Themes: Improve performance of applying background image styles in theme.json.

The cost of using `WP_Theme_JSON::get_block_nodes()` for this in its original shape was high enough to lead to a performance regression. Therefore this changeset introduces a new option on the method that allows to bypass all logic except for retrieving the node paths, which is much faster and everything that this functionality needs.

Follow up to [58936].

Props mukesh27, flixos90, ramonopoly, joemcgill, andrewserong, swissspidy.
Fixes #61858.

Built from https://develop.svn.wordpress.org/trunk@59213


git-svn-id: http://core.svn.wordpress.org/trunk@58606 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/class-wp-theme-json.php

@@ -2690,13 +2690,15 @@ class WP_Theme_JSON {
 	 * @since 6.1.0
 	 * @since 6.3.0 Refactored and stabilized selectors API.
 	 * @since 6.6.0 Added optional selectors and options for generating block nodes.
+	 * @since 6.7.0 Added $include_node_paths_only option.
 	 *
 	 * @param array $theme_json The theme.json converted to an array.
 	 * @param array $selectors  Optional list of selectors per block.
 	 * @param array $options {
 	 *     Optional. An array of options for now used for internal purposes only (may change without notice).
 	 *
-	 *     @type bool   $include_block_style_variations  Includes nodes for block style variations. Default false.
+	 *     @type bool $include_block_style_variations Include nodes for block style variations. Default false.
+	 *     @type bool $include_node_paths_only        Return only block nodes node paths. Default false.
 	 * }
 	 * @return array The block nodes in theme.json.
 	 */
@@ -2712,7 +2714,16 @@ class WP_Theme_JSON {
 			return $nodes;
 		}
 
+		$include_variations      = $options['include_block_style_variations'] ?? false;
+		$include_node_paths_only = $options['include_node_paths_only'] ?? false;
+
 		foreach ( $theme_json['styles']['blocks'] as $name => $node ) {
+			$node_path = array( 'styles', 'blocks', $name );
+			if ( $include_node_paths_only ) {
+				$nodes[] = array(
+					'path' => $node_path,
+				);
+			} else {
 				$selector = null;
 				if ( isset( $selectors[ $name ]['selector'] ) ) {
 					$selector = $selectors[ $name ]['selector'];
@@ -2729,7 +2740,6 @@ class WP_Theme_JSON {
 				}
 
 				$variation_selectors = array();
-			$include_variations  = $options['include_block_style_variations'] ?? false;
 				if ( $include_variations && isset( $node['variations'] ) ) {
 					foreach ( $node['variations'] as $variation => $node ) {
 						$variation_selectors[] = array(
@@ -2741,7 +2751,7 @@ class WP_Theme_JSON {
 
 				$nodes[] = array(
 					'name'       => $name,
-				'path'       => array( 'styles', 'blocks', $name ),
+					'path'       => $node_path,
 					'selector'   => $selector,
 					'selectors'  => $feature_selectors,
 					'duotone'    => $duotone_selector,
@@ -2749,11 +2759,20 @@ class WP_Theme_JSON {
 					'variations' => $variation_selectors,
 					'css'        => $selector,
 				);
+			}
 
 			if ( isset( $theme_json['styles']['blocks'][ $name ]['elements'] ) ) {
 				foreach ( $theme_json['styles']['blocks'][ $name ]['elements'] as $element => $node ) {
+					$node_path = array( 'styles', 'blocks', $name, 'elements', $element );
+					if ( $include_node_paths_only ) {
 						$nodes[] = array(
-						'path'     => array( 'styles', 'blocks', $name, 'elements', $element ),
+							'path' => $node_path,
+						);
+						continue;
+					}
+
+					$nodes[] = array(
+						'path'     => $node_path,
 						'selector' => $selectors[ $name ]['elements'][ $element ],
 					);
 
@@ -2761,8 +2780,16 @@ class WP_Theme_JSON {
 					if ( isset( static::VALID_ELEMENT_PSEUDO_SELECTORS[ $element ] ) ) {
 						foreach ( static::VALID_ELEMENT_PSEUDO_SELECTORS[ $element ] as $pseudo_selector ) {
 							if ( isset( $theme_json['styles']['blocks'][ $name ]['elements'][ $element ][ $pseudo_selector ] ) ) {
+								$node_path = array( 'styles', 'blocks', $name, 'elements', $element );
+								if ( $include_node_paths_only ) {
 									$nodes[] = array(
-									'path'     => array( 'styles', 'blocks', $name, 'elements', $element ),
+										'path' => $node_path,
+									);
+									continue;
+								}
+
+								$nodes[] = array(
+									'path'     => $node_path,
 									'selector' => static::append_to_selector( $selectors[ $name ]['elements'][ $element ], $pseudo_selector ),
 								);
 							}
@@ -3236,7 +3263,11 @@ class WP_Theme_JSON {
 		 * some values provide exceptions, namely style values that are
 		 * objects and represent unique definitions for the style.
 		 */
-		$style_nodes = static::get_styles_block_nodes();
+		$style_nodes = static::get_block_nodes(
+			$this->theme_json,
+			array(),
+			array( 'include_node_paths_only' => true )
+		);
 		foreach ( $style_nodes as $style_node ) {
 			$path = $style_node['path'];
 			/*

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.7-beta2-59210';
+$wp_version = '6.7-beta2-59213';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.