Bug 1587007 - P1 - Tunnel the prefs for Coop and Coep to js; r=jandem

Differential Revision: https://phabricator.services.mozilla.com/D51420

js/public/RealmOptions.h

@@ -128,6 +128,15 @@ class JS_PUBLIC_API RealmCreationOptions {
   bool getSharedMemoryAndAtomicsEnabled() const;
   RealmCreationOptions& setSharedMemoryAndAtomicsEnabled(bool flag);
 
+  // When these prefs (COOP and COEP) are not enabled, shared memory objects
+  // (e.g. SAB) are not allowed to be postMessage()'ed. And we want to provide
+  // a clear warning message to users/developer so that they would have an idea
+  // if the implementations of the COOP and COEP headers are finished or not. So
+  // that they would know if they can fix the SAB by deploying the COOP and
+  // COEP headers or not.
+  bool getCoopAndCoepEnabled() const;
+  RealmCreationOptions& setCoopAndCoepEnabled(bool flag);
+
   bool getStreamsEnabled() const { return streams_; }
   RealmCreationOptions& setStreamsEnabled(bool flag) {
     streams_ = flag;
@@ -199,6 +208,7 @@ class JS_PUBLIC_API RealmCreationOptions {
   bool preserveJitCode_ = false;
   bool cloneSingletons_ = false;
   bool sharedMemoryAndAtomics_ = false;
+  bool coopAndCoep_ = false;
   bool streams_ = false;
   bool readableByteStreams_ = false;
   bool byobStreamReaders_ = false;

js/src/jit-test/tests/structured-clone/sab-errMsg.js

@@ -0,0 +1,16 @@
+// |jit-test| skip-if: !this.sharedMemoryEnabled
+// Need this testing function to continue.
+
+// Check the error mssage when the prefs for COOP/COEP are both enable or not.
+var g = newGlobal();
+var ex;
+const sab = new SharedArrayBuffer();
+try {
+  g.serialize(sab);
+} catch (e) {
+  ex = e;
+}
+assertEq(ex.toString(),
+         `TypeError: The SharedArrayBuffer object cannot be serialized. The ` +
+         `Cross-Origin-Opener-Policy and Cross-Origin-Embedder-Policy HTTP ` +
+         `headers will enable this in the future.`);

js/src/jsapi.cpp

@@ -1717,6 +1717,16 @@ JS::RealmCreationOptions::setSharedMemoryAndAtomicsEnabled(bool flag) {
   return *this;
 }
 
+bool JS::RealmCreationOptions::getCoopAndCoepEnabled() const {
+  return coopAndCoep_;
+}
+
+JS::RealmCreationOptions& JS::RealmCreationOptions::setCoopAndCoepEnabled(
+    bool flag) {
+  coopAndCoep_ = flag;
+  return *this;
+}
+
 JS::RealmBehaviors& JS::RealmBehaviorsRef(JS::Realm* realm) {
   return realm->behaviors();
 }

js/src/shell/js.cpp

@@ -3731,6 +3731,7 @@ static const JSClass sandbox_class = {"sandbox", JSCLASS_GLOBAL_FLAGS,
 static void SetStandardRealmOptions(JS::RealmOptions& options) {
   options.creationOptions()
       .setSharedMemoryAndAtomicsEnabled(enableSharedMemory)
+      .setCoopAndCoepEnabled(false)
       .setStreamsEnabled(enableStreams)
       .setReadableByteStreamsEnabled(enableReadableByteStreams)
       .setBYOBStreamReadersEnabled(enableBYOBStreamReaders)
@@ -6201,6 +6202,13 @@ static bool NewGlobal(JSContext* cx, unsigned argc, Value* vp) {
       }
       principals.reset(newPrincipals);
     }
+
+    if (!JS_GetProperty(cx, opts, "enableCoopAndCoep", &v)) {
+      return false;
+    }
+    if (v.isBoolean()) {
+      creationOptions.setCoopAndCoepEnabled(v.toBoolean());
+    }
   }
 
   if (!CheckRealmOptions(cx, options, principals.get())) {

js/xpconnect/src/XPCJSContext.cpp

@@ -771,6 +771,9 @@ static mozilla::Atomic<bool> sAwaitFixEnabled(false);
 void xpc::SetPrefableRealmOptions(JS::RealmOptions& options) {
   options.creationOptions()
       .setSharedMemoryAndAtomicsEnabled(sSharedMemoryEnabled)
+      .setCoopAndCoepEnabled(
+          StaticPrefs::browser_tabs_remote_useCrossOriginOpenerPolicy() &&
+          StaticPrefs::browser_tabs_remote_useCrossOriginEmbedderPolicy())
       .setStreamsEnabled(sStreamsEnabled)
       .setWritableStreamsEnabled(
           StaticPrefs::javascript_options_writable_streams())