Allow to undo a change from event log.

src/DataTables/Column/IconLinkColumn.php

@@ -59,7 +59,7 @@ class IconLinkColumn extends AbstractColumn
 
         if ($href !== null) {
             return sprintf(
-                '<a href="%s" title="%s"><i class="%s"></i></a>',
+                '<a class="btn btn-primary btn-sm" href="%s" title="%s"><i class="%s"></i></a>',
                 $href,
                 $title,
                 $icon

src/DataTables/Column/RevertLogColumn.php

@@ -0,0 +1,69 @@
+<?php
+/**
+ * This file is part of Part-DB (https://github.com/Part-DB/Part-DB-symfony).
+ *
+ * Copyright (C) 2019 - 2020 Jan Böhmer (https://github.com/jbtronics)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published
+ * by the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+namespace App\DataTables\Column;
+
+
+use App\Entity\LogSystem\AbstractLogEntry;
+use App\Entity\LogSystem\CollectionElementDeleted;
+use App\Entity\LogSystem\ElementCreatedLogEntry;
+use App\Entity\LogSystem\ElementDeletedLogEntry;
+use App\Entity\LogSystem\ElementEditedLogEntry;
+use Omines\DataTablesBundle\Column\AbstractColumn;
+use Symfony\Contracts\Translation\TranslatorInterface;
+
+class RevertLogColumn extends AbstractColumn
+{
+    protected $translator;
+
+    public function __construct(TranslatorInterface $translator)
+    {
+        $this->translator = $translator;
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function normalize($value)
+    {
+        return $value;
+    }
+
+    public function render($value, $context)
+    {
+        if ($context instanceof ElementDeletedLogEntry || $context instanceof CollectionElementDeleted) {
+            $icon = 'fa-trash-restore';
+            $title = $this->translator->trans('log.undo.undelete');
+        } elseif ($context instanceof ElementEditedLogEntry || $context instanceof ElementCreatedLogEntry) {
+            $icon = 'fa-undo';
+            $title = $this->translator->trans('log.undo.undo');
+        } else {
+            return '';
+        }
+
+
+        return sprintf(
+            '<button type="submit" class="btn btn-outline-secondary btn-sm" name="undo" value="%d"><i class="fas fa-fw %s" title="%s"></i></button>',
+            $context->getID(),
+            $icon,
+            $title
+        );
+    }
+}

src/DataTables/LogDataTable.php

@@ -46,6 +46,7 @@ use App\DataTables\Column\IconLinkColumn;
 use App\DataTables\Column\LocaleDateTimeColumn;
 use App\DataTables\Column\LogEntryExtraColumn;
 use App\DataTables\Column\LogEntryTargetColumn;
+use App\DataTables\Column\RevertLogColumn;
 use App\Entity\Base\AbstractDBElement;
 use App\Entity\Contracts\TimeTravelInterface;
 use App\Entity\LogSystem\AbstractLogEntry;
@@ -218,8 +219,10 @@ class LogDataTable implements DataTableTypeInterface
                 ) {
                     try {
                         $target = $this->logRepo->getTargetElement($context);
-                        $str = $this->entityURLGenerator->timeTravelURL($target, $context->getTimestamp());
-                        return $str;
+                        if($target !== null) {
+                            $str = $this->entityURLGenerator->timeTravelURL($target, $context->getTimestamp());
+                            return $str;
+                        }
                     } catch (EntityNotSupportedException $exception) {
                         return null;
                     }
@@ -228,6 +231,10 @@ class LogDataTable implements DataTableTypeInterface
             }
         ]);
 
+        $dataTable->add('actionRevert', RevertLogColumn::class, [
+            'label' => ''
+        ]);
+
         $dataTable->addOrderBy('timestamp', DataTable::SORT_DESCENDING);
 
         $dataTable->createAdapter(ORMAdapter::class, [