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   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   */
  21  function 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  
  35  add_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   */
  46  function 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>/';
 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   */
 174  function 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  
 183  add_action( 'init', 'register_block_core_gallery' );