gutenberg / build / block-library / blocks / button.php

button.php in Gutenberg 18.9.0, at build/block-library/blocks/button.php

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1	<?php
2	/**
3	* Server-side rendering of the `core/button` block.
4	*
5	* @package WordPress
6	*/
7
8	/**
9	* Renders the `core/button` block on the server,
10	*
11	* @since 6.6.0
12	*
13	* @param array $attributes The block attributes.
14	* @param string $content The block content.
15	* @param WP_Block $block The block object.
16	*
17	* @return string The block content.
18	*/
19	function gutenberg_render_block_core_button( $attributes, $content ) {
20	/*
21	* The current Gutenberg plugin supports WordPress 6.4, but the next_token()
22	* method does not exist in WordPress 6.4. Therefore, if Gutenberg is used
23	* as a plugin, use the Gutenberg class that has the `next_token()` method.
24	*
25	* TODO: After the Gutenberg plugin drops support for WordPress 6.4, this
26	* conditional statement will be removed and the core class `WP_HTML_Tag_Processor`
27	* should be used.
28	*/
29	if ( defined( 'IS_GUTENBERG_PLUGIN' ) && IS_GUTENBERG_PLUGIN && class_exists( 'Gutenberg_HTML_Tag_Processor_6_7' ) ) {
30	$p = new Gutenberg_HTML_Tag_Processor_6_7( $content );
31	} else {
32	$p = new WP_HTML_Tag_Processor( $content );
33	}
34
35	/*
36	* The button block can render an `<a>` or `<button>` and also has a
37	* `<div>` wrapper. Find the a or button tag.
38	*/
39	$tag = null;
40	while ( $p->next_tag() ) {
41	$tag = $p->get_tag();
42	if ( 'A' === $tag \|\| 'BUTTON' === $tag ) {
43	break;
44	}
45	}
46
47	/*
48	* If this happens, the likelihood is there's no block content,
49	* or the block has been modified by a plugin.
50	*/
51	if ( null === $tag ) {
52	return $content;
53	}
54
55	// If the next token is the closing tag, the button is empty.
56	$is_empty = true;
57	while ( $p->next_token() && $tag !== $p->get_token_name() && $is_empty ) {
58	if ( '#comment' !== $p->get_token_type() ) {
59	/**
60	* Anything else implies this is not empty.
61	* This might include any text content (including a space),
62	* inline images or other HTML.
63	*/
64	$is_empty = false;
65	}
66	}
67
68	/*
69	* When there's no text, render nothing for the block.
70	* See https://github.com/WordPress/gutenberg/issues/17221 for the
71	* reasoning behind this.
72	*/
73	if ( $is_empty ) {
74	return '';
75	}
76
77	return $content;
78	}
79
80	/**
81	* Registers the `core/button` block on server.
82	*
83	* @since 6.6.0
84	*/
85	function gutenberg_register_block_core_button() {
86	register_block_type_from_metadata(
87	__DIR__ . '/button',
88	array(
89	'render_callback' => 'gutenberg_render_block_core_button',
90	)
91	);
92	}
93	add_action( 'init', 'gutenberg_register_block_core_button', 20 );
94