break up asset groups of over 150

concat-utils.php

@@ -1,6 +1,16 @@
 <?php
 
+if ( ! defined( 'VIP_CONCAT_MAX' ) ) {
+	define( 'VIP_CONCAT_MAX', 150 );
+}
+
 class WPCOM_Concat_Utils {
+
+	public static function get_concat_max() {
+		// no less than 10, no more than 150
+		return min( max( intval( VIP_CONCAT_MAX ), 10 ), 150 );
+	}
+
 	public static function is_internal_url( $test_url, $site_url ) {
 		$test_url_parsed = parse_url( is_string( $test_url ) ? $test_url : '' );
 		$site_url_parsed = parse_url( $site_url );

cssconcat.php

@@ -98,6 +98,10 @@ function do_items( $handles = false, $group = false ) {
 					$stylesheets[ $stylesheet_group_index ] = array();
 
 				$stylesheets[ $stylesheet_group_index ][ $media ][ $handle ] = $css_url_parsed['path'];
+
+				if ( count( $stylesheets[ $stylesheet_group_index ][ $media ] ) >= WPCOM_Concat_Utils::get_concat_max() ) {
+					$stylesheet_group_index++;
+				}
 				$this->done[] = $handle;
 			} else {
 				$stylesheet_group_index++;

jsconcat.php

@@ -129,6 +129,10 @@ function do_items( $handles = false, $group = false ) {
 				$javascripts[$level]['paths'][] = $js_url_parsed['path'];
 				$javascripts[$level]['handles'][] = $handle;
 
+				if ( count( $javascripts[$level]['paths'] ) >= WPCOM_Concat_Utils::get_concat_max() ) {
+					$level++;
+				}
+
 			} else {
 				$level++;
 				$javascripts[$level]['type'] = 'do_item';

ngx-http-concat.php

@@ -16,7 +16,6 @@
 require_once( __DIR__ . '/concat-utils.php' );
 
 /* Config */
-$concat_max_files = 150;
 $concat_unique = true;
 $concat_types = array(
 	'css' => 'text/css',
@@ -114,7 +113,7 @@ function concat_get_path( $uri ) {
 	concat_http_status_exit( 400 );
 
 // array( '/foo/bar.css', '/foo1/bar/baz.css' )
-if ( 0 == count( $args ) || count( $args ) > $concat_max_files )
+if ( 0 == count( $args ) || count( $args ) > WPCOM_Concat_Utils::get_concat_max() )
 	concat_http_status_exit( 400 );
 
 // If we're in a subdirectory context, use that as the root.