1 files changed, 177 insertions, 0 deletions
diff --git a/dom/bindings/SimpleGlobalObject.cpp b/dom/bindings/SimpleGlobalObject.cpp
new file mode 100644
index 0000000000..798efc94c1
--- /dev/null
+++ b/dom/bindings/SimpleGlobalObject.cpp
@@ -0,0 +1,177 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/dom/SimpleGlobalObject.h"
+
+#include "jsapi.h"
+#include "js/Class.h"
+#include "js/Object.h"  // JS::GetClass, JS::GetObjectISupports, JS::SetObjectISupports
+
+#include "nsJSPrincipals.h"
+#include "nsThreadUtils.h"
+#include "nsContentUtils.h"
+
+#include "xpcprivate.h"
+
+#include "mozilla/dom/ScriptSettings.h"
+#include "mozilla/NullPrincipal.h"
+
+namespace mozilla::dom {
+
+NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_CLASS(SimpleGlobalObject)
+
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(SimpleGlobalObject)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER
+  tmp->UnlinkObjectsInGlobal();
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(SimpleGlobalObject)
+  tmp->TraverseObjectsInGlobal(cb);
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(SimpleGlobalObject)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(SimpleGlobalObject)
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(SimpleGlobalObject)
+  NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
+  NS_INTERFACE_MAP_ENTRY(nsIGlobalObject)
+NS_INTERFACE_MAP_END
+
+static SimpleGlobalObject* GetSimpleGlobal(JSObject* global);
+
+static void SimpleGlobal_finalize(JS::GCContext* gcx, JSObject* obj) {
+  SimpleGlobalObject* globalObject = GetSimpleGlobal(obj);
+  if (globalObject) {
+    globalObject->ClearWrapper(obj);
+    NS_RELEASE(globalObject);
+  }
+}
+
+static size_t SimpleGlobal_moved(JSObject* obj, JSObject* old) {
+  SimpleGlobalObject* globalObject = GetSimpleGlobal(obj);
+  if (globalObject) {
+    globalObject->UpdateWrapper(obj, old);
+  }
+  return 0;
+}
+
+static const JSClassOps SimpleGlobalClassOps = {
+    nullptr,
+    nullptr,
+    nullptr,
+    JS_NewEnumerateStandardClasses,
+    JS_ResolveStandardClass,
+    JS_MayResolveStandardClass,
+    SimpleGlobal_finalize,
+    nullptr,
+    nullptr,
+    JS_GlobalObjectTraceHook,
+};
+
+static const js::ClassExtension SimpleGlobalClassExtension = {
+    SimpleGlobal_moved};
+
+static_assert(JSCLASS_GLOBAL_APPLICATION_SLOTS > 0,
+              "Need at least one slot for JSCLASS_SLOT0_IS_NSISUPPORTS");
+
+const JSClass SimpleGlobalClass = {"",
+                                   JSCLASS_GLOBAL_FLAGS |
+                                       JSCLASS_SLOT0_IS_NSISUPPORTS |
+                                       JSCLASS_FOREGROUND_FINALIZE,
+                                   &SimpleGlobalClassOps,
+                                   JS_NULL_CLASS_SPEC,
+                                   &SimpleGlobalClassExtension,
+                                   JS_NULL_OBJECT_OPS};
+
+static SimpleGlobalObject* GetSimpleGlobal(JSObject* global) {
+  MOZ_ASSERT(JS::GetClass(global) == &SimpleGlobalClass);
+
+  return JS::GetObjectISupports<SimpleGlobalObject>(global);
+}
+
+// static
+JSObject* SimpleGlobalObject::Create(GlobalType globalType,
+                                     JS::Handle<JS::Value> proto) {
+  // We can't root our return value with our AutoJSAPI because the rooting
+  // analysis thinks ~AutoJSAPI can GC.  So we need to root in a scope outside
+  // the lifetime of the AutoJSAPI.
+  JS::Rooted<JSObject*> global(RootingCx());
+
+  {  // Scope to ensure the AutoJSAPI destructor runs before we end up returning
+    AutoJSAPI jsapi;
+    jsapi.Init();
+    JSContext* cx = jsapi.cx();
+
+    JS::RealmOptions options;
+    options.creationOptions()
+        .setInvisibleToDebugger(true)
+        // Put our SimpleGlobalObjects in the system zone, so we won't create
+        // lots of zones for what are probably very short-lived
+        // compartments.  This should help them be GCed quicker and take up
+        // less memory before they're GCed.
+        .setNewCompartmentInSystemZone();
+
+    if (NS_IsMainThread()) {
+      nsCOMPtr<nsIPrincipal> principal =
+          NullPrincipal::CreateWithoutOriginAttributes();
+      options.creationOptions().setTrace(xpc::TraceXPCGlobal);
+      global = xpc::CreateGlobalObject(cx, &SimpleGlobalClass,
+                                       nsJSPrincipals::get(principal), options);
+    } else {
+      global = JS_NewGlobalObject(cx, &SimpleGlobalClass, nullptr,
+                                  JS::DontFireOnNewGlobalHook, options);
+    }
+
+    if (!global) {
+      jsapi.ClearException();
+      return nullptr;
+    }
+
+    JSAutoRealm ar(cx, global);
+
+    // It's important to create the nsIGlobalObject for our new global before we
+    // start trying to wrap things like the prototype into its compartment,
+    // because the wrap operation relies on the global having its
+    // nsIGlobalObject already.
+    RefPtr<SimpleGlobalObject> globalObject =
+        new SimpleGlobalObject(global, globalType);
+
+    // Pass on ownership of globalObject to |global|.
+    JS::SetObjectISupports(global, globalObject.forget().take());
+
+    if (proto.isObjectOrNull()) {
+      JS::Rooted<JSObject*> protoObj(cx, proto.toObjectOrNull());
+      if (!JS_WrapObject(cx, &protoObj)) {
+        jsapi.ClearException();
+        return nullptr;
+      }
+
+      if (!JS_SetPrototype(cx, global, protoObj)) {
+        jsapi.ClearException();
+        return nullptr;
+      }
+    } else if (!proto.isUndefined()) {
+      // Bogus proto.
+      return nullptr;
+    }
+
+    JS_FireOnNewGlobalObject(cx, global);
+  }
+
+  return global;
+}
+
+// static
+SimpleGlobalObject::GlobalType SimpleGlobalObject::SimpleGlobalType(
+    JSObject* obj) {
+  if (JS::GetClass(obj) != &SimpleGlobalClass) {
+    return SimpleGlobalObject::GlobalType::NotSimpleGlobal;
+  }
+
+  SimpleGlobalObject* globalObject = GetSimpleGlobal(obj);
+  return globalObject->Type();
+}
+
+}  // namespace mozilla::dom