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   1  <?php
   2  /**
   3   * Block support to enable per-section styling of block types via
   4   * block style variations.
   5   *
   6   * @package WordPress
   7   * @since 6.6.0
   8   */
   9  
  10  /**
  11   * Determines the block style variation names within a CSS class string.
  12   *
  13   * @since 6.6.0
  14   *
  15   * @param string $class_string CSS class string to look for a variation in.
  16   *
  17   * @return array|null The block style variation name if found.
  18   */
  19  function wp_get_block_style_variation_name_from_class( $class_string ) {
  20      if ( ! is_string( $class_string ) ) {
  21          return null;
  22      }
  23  
  24      preg_match_all( '/\bis-style-(?!default)(\S+)\b/', $class_string, $matches );
  25      return $matches[1] ?? null;
  26  }
  27  
  28  /**
  29   * Recursively resolves any `ref` values within a block style variation's data.
  30   *
  31   * @since 6.6.0
  32   * @access private
  33   *
  34   * @param array $variation_data Reference to the variation data being processed.
  35   * @param array $theme_json     Theme.json data to retrieve referenced values from.
  36   */
  37  function wp_resolve_block_style_variation_ref_values( &$variation_data, $theme_json ) {
  38      foreach ( $variation_data as $key => &$value ) {
  39          // Only need to potentially process arrays.
  40          if ( is_array( $value ) ) {
  41              // If ref value is set, attempt to find its matching value and update it.
  42              if ( array_key_exists( 'ref', $value ) ) {
  43                  // Clean up any invalid ref value.
  44                  if ( empty( $value['ref'] ) || ! is_string( $value['ref'] ) ) {
  45                      unset( $variation_data[ $key ] );
  46                  }
  47  
  48                  $value_path = explode( '.', $value['ref'] ?? '' );
  49                  $ref_value  = _wp_array_get( $theme_json, $value_path );
  50  
  51                  // Only update the current value if the referenced path matched a value.
  52                  if ( null === $ref_value ) {
  53                      unset( $variation_data[ $key ] );
  54                  } else {
  55                      $value = $ref_value;
  56                  }
  57              } else {
  58                  // Recursively look for ref instances.
  59                  wp_resolve_block_style_variation_ref_values( $value, $theme_json );
  60              }
  61          }
  62      }
  63  }
  64  /**
  65   * Renders the block style variation's styles.
  66   *
  67   * In the case of nested blocks with variations applied, we want the parent
  68   * variation's styles to be rendered before their descendants. This solves the
  69   * issue of a block type being styled in both the parent and descendant: we want
  70   * the descendant style to take priority, and this is done by loading it after,
  71   * in the DOM order. This is why the variation stylesheet generation is in a
  72   * different filter.
  73   *
  74   * @since 6.6.0
  75   * @access private
  76   *
  77   * @param array $parsed_block The parsed block.
  78   *
  79   * @return array The parsed block with block style variation classname added.
  80   */
  81  function wp_render_block_style_variation_support_styles( $parsed_block ) {
  82      $classes    = $parsed_block['attrs']['className'] ?? null;
  83      $variations = wp_get_block_style_variation_name_from_class( $classes );
  84  
  85      if ( ! $variations ) {
  86          return $parsed_block;
  87      }
  88  
  89      $tree       = WP_Theme_JSON_Resolver::get_merged_data();
  90      $theme_json = $tree->get_raw_data();
  91  
  92      // Only the first block style variation with data is supported.
  93      $variation_data = array();
  94      foreach ( $variations as $variation ) {
  95          $variation_data = $theme_json['styles']['blocks'][ $parsed_block['blockName'] ]['variations'][ $variation ] ?? array();
  96  
  97          if ( ! empty( $variation_data ) ) {
  98              break;
  99          }
 100      }
 101  
 102      if ( empty( $variation_data ) ) {
 103          return $parsed_block;
 104      }
 105  
 106      /*
 107       * Recursively resolve any ref values with the appropriate value within the
 108       * theme_json data.
 109       */
 110      wp_resolve_block_style_variation_ref_values( $variation_data, $theme_json );
 111  
 112      $variation_instance = wp_unique_id( $variation . '--' );
 113      $class_name         = "is-style-$variation_instance";
 114      $updated_class_name = $parsed_block['attrs']['className'] . " $class_name";
 115  
 116      /*
 117       * Even though block style variations are effectively theme.json partials,
 118       * they can't be processed completely as though they are.
 119       *
 120       * Block styles support custom selectors to direct specific types of styles
 121       * to inner elements. For example, borders on Image block's get applied to
 122       * the inner `img` element rather than the wrapping `figure`.
 123       *
 124       * The following relocates the "root" block style variation styles to
 125       * under an appropriate blocks property to leverage the preexisting style
 126       * generation for simple block style variations. This way they get the
 127       * custom selectors they need.
 128       *
 129       * The inner elements and block styles for the variation itself are
 130       * still included at the top level but scoped by the variation's selector
 131       * when the stylesheet is generated.
 132       */
 133      $elements_data = $variation_data['elements'] ?? array();
 134      $blocks_data   = $variation_data['blocks'] ?? array();
 135      unset( $variation_data['elements'] );
 136      unset( $variation_data['blocks'] );
 137  
 138      _wp_array_set(
 139          $blocks_data,
 140          array( $parsed_block['blockName'], 'variations', $variation_instance ),
 141          $variation_data
 142      );
 143  
 144      $config = array(
 145          'version' => WP_Theme_JSON::LATEST_SCHEMA,
 146          'styles'  => array(
 147              'elements' => $elements_data,
 148              'blocks'   => $blocks_data,
 149          ),
 150      );
 151  
 152      // Turn off filter that excludes block nodes. They are needed here for the variation's inner block types.
 153      if ( ! is_admin() ) {
 154          remove_filter( 'wp_theme_json_get_style_nodes', 'wp_filter_out_block_nodes' );
 155      }
 156  
 157      // Temporarily prevent variation instance from being sanitized while processing theme.json.
 158      $styles_registry = WP_Block_Styles_Registry::get_instance();
 159      $styles_registry->register( $parsed_block['blockName'], array( 'name' => $variation_instance ) );
 160  
 161      $variation_theme_json = new WP_Theme_JSON( $config, 'blocks' );
 162      $variation_styles     = $variation_theme_json->get_stylesheet(
 163          array( 'styles' ),
 164          array( 'custom' ),
 165          array(
 166              'include_block_style_variations' => true,
 167              'skip_root_layout_styles'        => true,
 168              'scope'                          => ".$class_name",
 169          )
 170      );
 171  
 172      // Clean up temporary block style now instance styles have been processed.
 173      $styles_registry->unregister( $parsed_block['blockName'], $variation_instance );
 174  
 175      // Restore filter that excludes block nodes.
 176      if ( ! is_admin() ) {
 177          add_filter( 'wp_theme_json_get_style_nodes', 'wp_filter_out_block_nodes' );
 178      }
 179  
 180      if ( empty( $variation_styles ) ) {
 181          return $parsed_block;
 182      }
 183  
 184      wp_register_style( 'block-style-variation-styles', false, array( 'wp-block-library', 'global-styles' ) );
 185      wp_add_inline_style( 'block-style-variation-styles', $variation_styles );
 186  
 187      /*
 188       * Add variation instance class name to block's className string so it can
 189       * be enforced in the block markup via render_block filter.
 190       */
 191      _wp_array_set( $parsed_block, array( 'attrs', 'className' ), $updated_class_name );
 192  
 193      return $parsed_block;
 194  }
 195  
 196  /**
 197   * Ensures the variation block support class name generated and added to
 198   * block attributes in the `render_block_data` filter gets applied to the
 199   * block's markup.
 200   *
 201   * @since 6.6.0
 202   * @access private
 203   *
 204   * @see wp_render_block_style_variation_support_styles
 205   *
 206   * @param  string $block_content Rendered block content.
 207   * @param  array  $block         Block object.
 208   *
 209   * @return string                Filtered block content.
 210   */
 211  function wp_render_block_style_variation_class_name( $block_content, $block ) {
 212      if ( ! $block_content || empty( $block['attrs']['className'] ) ) {
 213          return $block_content;
 214      }
 215  
 216      /*
 217       * Matches a class prefixed by `is-style`, followed by the
 218       * variation slug, then `--`, and finally an instance number.
 219       */
 220      preg_match( '/\bis-style-(\S+?--\d+)\b/', $block['attrs']['className'], $matches );
 221  
 222      if ( empty( $matches ) ) {
 223          return $block_content;
 224      }
 225  
 226      $tags = new WP_HTML_Tag_Processor( $block_content );
 227  
 228      if ( $tags->next_tag() ) {
 229          /*
 230           * Ensure the variation instance class name set in the
 231           * `render_block_data` filter is applied in markup.
 232           * See `wp_render_block_style_variation_support_styles`.
 233           */
 234          $tags->add_class( $matches[0] );
 235      }
 236  
 237      return $tags->get_updated_html();
 238  }
 239  
 240  /**
 241   * Enqueues styles for block style variations.
 242   *
 243   * @since 6.6.0
 244   * @access private
 245   */
 246  function wp_enqueue_block_style_variation_styles() {
 247      wp_enqueue_style( 'block-style-variation-styles' );
 248  }
 249  
 250  // Register the block support.
 251  WP_Block_Supports::get_instance()->register( 'block-style-variation', array() );
 252  
 253  add_filter( 'render_block_data', 'wp_render_block_style_variation_support_styles', 10, 2 );
 254  add_filter( 'render_block', 'wp_render_block_style_variation_class_name', 10, 2 );
 255  add_action( 'wp_enqueue_scripts', 'wp_enqueue_block_style_variation_styles', 1 );
 256  
 257  /**
 258   * Registers block style variations read in from theme.json partials.
 259   *
 260   * @since 6.6.0
 261   * @access private
 262   *
 263   * @param array $variations Shared block style variations.
 264   */
 265  function wp_register_block_style_variations_from_theme_json_partials( $variations ) {
 266      if ( empty( $variations ) ) {
 267          return;
 268      }
 269  
 270      $registry = WP_Block_Styles_Registry::get_instance();
 271  
 272      foreach ( $variations as $variation ) {
 273          if ( empty( $variation['blockTypes'] ) || empty( $variation['styles'] ) ) {
 274              continue;
 275          }
 276  
 277          $variation_name  = $variation['slug'] ?? _wp_to_kebab_case( $variation['title'] );
 278          $variation_label = $variation['title'] ?? $variation_name;
 279  
 280          foreach ( $variation['blockTypes'] as $block_type ) {
 281              $registered_styles = $registry->get_registered_styles_for_block( $block_type );
 282  
 283              // Register block style variation if it hasn't already been registered.
 284              if ( ! array_key_exists( $variation_name, $registered_styles ) ) {
 285                  register_block_style(
 286                      $block_type,
 287                      array(
 288                          'name'  => $variation_name,
 289                          'label' => $variation_label,
 290                      )
 291                  );
 292              }
 293          }
 294      }
 295  }