Allow to undo a change from event log.

src/Entity/Contracts/LogWithEventUndoInterface.php

@@ -0,0 +1,55 @@
+<?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\Entity\Contracts;
+
+
+use App\Entity\LogSystem\AbstractLogEntry;
+
+interface LogWithEventUndoInterface
+{
+    /**
+     * Checks if this element undoes another event.
+     * @return bool
+     */
+    public function isUndoEvent(): bool;
+
+    /**
+     * Returns the ID of the undone event or null if no event is undone.
+     * @return int|null
+     */
+    public function getUndoEventID(): ?int;
+
+    /**
+     * Sets the event that is undone, and the undo mode.
+     * @param  AbstractLogEntry  $event
+     * @param  string  $mode
+     * @return $this
+     */
+    public function setUndoneEvent(AbstractLogEntry $event, string $mode = 'undo'): self;
+
+    /**
+     * Returns the mode how the event was undone:
+     * "undo" = Only a single event was applied to element
+     * "revert" = Element was reverted to the state it was to the timestamp of the log.
+     * @return string
+     */
+    public function getUndoMode(): string;
+}