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apps/files_external/lib/Lib/Storage/SMB.php

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<?php
/**
 * @author Arthur Schiwon <blizzz@arthur-schiwon.de>
 * @author Jesús Macias <jmacias@solidgear.es>
 * @author Jörn Friedrich Dreyer <jfd@butonic.de>
 * @author Juan Pablo Villafañez <jvillafanez@solidgear.es>
 * @author Michael Gapczynski <GapczynskiM@gmail.com>
 * @author Morris Jobke <hey@morrisjobke.de>
 * @author Philipp Kapfer <philipp.kapfer@gmx.at>
 * @author Robin Appelman <icewind@owncloud.com>
 * @author Robin McCorkell <robin@mccorkell.me.uk>
 * @author Thomas Müller <thomas.mueller@tmit.eu>
 * @author Vincent Petry <pvince81@owncloud.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 OCA\Files_External\Lib\Storage;

use Icewind\SMB\Exception\AlreadyExistsException;
use Icewind\SMB\Exception\ConnectException;
use Icewind\SMB\Exception\Exception;
use Icewind\SMB\Exception\ForbiddenException;
use Icewind\SMB\Exception\NotFoundException;
use Icewind\SMB\BasicAuth;
use Icewind\SMB\IFileInfo;
use Icewind\SMB\IServer;
use Icewind\SMB\Native\NativeServer;
use Icewind\SMB\Wrapped\FileInfo;
use Icewind\SMB\ServerFactory;
use Icewind\SMB\System;
use Icewind\SMB\IShare;
use Icewind\Streams\CallbackWrapper;
use Icewind\Streams\IteratorDirectory;
use OC\Cache\CappedMemoryCache;
use OC\Files\Filesystem;
use OCP\Files\Storage\StorageAdapter;
use OCP\Files\StorageNotAvailableException;
use OCP\Util;

class SMB extends StorageAdapter {
    /** @var bool */
    protected $logActive;

    /**
     * @var IServer
     */
    protected $server;

    /**
     * @var IShare
     */
    protected $share;

    /**
     * @var string
     */
    protected $root;

    /**
     * @var CappedMemoryCache
     */
    protected $statCache;

    public function __construct($params) {
        // log switch might be set already (from a subclass), so don't change it.
        if (!isset($this->logActive)) {
            $this->logActive = \OC::$server->getConfig()->getSystemValue('smb.logging.enable', false) === true;
        }

        $loggedParams = $params;
        // remove password from log if it is set
        if (!empty($loggedParams['password'])) {
            $loggedParams['password'] = '***removed***';
        }
        $this->log('enter: '.__FUNCTION__.'('.\json_encode($loggedParams).')');

        if (isset($params['host'], $params['user'], $params['password'], $params['share'])) {
            $domain = $params['domain'] ?? '';

            $auth = new BasicAuth($params['user'], $domain, $params['password']);
            $serverFactory = new ServerFactory();
            $this->server = $serverFactory->createServer($params['host'], $auth);
            $this->share = $this->server->getShare(\trim($params['share'], '/'));

            $shareClass = \get_class($this->share);
            $this->log("using $shareClass for the connection");

            $this->root = isset($params['root']) ? $params['root'] : '/';
            if (!$this->root || $this->root[0] != '/') {
                $this->root = '/' . $this->root;
            }
            if (\substr($this->root, -1, 1) !== '/') {
                $this->root .= '/';
            }
        } else {
            $ex = new \Exception('Invalid configuration: '.\json_encode($loggedParams));
            $this->leave(__FUNCTION__, $ex);
            throw $ex;
        }
        $this->statCache = new CappedMemoryCache();
        $this->log('leave: '.__FUNCTION__.', getId:'.$this->getId());
    }

    public function getId(): string {
        // FIXME: double slash to keep compatible with the old storage ids,
        // failure to do so will lead to creation of a new storage id and
        // loss of shares from the storage
        return 'smb::' . $this->server->getAuth()->getUsername() . '@' . $this->server->getHost() . '//' . $this->share->getName() . '/' . $this->root;
    }

    /**
     * @param string $path
     * @return string
     */
    protected function buildPath($path) {
        $this->log('enter: '.__FUNCTION__."($path)");
        $result = Filesystem::normalizePath($this->root . '/' . $path, true, false, true);
        return $this->leave(__FUNCTION__, $result);
    }

    /**
     * @param string $path
     * @return \Icewind\SMB\IFileInfo
     * @throws StorageNotAvailableException
     * @throws ForbiddenException
     * @throws NotFoundException
     */
    protected function getFileInfo($path) {
        $this->log('enter: '.__FUNCTION__."($path)");
        $path = $this->buildPath($path);
        if (!isset($this->statCache[$path])) {
            try {
                $this->log("stat fetching '$path'");
                try {
                    $this->statCache[$path] = $this->share->stat($path);
                } catch (NotFoundException $e) {
                    if ($this->share instanceof IShare) {
                        // smbclient may have problems with the allinfo cmd
                        $this->log("stat for '$path' failed, trying to read parent dir");
                        $infos = $this->share->dir(\dirname($path));
                        foreach ($infos as $fileInfo) {
                            if ($fileInfo->getName() === \basename($path)) {
                                $this->statCache[$path] = $fileInfo;
                                break;
                            }
                        }
                        if (empty($this->statCache[$path])) {
                            $this->leave(__FUNCTION__, $e);
                            throw $e;
                        }
                    } else {
                        // trust the results of libsmb
                        $this->leave(__FUNCTION__, $e);
                        throw $e;
                    }
                }
                if ($this->isRootDir($path) && $this->statCache[$path]->isHidden()) {
                    $this->log("unhiding stat for '$path'");
                    // make root never hidden, may happen when accessing a shared drive (mode is 22, archived and readonly - neither is true ... whatever)
                    if ($this->statCache[$path]->isReadOnly()) {
                        $mode = IFileInfo::MODE_DIRECTORY & IFileInfo::MODE_READONLY;
                    } else {
                        $mode = IFileInfo::MODE_DIRECTORY;
                    }
                    $this->statCache[$path] = new FileInfo(
                        $path,
                        '',
                        0,
                        $this->statCache[$path]->getMTime(),
                        $mode,
                        function () {
                            return [];
                        }
                    );
                }
            } catch (ConnectException $e) {
                $ex = new StorageNotAvailableException(
                    $e->getMessage(),
                    $e->getCode(),
                    $e
                );
                $this->leave(__FUNCTION__, $ex);
                throw $ex;
            } catch (ForbiddenException $e) {
                if ($this->remoteIsShare() && $this->isRootDir($path)) { //mtime may not work for share root
                    $this->log("faking stat for forbidden '$path'");
                    $this->statCache[$path] = new FileInfo(
                        $path,
                        '',
                        0,
                        $this->shareMTime(),
                        IFileInfo::MODE_DIRECTORY,
                        function () {
                            return [];
                        }
                    );
                } else {
                    $this->leave(__FUNCTION__, $e);
                    throw $e;
                }
            }
        } else {
            $this->log("stat cache hit for '$path'");
        }
        $result = $this->statCache[$path];
        return $this->leave(__FUNCTION__, $result);
    }

    /**
     * @param string $path
     * @return \Icewind\SMB\IFileInfo[]
     * @throws StorageNotAvailableException
     */
    protected function getFolderContents($path) {
        $this->log('enter: '.__FUNCTION__."($path)");
        try {
            $path = $this->buildPath($path);
            $result = [];
            $children = $this->share->dir($path);
            $trimmedPath = \rtrim($path, '/');
            foreach ($children as $fileInfo) {
                $fullPath = "{$trimmedPath}/{$fileInfo->getName()}";
                if (isset($this->statCache[$fullPath])) {
                    // reference in the cache might have its fileinfo's mode
                    // already resolved, so use that
                    $fileInfo = $this->statCache[$fullPath];
                }
                // check if the file is readable before adding it to the list
                // can't use "isReadable" function here, use smb internals instead
                try {
                    if ($fileInfo->isHidden()) {
                        $this->log("{$fileInfo->getName()} isn't readable, skipping", Util::DEBUG);
                    } else {
                        $result[] = $fileInfo;
                        //remember entry so we can answer file_exists and filetype without a full stat
                        $this->statCache[$fullPath] = $fileInfo;
                    }
                } catch (NotFoundException $e) {
                    $this->swallow(__FUNCTION__, $e);
                } catch (ForbiddenException $e) {
                    $this->swallow(__FUNCTION__, $e);
                }
            }
        } catch (ConnectException $e) {
            $ex = new StorageNotAvailableException(
                $e->getMessage(),
                $e->getCode(),
                $e
            );
            $this->leave(__FUNCTION__, $ex);
            throw $ex;
        }
        return $this->leave(__FUNCTION__, $result);
    }

    /**
     * @param \Icewind\SMB\IFileInfo $info
     * @return array
     */
    protected function formatInfo($info) {
        $result = [
            'size' => $info->getSize(),
            'mtime' => $info->getMTime(),
        ];
        if ($info->isDirectory()) {
            $result['type'] = 'dir';
        } else {
            $result['type'] = 'file';
        }
        return $result;
    }

    /**
     * Rename the files. If the source or the target is the root, the rename won't happen.
     *
     * @param string $source the old name of the path
     * @param string $target the new name of the path
     * @return bool true if the rename is successful, false otherwise
     */
    public function rename($source, $target) {
        $this->log("enter: rename('$source', '$target')", Util::DEBUG);

        if ($this->isRootDir($source) || $this->isRootDir($target)) {
            $this->log("refusing to rename \"$source\" to \"$target\"");
            return $this->leave(__FUNCTION__, false);
        }

        $buildSource = $this->buildPath($source);
        $buildTarget = $this->buildPath($target);
        try {
            $result = $this->share->rename($buildSource, $buildTarget);
            if ($result) {
                $this->removeFromCache($buildSource);
                $this->removeFromCache($buildTarget);
            }
        } catch (AlreadyExistsException $e) {
            $this->swallow(__FUNCTION__, $e);
            if ($this->unlink($target)) {
                $result = $this->share->rename($buildSource, $buildTarget);
                if ($result) {
                    $this->removeFromCache($buildSource);
                    $this->removeFromCache($buildTarget);
                }
            } else {
                $result = false;
            }
        } catch (ConnectException $e) {
            $ex = new StorageNotAvailableException($e->getMessage(), $e->getCode(), $e);
            $this->leave(__FUNCTION__, $ex);
            throw $ex;
        } catch (Exception $e) {
            $this->swallow(__FUNCTION__, $e);
            // Icewind\SMB\Exception\Exception, not a plain exception
            if ($e->getCode() === 22) {
                // some servers seem to return an error code 22 instead of the expected AlreadyExistException
                if ($this->unlink($target)) {
                    $result = $this->share->rename($buildSource, $buildTarget);
                    if ($result) {
                        $this->removeFromCache($buildSource);
                        $this->removeFromCache($buildTarget);
                    }
                } else {
                    $result = false;
                }
            } else {
                $result = false;
            }
        } catch (\Exception $e) {
            $this->swallow(__FUNCTION__, $e);
            $result = false;
        }
        return $this->leave(__FUNCTION__, $result);
    }

    private function removeFromCache($path) {
        // TODO The CappedCache does not really clear by prefix. It just clears all.
        '@phan-var \OC\Cache\CappedMemoryCache $this->statCache';
        $this->statCache->clear("$path/");
        unset($this->statCache[$path]);
    }
    /**
     * @param string $path
     * @return array
     */
    public function stat($path) {
        $this->log('enter: '.__FUNCTION__."($path)");
        try {
            $result = $this->formatInfo($this->getFileInfo($path));
        } catch (ConnectException $e) {
            $ex = new StorageNotAvailableException($e->getMessage(), $e->getCode(), $e);
            $this->leave(__FUNCTION__, $ex);
            throw $ex;
        } catch (Exception $e) {
            $this->swallow(__FUNCTION__, $e);
            $result = false;
        }
        return $this->leave(__FUNCTION__, $result);
    }

    /**
     * get the best guess for the modification time of the share
     * NOTE: modification times do not bubble up the directory tree, basically
     * we are just guessing a time
     *
     * @return int the calculated mtime for the folder
     */
    private function shareMTime() {
        $this->log('enter: '.__FUNCTION__, Util::DEBUG);
        $files = $this->share->dir($this->root);
        $result = 0;
        foreach ($files as $fileInfo) {
            if ($fileInfo->getMTime() > $result) {
                $result = $fileInfo->getMTime();
            }
        }
        return $this->leave(__FUNCTION__, $result);
    }
    /**
     * Check if the path is our root dir (not the smb one)
     *
     * @param string $path the path
     * @return bool true if it's root, false if not
     */
    private function isRootDir($path) {
        $this->log('enter: '.__FUNCTION__."($path)", Util::DEBUG);
        $result = $path === '' || $path === '/' || $path === '.';
        return $this->leave(__FUNCTION__, $result);
    }
    /**
     * Check if our root points to a smb share
     *
     * @return bool true if our root points to a share false otherwise
     */
    private function remoteIsShare() {
        $this->log('enter: '.__FUNCTION__, Util::DEBUG);
        $result = $this->share->getName() && (!$this->root || $this->root === '/');
        return $this->leave(__FUNCTION__, $result);
    }
    /**
     * @param string $path
     * @return bool
     * @throws StorageNotAvailableException
     */
    public function unlink($path) {
        $this->log('enter: '.__FUNCTION__."($path)");

        if ($this->isRootDir($path)) {
            $this->log("refusing to unlink \"$path\"");
            return $this->leave(__FUNCTION__, false);
        }

        $result = false;
        try {
            if ($this->is_dir($path)) {
                $result = $this->rmdir($path);
            } else {
                $buildPath = $this->buildPath($path);
                $this->share->del($buildPath);
                unset($this->statCache[$buildPath]);
                $result = true;
            }
        } catch (ConnectException $e) {
            $ex = new StorageNotAvailableException($e->getMessage(), $e->getCode(), $e);
            $this->leave(__FUNCTION__, $ex);
            throw $ex;
        } catch (Exception $e) {
            $this->swallow(__FUNCTION__, $e);
        }
        return $this->leave(__FUNCTION__, $result);
    }

    /**
     * check if a file or folder has been updated since $time
     *
     * @param string $path
     * @param int $time
     * @return bool
     */
    public function hasUpdated($path, $time) {
        $this->log('enter: '.__FUNCTION__."($path, $time)");
        $actualTime = $this->filemtime($path);
        $result = $actualTime > $time;
        return $this->leave(__FUNCTION__, $result);
    }

    /**
     * @param string $path
     * @param string $mode
     * @return resource
     * @throws StorageNotAvailableException
     */
    public function fopen($path, $mode) {
        $this->log('enter: '.__FUNCTION__."($path, $mode)");
        $fullPath = $this->buildPath($path);
        $result = false;
        try {
            switch ($mode) {
                case 'r':
                case 'rb':
                    if ($this->file_exists($path)) {
                        $result = $this->share->read($fullPath);
                    }
                    break;
                case 'w':
                case 'wb':
                    $source = $this->share->write($fullPath);
                    $result = CallBackWrapper::wrap($source, null, null, function () use ($fullPath) {
                        unset($this->statCache[$fullPath]);
                    });
                    break;
                case 'a':
                case 'ab':
                case 'r+':
                case 'w+':
                case 'wb+':
                case 'a+':
                case 'x':
                case 'x+':
                case 'c':
                case 'c+':
                    //emulate these
                    if (\strrpos($path, '.') !== false) {
                        $ext = \substr($path, \strrpos($path, '.'));
                    } else {
                        $ext = '';
                    }
                    if ($this->file_exists($path)) {
                        if (!$this->isUpdatable($path)) {
                            break;
                        }
                        $tmpFile = $this->getCachedFile($path);
                    } else {
                        if (!$this->isCreatable(\dirname($path))) {
                            break;
                        }
                        $tmpFile = \OC::$server->getTempManager()->getTemporaryFile($ext);
                    }
                    $source = \fopen($tmpFile, $mode);
                    $share = $this->share;
                    $result = CallbackWrapper::wrap($source, null, null, function () use ($tmpFile, $fullPath, $share) {
                        unset($this->statCache[$fullPath]);
                        $share->put($tmpFile, $fullPath);
                        \unlink($tmpFile);
                    });
            }
        } catch (ConnectException $e) {
            $ex = new StorageNotAvailableException($e->getMessage(), $e->getCode(), $e);
            $this->leave(__FUNCTION__, $ex);
            throw $ex;
        } catch (Exception $e) {
            $this->swallow(__FUNCTION__, $e);
        }
        return $this->leave(__FUNCTION__, $result);
    }

    public function rmdir($path) {
        $this->log('enter: '.__FUNCTION__."($path)");

        if ($this->isRootDir($path)) {
            $this->log("refusing to delete \"$path\"");
            return $this->leave(__FUNCTION__, false);
        }

        $result = false;
        try {
            $buildPath = $this->buildPath($path);
            $content = $this->share->dir($buildPath);
            foreach ($content as $file) {
                if ($file->isDirectory()) {
                    $this->rmdir($path . '/' . $file->getName());
                } else {
                    $this->share->del($file->getPath());
                }
            }
            $this->share->rmdir($buildPath);
            $this->removeFromCache($buildPath);
            $result = true;
        } catch (ConnectException $e) {
            $ex = new StorageNotAvailableException($e->getMessage(), $e->getCode(), $e);
            $this->leave(__FUNCTION__, $ex);
            throw $ex;
        } catch (Exception $e) {
            $this->swallow(__FUNCTION__, $e);
        }
        return $this->leave(__FUNCTION__, $result);
    }

    public function touch($path, $time = null) {
        $this->log('enter: '.__FUNCTION__."($path, $time)");
        $result = false;
        try {
            if (!$this->file_exists($path)) {
                $fh = $this->share->write($this->buildPath($path));
                \fclose($fh);
                $result = true;
            }
        } catch (ConnectException $e) {
            $ex = new StorageNotAvailableException($e->getMessage(), $e->getCode(), $e);
            $this->leave(__FUNCTION__, $ex);
            throw $ex;
        } catch (Exception $e) {
            $this->swallow(__FUNCTION__, $e);
        }
        return $this->leave(__FUNCTION__, $result);
    }

    public function opendir($path) {
        $this->log('enter: '.__FUNCTION__."($path)");
        $result = false;
        try {
            $files = $this->getFolderContents($path);
            $names = \array_map(function ($info) {
                /** @var \Icewind\SMB\IFileInfo $info */
                return $info->getName();
            }, $files);
            $result = IteratorDirectory::wrap($names);
        } catch (ConnectException $e) {
            $ex = new StorageNotAvailableException($e->getMessage(), $e->getCode(), $e);
            $this->leave(__FUNCTION__, $ex);
            throw $ex;
        } catch (Exception $e) {
            $this->swallow(__FUNCTION__, $e);
        }
        return $this->leave(__FUNCTION__, $result);
    }

    public function filetype($path) {
        $this->log('enter: '.__FUNCTION__."($path)");
        $result = false;
        try {
            $result = $this->getFileInfo($path)->isDirectory() ? 'dir' : 'file';
        } catch (ConnectException $e) {
            $ex = new StorageNotAvailableException($e->getMessage(), $e->getCode(), $e);
            $this->leave(__FUNCTION__, $ex);
            throw $ex;
        } catch (Exception $e) {
            $this->swallow(__FUNCTION__, $e);
        }
        return $this->leave(__FUNCTION__, $result);
    }

    public function mkdir($path) {
        $this->log('enter: '.__FUNCTION__."($path)");
        $result = false;
        $path = $this->buildPath($path);
        try {
            $result = $this->share->mkdir($path);
        } catch (ConnectException $e) {
            $ex = new StorageNotAvailableException($e->getMessage(), $e->getCode(), $e);
            $this->leave(__FUNCTION__, $ex);
            throw $ex;
        } catch (Exception $e) {
            $this->swallow(__FUNCTION__, $e);
        }
        return $this->leave(__FUNCTION__, $result);
    }

    public function file_exists($path) {
        $this->log('enter: '.__FUNCTION__."($path)");
        $result = false;
        try {
            $this->getFileInfo($path);
            $result = true;
        } catch (ConnectException $e) {
            $ex = new StorageNotAvailableException($e->getMessage(), $e->getCode(), $e);
            $this->leave(__FUNCTION__, $ex);
            throw $ex;
        } catch (Exception $e) {
            $this->swallow(__FUNCTION__, $e);
        }
        return $this->leave(__FUNCTION__, $result);
    }

    public function isReadable($path) {
        $this->log('enter: '.__FUNCTION__."($path)");
        if ($this->isRootDir($path)) {
            return $this->leave(__FUNCTION__, true);
        }

        $result = false;
        try {
            $info = $this->getFileInfo($path);
            $result = !$info->isHidden();
        } catch (ConnectException $e) {
            $ex = new StorageNotAvailableException($e->getMessage(), $e->getCode(), $e);
            $this->leave(__FUNCTION__, $ex);
            throw $ex;
        } catch (Exception $e) {
            $this->swallow(__FUNCTION__, $e);
        }
        return $this->leave(__FUNCTION__, $result);
    }

    public function isCreatable($path) {
        $this->log('enter: '.__FUNCTION__."($path)");
        if ($this->isRootDir($path)) {
            return $this->leave(__FUNCTION__, true);
        }
        return $this->leave(__FUNCTION__, parent::isCreatable($path));
    }

    public function isUpdatable($path) {
        $this->log('enter: '.__FUNCTION__."($path)");
        if ($this->isRootDir($path)) {
            // root path mustn't be changed
            return $this->leave(__FUNCTION__, false);
        }

        $result = false;
        try {
            $info = $this->getFileInfo($path);
            // following windows behaviour for read-only folders: they can be written into
            // (https://support.microsoft.com/en-us/kb/326549 - "cause" section)
            $result = !$info->isHidden() && (!$info->isReadOnly() || $this->is_dir($path));
        } catch (ConnectException $e) {
            $ex = new StorageNotAvailableException($e->getMessage(), $e->getCode(), $e);
            $this->leave(__FUNCTION__, $ex);
            throw $ex;
        } catch (Exception $e) {
            $this->swallow(__FUNCTION__, $e);
        }
        return $this->leave(__FUNCTION__, $result);
    }

    public function isDeletable($path) {
        $this->log('enter: '.__FUNCTION__."($path)");
        if ($this->isRootDir($path)) {
            // root path mustn't be deleted
            return $this->leave(__FUNCTION__, false);
        }

        $result = false;
        try {
            $info = $this->getFileInfo($path);
            $result = !$info->isHidden() && !$info->isReadOnly();
        } catch (ConnectException $e) {
            $ex = new StorageNotAvailableException($e->getMessage(), $e->getCode(), $e);
            $this->leave(__FUNCTION__, $ex);
            throw $ex;
        } catch (Exception $e) {
            $this->swallow(__FUNCTION__, $e);
        }
        return $this->leave(__FUNCTION__, $result);
    }

    /**
     * check if smbclient is installed
     */
    public static function checkDependencies() {
        return (
            (bool)\OC_Helper::findBinaryPath('smbclient')
            || NativeServer::available(new System())
        ) ? true : ['smbclient'];
    }

    /**
     * Test a storage for availability
     *
     * @return bool
     */
    public function test() {
        $this->log('enter: '.__FUNCTION__."()");
        $result = false;
        try {
            $result = parent::test();
        } catch (Exception $e) {
            $this->swallow(__FUNCTION__, $e);
        }
        return $this->leave(__FUNCTION__, $result);
    }

    /**
     * @param string $message
     * @param int $level
     * @param string $from
     */
    private function log($message, $level = Util::DEBUG, $from = 'smb') {
        if ($this->logActive) {
            Util::writeLog($from, $message, $level);
        }
    }

    /**
     * if smb.logging.enable is set to true in the config will log a leave line
     * with the given function, the return value or the exception
     *
     * @param $function
     * @param mixed $result an exception will be logged and then returned
     * @return mixed
     */
    private function leave($function, $result) {
        if (!$this->logActive) {
            //don't bother building log strings
            return $result;
        } elseif ($result === true) {
            Util::writeLog('smb', "leave: $function, return true", Util::DEBUG);
        } elseif ($result === false) {
            Util::writeLog('smb', "leave: $function, return false", Util::DEBUG);
        } elseif (\is_string($result)) {
            Util::writeLog('smb', "leave: $function, return '$result'", Util::DEBUG);
        } elseif (\is_resource($result)) {
            Util::writeLog('smb', "leave: $function, return resource", Util::DEBUG);
        } elseif ($result instanceof \Exception) {
            Util::writeLog('smb', "leave: $function, throw ".\get_class($result)
                .' - code: '.$result->getCode()
                .' message: '.$result->getMessage()
                .' trace: '.$result->getTraceAsString(), Util::DEBUG);
        } else {
            Util::writeLog('smb', "leave: $function, return ".\json_encode($result, true), Util::DEBUG);
        }
        return $result;
    }

    private function swallow($function, \Exception $exception) {
        if ($this->logActive) {
            Util::writeLog('smb', "$function swallowing ".\get_class($exception)
                .' - code: '.$exception->getCode()
                .' message: '.$exception->getMessage()
                .' trace: '.$exception->getTraceAsString(), Util::DEBUG);
        }
    }

    /**
     * immediately close / free connection
     */
    public function __destruct() {
        unset($this->share);
    }
}