1<?php
  2/**
  3 * Server-side rendering of the `core/gallery` block.
  4 *
  5 * @package WordPress
  6 */
  7
  8/**
  9 * Handles backwards compatibility for Gallery Blocks,
 10 * whose images feature a `data-id` attribute.
 11 *
 12 * Now that the Gallery Block contains inner Image Blocks,
 13 * we add a custom `data-id` attribute before rendering the gallery
 14 * so that the Image Block can pick it up in its render_callback.
 15 *
 16 * @since 5.9.0
 17 *
 18 * @param array $parsed_block The block being rendered.
 19 * @return array The migrated block object.
 20 */
 21function block_core_gallery_data_id_backcompatibility( $parsed_block ) {
 22	if ( 'core/gallery' === $parsed_block['blockName'] ) {
 23		foreach ( $parsed_block['innerBlocks'] as $key => $inner_block ) {
 24			if ( 'core/image' === $inner_block['blockName'] ) {
 25				if ( ! isset( $parsed_block['innerBlocks'][ $key ]['attrs']['data-id'] ) && isset( $inner_block['attrs']['id'] ) ) {
 26					$parsed_block['innerBlocks'][ $key ]['attrs']['data-id'] = esc_attr( $inner_block['attrs']['id'] );
 27				}
 28			}
 29		}
 30	}
 31
 32	return $parsed_block;
 33}
 34
 35add_filter( 'render_block_data', 'block_core_gallery_data_id_backcompatibility' );
 36
 37/**
 38 * Renders the `core/gallery` block on the server.
 39 *
 40 * @since 6.0.0
 41 *
 42 * @param array  $attributes Attributes of the block being rendered.
 43 * @param string $content Content of the block being rendered.
 44 * @return string The content of the block being rendered.
 45 */
 46function block_core_gallery_render( $attributes, $content ) {
 47	// Adds a style tag for the --wp--style--unstable-gallery-gap var.
 48	// The Gallery block needs to recalculate Image block width based on
 49	// the current gap setting in order to maintain the number of flex columns
 50	// so a css var is added to allow this.
 51
 52	$gap = $attributes['style']['spacing']['blockGap'] ?? null;
 53	// Skip if gap value contains unsupported characters.
 54	// Regex for CSS value borrowed from `safecss_filter_attr`, and used here
 55	// because we only want to match against the value, not the CSS attribute.
 56	if ( is_array( $gap ) ) {
 57		foreach ( $gap as $key => $value ) {
 58			// Make sure $value is a string to avoid PHP 8.1 deprecation error in preg_match() when the value is null.
 59			$value = is_string( $value ) ? $value : '';
 60			$value = $value && preg_match( '%[\\\(&=}]|/\*%', $value ) ? null : $value;
 61
 62			// Get spacing CSS variable from preset value if provided.
 63			if ( is_string( $value ) && str_contains( $value, 'var:preset|spacing|' ) ) {
 64				$index_to_splice = strrpos( $value, '|' ) + 1;
 65				$slug            = _wp_to_kebab_case( substr( $value, $index_to_splice ) );
 66				$value           = "var(--wp--preset--spacing--$slug)";
 67			}
 68
 69			$gap[ $key ] = $value;
 70		}
 71	} else {
 72		// Make sure $gap is a string to avoid PHP 8.1 deprecation error in preg_match() when the value is null.
 73		$gap = is_string( $gap ) ? $gap : '';
 74		$gap = $gap && preg_match( '%[\\\(&=}]|/\*%', $gap ) ? null : $gap;
 75
 76		// Get spacing CSS variable from preset value if provided.
 77		if ( is_string( $gap ) && str_contains( $gap, 'var:preset|spacing|' ) ) {
 78			$index_to_splice = strrpos( $gap, '|' ) + 1;
 79			$slug            = _wp_to_kebab_case( substr( $gap, $index_to_splice ) );
 80			$gap             = "var(--wp--preset--spacing--$slug)";
 81		}
 82	}
 83
 84	$unique_gallery_classname = wp_unique_id( 'wp-block-gallery-' );
 85	$processed_content        = new WP_HTML_Tag_Processor( $content );
 86	$processed_content->next_tag();
 87	$processed_content->add_class( $unique_gallery_classname );
 88
 89	// --gallery-block--gutter-size is deprecated. --wp--style--gallery-gap-default should be used by themes that want to set a default
 90	// gap on the gallery.
 91	$fallback_gap = 'var( --wp--style--gallery-gap-default, var( --gallery-block--gutter-size, var( --wp--style--block-gap, 0.5em ) ) )';
 92	$gap_value    = $gap ? $gap : $fallback_gap;
 93	$gap_column   = $gap_value;
 94
 95	if ( is_array( $gap_value ) ) {
 96		$gap_row    = isset( $gap_value['top'] ) ? $gap_value['top'] : $fallback_gap;
 97		$gap_column = isset( $gap_value['left'] ) ? $gap_value['left'] : $fallback_gap;
 98		$gap_value  = $gap_row === $gap_column ? $gap_row : $gap_row . ' ' . $gap_column;
 99	}
100
101	// The unstable gallery gap calculation requires a real value (such as `0px`) and not `0`.
102	if ( '0' === $gap_column ) {
103		$gap_column = '0px';
104	}
105
106	// Set the CSS variable to the column value, and the `gap` property to the combined gap value.
107	$gallery_styles = array(
108		array(
109			'selector'     => ".wp-block-gallery.{$unique_gallery_classname}",
110			'declarations' => array(
111				'--wp--style--unstable-gallery-gap' => $gap_column,
112				'gap'                               => $gap_value,
113			),
114		),
115	);
116
117	wp_style_engine_get_stylesheet_from_css_rules(
118		$gallery_styles,
119		array(
120			'context' => 'block-supports',
121		)
122	);
123
124	// The WP_HTML_Tag_Processor class calls get_updated_html() internally
125	// when the instance is treated as a string, but here we explicitly
126	// convert it to a string.
127	$updated_content = $processed_content->get_updated_html();
128
129	/*
130	 * Randomize the order of image blocks. Ideally we should shuffle
131	 * the `$parsed_block['innerBlocks']` via the `render_block_data` hook.
132	 * However, this hook doesn't apply inner block updates when blocks are
133	 * nested.
134	 * @todo In the future, if this hook supports updating innerBlocks in
135	 * nested blocks, it should be refactored.
136	 *
137	 * @see: https://github.com/WordPress/gutenberg/pull/58733
138	 */
139	if ( empty( $attributes['randomOrder'] ) ) {
140		return $updated_content;
141	}
142
143	// This pattern matches figure elements with the `wp-block-image` class to
144	// avoid the gallery's wrapping `figure` element and extract images only.
145	$pattern = '/<figure[^>]*\bwp-block-image\b[^>]*>.*?<\/figure>/s';
146
147	// Find all Image blocks.
148	preg_match_all( $pattern, $updated_content, $matches );
149	if ( ! $matches ) {
150		return $updated_content;
151	}
152	$image_blocks = $matches[0];
153
154	// Randomize the order of Image blocks.
155	shuffle( $image_blocks );
156	$i       = 0;
157	$content = preg_replace_callback(
158		$pattern,
159		static function () use ( $image_blocks, &$i ) {
160			$new_image_block = $image_blocks[ $i ];
161			++$i;
162			return $new_image_block;
163		},
164		$updated_content
165	);
166
167	return $content;
168}
169/**
170 * Registers the `core/gallery` block on server.
171 *
172 * @since 5.9.0
173 */
174function register_block_core_gallery() {
175	register_block_type_from_metadata(
176		__DIR__ . '/gallery',
177		array(
178			'render_callback' => 'block_core_gallery_render',
179		)
180	);
181}
182
183add_action( 'init', 'register_block_core_gallery' );
184