1 files changed, 90 insertions, 0 deletions
diff --git a/dom/ipc/jsactor/nsQueryActor.h b/dom/ipc/jsactor/nsQueryActor.h
new file mode 100644
index 0000000000..cbbda7e473
--- /dev/null
+++ b/dom/ipc/jsactor/nsQueryActor.h
@@ -0,0 +1,90 @@
+/* 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/. */
+
+#ifndef nsQueryActor_h
+#define nsQueryActor_h
+
+#include <type_traits>
+
+#include "nsCOMPtr.h"
+#include "nsPIDOMWindow.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/JSActor.h"
+#include "mozilla/dom/JSActorManager.h"
+#include "mozilla/dom/ScriptSettings.h"
+#include "mozilla/dom/WindowGlobalChild.h"
+
+class nsIDOMProcessChild;
+class nsIDOMProcessParent;
+
+// This type is used to get an XPCOM interface implemented by a JSActor from its
+// native manager.
+class MOZ_STACK_CLASS nsQueryJSActor final : public nsCOMPtr_helper {
+ public:
+  nsQueryJSActor(const nsLiteralCString aActorName,
+                 mozilla::dom::JSActorManager* aManager)
+      : mActorName(aActorName), mManager(aManager) {}
+
+  nsresult NS_FASTCALL operator()(const nsIID& aIID,
+                                  void** aResult) const override {
+    if (!mManager) {
+      return NS_ERROR_NO_INTERFACE;
+    }
+
+    mozilla::dom::AutoJSAPI jsapi;
+    jsapi.Init();
+
+    RefPtr<mozilla::dom::JSActor> actor =
+        mManager->GetActor(jsapi.cx(), mActorName, mozilla::IgnoreErrors());
+    if (!actor) {
+      return NS_ERROR_NO_INTERFACE;
+    }
+
+    return actor->QueryInterfaceActor(aIID, aResult);
+  }
+
+ private:
+  const nsLiteralCString mActorName;
+  mozilla::dom::JSActorManager* mManager;
+};
+
+// Request an XPCOM interface from a JSActor managed by `aManager`.
+//
+// These APIs will work with both JSWindowActors and JSProcessActors.
+template <size_t length>
+inline nsQueryJSActor do_QueryActor(const char (&aActorName)[length],
+                                    mozilla::dom::JSActorManager* aManager) {
+  return nsQueryJSActor(nsLiteralCString(aActorName), aManager);
+}
+
+// Overload for directly querying a JSWindowActorChild from an inner window.
+template <size_t length>
+inline nsQueryJSActor do_QueryActor(const char (&aActorName)[length],
+                                    nsPIDOMWindowInner* aWindow) {
+  return nsQueryJSActor(nsLiteralCString(aActorName),
+                        aWindow ? aWindow->GetWindowGlobalChild() : nullptr);
+}
+
+// Overload for directly querying a JSWindowActorChild from a document.
+template <size_t length>
+inline nsQueryJSActor do_QueryActor(const char (&aActorName)[length],
+                                    mozilla::dom::Document* aDoc) {
+  return nsQueryJSActor(nsLiteralCString(aActorName),
+                        aDoc ? aDoc->GetWindowGlobalChild() : nullptr);
+}
+
+// Overload for directly querying from a nsIDOMProcess{Parent,Child} without
+// confusing overload selection for types inheriting from both
+// nsIDOMProcess{Parent,Child} and JSActorManager.
+template <size_t length, typename T,
+          typename = std::enable_if_t<std::is_same_v<T, nsIDOMProcessParent> ||
+                                      std::is_same_v<T, nsIDOMProcessChild>>>
+inline nsQueryJSActor do_QueryActor(const char (&aActorName)[length],
+                                    T* aManager) {
+  return nsQueryJSActor(nsLiteralCString(aActorName),
+                        aManager ? aManager->AsJSActorManager() : nullptr);
+}
+
+#endif  // defined nsQueryActor_h