1	<?php
2
3	declare(strict_types=1);
4
5	namespace Drupal\display_builder\Entity;
6
7	use Drupal\display_builder\Plugin\Field\FieldType\HistoryStep;
8
9	/**
10	* History interface.
11	*
12	* When you implement Undo and Redo, you want to keep track of the history
13	* of this state at different points in time.
14	*
15	* Inspired from https://redux.js.org/usage/implementing-undo-history
16	*/
17	interface HistoryInterface {
18
19	/**
20	* Get current step.
21	*
22	* @return \Drupal\display_builder\Plugin\Field\FieldType\HistoryStep|null
23	*   The current data.
24	*/
25	public function getCurrent(): ?HistoryStep;
26
27	/**
28	* Get the state of the current step.
29	*
30	* @return array
31	*   The current state.
32	*/
33	public function getCurrentState(): array;
34
35	/**
36	* Set a new present.
37	*
38	* @param array $state
39	*   The state to set.
40	* @param string|\Stringable $log_message
41	*   (Optional) The log message.
42	* @param bool $check_hash
43	*   (Optional) Should check hash to avoid duplicates. Default to TRUE.
44	* @param bool $index
45	*   (Optional) When TRUE the raw $state is normalized through SourceTree
46	*   before storing. Set to FALSE when the data was already produced by
47	*   SourceTree::getTree() to skip redundant normalization. Default to TRUE.
48	*/
49	public function setNewPresent(array $state, string|\Stringable $log_message = '', bool $check_hash = TRUE, bool $index = TRUE): void;
50
51	/**
52	* Get the past steps.
53	*
54	* @return array
55	*   The past steps.
56	*/
57	public function getPast(): array;
58
59	/**
60	* Get the future steps.
61	*
62	* @return array
63	*   The future steps.
64	*/
65	public function getFuture(): array;
66
67	/**
68	* Move history to the last past state.
69	*/
70	public function undo(): void;
71
72	/**
73	* Move history to the first future state.
74	*/
75	public function redo(): void;
76
77	/**
78	* Reset history to the current state.
79	*/
80	public function clear(): void;
81
82	}

---

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