->execute();
                }
            }

            foreach ($items as $item) {
                \OC_Hook::emit('OCP\Share', 'post_update_permissions', ['share' => $item]);
            }

            return true;
        }
        $message = 'Setting permissions for %s failed, because the item was not found';
        $message_t = $l->t('Setting permissions for %s failed, because the item was not found', [$itemSource]);

        \OCP\Util::writeLog('OCP\Share', \sprintf($message, $itemSource), \OCP\Util::DEBUG);
        throw new \Exception($message_t);
    }

    /**
     * validate expiration date if it meets all constraints
     *
     * @param string $expireDate well formatted date string, e.g. "DD-MM-YYYY"
     * @param string $shareTime timestamp when the file was shared
     * @param string $itemType
     * @param string $itemSource
     * @return \DateTime validated date
     * @throws \Exception when the expire date is in the past or further in the future then the enforced date
     */
    private static function validateExpireDate($expireDate, $shareTime, $itemType, $itemSource) {
        $l = \OC::$server->getL10N('lib');
        $date = new \DateTime($expireDate);
        $today = new \DateTime('now');

        // if the user doesn't provide a share time we need to get it from the database
        // fall-back mode to keep API stable, because the $shareTime parameter was added later
        $defaultExpireDateEnforced = \OCP\Util::isDefaultExpireDateEnforced();
        if ($defaultExpireDateEnforced && $shareTime === null) {
            $items = self::getItemShared($itemType, $itemSource);
            $firstItem = \reset($items);
            $shareTime = (int)$firstItem['stime'];
        }

        if ($defaultExpireDateEnforced) {
            // initialize max date with share time
            $maxDate = new \DateTime();
            $maxDate->setTimestamp($shareTime);
            $maxDays = \OC::$server->getConfig()->getAppValue('core', 'shareapi_expire_after_n_days', '7');
            $maxDate->add(new \DateInterval('P' . $maxDays . 'D'));
            if ($date > $maxDate) {
                $warning = 'Cannot set expiration date. Shares cannot expire later than ' . $maxDays . ' after they have been shared';
                $warning_t = $l->t('Cannot set expiration date. Shares cannot expire later than %s after they have been shared', [$maxDays]);
                \OCP\Util::writeLog('OCP\Share', $warning, \OCP\Util::WARN);
                throw new \Exception($warning_t);
            }
        }

        if ($date < $today) {
            $message = 'Cannot set expiration date. Expiration date is in the past';
            $message_t = $l->t('Cannot set expiration date. Expiration date is in the past');
            \OCP\Util::writeLog('OCP\Share', $message, \OCP\Util::WARN);
            throw new \Exception($message_t);
        }

        return $date;
    }

    /**
     * Set expiration date for a share
     * @param string $itemType
     * @param string $itemSource
     * @param string $date expiration date
     * @param int $shareTime timestamp from when the file was shared
     * @return boolean
     * @throws \Exception when the expire date is not set, in the past or further in the future then the enforced date
     */
    public static function setExpirationDate($itemType, $itemSource, $date, $shareTime = null) {
        $user = \OC_User::getUser();
        $l = \OC::$server->getL10N('lib');

        if ($date == '') {
            if (\OCP\Util::isDefaultExpireDateEnforced()) {
                $warning = 'Cannot clear expiration date. Shares are required to have an expiration date.';
                $warning_t = $l->t('Cannot clear expiration date. Shares are required to have an expiration date.');
                \OCP\Util::writeLog('OCP\Share', $warning, \OCP\Util::WARN);
                throw new \Exception($warning_t);
            } else {
                $date = null;
            }
        } else {
            $date = self::validateExpireDate($date, $shareTime, $itemType, $itemSource);
        }
        $query = \OC_DB::prepare('UPDATE `*PREFIX*share` SET `expiration` = ? WHERE `item_type` = ? AND `item_source` = ?  AND `uid_owner` = ? AND `share_type` = ?');
        $query->bindValue(1, $date, 'datetime');
        $query->bindValue(2, $itemType);
        $query->bindValue(3, $itemSource);
        $query->bindValue(4, $user);
        $query->bindValue(5, \OCP\Share::SHARE_TYPE_LINK);

        $query->execute();

        \OC_Hook::emit('OCP\Share', 'post_set_expiration_date', [
            'itemType' => $itemType,
            'itemSource' => $itemSource,
            'date' => $date,
            'uidOwner' => $user
        ]);

        return true;
    }

    /**
     * Retrieve the owner of a connection
     *
     * @param IDBConnection $connection
     * @param int $shareId
     * @throws \Exception
     * @return string uid of share owner
     */
    private static function getShareOwner(IDBConnection $connection, $shareId) {
        $qb = $connection->getQueryBuilder();

        $qb->select('uid_owner')
            ->from('share')
            ->where($qb->expr()->eq('id', $qb->createParameter('shareId')))
            ->setParameter(':shareId', $shareId);
        $result = $qb->execute();
        $result = $result->fetch();

        if (empty($result)) {
            throw new \Exception('Share not found');
        }

        return $result['uid_owner'];
    }

    /**
     * Set password for a public link share
     *
     * @param IUserSession $userSession
     * @param IDBConnection $connection
     * @param IConfig $config
     * @param int $shareId
     * @param string $password
     * @throws \Exception
     * @return boolean
     */
    public static function setPassword(
        IUserSession $userSession,
        IDBConnection $connection,
        IConfig $config,
        $shareId,
        $password
    ) {
        $user = $userSession->getUser();
        if ($user === null) {
            throw new \Exception("User not logged in");
        }

        $uid = self::getShareOwner($connection, $shareId);

        if ($uid !== $user->getUID()) {
            throw new \Exception('Cannot update share of a different user');
        }

        if ($password === '') {
            $password = null;
        }

        //If passwords are enforced the password can't be null
        if (self::enforcePassword($config) && $password === null) {
            throw new \Exception('Cannot remove password');
        }

        self::verifyPassword($password);

        $qb = $connection->getQueryBuilder();
        $qb->update('share')
            ->set('share_with', $qb->createParameter('pass'))
            ->where($qb->expr()->eq('id', $qb->createParameter('shareId')))
            ->setParameter(':pass', $password === null ? null : \OC::$server->getHasher()->hash($password))
            ->setParameter(':shareId', $shareId);

        $qb->execute();

        return true;
    }

    /**
     * Checks whether a share has expired, calls unshareItem() if yes.
     * @param array $item Share data (usually database row)
     * @return boolean True if item was expired, false otherwise.
     */
    protected static function expireItem(array $item) {
        $result = false;

        // only use default expiration date for link shares
        if ((int) $item['share_type'] === self::SHARE_TYPE_LINK) {
            // calculate expiration date
            if (!empty($item['expiration'])) {
                $userDefinedExpire = new \DateTime($item['expiration']);
                $expires = $userDefinedExpire->getTimestamp();
            } else {
                $expires = null;
            }

            // get default expiration settings
            $defaultSettings = Helper::getDefaultExpireSetting();
            $expires = Helper::calculateExpireDate($defaultSettings, $item['stime'], $expires);

            if (\is_int($expires)) {
                $now = \time();
                if ($now > $expires) {
                    self::unshareItem($item);
                    $result = true;
                }
            }
        }
        return $result;
    }

    /**
     * Unshares a share given a share data array
     * @param array $item Share data (usually database row)
     * @param int $newParent parent ID
     * @return void
     */
    protected static function unshareItem(array $item, $newParent = null) {
        $shareType = (int)$item['share_type'];
        $shareWith = null;
        if ($shareType !== \OCP\Share::SHARE_TYPE_LINK) {
            $shareWith = $item['share_with'];
        }

        // Pass all the vars we have for now, they may be useful
        $hookParams = [
            'id'            => $item['id'],
            'itemType'      => $item['item_type'],
            'itemSource'    => $item['item_source'],
            'shareType'     => $shareType,
            'shareWith'     => $shareWith,
            'itemParent'    => $item['parent'],
            'uidOwner'      => $item['uid_owner'],
        ];
        if ($item['item_type'] === 'file' || $item['item_type'] === 'folder') {
            $hookParams['fileSource'] = $item['file_source'];
            $hookParams['fileTarget'] = $item['file_target'];
        }

        \OC_Hook::emit('OCP\Share', 'pre_unshare', $hookParams);
        $deletedShares = Helper::delete($item['id'], false, null, $newParent);
        $deletedShares[] = $hookParams;
        $hookParams['deletedShares'] = $deletedShares;
        \OC_Hook::emit('OCP\Share', 'post_unshare', $hookParams);
        if ((int)$item['share_type'] === \OCP\Share::SHARE_TYPE_REMOTE && \OC::$server->getUserSession()->getUser()) {
            list(, $remote) = Helper::splitUserRemote($item['share_with']);
            self::sendRemoteUnshare($remote, $item['id'], $item['token']);
        }
    }

    /**
     * Get the backend class for the specified item type
     * @param string $itemType
     * @throws \Exception
     * @return \OCP\Share_Backend
     */
    public static function getBackend($itemType) {
        $l = \OC::$server->getL10N('lib');
        if (isset(self::$backends[$itemType])) {
            return self::$backends[$itemType];
        } elseif (isset(self::$backendTypes[$itemType]['class'])) {
            $class = self::$backendTypes[$itemType]['class'];
            if (\class_exists($class)) {
                self::$backends[$itemType] = new $class;
                if (!(self::$backends[$itemType] instanceof \OCP\Share_Backend)) {
                    $message = 'Sharing backend %s must implement the interface OCP\Share_Backend';
                    $message_t = $l->t('Sharing backend %s must implement the interface OCP\Share_Backend', [$class]);
                    \OCP\Util::writeLog('OCP\Share', \sprintf($message, $class), \OCP\Util::ERROR);
                    throw new \Exception($message_t);
                }
                return self::$backends[$itemType];
            } else {
                $message = 'Sharing backend %s not found';
                $message_t = $l->t('Sharing backend %s not found', [$class]);
                \OCP\Util::writeLog('OCP\Share', \sprintf($message, $class), \OCP\Util::ERROR);
                throw new \Exception($message_t);
            }
        }
        $message = 'Sharing backend for %s not found';
        $message_t = $l->t('Sharing backend for %s not found', [$itemType]);
        \OCP\Util::writeLog('OCP\Share', \sprintf($message, $itemType), \OCP\Util::ERROR);
        throw new \Exception($message_t);
    }

    /**
     * Check if resharing is allowed
     * @return boolean true if allowed or false
     *
     * Resharing is allowed by default if not configured
     */
    public static function isResharingAllowed() {
        if (!isset(self::$isResharingAllowed)) {
            if (\OC::$server->getAppConfig()->getValue('core', 'shareapi_allow_resharing', 'yes') == 'yes') {
                self::$isResharingAllowed = true;
            } else {
                self::$isResharingAllowed = false;
            }
        }
        return self::$isResharingAllowed;
    }

    /**
     * Get a list of collection item types for the specified item type
     * @param string $itemType
     * @return array
     */
    private static function getCollectionItemTypes($itemType) {
        $collectionTypes = [$itemType];
        foreach (self::$backendTypes as $type => $backend) {
            if (\in_array($backend['collectionOf'], $collectionTypes)) {
                $collectionTypes[] = $type;
            }
        }
        // TODO Add option for collections to be collection of themselves, only 'folder' does it now...
        if (isset(self::$backendTypes[$itemType]) && (!self::getBackend($itemType) instanceof \OCP\Share_Backend_Collection || $itemType != 'folder')) {
            unset($collectionTypes[0]);
        }
        // Return array if collections were found or the item type is a
        // collection itself - collections can be inside collections
        if (\count($collectionTypes) > 0) {
            return $collectionTypes;
        }
        return false;
    }

    /**
     * Get the owners of items shared with a user.
     *
     * @param string $user The user the items are shared with.
     * @param string $type The type of the items shared with the user.
     * @param boolean $includeCollections Include collection item types (optional)
     * @param boolean $includeOwner include owner in the list of users the item is shared with (optional)
     * @return array
     */
    public static function getSharedItemsOwners($user, $type, $includeCollections = false, $includeOwner = false) {
        // First, we find out if $type is part of a collection (and if that collection is part of
        // another one and so on).
        $collectionTypes = [];
        if (!$includeCollections || !$collectionTypes = self::getCollectionItemTypes($type)) {
            $collectionTypes[] = $type;
        }

        // Of these collection types, along with our original $type, we make a
        // list of the ones for which a sharing backend has been registered.
        // FIXME: Ideally, we wouldn't need to nest getItemsSharedWith in this loop but just call it
        // with its $includeCollections parameter set to true. Unfortunately, this fails currently.
        $allMaybeSharedItems = [];
        foreach ($collectionTypes as $collectionType) {
            if (isset(self::$backends[$collectionType])) {
                $allMaybeSharedItems[$collectionType] = self::getItemsSharedWithUser(
                    $collectionType,
                    $user,
                    self::FORMAT_NONE
                );
            }
        }

        $owners = [];
        if ($includeOwner) {
            $owners[] = $user;
        }

        // We take a look at all shared items of the given $type (or of the collections it is part of)
        // and find out their owners. Then, we gather the tags for the original $type from all owners,
        // and return them as elements of a list that look like "Tag (owner)".
        foreach ($allMaybeSharedItems as $collectionType => $maybeSharedItems) {
            foreach ($maybeSharedItems as $sharedItem) {
                if (isset($sharedItem['id'])) { //workaround for https://github.com/owncloud/core/issues/2814
                    $owners[] = $sharedItem['uid_owner'];
                }
            }
        }

        return $owners;
    }

    /**
     * Get shared items from the database
     * @param string $itemType
     * @param string $item Item source or target (optional)
     * @param int $shareType SHARE_TYPE_USER, SHARE_TYPE_GROUP, SHARE_TYPE_LINK, $shareTypeUserAndGroups, or $shareTypeGroupUserUnique
     * @param string $shareWith User or group the item is being shared with
     * @param string $uidOwner User that is the owner of shared items (optional)
     * @param int $format Format to convert items to with formatItems() (optional)
     * @param mixed $parameters to pass to formatItems() (optional)
     * @param int $limit Number of items to return, -1 to return all matches (optional)
     * @param boolean $includeCollections Include collection item types (optional)
     * @param boolean $itemShareWithBySource (optional)
     * @param boolean $checkExpireDate
     * @return array
     *
     * See public functions getItem(s)... for parameter usage
     *
     */
    public static function getItems(
        $itemType,
        $item = null,
        $shareType = null,
        $shareWith = null,
        $uidOwner = null,
        $format = self::FORMAT_NONE,
        $parameters = null,
        $limit = -1,
        $includeCollections = false,
        $itemShareWithBySource = false,
        $checkExpireDate  = true
    ) {
        if (!self::isEnabled()) {
            return [];
        }
        $backend = self::getBackend($itemType);
        $collectionTypes = false;
        // Get filesystem root to add it to the file target and remove from the
        // file source, match file_source with the file cache
        if ($itemType == 'file' || $itemType == 'folder') {
            if ($uidOwner !== null) {
                $root = \OC\Files\Filesystem::getRoot();
            } else {
                $root = '';
            }
            $where = 'INNER JOIN `*PREFIX*filecache` ON `file_source` = `*PREFIX*filecache`.`fileid` ';
            if (!isset($item)) {
                $where .= ' AND `file_target` IS NOT NULL ';
            }
            $where .= 'INNER JOIN `*PREFIX*storages` ON `numeric_id` = `*PREFIX*filecache`.`storage` ';
            $fileDependent = true;
            $queryArgs = [];
        } else {
            $fileDependent = false;
            $root = '';
            $collectionTypes = self::getCollectionItemTypes($itemType);
            if ($includeCollections && !isset($item) && $collectionTypes) {
                // If includeCollections is true, find collections of this item type, e.g. a music album contains songs
                if (!\in_array($itemType, $collectionTypes)) {
                    $itemTypes = \array_merge([$itemType], $collectionTypes);
                } else {
                    $itemTypes = $collectionTypes;
                }
                $placeholders = \join(',', \array_fill(0, \count($itemTypes), '?'));
                $where = ' WHERE `item_type` IN ('.$placeholders.'))';
                $queryArgs = $itemTypes;
            } else {
                $where = ' WHERE `item_type` = ?';
                $queryArgs = [$itemType];
            }
        }
        if (\OC::$server->getAppConfig()->getValue('core', 'shareapi_allow_links', 'yes') !== 'yes') {
            $where .= ' AND `share_type` != ?';
            $queryArgs[] = self::SHARE_TYPE_LINK;
        }
        if (isset($shareType)) {
            // Include all user and group items
            if ($shareType == self::$shareTypeUserAndGroups && isset($shareWith)) {
                $where .= ' AND ((`share_type` in (?, ?) AND `share_with` = ?) ';
                $queryArgs[] = self::SHARE_TYPE_USER;
                $queryArgs[] = self::$shareTypeGroupUserUnique;
                $queryArgs[] = $shareWith;
                $groups = self::getGroupsForUser($shareWith);
                if (!empty($groups)) {
                    $placeholders = \join(',', \array_fill(0, \count($groups), '?'));
                    $where .= ' OR (`share_type` = ? AND `share_with` IN ('.$placeholders.')) ';
                    $queryArgs[] = self::SHARE_TYPE_GROUP;
                    $queryArgs = \array_merge($queryArgs, $groups);
                }
                $where .= ')';
                // Don't include own group shares
                $where .= ' AND `uid_owner` != ?';
                $queryArgs[] = $shareWith;
            } else {
                $where .= ' AND `share_type` = ?';
                $queryArgs[] = $shareType;
                if (isset($shareWith)) {
                    $where .= ' AND `share_with` = ?';
                    $queryArgs[] = $shareWith;
                }
            }
        }
        if (isset($uidOwner)) {
            $where .= ' AND `uid_owner` = ?';
            $queryArgs[] = $uidOwner;
            if (!isset($shareType)) {
                // Prevent unique user targets for group shares from being selected
                $where .= ' AND `share_type` != ?';
                $queryArgs[] = self::$shareTypeGroupUserUnique;
            }
            if ($fileDependent) {
                $column = 'file_source';
            } else {
                $column = 'item_source';
            }
        } else {
            if ($fileDependent) {
                $column = 'file_target';
            } else {
                $column = 'item_target';
            }
        }
        if (isset($item)) {
            $collectionTypes = self::getCollectionItemTypes($itemType);
            if ($includeCollections && $collectionTypes && !\in_array('folder', $collectionTypes)) {
                $where .= ' AND (';
            } else {
                $where .= ' AND';
            }
            // If looking for own shared items, check item_source else check item_target
            if (isset($uidOwner) || $itemShareWithBySource) {
                // If item type is a file, file source needs to be checked in case the item was converted
                if ($fileDependent) {
                    $where .= ' `file_source` = ?';
                    $column = 'file_source';
                } else {
                    $where .= ' `item_source` = ?';
                    $column = 'item_source';
                }
            } else {
                if ($fileDependent) {
                    $where .= ' `file_target` = ?';
                    $item = \OC\Files\Filesystem::normalizePath($item);
                } else {
                    $where .= ' `item_target` = ?';
                }
            }
            $queryArgs[] = $item;
            if ($includeCollections && $collectionTypes && !\in_array('folder', $collectionTypes)) {
                $placeholders = \join(',', \array_fill(0, \count($collectionTypes), '?'));
                $where .= ' OR `item_type` IN ('.$placeholders.'))';
                $queryArgs = \array_merge($queryArgs, $collectionTypes);
            }
        }

        if ($shareType == self::$shareTypeUserAndGroups && $limit === 1) {
            // Make sure the unique user target is returned if it exists,
            // unique targets should follow the group share in the database
            // If the limit is not 1, the filtering can be done later
            $where .= ' ORDER BY `*PREFIX*share`.`id` DESC';
        } else {
            $where .= ' ORDER BY `*PREFIX*share`.`id` ASC';
        }

        if ($limit != -1 && !$includeCollections) {
            // The limit must be at least 3, because filtering needs to be done
            if ($limit < 3) {
                $queryLimit = 3;
            } else {
                $queryLimit = $limit;
            }
        } else {
            $queryLimit = null;
        }
        $select = self::createSelectStatement($format, $fileDependent, $uidOwner);
        $root = \strlen($root);
        $query = \OC_DB::prepare('SELECT '.$select.' FROM `*PREFIX*share` '.$where, $queryLimit);
        $result = $query->execute($queryArgs);
        if ($result === false) {
            \OCP\Util::writeLog(
                'OCP\Share',
                \OC_DB::getErrorMessage() . ', select=' . $select . ' where=',
                \OCP\Util::ERROR
            );
        }
        $items = [];
        $targets = [];
        $switchedItems = [];
        $mounts = [];
        while ($row = $result->fetchRow()) {
            self::transformDBResults($row);
            // Filter out duplicate group shares for users with unique targets
            if ($fileDependent && !self::isFileReachable($row['path'], $row['storage_id'])) {
                continue;
            }
            if ($row['share_type'] == self::$shareTypeGroupUserUnique && isset($items[$row['parent']])) {
                $row['share_type'] = self::SHARE_TYPE_GROUP;
                $row['unique_name'] = true; // remember that we use a unique name for this user
                $row['share_with'] = $items[$row['parent']]['share_with'];
                // if the group share was unshared from the user we keep the permission, otherwise
                // we take the permission from the parent because this is always the up-to-date
                // permission for the group share
                if ($row['permissions'] > 0) {
                    $row['permissions'] = $items[$row['parent']]['permissions'];
                }
                // Remove the parent group share
                unset($items[$row['parent']]);
                if ($row['permissions'] == 0) {
                    continue;
                }
            } elseif (!isset($uidOwner)) {
                // Check if the same target already exists
                if (isset($targets[$row['id']])) {
                    // Check if the same owner shared with the user twice
                    // through a group and user share - this is allowed
                    $id = $targets[$row['id']];
                    if (isset($items[$id]) && $items[$id]['uid_owner'] == $row['uid_owner']) {
                        // Switch to group share type to ensure resharing conditions aren't bypassed
                        if ($items[$id]['share_type'] != self::SHARE_TYPE_GROUP) {
                            $items[$id]['share_type'] = self::SHARE_TYPE_GROUP;
                            $items[$id]['share_with'] = $row['share_with'];
                        }
                        // Switch ids if sharing permission is granted on only
                        // one share to ensure correct parent is used if resharing
                        if (~(int)$items[$id]['permissions'] & \OCP\Constants::PERMISSION_SHARE
                            && (int)$row['permissions'] & \OCP\Constants::PERMISSION_SHARE) {
                            $items[$row['id']] = $items[$id];
                            $switchedItems[$id] = $row['id'];
                            unset($items[$id]);
                            $id = $row['id'];
                        }
                        $items[$id]['permissions'] |= (int)$row['permissions'];
                    }
                    continue;
                } elseif (!empty($row['parent'])) {
                    $targets[$row['parent']] = $row['id'];
                }
            }
            // Remove root from file source paths if retrieving own shared items
            if (isset($uidOwner, $row['path'])) {
                if (isset($row['parent'])) {
                    $query = \OC_DB::prepare('SELECT `file_target` FROM `*PREFIX*share` WHERE `id` = ?');
                    $parentResult = $query->execute([$row['parent']]);
                    if ($result === false) {
                        \OCP\Util::writeLog(
                            'OCP\Share',
                            'Can\'t select parent: ' .
                            \OC_DB::getErrorMessage() . ', select=' . $select . ' where=' . $where,
                            \OCP\Util::ERROR
                        );
                    } else {
                        $parentRow = $parentResult->fetchRow();
                        $tmpPath = $parentRow['file_target'];
                        // find the right position where the row path continues from the target path
                        $pos = \strrpos($row['path'], $parentRow['file_target']);
                        $subPath = \substr($row['path'], $pos);
                        $splitPath = \explode('/', $subPath);
                        foreach (\array_slice($splitPath, 2) as $pathPart) {
                            $tmpPath = $tmpPath . '/' . $pathPart;
                        }
                        $row['path'] = $tmpPath;
                    }
                } else {
                    if (!isset($mounts[$row['storage']])) {
                        $mountPoints = \OC\Files\Filesystem::getMountByNumericId($row['storage']);
                        if (\is_array($mountPoints) && !empty($mountPoints)) {
                            $mounts[$row['storage']] = \current($mountPoints);
                        }
                    }
                    if (!empty($mounts[$row['storage']])) {
                        $path = $mounts[$row['storage']]->getMountPoint().$row['path'];
                        $relPath = \substr($path, $root); // path relative to data/user
                        $row['path'] = \rtrim($relPath, '/');
                    }
                }
            }

            if ($checkExpireDate) {
                if (self::expireItem($row)) {
                    continue;
                }
            }
            // Check if resharing is allowed, if not remove share permission
            if (isset($row['permissions']) && (!self::isResharingAllowed() | \OCP\Util::isSharingDisabledForUser())) {
                $row['permissions'] &= ~\OCP\Constants::PERMISSION_SHARE;
            }
            // Add display names to result
            $row['share_with_displayname'] = $row['share_with'];
            if (isset($row['share_with']) && $row['share_with'] != '' &&
                $row['share_type'] === self::SHARE_TYPE_USER) {
                $row['share_with_displayname'] = \OCP\User::getDisplayName($row['share_with']);
            } elseif (isset($row['share_with']) && $row['share_with'] != '' &&
                $row['share_type'] === self::SHARE_TYPE_REMOTE) {
                $addressBookEntries = \OC::$server->getContactsManager()->search($row['share_with'], ['CLOUD']);
                foreach ($addressBookEntries as $entry) {
                    foreach ($entry['CLOUD'] as $cloudID) {
                        if ($cloudID === $row['share_with']) {
                            $row['share_with_displayname'] = $entry['FN'];
                        }
                    }
                }
            }
            if (isset($row['uid_owner']) && $row['uid_owner'] != '') {
                $row['displayname_owner'] = \OCP\User::getDisplayName($row['uid_owner']);
            }

            if ($row['permissions'] > 0) {
                $items[$row['id']] = $row;
            }
        }

        // group items if we are looking for items shared with the current user
        if (isset($shareWith) && $shareWith === \OCP\User::getUser()) {
            $items = self::groupItems($items, $itemType);
        }

        if (!empty($items)) {
            $collectionItems = [];
            foreach ($items as &$row) {
                // Return only the item instead of a 2-dimensional array
                if ($limit == 1 && $row[$column] == $item && ($row['item_type'] == $itemType || $itemType == 'file')) {
                    if ($format == self::FORMAT_NONE) {
                        return $row;
                    } else {
                        break;
                    }
                }
                // Check if this is a collection of the requested item type
                if ($includeCollections && $collectionTypes && $row['item_type'] !== 'folder' && \in_array($row['item_type'], $collectionTypes)) {
                    if (($collectionBackend = self::getBackend($row['item_type']))
                        && $collectionBackend instanceof \OCP\Share_Backend_Collection) {
                        // Collections can be inside collections, check if the item is a collection
                        if (isset($item) && $row['item_type'] == $itemType && $row[$column] == $item) {
                            $collectionItems[] = $row;
                        } else {
                            $collection = [];
                            $collection['item_type'] = $row['item_type'];
                            if ($row['item_type'] == 'file' || $row['item_type'] == 'folder') {
                                $collection['path'] = \basename($row['path']);
                            }
                            $row['collection'] = $collection;
                            // Fetch all of the children sources
                            $children = $collectionBackend->getChildren($row[$column]);
                            foreach ($children as $child) {
                                $childItem = $row;
                                $childItem['item_type'] = $itemType;
                                if ($row['item_type'] != 'file' && $row['item_type'] != 'folder') {
                                    $childItem['item_source'] = $child['source'];
                                    $childItem['item_target'] = $child['target'];
                                }
                                if ($backend instanceof \OCP\Share_Backend_File_Dependent) {
                                    if ($row['item_type'] == 'file' || $row['item_type'] == 'folder') {
                                        $childItem['file_source'] = $child['source'];
                                    } else { // TODO is this really needed if we already know that we use the file backend?
                                        $meta = \OC\Files\Filesystem::getFileInfo($child['file_path']);
                                        $childItem['file_source'] = $meta['fileid'];
                                    }
                                    $childItem['file_target'] =
                                        \OC\Files\Filesystem::normalizePath($child['file_path']);
                                }
                                if (isset($item)) {
                                    if ($childItem[$column] == $item) {
                                        // Return only the item instead of a 2-dimensional array
                                        if ($limit == 1) {
                                            if ($format == self::FORMAT_NONE) {
                                                return $childItem;
                                            } else {
                                                // Unset the items array and break out of both loops
                                                $items = [];
                                                $items[] = $childItem;
                                                break 2;
                                            }
                                        } else {
                                            $collectionItems[] = $childItem;
                                        }
                                    }
                                } else {
                                    $collectionItems[] = $childItem;
                                }
                            }
                        }
                    }
                    // Remove collection item
                    $toRemove = $row['id'];
                    if (\array_key_exists($toRemove, $switchedItems)) {
                        $toRemove = $switchedItems[$toRemove];
                    }
                    unset($items[$toRemove]);
                } elseif ($includeCollections && $collectionTypes && \in_array($row['item_type'], $collectionTypes)) {
                    // FIXME: Thats a dirty hack to improve file sharing performance,
                    // see github issue #10588 for more details
                    // Need to find a solution which works for all back-ends
                    $collectionBackend = self::getBackend($row['item_type']);
                    // and need to sort out exactly what class or interface this always is
                    /* @phan-suppress-next-line PhanUndeclaredMethod */
                    $sharedParents = $collectionBackend->getParents($row['item_source']);
                    foreach ($sharedParents as $parent) {
                        $collectionItems[] = $parent;
                    }
                }
            }
            if (!empty($collectionItems)) {
                $collectionItems = \array_unique($collectionItems, SORT_REGULAR);
                $items = \array_merge($items, $collectionItems);
            }

            // filter out invalid items, these can appear when subshare entries exist
            // for a group in which the requested user isn't a member any more
            $items = \array_filter($items, function ($item) {
                return $item['share_type'] !== self::$shareTypeGroupUserUnique;
            });

            return self::formatResult($items, $column, $backend, $format, $parameters);
        } elseif ($includeCollections && $collectionTypes && \in_array('folder', $collectionTypes)) {
            // FIXME: Thats a dirty hack to improve file sharing performance,
            // see github issue #10588 for more details
            // Need to find a solution which works for all back-ends
            $collectionItems = [];
            $collectionBackend = self::getBackend('folder');
            // and need to sort out exactly what class or interface this always is
            /* @phan-suppress-next-line PhanUndeclaredMethod */
            $sharedParents = $collectionBackend->getParents($item, $shareWith, $uidOwner);
            foreach ($sharedParents as $parent) {
                $collectionItems[] = $parent;
            }
            if ($limit === 1) {
                return \reset($collectionItems);
            }
            return self::formatResult($collectionItems, $column, $backend, $format, $parameters);
        }

        return [];
    }

    /**
     * group items with link to the same source
     *
     * @param array $items
     * @param string $itemType
     * @return array of grouped items
     */
    protected static function groupItems($items, $itemType) {
        $fileSharing = ($itemType === 'file' || $itemType === 'folder') ? true : false;

        $result = [];

        foreach ($items as $item) {
            $grouped = false;
            foreach ($result as $key => $r) {
                // for file/folder shares we need to compare file_source, otherwise we compare item_source
                // only group shares if they already point to the same target, otherwise the file where shared
                // before grouping of shares was added. In this case we don't group them toi avoid confusions
                if (($fileSharing && $item['file_source'] === $r['file_source'] && $item['file_target'] === $r['file_target']) ||
                    (!$fileSharing && $item['item_source'] === $r['item_source'] && $item['item_target'] === $r['item_target'])) {
                    // add the first item to the list of grouped shares
                    if (!isset($result[$key]['grouped'])) {
                        $result[$key]['grouped'][] = $result[$key];
                    }
                    $result[$key]['permissions'] = (int) $item['permissions'] | (int) $r['permissions'];
                    $result[$key]['grouped'][] = $item;
                    $grouped = true;
                    break;
                }
            }

            if (!$grouped) {
                $result[] = $item;
            }
        }

        return $result;
    }

    /**
     * Put shared item into the database
     * @param string $itemType Item type
     * @param string $itemSource Item source
     * @param int $shareType SHARE_TYPE_USER, SHARE_TYPE_GROUP, or SHARE_TYPE_LINK
     * @param string $shareWith User or group the item is being shared with
     * @param string $uidOwner User that is the owner of shared item
     * @param int $permissions CRUDS permissions
     * @param boolean|array $parentFolder Parent folder target (optional)
     * @param string $token (optional)
     * @param string $itemSourceName name of the source item (optional)
     * @param \DateTime $expirationDate (optional)
     * @throws \Exception
     * @return mixed id of the new share or false
     */
    private static function put(
        $itemType,
        $itemSource,
        $shareType,
        $shareWith,
        $uidOwner,
        $permissions,
        $parentFolder = null,
        $token = null,
        $itemSourceName = null,
        \DateTime $expirationDate = null
    ) {
        $queriesToExecute = [];
        $suggestedItemTarget = null;
        $groupFileTarget = $fileTarget = $suggestedFileTarget = $filePath = '';
        $groupItemTarget = $itemTarget = $fileSource = $parent = 0;

        $result = self::checkReshare($itemType, $itemSource, $shareType, $shareWith, $uidOwner, $permissions, $itemSourceName, $expirationDate);
        if (!empty($result)) {
            $parent = $result['parent'];
            $itemSource = $result['itemSource'];
            $fileSource = $result['fileSource'];
            $suggestedItemTarget = $result['suggestedItemTarget'];
            $suggestedFileTarget = $result['suggestedFileTarget'];
            $filePath = $result['filePath'];
        }

        $isGroupShare = false;
        if ($shareType == self::SHARE_TYPE_GROUP) {
            $isGroupShare = true;
            if (isset($shareWith['users'])) {
                $users = $shareWith['users'];
            } else {
                $users = self::usersInGroup($shareWith['group']);
            }
            // remove current user from list
            if (\in_array(\OCP\User::getUser(), $users)) {
                unset($users[\array_search(\OCP\User::getUser(), $users)]);
            }
            $groupItemTarget = Helper::generateTarget(
                $itemType,
                $itemSource,
                $shareType,
                $shareWith['group'],
                $uidOwner,
                $suggestedItemTarget
            );
            $groupFileTarget = Helper::generateTarget(
                $itemType,
                $itemSource,
                $shareType,
                $shareWith['group'],
                $uidOwner,
                $filePath
            );

            // add group share to table and remember the id as parent
            $queriesToExecute['groupShare'] = [
                'itemType'            => $itemType,
                'itemSource'        => $itemSource,
                'itemTarget'        => $groupItemTarget,
                'shareType'            => $shareType,
                'shareWith'            => $shareWith['group'],
                'uidOwner'            => $uidOwner,
                'permissions'        => $permissions,
                'shareTime'            => \time(),
                'fileSource'        => $fileSource,
                'fileTarget'        => $groupFileTarget,
                'token'                => $token,
                'parent'            => $parent,
                'expiration'        => $expirationDate,
            ];
        } else {
            $users = [$shareWith];
            $itemTarget = Helper::generateTarget(
                $itemType,
                $itemSource,
                $shareType,
                $shareWith,
                $uidOwner,
                $suggestedItemTarget
            );
        }

        $run = true;
        $error = '';
        $preHookData = [
            'itemType' => $itemType,
            'itemSource' => $itemSource,
            'shareType' => $shareType,
            'uidOwner' => $uidOwner,
            'permissions' => $permissions,
            'fileSource' => $fileSource,
            'expiration' => $expirationDate,
            'token' => $token,
            'run' => &$run,
            'error' => &$error
        ];

        $preHookData['itemTarget'] = ($isGroupShare) ? $groupItemTarget : $itemTarget;
        $preHookData['shareWith'] = ($isGroupShare) ? $shareWith['group'] : $shareWith;

        \OC_Hook::emit('OCP\Share', 'pre_shared', $preHookData);

        if ($run === false) {
            throw new \Exception($error);
        }

        foreach ($users as $user) {
            $sourceId = ($itemType === 'file' || $itemType === 'folder') ? $fileSource : $itemSource;
            $sourceExists = self::getItemSharedWithBySource($itemType, $sourceId, self::FORMAT_NONE, null, true, $user);

            $userShareType = ($isGroupShare) ? self::$shareTypeGroupUserUnique : $shareType;

            if ($sourceExists && $sourceExists['item_source'] === $itemSource) {
                $fileTarget = $sourceExists['file_target'];
                $itemTarget = $sourceExists['item_target'];

                // for group shares we don't need a additional entry if the target is the same
                if ($isGroupShare && $groupItemTarget === $itemTarget) {
                    continue;
                }
            } elseif (!$sourceExists && !$isGroupShare) {
                $itemTarget = Helper::generateTarget(
                    $itemType,
                    $itemSource,
                    $userShareType,
                    $user,
                    $uidOwner,
                    $suggestedItemTarget,
                    $parent
                );
                if (isset($fileSource)) {
                    if ($parentFolder) {
                        if ($parentFolder === true) {
                            $fileTarget = Helper::generateTarget(
                                'file',
                                $filePath,
                                $userShareType,
                                $user,
                                $uidOwner,
                                $suggestedFileTarget,
                                $parent
                            );
                            if ($fileTarget != $groupFileTarget) {
                                $parentFolders[$user]['folder'] = $fileTarget;
                            }
                        } elseif (isset($parentFolder[$user])) {
                            $fileTarget = $parentFolder[$user]['folder'].$itemSource;
                            $parent = $parentFolder[$user]['id'];
                        }
                    } else {
                        $fileTarget = Helper::generateTarget(
                            'file',
                            $filePath,
                            $userShareType,
                            $user,
                            $uidOwner,
                            $suggestedFileTarget,
                            $parent
                        );
                    }
                } else {
                    $fileTarget = null;
                }
            } else {
                // group share which doesn't exists until now, check if we need a unique target for this user

                $itemTarget = Helper::generateTarget(
                    $itemType,
                    $itemSource,
                    self::SHARE_TYPE_USER,
                    $user,
                    $uidOwner,
                    $suggestedItemTarget,
                    $parent
                );

                // do we also need a file target
                if (isset($fileSource)) {
                    $fileTarget = Helper::generateTarget(
                        'file',
                        $filePath,
                        self::SHARE_TYPE_USER,
                        $user,
                        $uidOwner,
                        $suggestedFileTarget,
                        $parent
                    );
                } else {
                    $fileTarget = null;
                }

                if (($itemTarget === $groupItemTarget) &&
                    (!isset($fileSource) || $fileTarget === $groupFileTarget)) {
                    continue;
                }
            }

            $queriesToExecute[] = [
                'itemType'            => $itemType,
                'itemSource'        => $itemSource,
                'itemTarget'        => $itemTarget,
                'shareType'            => $userShareType,
                'shareWith'            => $user,
                'uidOwner'            => $uidOwner,
                'permissions'        => $permissions,
                'shareTime'            => \time(),
                'fileSource'        => $fileSource,
                'fileTarget'        => $fileTarget,
                'token'                => $token,
                'parent'            => $parent,
                'expiration'        => $expirationDate,
            ];
        }

        $id = false;
        if ($isGroupShare) {
            $id = self::insertShare($queriesToExecute['groupShare']);
            // Save this id, any extra rows for this group share will need to reference it
            $parent = \OC::$server->getDatabaseConnection()->lastInsertId('*PREFIX*share');
            unset($queriesToExecute['groupShare']);
        }

        foreach ($queriesToExecute as $shareQuery) {
            $shareQuery['parent'] = $parent;
            $id = self::insertShare($shareQuery);
        }

        $postHookData = [
            'itemType' => $itemType,
            'itemSource' => $itemSource,
            'parent' => $parent,
            'shareType' => $shareType,
            'uidOwner' => $uidOwner,
            'permissions' => $permissions,
            'fileSource' => $fileSource,
            'id' => $parent,
            'token' => $token,
            'expirationDate' => $expirationDate,
        ];

        $postHookData['shareWith'] = ($isGroupShare) ? $shareWith['group'] : $shareWith;
        $postHookData['itemTarget'] = ($isGroupShare) ? $groupItemTarget : $itemTarget;
        $postHookData['fileTarget'] = ($isGroupShare) ? $groupFileTarget : $fileTarget;

        \OC_Hook::emit('OCP\Share', 'post_shared', $postHookData);

        return $id ? $id : false;
    }

    /**
     * @param string $itemType
     * @param string $itemSource
     * @param int $shareType
     * @param string $shareWith
     * @param string $uidOwner
     * @param int $permissions
     * @param string|null $itemSourceName
     * @param null|\DateTime $expirationDate
     */
    private static function checkReshare($itemType, $itemSource, $shareType, $shareWith, $uidOwner, $permissions, $itemSourceName, $expirationDate) {
        $backend = self::getBackend($itemType);

        $l = \OC::$server->getL10N('lib');
        $result = [];

        $column = ($itemType === 'file' || $itemType === 'folder') ? 'file_source' : 'item_source';

        $checkReshare = self::getItemSharedWithBySource($itemType, $itemSource, self::FORMAT_NONE, null, true);
        if ($checkReshare) {
            // Check if attempting to share back to owner
            if ($checkReshare['uid_owner'] == $shareWith && $shareType == self::SHARE_TYPE_USER) {
                $message = 'Sharing %s failed, because the user %s is the original sharer';
                $message_t = $l->t('Sharing failed, because the user %s is the original sharer', [$shareWith]);

                \OCP\Util::writeLog('OCP\Share', \sprintf($message, $itemSourceName, $shareWith), \OCP\Util::DEBUG);
                throw new \Exception($message_t);
            }
        }

        if ($checkReshare && $checkReshare['uid_owner'] !== \OC_User::getUser()) {
            // Check if share permissions is granted
            if (self::isResharingAllowed() && (int)$checkReshare['permissions'] & \OCP\Constants::PERMISSION_SHARE) {
                if (~(int)$checkReshare['permissions'] & $permissions) {
                    $message = 'Sharing %s failed, because the permissions exceed permissions granted to %s';
                    $message_t = $l->t('Sharing %s failed, because the permissions exceed permissions granted to %s', [$itemSourceName, $uidOwner]);

                    \OCP\Util::writeLog('OCP\Share', \sprintf($message, $itemSourceName, $uidOwner), \OCP\Util::DEBUG);
                    throw new \Exception($message_t);
                } else {
                    // TODO Don't check if inside folder
                    $result['parent'] = $checkReshare['id'];

                    $result['expirationDate'] = $expirationDate;
                    // $checkReshare['expiration'] could be null and then is always less than any value
                    if (isset($checkReshare['expiration']) && $checkReshare['expiration'] < $expirationDate) {
                        $result['expirationDate'] = $checkReshare['expiration'];
                    }

                    // only suggest the same name as new target if it is a reshare of the
                    // same file/folder and not the reshare of a child
                    if ($checkReshare[$column] === $itemSource) {
                        $result['filePath'] = $checkReshare['file_target'];
                        $result['itemSource'] = $checkReshare['item_source'];
                        $result['fileSource'] = $checkReshare['file_source'];
                        $result['suggestedItemTarget'] = $checkReshare['item_target'];
                        $result['suggestedFileTarget'] = $checkReshare['file_target'];
                    } else {
                        $result['filePath'] = ($backend instanceof \OCP\Share_Backend_File_Dependent) ? $backend->getFilePath($itemSource, $uidOwner) : null;
                        $result['suggestedItemTarget'] = null;
                        $result['suggestedFileTarget'] = null;
                        $result['itemSource'] = $itemSource;
                        $result['fileSource'] = ($backend instanceof \OCP\Share_Backend_File_Dependent) ? $itemSource : null;
                    }
                }
            } else {
                $message = 'Sharing %s failed, because resharing is not allowed';
                $message_t = $l->t('Sharing %s failed, because resharing is not allowed', [$itemSourceName]);

                \OCP\Util::writeLog('OCP\Share', \sprintf($message, $itemSourceName), \OCP\Util::DEBUG);
                throw new \Exception($message_t);
            }
        } else {
            $result['parent'] = null;
            $result['suggestedItemTarget'] = null;
            $result['suggestedFileTarget'] = null;
            $result['itemSource'] = $itemSource;
            $result['expirationDate'] = $expirationDate;
            if (!$backend->isValidSource($itemSource, $uidOwner)) {
                $message = 'Sharing %s failed, because the sharing backend for '
                    .'%s could not find its source';
                $message_t = $l->t('Sharing %s failed, because the sharing backend for %s could not find its source', [$itemSource, $itemType]);
                \OCP\Util::writeLog('OCP\Share', \sprintf($message, $itemSource, $itemType), \OCP\Util::DEBUG);
                throw new \Exception($message_t);
            }
            if ($backend instanceof \OCP\Share_Backend_File_Dependent) {
                $result['filePath'] = $backend->getFilePath($itemSource, $uidOwner);
                if ($itemType == 'file' || $itemType == 'folder') {
                    $result['fileSource'] = $itemSource;
                } else {
                    $meta = \OC\Files\Filesystem::getFileInfo($result['filePath']);
                    $result['fileSource'] = $meta['fileid'];
                }
                if ($result['fileSource'] == -1) {
                    $message = 'Sharing %s failed, because the file could not be found in the file cache';
                    $message_t = $l->t('Sharing %s failed, because the file could not be found in the file cache', [$itemSource]);

                    \OCP\Util::writeLog('OCP\Share', \sprintf($message, $itemSource), \OCP\Util::DEBUG);
                    throw new \Exception($message_t);
                }
            } else {
                $result['filePath'] = null;
                $result['fileSource'] = null;
            }
        }

        return $result;
    }

    /**
     *
     * @param array $shareData
     * @return mixed false in case of a failure or the id of the new share
     */
    private static function insertShare(array $shareData) {
        $query = \OC_DB::prepare('INSERT INTO `*PREFIX*share` ('
            .' `item_type`, `item_source`, `item_target`, `share_type`,'
            .' `share_with`, `uid_owner`, `permissions`, `stime`, `file_source`,'
            .' `file_target`, `token`, `parent`, `expiration`) VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?)');
        $query->bindValue(1, $shareData['itemType']);
        $query->bindValue(2, $shareData['itemSource']);
        $query->bindValue(3, $shareData['itemTarget']);
        $query->bindValue(4, $shareData['shareType']);
        $query->bindValue(5, $shareData['shareWith']);
        $query->bindValue(6, $shareData['uidOwner']);
        $query->bindValue(7, $shareData['permissions']);
        $query->bindValue(8, $shareData['shareTime']);
        $query->bindValue(9, $shareData['fileSource']);
        $query->bindValue(10, $shareData['fileTarget']);
        $query->bindValue(11, $shareData['token']);
        $query->bindValue(12, $shareData['parent']);
        $query->bindValue(13, $shareData['expiration'], 'datetime');
        $result = $query->execute();

        $id = false;
        if ($result) {
            $id =  \OC::$server->getDatabaseConnection()->lastInsertId('*PREFIX*share');
        }

        return $id;
    }

    /**
     * Delete all shares with type SHARE_TYPE_LINK
     */
    public static function removeAllLinkShares() {
        // Delete any link shares
        $query = \OC_DB::prepare('SELECT `id` FROM `*PREFIX*share` WHERE `share_type` = ?');
        $result = $query->execute([self::SHARE_TYPE_LINK]);
        while ($item = $result->fetchRow()) {
            Helper::delete($item['id']);
        }
    }

    /**
     * In case a password protected link is not yet authenticated this function will return false
     *
     * @param array $linkItem
     * @return boolean
     */
    public static function checkPasswordProtectedShare(array $linkItem) {
        if (!isset($linkItem['share_with'])) {
            return true;
        }
        if (!isset($linkItem['share_type'])) {
            return true;
        }
        if (!isset($linkItem['id'])) {
            return true;
        }

        if ($linkItem['share_type'] != \OCP\Share::SHARE_TYPE_LINK) {
            return true;
        }

        if (\OC::$server->getSession()->exists('public_link_authenticated')
            && \OC::$server->getSession()->get('public_link_authenticated') === (string)$linkItem['id']) {
            return true;
        }

        return false;
    }

    /**
     * construct select statement
     * @param int $format
     * @param boolean $fileDependent ist it a file/folder share or a general share
     * @param string $uidOwner
     * @return string select statement
     */
    private static function createSelectStatement($format, $fileDependent, $uidOwner = null) {
        $select = '*';
        if ($format == self::FORMAT_STATUSES) {
            if ($fileDependent) {
                $select = '`*PREFIX*share`.`id`, `*PREFIX*share`.`parent`, `share_type`, `path`, `storage`, '
                    . '`share_with`, `uid_owner` , `file_source`, `stime`, `*PREFIX*share`.`permissions`, '
                    . '`*PREFIX*storages`.`id` AS `storage_id`, `*PREFIX*filecache`.`parent` as `file_parent`, '
                    . '`uid_initiator`';
            } else {
                $select = '`id`, `parent`, `share_type`, `share_with`, `uid_owner`, `item_source`, `stime`, `*PREFIX*share`.`permissions`';
            }
        } else {
            if (isset($uidOwner)) {
                if ($fileDependent) {
                    $select = '`*PREFIX*share`.`id`, `item_type`, `item_source`, `*PREFIX*share`.`parent`,'
                        . ' `share_type`, `share_with`, `file_source`, `file_target`, `path`, `*PREFIX*share`.`permissions`, `stime`,'
                        . ' `expiration`, `token`, `storage`, `mail_send`, `uid_owner`, '
                        . '`*PREFIX*storages`.`id` AS `storage_id`, `*PREFIX*filecache`.`parent` as `file_parent`';
                } else {
                    $select = '`id`, `item_type`, `item_source`, `parent`, `share_type`, `share_with`, `*PREFIX*share`.`permissions`,'
                        . ' `stime`, `file_source`, `expiration`, `token`, `mail_send`, `uid_owner`';
                }
            } else {
                if ($fileDependent) {
                    if ($format == \OCA\Files_Sharing\ShareBackend\File::FORMAT_GET_FOLDER_CONTENTS || $format == \OCA\Files_Sharing\ShareBackend\File::FORMAT_FILE_APP_ROOT) {
                        $select = '`*PREFIX*share`.`id`, `item_type`, `item_source`, `*PREFIX*share`.`parent`, `uid_owner`, '
                            . '`share_type`, `share_with`, `file_source`, `path`, `file_target`, `stime`, '
                            . '`*PREFIX*share`.`permissions`, `expiration`, `storage`, `*PREFIX*filecache`.`parent` as `file_parent`, '
                            . '`name`, `mtime`, `mimetype`, `mimepart`, `size`, `encrypted`, `etag`, `mail_send`';
                    } else {
                        $select = '`*PREFIX*share`.`id`, `item_type`, `item_source`, `item_target`,'
                            . '`*PREFIX*share`.`parent`, `share_type`, `share_with`, `uid_owner`,'
                            . '`file_source`, `path`, `file_target`, `*PREFIX*share`.`permissions`,'
                            . '`stime`, `expiration`, `token`, `storage`, `mail_send`,'
                            . '`*PREFIX*storages`.`id` AS `storage_id`, `*PREFIX*filecache`.`parent` as `file_parent`';
                    }
                }
            }
        }
        return $select;
    }

    /**
     * transform db results
     * @param array $row result
     */
    private static function transformDBResults(&$row) {
        if (isset($row['id'])) {
            $row['id'] = (int) $row['id'];
        }
        if (isset($row['share_type'])) {
            $row['share_type'] = (int) $row['share_type'];
        }
        if (isset($row['parent'])) {
            $row['parent'] = (int) $row['parent'];
        }
        if (isset($row['file_parent'])) {
            $row['file_parent'] = (int) $row['file_parent'];
        }
        if (isset($row['file_source'])) {
            $row['file_source'] = (int) $row['file_source'];
        }
        if (isset($row['permissions'])) {
            $row['permissions'] = (int) $row['permissions'];
        }
        if (isset($row['storage'])) {
            $row['storage'] = (int) $row['storage'];
        }
        if (isset($row['stime'])) {
            $row['stime'] = (int) $row['stime'];
        }
        if (isset($row['expiration']) && $row['share_type'] !== self::SHARE_TYPE_LINK) {
            // discard expiration date for non-link shares, which might have been
            // set by ancient bugs
            $row['expiration'] = null;
        }
    }

    /**
     * format result
     * @param array $items result
     * @param string $column is it a file share or a general share ('file_target' or 'item_target')
     * @param \OCP\Share_Backend $backend sharing backend
     * @param int $format
     * @param array $parameters additional format parameters
     * @return array format result
     */
    private static function formatResult($items, $column, $backend, $format = self::FORMAT_NONE, $parameters = null) {
        if ($format === self::FORMAT_NONE) {
            return $items;
        } elseif ($format === self::FORMAT_STATUSES) {
            $statuses = [];
            foreach ($items as $item) {
                if ($item['share_type'] === self::SHARE_TYPE_LINK) {
                    if ($item['uid_initiator'] !== \OC::$server->getUserSession()->getUser()->getUID()) {
                        continue;
                    }
                    $statuses[$item[$column]]['link'] = true;
                } elseif (!isset($statuses[$item[$column]])) {
                    $statuses[$item[$column]]['link'] = false;
                }
                if (!empty($item['file_target'])) {
                    $statuses[$item[$column]]['path'] = $item['path'];
                }
            }
            return $statuses;
        } else {
            return $backend->formatItems($items, $format, $parameters);
        }
    }

    /**
     * remove protocol from URL
     *
     * @param string $url
     * @return string
     */
    public static function removeProtocolFromUrl($url) {
        if (\strpos($url, 'https://') === 0) {
            return \substr($url, \strlen('https://'));
        } elseif (\strpos($url, 'http://') === 0) {
            return \substr($url, \strlen('http://'));
        }

        return $url;
    }

    /**
     * try http post first with https and then with http as a fallback
     *
     * @param string $remoteDomain
     * @param string $urlSuffix
     * @param array $fields post parameters
     * @return array
     */
    private static function tryHttpPostToShareEndpoint($remoteDomain, $urlSuffix, array $fields) {
        $allowHttpFallback = \OC::$server->getConfig()->getSystemValue('sharing.federation.allowHttpFallback', false) === true;
        // Always try https first
        $protocol = 'https://';
        $discoveryManager = new DiscoveryManager(
            \OC::$server->getMemCacheFactory(),
            \OC::$server->getHTTPClientService()
        );

        $endpoint = $discoveryManager->getShareEndpoint($protocol . $remoteDomain);
        // Try HTTPS
        $result = \OC::$server->getHTTPHelper()->post(
            $protocol . $remoteDomain . $endpoint . $urlSuffix . '?format=' . self::RESPONSE_FORMAT,
            $fields
        );

        if (isset($result['success']) && $result['success'] === true) {
            // Return if https worked
            return $result;
        } elseif (isset($result['success']) && $result['success'] === false && $allowHttpFallback) {
            // If https failed and we can try http - try that
            $protocol = 'http://';
            $result = \OC::$server->getHTTPHelper()->post(
                $protocol . $remoteDomain . $endpoint . $urlSuffix . '?format=' . self::RESPONSE_FORMAT,
                $fields
            );
            return $result;
        } else {
            // Else we just return the failure
            return $result;
        }
    }

    /**
     * send server-to-server share to remote server
     *
     * @param string $token
     * @param string $shareWith
     * @param string $name
     * @param int $remote_id
     * @param string $owner
     * @return bool
     */
    private static function sendRemoteShare($token, $shareWith, $name, $remote_id, $owner) {
        list($user, $remote) = Helper::splitUserRemote($shareWith);

        if ($user && $remote) {
            $url = $remote;

            $local = \OC::$server->getURLGenerator()->getAbsoluteURL('/');

            $fields = [
                'shareWith' => $user,
                'token' => $token,
                'name' => $name,
                'remoteId' => $remote_id,
                'owner' => $owner,
                'remote' => $local,
            ];

            $url = self::removeProtocolFromUrl($url);
            $result = self::tryHttpPostToShareEndpoint($url, '', $fields);
            $status = \json_decode($result['result'], true);

            if ($result['success'] && ($status['ocs']['meta']['statuscode'] === 100 || $status['ocs']['meta']['statuscode'] === 200)) {
                \OC_Hook::emit('OCP\Share', 'federated_share_added', ['server' => $remote]);
                return true;
            }
        }

        return false;
    }

    /**
     * send server-to-server unshare to remote server
     *
     * @param string $remote url
     * @param int $id share id
     * @param string $token
     * @return bool
     */
    private static function sendRemoteUnshare($remote, $id, $token) {
        $url = \rtrim($remote, '/');
        $fields = ['token' => $token, 'format' => 'json'];
        $url = self::removeProtocolFromUrl($url);
        $result = self::tryHttpPostToShareEndpoint($url, '/'.$id.'/unshare', $fields);
        if (!isset($result['result'])) {
            return false;
        }
        $status = \json_decode($result['result'], true);

        return ($result['success'] && ($status['ocs']['meta']['statuscode'] === 100 || $status['ocs']['meta']['statuscode'] === 200));
    }

    /**
     * check if user can only share with group members
     * @return bool
     */
    public static function shareWithGroupMembersOnly() {
        $value = \OC::$server->getAppConfig()->getValue('core', 'shareapi_only_share_with_group_members', 'no');
        return ($value === 'yes') ? true : false;
    }

    /**
     * check if user can only share with groups he's member of
     * @return bool
     */
    public static function shareWithMembershipGroupOnly() {
        $value = \OC::$server->getAppConfig()->getValue('core', 'shareapi_only_share_with_membership_groups', 'no');
        return ($value === 'yes') ? true : false;
    }

    /**
     * @return bool
     */
    public static function isDefaultExpireDateEnabled() {
        $defaultExpireDateEnabled = \OC::$server->getConfig()->getAppValue('core', 'shareapi_default_expire_date', 'no');
        return ($defaultExpireDateEnabled === "yes") ? true : false;
    }

    /**
     * @return bool
     */
    public static function enforceDefaultExpireDate() {
        $enforceDefaultExpireDate = \OC::$server->getConfig()->getAppValue('core', 'shareapi_enforce_expire_date', 'no');
        return ($enforceDefaultExpireDate === "yes") ? true : false;
    }

    /**
     * @return int
     */
    public static function getExpireInterval() {
        return (int)\OC::$server->getConfig()->getAppValue('core', 'shareapi_expire_after_n_days', '7');
    }

    /**
     * Checks whether the given path is reachable for the given owner
     *
     * @param string $path path relative to files
     * @param string $ownerStorageId storage id of the owner
     *
     * @return boolean true if file is reachable, false otherwise
     */
    private static function isFileReachable($path, $ownerStorageId) {
        // if outside the home storage, file is always considered reachable
        if (!(
            \substr($ownerStorageId, 0, 6) === 'home::' ||
            \substr($ownerStorageId, 0, 13) === 'object::user:'
        )) {
            return true;
        }

        // if inside the home storage, the file has to be under "/files/"
        $path = \ltrim($path, '/');
        if (\substr($path, 0, 6) === 'files/') {
            return true;
        }

        return false;
    }

    /**
     * @param IConfig $config
     * @return bool
     */
    public static function enforcePassword(IConfig $config) {
        $enforcePassword = $config->getAppValue('core', 'shareapi_enforce_links_password', 'no');
        return ($enforcePassword === "yes") ? true : false;
    }

    /**
     * Get all share entries, including non-unique group items
     *
     * @param string $owner
     * @return array
     */
    public static function getAllSharesForOwner($owner) {
        $query = 'SELECT * FROM `*PREFIX*share` WHERE `uid_owner` = ?';
        $result = \OC::$server->getDatabaseConnection()->executeQuery($query, [$owner]);
        return $result->fetchAll();
    }

    /**
     * Get all share entries, including non-unique group items for a file
     *
     * @param int $id
     * @return array
     */
    public static function getAllSharesForFileId($id) {
        $query = 'SELECT * FROM `*PREFIX*share` WHERE `file_source` = ?';
        $result = \OC::$server->getDatabaseConnection()->executeQuery($query, [$id]);
        return $result->fetchAll();
    }

    /**
     * @param string $password
     * @throws \Exception
     */
    private static function verifyPassword($password) {
        $accepted = true;
        $message = '';
        \OCP\Util::emitHook('\OC\Share', 'verifyPassword', [
            'password' => $password,
            'accepted' => &$accepted,
            'message' => &$message
        ]);

        if (!$accepted) {
            throw new \Exception($message);
        }

        \OC::$server->getEventDispatcher()->dispatch(
            new GenericEvent(null, ['password' => $password]),
            'OCP\Share::validatePassword'
        );
    }

    /**
     * @param $user
     * @return Group[]
     */
    private static function getGroupsForUser($user) {
        $groups = \OC::$server->getGroupManager()->getUserIdGroups($user, 'sharing');
        return \array_values(\array_map(function (Group $g) {
            return $g->getGID();
        }, $groups));
    }

    /**
     * @param $group
     * @return mixed
     */
    private static function usersInGroup($group) {
        $g = \OC::$server->getGroupManager()->get($group);
        if ($g === null) {
            return [];
        }
        return \array_values(\array_map(function (IUser $u) {
            return $u->getUID();
        }, $g->getUsers()));
    }
}