Editor: Improve block loading PHP performance.

This commit improves PHP performance for core blocks by reading a single PHP file with block metadata, instead of reading a JSON file per-block and then decoding from JSON to PHP.

Includes:
* Adding a new Grunt task to convert `block.json` files to `block-json.php`.
* Using the new `block-json.php` file in the `register_block_type_from_metadata()` function.

Follow-up to [48141].

Props aristath, gziolo, johnbillion, presstoke, mukesh27, hellofromTonya, petitphp, adamsilverstein, costdev, desrosj, SergeyBiryukov.
Fixes #55005.

git-svn-id: https://develop.svn.wordpress.org/trunk@54276 602fd350-edb4-49c9-b593-d223f7449a82

Author: SergeyBiryukov

Gruntfile.js

@@ -3,6 +3,7 @@
 /* globals Set */
 var webpackConfig = require( './webpack.config' );
 var installChanged = require( 'install-changed' );
+var json2php = require( 'json2php' );
 
 module.exports = function(grunt) {
 	var path = require('path'),
@@ -1403,6 +1404,19 @@ module.exports = function(grunt) {
 		}
 	} );
 
+	grunt.registerTask( 'copy:block-json', 'Copies block.json file contents to block-json.php.', function() {
+		var blocks = {};
+		grunt.file.recurse( SOURCE_DIR + 'wp-includes/blocks', function( abspath, rootdir, subdir, filename ) {
+			if ( /^block\.json$/.test( filename ) ) {
+				blocks[ subdir ] = grunt.file.readJSON( abspath );
+			}
+		} );
+		grunt.file.write(
+			SOURCE_DIR + 'wp-includes/blocks/blocks-json.php',
+			'<?php return ' + json2php( blocks ) + ';'
+		);
+	} );
+
 	grunt.registerTask( 'copy:js', [
 		'copy:npm-packages',
 		'copy:vendor-js',
@@ -1451,6 +1465,7 @@ module.exports = function(grunt) {
 	grunt.registerTask( 'build:files', [
 		'clean:files',
 		'copy:files',
+		'copy:block-json',
 		'copy:version',
 	] );
 

package-lock.json

@@ -143,6 +143,7 @@
 		"jquery-color": "2.2.0",
 		"jquery-form": "4.3.0",
 		"jquery-hoverintent": "1.10.2",
+		"json2php": "^0.0.5",
 		"lodash": "4.17.21",
 		"masonry-layout": "4.2.2",
 		"moment": "2.29.4",

package.json

@@ -283,15 +283,39 @@ function get_block_metadata_i18n_schema() {
  * @return WP_Block_Type|false The registered block type on success, or false on failure.
  */
 function register_block_type_from_metadata( $file_or_folder, $args = array() ) {
-	$filename      = 'block.json';
-	$metadata_file = ( substr( $file_or_folder, -strlen( $filename ) ) !== $filename ) ?
-		trailingslashit( $file_or_folder ) . $filename :
+	/*
+	 * Get an array of metadata from a PHP file.
+	 * This improves performance for core blocks as it's only necessary to read a single PHP file
+	 * instead of reading a JSON file per-block, and then decoding from JSON to PHP.
+	 * Using a static variable ensures that the metadata is only read once per request.
+	 */
+	static $core_blocks_meta;
+	if ( ! $core_blocks_meta ) {
+		$core_blocks_meta = include_once ABSPATH . WPINC . '/blocks/blocks-json.php';
+	}
+
+	$metadata_file = ( ! str_ends_with( $file_or_folder, 'block.json' ) ) ?
+		trailingslashit( $file_or_folder ) . 'block.json' :
 		$file_or_folder;
+
 	if ( ! file_exists( $metadata_file ) ) {
 		return false;
 	}
 
-	$metadata = wp_json_file_decode( $metadata_file, array( 'associative' => true ) );
+	// Try to get metadata from the static cache for core blocks.
+	$metadata = false;
+	if ( str_starts_with( $file_or_folder, ABSPATH . WPINC ) ) {
+		$core_block_name = str_replace( ABSPATH . WPINC . '/blocks/', '', $file_or_folder );
+		if ( ! empty( $core_blocks_meta[ $core_block_name ] ) ) {
+			$metadata = $core_blocks_meta[ $core_block_name ];
+		}
+	}
+
+	// If metadata is not found in the static cache, read it from the file.
+	if ( ! $metadata ) {
+		$metadata = wp_json_file_decode( $metadata_file, array( 'associative' => true ) );
+	}
+
 	if ( ! is_array( $metadata ) || empty( $metadata['name'] ) ) {
 		return false;
 	}