class-gutenberg-hierarchical-sort.php in Gutenberg 23.2.0, at lib/experimental/class-gutenberg-hierarchical-sort.php

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1	<?php
2
3	/**
4	* Modifies the Post controller endpoint to support orderby_hierarchy.
5	*
6	* @package gutenberg
7	* @since 6.8.0
8	*/
9
10	class Gutenberg_Hierarchical_Sort {
11	private static $post_ids = array();
12	private static $levels = array();
13	private static $instance;
14
15	public static function get_instance() {
16	if ( null === self::$instance ) {
17	self::$instance = new self();
18	}
19
20	return self::$instance;
21	}
22
23	public function run( $args ) {
24	$new_args = array_merge(
25	$args,
26	array(
27	'fields' => 'id=>parent',
28	'posts_per_page' => -1,
29	)
30	);
31	$query = new WP_Query( $new_args );
32	$posts = $query->posts;
33	$result = self::sort( $posts );
34
35	self::$post_ids = $result['post_ids'];
36	self::$levels = $result['levels'];
37	}
38
39	/**
40	* Check if the request is eligible for hierarchical sorting.
41	*
42	* @param array $request The request data.
43	*
44	* @return bool Return true if the request is eligible for hierarchical sorting.
45	*/
46	public static function is_eligible( $request ) {
47	if ( ! isset( $request['orderby_hierarchy'] ) \|\| true !== $request['orderby_hierarchy'] ) {
48	return false;
49	}
50
51	return true;
52	}
53
54	public static function get_ancestor( $post_id ) {
55	return get_post( $post_id )->post_parent ?? 0;
56	}
57
58	/**
59	* Sort posts by hierarchy.
60	*
61	* Takes an array of posts and sorts them based on their parent-child relationships.
62	* It also tracks the level depth of each post in the hierarchy.
63	*
64	* Example input:
65	* ```
66	* [
67	* ['ID' => 4, 'post_parent' => 2],
68	* ['ID' => 2, 'post_parent' => 0],
69	* ['ID' => 3, 'post_parent' => 2],
70	* ]
71	* ```
72	*
73	* Example output:
74	* ```
75	* [
76	* 'post_ids' => [2, 4, 3],
77	* 'levels' => [0, 1, 1]
78	* ]
79	* ```
80	*
81	* @param array $posts Array of post objects containing ID and post_parent properties.
82	*
83	* @return array {
84	* Sorted post IDs and their hierarchical levels
85	*
86	* @type array $post_ids Array of post IDs
87	* @type array $levels Array of levels for the corresponding post ID in the same index
88	* }
89	*/
90	public static function sort( $posts ) {
91	/*
92	* Arrange pages in two arrays:
93	*
94	* - $top_level: posts whose parent is 0
95	* - $children: post ID as the key and an array of children post IDs as the value.
96	* Example: $children[10][] contains all sub-pages whose parent is 10.
97	*
98	* Additionally, keep track of the levels of each post in $levels.
99	* Example: $levels[10] = 0 means the post ID is a top-level page.
100	*
101	*/
102	$top_level = array();
103	$children = array();
104	foreach ( $posts as $post ) {
105	if ( empty( $post->post_parent ) ) {
106	$top_level[] = $post->ID;
107	} else {
108	$children[ $post->post_parent ][] = $post->ID;
109	}
110	}
111
112	$ids = array();
113	$levels = array();
114	self::add_hierarchical_ids( $ids, $levels, 0, $top_level, $children );
115
116	// Process remaining children.
117	if ( ! empty( $children ) ) {
118	foreach ( $children as $parent_id => $child_ids ) {
119	$level = 0;
120	$ancestor = $parent_id;
121	while ( 0 !== $ancestor ) {
122	++$level;
123	$ancestor = self::get_ancestor( $ancestor );
124	}
125	self::add_hierarchical_ids( $ids, $levels, $level, $child_ids, $children );
126	}
127	}
128
129	return array(
130	'post_ids' => $ids,
131	'levels' => $levels,
132	);
133	}
134
135	private static function add_hierarchical_ids( &$ids, &$levels, $level, $to_process, $children ) {
136	foreach ( $to_process as $id ) {
137	if ( in_array( $id, $ids, true ) ) {
138	continue;
139	}
140	$ids[] = $id;
141	$levels[ $id ] = $level;
142
143	if ( isset( $children[ $id ] ) ) {
144	self::add_hierarchical_ids( $ids, $levels, $level + 1, $children[ $id ], $children );
145	unset( $children[ $id ] );
146	}
147	}
148	}
149
150	public static function get_post_ids() {
151	return self::$post_ids;
152	}
153
154	public static function get_levels() {
155	return self::$levels;
156	}
157	}
158
159	add_filter(
160	'rest_page_collection_params',
161	function ( $params ) {
162	$params['orderby_hierarchy'] = array(
163	'description' => 'Sort pages by hierarchy.',
164	'type' => 'boolean',
165	'default' => false,
166	);
167	return $params;
168	}
169	);
170
171	add_filter(
172	'rest_page_query',
173	function ( $args, $request ) {
174	if ( ! Gutenberg_Hierarchical_Sort::is_eligible( $request ) ) {
175	return $args;
176	}
177
178	$hs = Gutenberg_Hierarchical_Sort::get_instance();
179	$hs->run( $args );
180
181	// Reconfigure the args to display only the ids in the list.
182	$args['post__in'] = $hs->get_post_ids();
183	$args['orderby'] = 'post__in';
184
185	return $args;
186	},
187	10,
188	2
189	);
190
191	add_filter(
192	'rest_prepare_page',
193	function ( $response, $post, $request ) {
194	if ( ! Gutenberg_Hierarchical_Sort::is_eligible( $request ) ) {
195	return $response;
196	}
197
198	$hs = Gutenberg_Hierarchical_Sort::get_instance();
199	$response->data['level'] = $hs->get_levels()[ $post->ID ];
200
201	return $response;
202	},
203	10,
204	3
205	);
206