Script Loader: Optimize performance of `_wp_normalize_relative_css_links()` by more than 2x.

- Replace `preg_match_all()` and its secondary `str_replace()` call with `preg_replace_callback()`.
- Fix case where paths beginning with `http` and `https` (but not `http:` and `https:`) were erroneously not counted as relative.
- Improve code style and readability by consolidating conditions and returning once.
- Use `str_starts_with()` consistently instead of `strpos()`.

Follow-up to [52036], [52695], and [52754].

Props westonruter, adamsilverstein, azaozz.
Merges [55658] and [55669] to the 6.2 branch.
Fixes #58069.
See #54243.

Built from https://develop.svn.wordpress.org/branches/6.2@55736


git-svn-id: http://core.svn.wordpress.org/branches/6.2@55248 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/script-loader.php

@@ -2941,41 +2941,33 @@ function wp_maybe_inline_styles() {
  * @return string The CSS with URLs made relative to the WordPress installation.
  */
 function _wp_normalize_relative_css_links( $css, $stylesheet_url ) {
-	$has_src_results = preg_match_all( '#url\s*\(\s*[\'"]?\s*([^\'"\)]+)#', $css, $src_results );
-	if ( $has_src_results ) {
-		// Loop through the URLs to find relative ones.
-		foreach ( $src_results[1] as $src_index => $src_result ) {
-			// Skip if this is an absolute URL.
-			if ( 0 === strpos( $src_result, 'http' ) || 0 === strpos( $src_result, '//' ) ) {
-				continue;
-			}
+	return preg_replace_callback(
+		'#(url\s*\(\s*[\'"]?\s*)([^\'"\)]+)#',
+		static function ( $matches ) use ( $stylesheet_url ) {
+			list( , $prefix, $url ) = $matches;
 
-			// Skip if the URL is an HTML ID.
-			if ( str_starts_with( $src_result, '#' ) ) {
-				continue;
-			}
-
-			// Skip if the URL is a data URI.
-			if ( str_starts_with( $src_result, 'data:' ) ) {
-				continue;
+			// Short-circuit if the URL does not require normalization.
+			if (
+				str_starts_with( $url, 'http:' ) ||
+				str_starts_with( $url, 'https:' ) ||
+				str_starts_with( $url, '//' ) ||
+				str_starts_with( $url, '#' ) ||
+				str_starts_with( $url, 'data:' )
+			) {
+				return $matches[0];
 			}
 
 			// Build the absolute URL.
-			$absolute_url = dirname( $stylesheet_url ) . '/' . $src_result;
+			$absolute_url = dirname( $stylesheet_url ) . '/' . $url;
 			$absolute_url = str_replace( '/./', '/', $absolute_url );
+
 			// Convert to URL related to the site root.
-			$relative_url = wp_make_link_relative( $absolute_url );
+			$url = wp_make_link_relative( $absolute_url );
 
-			// Replace the URL in the CSS.
-			$css = str_replace(
-				$src_results[0][ $src_index ],
-				str_replace( $src_result, $relative_url, $src_results[0][ $src_index ] ),
-				$css
-			);
-		}
-	}
-
-	return $css;
+			return $prefix . $url;
+		},
+		$css
+	);
 }
 
 /**

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.2.1-alpha-55735';
+$wp_version = '6.2.1-alpha-55736';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.