RecordHistory.php

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<?php
namespace TYPO3\CMS\Backend\History;

/*
 * This file is part of the TYPO3 CMS project.
 *
 * It is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License, either version 2
 * of the License, or any later version.
 *
 * For the full copyright and license information, please read the
 * LICENSE.txt file that was distributed with this source code.
 *
 * The TYPO3 project - inspiring people to share!
 */

use TYPO3\CMS\Backend\Backend\Avatar\Avatar;
use TYPO3\CMS\Backend\Utility\BackendUtility;
use TYPO3\CMS\Core\DataHandling\DataHandler;
use TYPO3\CMS\Core\Imaging\Icon;
use TYPO3\CMS\Core\Imaging\IconFactory;
use TYPO3\CMS\Core\Type\Bitmask\Permission;
use TYPO3\CMS\Core\Utility\DiffUtility;
use TYPO3\CMS\Core\Utility\GeneralUtility;
use TYPO3\CMS\Core\Utility\HttpUtility;

class RecordHistory
{
    public $maxSteps = 20;

    public $showDiff = 1;

    public $showSubElements = 1;

    public $showInsertDelete = 1;

    public $element;

    public $lastSyslogId;

    public $returnUrl;

    public $changeLog = [];

    public $showMarked = false;

    protected $recordCache = [];

    protected $pageAccessCache = [];

    protected $iconFactory;

    public function __construct()
    {
        $this->iconFactory = GeneralUtility::makeInstance(IconFactory::class);
        // GPvars:
        $this->element = $this->getArgument('element');
        $this->returnUrl = $this->getArgument('returnUrl');
        $this->lastSyslogId = $this->getArgument('diff');
        $this->rollbackFields = $this->getArgument('rollbackFields');
        // Resolve sh_uid if set
        $this->resolveShUid();
    }

    public function main()
    {
        $content = '';
        // Single-click rollback
        if ($this->getArgument('revert') && $this->getArgument('sumUp')) {
            $this->rollbackFields = $this->getArgument('revert');
            $this->showInsertDelete = 0;
            $this->showSubElements = 0;
            $element = explode(':', $this->element);
            $record = $this->getDatabaseConnection()->exec_SELECTgetSingleRow(
                '*',
                'sys_history',
                'tablename=' . $this->getDatabaseConnection()->fullQuoteStr($element[0], 'sys_history') . ' AND recuid=' . (int)$element[1],
                '',
                'uid DESC'
            );
            $this->lastSyslogId = $record['sys_log_uid'];
            $this->createChangeLog();
            $completeDiff = $this->createMultipleDiff();
            $this->performRollback($completeDiff);
            HttpUtility::redirect($this->returnUrl);
        }
        // Save snapshot
        if ($this->getArgument('highlight') && !$this->getArgument('settings')) {
            $this->toggleHighlight($this->getArgument('highlight'));
        }

        $content .= $this->displaySettings();

        if ($this->createChangeLog()) {
            if ($this->rollbackFields) {
                $completeDiff = $this->createMultipleDiff();
                $content .= $this->performRollback($completeDiff);
            }
            if ($this->lastSyslogId) {
                $completeDiff = $this->createMultipleDiff();
                $content .= $this->displayMultipleDiff($completeDiff);
            }
            if ($this->element) {
                $content .= $this->displayHistory();
            }
        }
        return $content;
    }

    /*******************************
     *
     * database actions
     *
     *******************************/
    public function toggleHighlight($uid)
    {
        $uid = (int)$uid;
        $row = $this->getDatabaseConnection()->exec_SELECTgetSingleRow('snapshot', 'sys_history', 'uid=' . $uid);
        if (!empty($row)) {
            $this->getDatabaseConnection()->exec_UPDATEquery('sys_history', 'uid=' . $uid, ['snapshot' => !$row['snapshot']]);
        }
    }

    public function performRollback($diff)
    {
        if (!$this->rollbackFields) {
            return '';
        }
        $reloadPageFrame = 0;
        $rollbackData = explode(':', $this->rollbackFields);
        // PROCESS INSERTS AND DELETES
        // rewrite inserts and deletes
        $cmdmapArray = [];
        $data = [];
        if ($diff['insertsDeletes']) {
            switch (count($rollbackData)) {
                case 1:
                    // all tables
                    $data = $diff['insertsDeletes'];
                    break;
                case 2:
                    // one record
                    if ($diff['insertsDeletes'][$this->rollbackFields]) {
                        $data[$this->rollbackFields] = $diff['insertsDeletes'][$this->rollbackFields];
                    }
                    break;
                case 3:
                    // one field in one record -- ignore!
                    break;
            }
            if (!empty($data)) {
                foreach ($data as $key => $action) {
                    $elParts = explode(':', $key);
                    if ((int)$action === 1) {
                        // inserted records should be deleted
                        $cmdmapArray[$elParts[0]][$elParts[1]]['delete'] = 1;
                        // When the record is deleted, the contents of the record do not need to be updated
                        unset($diff['oldData'][$key]);
                        unset($diff['newData'][$key]);
                    } elseif ((int)$action === -1) {
                        // deleted records should be inserted again
                        $cmdmapArray[$elParts[0]][$elParts[1]]['undelete'] = 1;
                    }
                }
            }
        }
        // Writes the data:
        if ($cmdmapArray) {
            $tce = GeneralUtility::makeInstance(DataHandler::class);
            $tce->stripslashes_values = 0;
            $tce->debug = 0;
            $tce->dontProcessTransformations = 1;
            $tce->start([], $cmdmapArray);
            $tce->process_cmdmap();
            unset($tce);
            if (isset($cmdmapArray['pages'])) {
                $reloadPageFrame = 1;
            }
        }
        // PROCESS CHANGES
        // create an array for process_datamap
        $diffModified = [];
        foreach ($diff['oldData'] as $key => $value) {
            $splitKey = explode(':', $key);
            $diffModified[$splitKey[0]][$splitKey[1]] = $value;
        }
        switch (count($rollbackData)) {
            case 1:
                // all tables
                $data = $diffModified;
                break;
            case 2:
                // one record
                $data[$rollbackData[0]][$rollbackData[1]] = $diffModified[$rollbackData[0]][$rollbackData[1]];
                break;
            case 3:
                // one field in one record
                $data[$rollbackData[0]][$rollbackData[1]][$rollbackData[2]] = $diffModified[$rollbackData[0]][$rollbackData[1]][$rollbackData[2]];
                break;
        }
        // Removing fields:
        $data = $this->removeFilefields($rollbackData[0], $data);
        // Writes the data:
        $tce = GeneralUtility::makeInstance(DataHandler::class);
        $tce->stripslashes_values = 0;
        $tce->debug = 0;
        $tce->dontProcessTransformations = 1;
        $tce->start($data, []);
        $tce->process_datamap();
        unset($tce);
        if (isset($data['pages'])) {
            $reloadPageFrame = 1;
        }
        // Return to normal operation
        $this->lastSyslogId = false;
        $this->rollbackFields = false;
        $this->createChangeLog();
        // Reload page frame if necessary
        if ($reloadPageFrame) {
            return '<script type="text/javascript">
            /*<![CDATA[*/
            if (top.content && top.content.nav_frame && top.content.nav_frame.refresh_nav) {
                top.content.nav_frame.refresh_nav();
            }
            /*]]>*/
            </script>';
        }
        return '';
    }

    /*******************************
     *
     * Display functions
     *
     *******************************/
    public function displaySettings()
    {
        // Get current selection from UC, merge data, write it back to UC
        $currentSelection = is_array($this->getBackendUser()->uc['moduleData']['history'])
            ? $this->getBackendUser()->uc['moduleData']['history']
            : ['maxSteps' => '', 'showDiff' => 1, 'showSubElements' => 1, 'showInsertDelete' => 1];
        $currentSelectionOverride = $this->getArgument('settings');
        if ($currentSelectionOverride) {
            $currentSelection = array_merge($currentSelection, $currentSelectionOverride);
            $this->getBackendUser()->uc['moduleData']['history'] = $currentSelection;
            $this->getBackendUser()->writeUC($this->getBackendUser()->uc);
        }
        // Display selector for number of history entries
        $selector['maxSteps'] = [
            10 => 10,
            20 => 20,
            50 => 50,
            100 => 100,
            '' => 'maxSteps_all',
            'marked' => 'maxSteps_marked'
        ];
        $selector['showDiff'] = [
            0 => 'showDiff_no',
            1 => 'showDiff_inline'
        ];
        $selector['showSubElements'] = [
            0 => 'no',
            1 => 'yes'
        ];
        $selector['showInsertDelete'] = [
            0 => 'no',
            1 => 'yes'
        ];
        // render selectors
        $displayCode = '';
        $scriptUrl = GeneralUtility::linkThisScript();
        $languageService = $this->getLanguageService();
        foreach ($selector as $key => $values) {
            $displayCode .= '<tr><td>' . $languageService->getLL($key, true) . '</td>';

            $label = ($currentSelection[$key] !== ''
                ? ($languageService->getLL($selector[$key][$currentSelection[$key]], true) ?: $selector[$key][$currentSelection[$key]])
                : ($languageService->getLL($selector[$key][$currentSelection[0]], true) ?: $selector[$key][$currentSelection[0]])
            );

            $displayCode .= '<td>
            <div class="btn-group">
                <button class="btn btn-default dropdown-toggle" type="button" id="copymodeSelector" data-toggle="dropdown" aria-haspopup="true" aria-expanded="true">
                    ' . $label . '
                    <span class="caret"></span>
                </button>
                <ul class="dropdown-menu" aria-labelledby="copymodeSelector">';

            foreach ($values as $singleKey => $singleVal) {
                $caption = $languageService->getLL($singleVal, true) ?: htmlspecialchars($singleVal);
                $displayCode .= '<li><a href="#" onclick="document.settings.method=\'POST\'; document.settings.action=' . htmlspecialchars(GeneralUtility::quoteJSvalue($scriptUrl . '&settings[' . $key . ']=' . $singleKey)) . '; document.settings.submit()">' . $caption . '</a></li>';
            }

            $displayCode .= '
                </ul>
            </div>
            </td></tr>
            ';
        }
        // set values correctly
        if ($currentSelection['maxSteps'] !== 'marked') {
            $this->maxSteps = $currentSelection['maxSteps'] ? (int)$currentSelection['maxSteps'] : '';
        } else {
            $this->showMarked = true;
            $this->maxSteps = false;
        }
        $this->showDiff = (int)$currentSelection['showDiff'];
        $this->showSubElements = (int)$currentSelection['showSubElements'];
        $this->showInsertDelete = (int)$currentSelection['showInsertDelete'];
        $content = '';
        // Get link to page history if the element history is shown
        $elParts = explode(':', $this->element);
        if (!empty($this->element) && $elParts[0] !== 'pages') {
            $content .= '<strong>' . $languageService->getLL('elementHistory', true) . '</strong><br />';
            $pid = $this->getRecord($elParts[0], $elParts[1]);

            if ($this->hasPageAccess('pages', $pid['pid'])) {
                $content .= $this->linkPage('<span class="btn btn-default" style="margin-bottom: 5px;">' . $languageService->getLL('elementHistory_link', true) . '</span>', ['element' => 'pages:' . $pid['pid']]);
            }
        }

        $content .= '<a name="settings_head"></a>
            <form name="settings" action="' . htmlspecialchars(GeneralUtility::getIndpEnv('TYPO3_REQUEST_URL')) . '" method="post">
                <div class="row">
                    <div class="col-sm-12 col-md-6 col-lg-4">
                        <div class="panel panel-default">
                            <div class="panel-heading">' . $languageService->getLL('settings', true) . '</div>
                                <table class="table">
            ' . $displayCode . '
                                </table>
                        </div>
                    </div>
            </div>
            </form>
        ';

        return '<div>' . $content . '</div>';
    }

    public function displayHistory()
    {
        if (empty($this->changeLog)) {
            return '';
        }
        $languageService = $this->getLanguageService();
        $lines = [];
        // Initialize:
        $lines[] = '<thead><tr>
                <th>' . $languageService->getLL('rollback', true) . '</th>
                <th>' . $languageService->getLL('time', true) . '</th>
                <th>' . $languageService->getLL('age', true) . '</th>
                <th>' . $languageService->getLL('user', true) . '</th>
                <th>' . $languageService->getLL('tableUid', true) . '</th>
                <th>' . $languageService->getLL('differences', true) . '</th>
                <th>&nbsp;</th>
            </tr></thead>';
        $beUserArray = BackendUtility::getUserNames();

        $i = 0;
        $avatar = GeneralUtility::makeInstance(Avatar::class);

        // Traverse changeLog array:
        foreach ($this->changeLog as $sysLogUid => $entry) {
            // stop after maxSteps
            if ($this->maxSteps && $i > $this->maxSteps) {
                break;
            }
            // Show only marked states
            if (!$entry['snapshot'] && $this->showMarked) {
                continue;
            }
            $i++;
            // Get user names
            // Build up single line
            $singleLine = [];
            $userName = $entry['user'] ? $beUserArray[$entry['user']]['username'] : $languageService->getLL('externalChange');
            // Executed by switch-user
            if (!empty($entry['originalUser'])) {
                $userName .= ' (' . $languageService->getLL('viaUser') . ' ' . $beUserArray[$entry['originalUser']]['username'] . ')';
            }

            // Diff link
            $image = '<span title="' . $languageService->getLL('sumUpChanges', true) . '">' . $this->iconFactory->getIcon('actions-document-history-open', Icon::SIZE_SMALL)->render() . '</span>';
            $singleLine[] = '<span>' . $this->linkPage($image, ['diff' => $sysLogUid]) . '</span>';
            // remove first link
            $singleLine[] = htmlspecialchars(BackendUtility::datetime($entry['tstamp']));
            // add time
            $singleLine[] = htmlspecialchars(BackendUtility::calcAge($GLOBALS['EXEC_TIME'] - $entry['tstamp'], $languageService->sL('LLL:EXT:lang/locallang_core.xlf:labels.minutesHoursDaysYears')));
            // add age
            $userEntry = is_array($beUserArray[$entry['user']]) ? $beUserArray[$entry['user']] : null;
            $singleLine[] = $avatar->render($userEntry) . ' ' . htmlspecialchars($userName);
            // add user name
            $singleLine[] = $this->linkPage(
                $this->generateTitle($entry['tablename'], $entry['recuid']),
                ['element' => $entry['tablename'] . ':' . $entry['recuid']],
                '',
                $languageService->getLL('linkRecordHistory', true)
            );
            // add record UID
            // Show insert/delete/diff/changed field names
            if ($entry['action']) {
                // insert or delete of element
                $singleLine[] = '<strong>' . htmlspecialchars($languageService->getLL($entry['action'], true)) . '</strong>';
            } else {
                // Display field names instead of full diff
                if (!$this->showDiff) {
                    // Re-write field names with labels
                    $tmpFieldList = explode(',', $entry['fieldlist']);
                    foreach ($tmpFieldList as $key => $value) {
                        $tmp = str_replace(':', '', $languageService->sl(BackendUtility::getItemLabel($entry['tablename'], $value), true));
                        if ($tmp) {
                            $tmpFieldList[$key] = $tmp;
                        } else {
                            // remove fields if no label available
                            unset($tmpFieldList[$key]);
                        }
                    }
                    $singleLine[] = htmlspecialchars(implode(',', $tmpFieldList));
                } else {
                    // Display diff
                    $diff = $this->renderDiff($entry, $entry['tablename']);
                    $singleLine[] = $diff;
                }
            }
            // Show link to mark/unmark state
            if (!$entry['action']) {
                if ($entry['snapshot']) {
                    $title = $languageService->getLL('unmarkState', true);
                    $image = $this->iconFactory->getIcon('actions-unmarkstate', Icon::SIZE_SMALL)->render();
                } else {
                    $title = $languageService->getLL('markState', true);
                    $image = $this->iconFactory->getIcon('actions-markstate', Icon::SIZE_SMALL)->render();
                }
                $singleLine[] = $this->linkPage($image, ['highlight' => $entry['uid']], '', $title);
            } else {
                $singleLine[] = '';
            }
            // put line together
            $lines[] = '
                <tr>
                    <td>' . implode('</td><td>', $singleLine) . '</td>
                </tr>';
        }

        // @TODO: introduce Fluid Standalone view and use callout viewHelper
        $theCode = '<div class="callout callout-info">'
            . '<div class="media"><div class="media-left"><span class="fa-stack fa-lg callout-icon"><i class="fa fa-circle fa-stack-2x"></i><i class="fa fa-info fa-stack-1x"></i></span></div>'
            . '<div class="media-body">'
            . '<p>' . $languageService->getLL('differenceMsg') . '</p>'
            . ' <div class="callout-body">'
            . ' </div></div></div></div>';

        // Finally, put it all together:
        $theCode .= '
            <!--
                History (list):
            -->

            <table class="table table-striped table-hover table-vertical-top" id="typo3-history">
                ' . implode('', $lines) . '
            </table>';
        if ($this->lastSyslogId) {
            $theCode .= '<br />' . $this->linkPage('<span class="btn btn-default">' . $languageService->getLL('fullView', true) . '</span>', ['diff' => '']);
        }

        $theCode .= '<br /><br />';

        // Add the whole content as a module section:
        return '<h2>' . $languageService->getLL('changes', true) . '</h2><div>' . $theCode . '</div>';
    }

    public function displayMultipleDiff($diff)
    {
        $content = '';
        // Get all array keys needed
        $arrayKeys = array_merge(array_keys($diff['newData']), array_keys($diff['insertsDeletes']), array_keys($diff['oldData']));
        $arrayKeys = array_unique($arrayKeys);
        $languageService = $this->getLanguageService();
        if ($arrayKeys) {
            foreach ($arrayKeys as $key) {
                $record = '';
                $elParts = explode(':', $key);
                // Turn around diff because it should be a "rollback preview"
                if ((int)$diff['insertsDeletes'][$key] === 1) {
                    // insert
                    $record .= '<strong>' . $languageService->getLL('delete', true) . '</strong>';
                    $record .= '<br />';
                } elseif ((int)$diff['insertsDeletes'][$key] === -1) {
                    $record .= '<strong>' . $languageService->getLL('insert', true) . '</strong>';
                    $record .= '<br />';
                }
                // Build up temporary diff array
                // turn around diff because it should be a "rollback preview"
                if ($diff['newData'][$key]) {
                    $tmpArr['newRecord'] = $diff['oldData'][$key];
                    $tmpArr['oldRecord'] = $diff['newData'][$key];
                    $record .= $this->renderDiff($tmpArr, $elParts[0], $elParts[1]);
                }
                $elParts = explode(':', $key);
                $titleLine = $this->createRollbackLink($key, $languageService->getLL('revertRecord', true), 1) . $this->generateTitle($elParts[0], $elParts[1]);
                $record = '<div style="padding-left:10px;border-left:5px solid darkgray;border-bottom:1px dotted darkgray;padding-bottom:2px;">' . $record . '</div>';
                // $titleLine contains HTML, no htmlspecialchars here.
                $content .= '<h3>' . $titleLine . '</h3><div>' . $record . '</div>';
            }
            $content = $this->createRollbackLink(
                    'ALL',
                    $languageService->getLL('revertAll', true),
                    0
                ) . '<div style="padding-left:10px;border-left:5px solid darkgray;border-bottom:1px dotted darkgray;padding-bottom:2px;">' . $content . '</div>';
        } else {
            $content = $languageService->getLL('noDifferences', true);
        }
        return '<h2>' . $languageService->getLL('mergedDifferences', true) . '</h2><div>' . $content . '</div>';
    }

    public function renderDiff($entry, $table, $rollbackUid = 0)
    {
        $lines = [];
        if (is_array($entry['newRecord'])) {
            $diffUtility = GeneralUtility::makeInstance(DiffUtility::class);
            $diffUtility->stripTags = false;
            $fieldsToDisplay = array_keys($entry['newRecord']);
            $languageService = $this->getLanguageService();
            foreach ($fieldsToDisplay as $fN) {
                if (is_array($GLOBALS['TCA'][$table]['columns'][$fN]) && $GLOBALS['TCA'][$table]['columns'][$fN]['config']['type'] !== 'passthrough') {
                    // Create diff-result:
                    $diffres = $diffUtility->makeDiffDisplay(
                        BackendUtility::getProcessedValue($table, $fN, $entry['oldRecord'][$fN], 0, true),
                        BackendUtility::getProcessedValue($table, $fN, $entry['newRecord'][$fN], 0, true)
                    );
                    $lines[] = '
                        <div class="diff-item">
                            <div class="diff-item-title">
                                ' . ($rollbackUid ? $this->createRollbackLink(($table . ':' . $rollbackUid . ':' . $fN), $languageService->getLL('revertField', true), 2) : '') . '
                                ' . $languageService->sl(BackendUtility::getItemLabel($table, $fN), true) . '
                            </div>
                            <div class="diff-item-result">' . str_replace('\n', PHP_EOL, str_replace('\r\n', '\n', $diffres)) . '</div>
                        </div>';
                }
            }
        }
        if ($lines) {
            return '<div class="diff">' . implode('', $lines) . '</div>';
        }
        // error fallback
        return null;
    }

    /*******************************
     *
     * build up history
     *
     *******************************/
    public function createMultipleDiff()
    {
        $insertsDeletes = [];
        $newArr = [];
        $differences = [];
        if (!$this->changeLog) {
            return 0;
        }
        // traverse changelog array
        foreach ($this->changeLog as $value) {
            $field = $value['tablename'] . ':' . $value['recuid'];
            // inserts / deletes
            if ($value['action']) {
                if (!$insertsDeletes[$field]) {
                    $insertsDeletes[$field] = 0;
                }
                if ($value['action'] === 'insert') {
                    $insertsDeletes[$field]++;
                } else {
                    $insertsDeletes[$field]--;
                }
                // unset not needed fields
                if ($insertsDeletes[$field] === 0) {
                    unset($insertsDeletes[$field]);
                }
            } else {
                // update fields
                // first row of field
                if (!isset($newArr[$field])) {
                    $newArr[$field] = $value['newRecord'];
                    $differences[$field] = $value['oldRecord'];
                } else {
                    // standard
                    $differences[$field] = array_merge($differences[$field], $value['oldRecord']);
                }
            }
        }
        // remove entries where there were no changes effectively
        foreach ($newArr as $record => $value) {
            foreach ($value as $key => $innerVal) {
                if ($newArr[$record][$key] == $differences[$record][$key]) {
                    unset($newArr[$record][$key]);
                    unset($differences[$record][$key]);
                }
            }
            if (empty($newArr[$record]) && empty($differences[$record])) {
                unset($newArr[$record]);
                unset($differences[$record]);
            }
        }
        return [
            'newData' => $newArr,
            'oldData' => $differences,
            'insertsDeletes' => $insertsDeletes
        ];
    }

    public function createChangeLog()
    {
        $elParts = explode(':', $this->element);

        if (empty($this->element)) {
            return 0;
        }

        $changeLog = $this->getHistoryData($elParts[0], $elParts[1]);
        // get history of tables of this page and merge it into changelog
        if ($elParts[0] == 'pages' && $this->showSubElements && $this->hasPageAccess('pages', $elParts[1])) {
            foreach ($GLOBALS['TCA'] as $tablename => $value) {
                // check if there are records on the page
                $rows = $this->getDatabaseConnection()->exec_SELECTgetRows('uid', $tablename, 'pid=' . (int)$elParts[1]);
                if (empty($rows)) {
                    continue;
                }
                foreach ($rows as $row) {
                    // if there is history data available, merge it into changelog
                    $newChangeLog = $this->getHistoryData($tablename, $row['uid']);
                    if (is_array($newChangeLog) && !empty($newChangeLog)) {
                        foreach ($newChangeLog as $key => $newChangeLogEntry) {
                            $changeLog[$key] = $newChangeLogEntry;
                        }
                    }
                }
            }
        }
        if (!$changeLog) {
            return 0;
        }
        krsort($changeLog);
        $this->changeLog = $changeLog;
        return 1;
    }

    public function getHistoryData($table, $uid)
    {
        if (empty($GLOBALS['TCA'][$table]) || !$this->hasTableAccess($table) || !$this->hasPageAccess($table, $uid)) {
            // error fallback
            return 0;
        }
        // If table is found in $GLOBALS['TCA']:
        $databaseConnection = $this->getDatabaseConnection();
        $uid = $this->resolveElement($table, $uid);
        // Selecting the $this->maxSteps most recent states:
        $rows = $databaseConnection->exec_SELECTgetRows('sys_history.*, sys_log.userid, sys_log.log_data', 'sys_history, sys_log', 'sys_history.sys_log_uid = sys_log.uid
                        AND sys_history.tablename = ' . $databaseConnection->fullQuoteStr($table, 'sys_history') . '
                        AND sys_history.recuid = ' . (int)$uid, '', 'sys_log.uid DESC', $this->maxSteps);
        $changeLog = [];
        if (!empty($rows)) {
            // Traversing the result, building up changesArray / changeLog:
            foreach ($rows as $row) {
                // Only history until a certain syslog ID needed
                if ($this->lastSyslogId && $row['sys_log_uid'] < $this->lastSyslogId) {
                    continue;
                }
                $hisDat = unserialize($row['history_data']);
                $logData = unserialize($row['log_data']);
                if (is_array($hisDat['newRecord']) && is_array($hisDat['oldRecord'])) {
                    // Add information about the history to the changeLog
                    $hisDat['uid'] = $row['uid'];
                    $hisDat['tstamp'] = $row['tstamp'];
                    $hisDat['user'] = $row['userid'];
                    $hisDat['originalUser'] = (empty($logData['originalUser']) ? null : $logData['originalUser']);
                    $hisDat['snapshot'] = $row['snapshot'];
                    $hisDat['fieldlist'] = $row['fieldlist'];
                    $hisDat['tablename'] = $row['tablename'];
                    $hisDat['recuid'] = $row['recuid'];
                    $changeLog[$row['sys_log_uid']] = $hisDat;
                } else {
                    debug('ERROR: [getHistoryData]');
                    // error fallback
                    return 0;
                }
            }
        }
        // SELECT INSERTS/DELETES
        if ($this->showInsertDelete) {
            // Select most recent inserts and deletes // WITHOUT snapshots
            $rows = $databaseConnection->exec_SELECTgetRows('uid, userid, action, tstamp, log_data', 'sys_log', 'type = 1
                        AND (action=1 OR action=3)
                        AND tablename = ' . $databaseConnection->fullQuoteStr($table, 'sys_log') . '
                        AND recuid = ' . (int)$uid, '', 'uid DESC', $this->maxSteps);
            // If none are found, nothing more to do
            if (empty($rows)) {
                return $changeLog;
            }
            foreach ($rows as $row) {
                if ($this->lastSyslogId && $row['uid'] < $this->lastSyslogId) {
                    continue;
                }
                $hisDat = [];
                $logData = unserialize($row['log_data']);
                switch ($row['action']) {
                    case 1:
                        // Insert
                        $hisDat['action'] = 'insert';
                        break;
                    case 3:
                        // Delete
                        $hisDat['action'] = 'delete';
                        break;
                }
                $hisDat['tstamp'] = $row['tstamp'];
                $hisDat['user'] = $row['userid'];
                $hisDat['originalUser'] = (empty($logData['originalUser']) ? null : $logData['originalUser']);
                $hisDat['tablename'] = $table;
                $hisDat['recuid'] = $uid;
                $changeLog[$row['uid']] = $hisDat;
            }
        }
        return $changeLog;
    }

    /*******************************
     *
     * Various helper functions
     *
     *******************************/
    public function generateTitle($table, $uid)
    {
        $out = $table . ':' . $uid;
        if ($labelField = $GLOBALS['TCA'][$table]['ctrl']['label']) {
            $record = $this->getRecord($table, $uid);
            $out .= ' (' . BackendUtility::getRecordTitle($table, $record, true) . ')';
        }
        return $out;
    }

    public function createRollbackLink($key, $alt = '', $type = 0)
    {
        return $this->linkPage('<span class="btn btn-default" style="margin-right: 5px;">' . $alt . '</span>', ['rollbackFields' => $key]);
    }

    public function linkPage($str, $inparams = [], $anchor = '', $title = '')
    {
        // Setting default values based on GET parameters:
        $params['element'] = $this->element;
        $params['returnUrl'] = $this->returnUrl;
        $params['diff'] = $this->lastSyslogId;
        // Merging overriding values:
        $params = array_merge($params, $inparams);
        // Make the link:
        $link = BackendUtility::getModuleUrl('record_history', $params) . ($anchor ? '#' . $anchor : '');
        return '<a href="' . htmlspecialchars($link) . '"' . ($title ? ' title="' . $title . '"' : '') . '>' . $str . '</a>';
    }

    public function removeFilefields($table, $dataArray)
    {
        if ($GLOBALS['TCA'][$table]) {
            foreach ($GLOBALS['TCA'][$table]['columns'] as $field => $config) {
                if ($config['config']['type'] === 'group' && $config['config']['internal_type'] === 'file') {
                    unset($dataArray[$field]);
                }
            }
        }
        return $dataArray;
    }

    public function resolveElement($table, $uid)
    {
        if (isset($GLOBALS['TCA'][$table])) {
            if ($workspaceVersion = BackendUtility::getWorkspaceVersionOfRecord($this->getBackendUser()->workspace, $table, $uid, 'uid')) {
                $uid = $workspaceVersion['uid'];
            }
        }
        return $uid;
    }

    public function resolveShUid()
    {
        $shUid = $this->getArgument('sh_uid');
        if (empty($shUid)) {
            return;
        }
        $record = $this->getDatabaseConnection()->exec_SELECTgetSingleRow('*', 'sys_history', 'uid=' . (int)$shUid);
        if (empty($record)) {
            return;
        }
        $this->element = $record['tablename'] . ':' . $record['recuid'];
        $this->lastSyslogId = $record['sys_log_uid'] - 1;
    }

    protected function hasPageAccess($table, $uid)
    {
        $uid = (int)$uid;

        if ($table === 'pages') {
            $pageId = $uid;
        } else {
            $record = $this->getRecord($table, $uid);
            $pageId = $record['pid'];
        }

        if (!isset($this->pageAccessCache[$pageId])) {
            $isDeletedPage = false;
            if ($this->showInsertDelete && isset($GLOBALS['TCA']['pages']['ctrl']['delete'])) {
                $deletedField = $GLOBALS['TCA']['pages']['ctrl']['delete'];
                $pageRecord = $this->getRecord('pages', $pageId);
                $isDeletedPage = (bool)$pageRecord[$deletedField];
            }
            if ($isDeletedPage) {
                // The page is deleted, so we fake its uid to be the one of the parent page.
                // By doing so, the following API will use this id to traverse the rootline
                // and check whether it is in the users' web mounts.
                // We check however if the user has (or better had) access to the deleted page itself.
                // Since the only way we got here is by requesting the history of the parent page
                // we can be sure this parent page actually exists.
                $pageRecord['uid'] = $pageRecord['pid'];
                $this->pageAccessCache[$pageId] = $this->getBackendUser()->doesUserHaveAccess($pageRecord, Permission::PAGE_SHOW);
            } else {
                $this->pageAccessCache[$pageId] = BackendUtility::readPageAccess(
                    $pageId,
                    $this->getBackendUser()->getPagePermsClause(Permission::PAGE_SHOW)
                );
            }
        }

        return $this->pageAccessCache[$pageId] !== false;
    }

    protected function hasTableAccess($table)
    {
        return $this->getBackendUser()->check('tables_select', $table);
    }

    protected function getRecord($table, $uid)
    {
        if (!isset($this->recordCache[$table][$uid])) {
            $this->recordCache[$table][$uid] = BackendUtility::getRecord($table, $uid, '*', '', false);
        }
        return $this->recordCache[$table][$uid];
    }

    protected function getBackendUser()
    {
        return $GLOBALS['BE_USER'];
    }

    protected function getArgument($name)
    {
        $value = GeneralUtility::_GP($name);

        switch ($name) {
            case 'element':
                if ($value !== '' && !preg_match('#^[a-z0-9_.]+:[0-9]+$#i', $value)) {
                    $value = '';
                }
                break;
            case 'rollbackFields':
            case 'revert':
                if ($value !== '' && !preg_match('#^[a-z0-9_.]+(:[0-9]+(:[a-z0-9_.]+)?)?$#i', $value)) {
                    $value = '';
                }
                break;
            case 'returnUrl':
                $value = GeneralUtility::sanitizeLocalUrl($value);
                break;
            case 'diff':
            case 'highlight':
            case 'sh_uid':
                $value = (int)$value;
                break;
            case 'settings':
                if (!is_array($value)) {
                    $value = [];
                }
                break;
            default:
                $value = '';
        }

        return $value;
    }

    protected function getLanguageService()
    {
        return $GLOBALS['LANG'];
    }

    protected function getDatabaseConnection()
    {
        return $GLOBALS['TYPO3_DB'];
    }
}