perf: lazy bootstrap options - first pass (#21164)

Move most runtime options to be lazily loaded. Constant options will be
covered in a different PR.

Towards https://github.com/denoland/deno/issues/21133

1 files changed, 21 insertions, 22 deletions

diff --git a/runtime/js/98_global_scope.js b/runtime/js/98_global_scope.js
index 6c650da10..aada57d70 100644
--- a/runtime/js/98_global_scope.js
+++ b/runtime/js/98_global_scope.js
@@ -1,6 +1,7 @@
 // Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
 
 const core = globalThis.Deno.core;
+const ops = core.ops;
 const primordials = globalThis.__bootstrap.primordials;
 const {
   ObjectDefineProperties,
@@ -157,19 +158,19 @@ class Navigator {
 
 const navigator = webidl.createBranded(Navigator);
 
-let numCpus, userAgent, language;
-
-function setNumCpus(val) {
-  numCpus = val;
-}
-
-function setUserAgent(val) {
-  userAgent = val;
+function memoizeLazy(f) {
+  let v_ = null;
+  return () => {
+    if (v_ === null) {
+      v_ = f();
+    }
+    return v_;
+  };
 }
 
-function setLanguage(val) {
-  language = val;
-}
+const numCpus = memoizeLazy(() => ops.op_bootstrap_numcpus());
+const userAgent = memoizeLazy(() => ops.op_bootstrap_user_agent());
+const language = memoizeLazy(() => ops.op_bootstrap_language());
 
 ObjectDefineProperties(Navigator.prototype, {
   hardwareConcurrency: {
@@ -177,7 +178,7 @@ ObjectDefineProperties(Navigator.prototype, {
     enumerable: true,
     get() {
       webidl.assertBranded(this, NavigatorPrototype);
-      return numCpus;
+      return numCpus();
     },
   },
   userAgent: {
@@ -185,7 +186,7 @@ ObjectDefineProperties(Navigator.prototype, {
     enumerable: true,
     get() {
       webidl.assertBranded(this, NavigatorPrototype);
-      return userAgent;
+      return userAgent();
     },
   },
   language: {
@@ -193,7 +194,7 @@ ObjectDefineProperties(Navigator.prototype, {
     enumerable: true,
     get() {
       webidl.assertBranded(this, NavigatorPrototype);
-      return language;
+      return language();
     },
   },
   languages: {
@@ -201,7 +202,7 @@ ObjectDefineProperties(Navigator.prototype, {
     enumerable: true,
     get() {
       webidl.assertBranded(this, NavigatorPrototype);
-      return [language];
+      return [language()];
     },
   },
 });
@@ -225,7 +226,7 @@ ObjectDefineProperties(WorkerNavigator.prototype, {
     enumerable: true,
     get() {
       webidl.assertBranded(this, WorkerNavigatorPrototype);
-      return numCpus;
+      return numCpus();
     },
   },
   userAgent: {
@@ -233,7 +234,7 @@ ObjectDefineProperties(WorkerNavigator.prototype, {
     enumerable: true,
     get() {
       webidl.assertBranded(this, WorkerNavigatorPrototype);
-      return userAgent;
+      return userAgent();
     },
   },
   language: {
@@ -241,7 +242,7 @@ ObjectDefineProperties(WorkerNavigator.prototype, {
     enumerable: true,
     get() {
       webidl.assertBranded(this, WorkerNavigatorPrototype);
-      return language;
+      return language();
     },
   },
   languages: {
@@ -249,7 +250,7 @@ ObjectDefineProperties(WorkerNavigator.prototype, {
     enumerable: true,
     get() {
       webidl.assertBranded(this, WorkerNavigatorPrototype);
-      return [language];
+      return [language()];
     },
   },
 });
@@ -284,9 +285,7 @@ const workerRuntimeGlobalProperties = {
 
 export {
   mainRuntimeGlobalProperties,
-  setLanguage,
-  setNumCpus,
-  setUserAgent,
+  memoizeLazy,
   unstableWindowOrWorkerGlobalScope,
   windowOrWorkerGlobalScope,
   workerRuntimeGlobalProperties,