1 files changed, 77 insertions, 0 deletions
diff --git a/dom/base/WindowProxyHolder.h b/dom/base/WindowProxyHolder.h
new file mode 100644
index 0000000000..b2887f236c
--- /dev/null
+++ b/dom/base/WindowProxyHolder.h
@@ -0,0 +1,77 @@
+/* -*- 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/. */
+
+#ifndef mozilla_dom_WindowProxyHolder_h__
+#define mozilla_dom_WindowProxyHolder_h__
+
+#include "mozilla/dom/BrowsingContext.h"
+
+struct JSContext;
+class JSObject;
+
+namespace JS {
+template <typename T>
+class MutableHandle;
+}  // namespace JS
+
+namespace mozilla::dom {
+
+/**
+ * This class is used for passing arguments and the return value for WebIDL
+ * binding code that takes/returns a WindowProxy object and for WebIDL
+ * unions/dictionaries that contain a WindowProxy member. It should never
+ * contain null; if the value in WebIDL is nullable the binding code will use a
+ * Nullable<WindowProxyHolder>.
+ */
+class WindowProxyHolder {
+ public:
+  WindowProxyHolder() = default;
+  explicit WindowProxyHolder(BrowsingContext* aBC) : mBrowsingContext(aBC) {
+    MOZ_ASSERT(mBrowsingContext, "Don't set WindowProxyHolder to null.");
+  }
+  explicit WindowProxyHolder(RefPtr<BrowsingContext>&& aBC)
+      : mBrowsingContext(std::move(aBC)) {
+    MOZ_ASSERT(mBrowsingContext, "Don't set WindowProxyHolder to null.");
+  }
+  WindowProxyHolder& operator=(BrowsingContext* aBC) {
+    mBrowsingContext = aBC;
+    MOZ_ASSERT(mBrowsingContext, "Don't set WindowProxyHolder to null.");
+    return *this;
+  }
+  WindowProxyHolder& operator=(RefPtr<BrowsingContext>&& aBC) {
+    mBrowsingContext = std::move(aBC);
+    MOZ_ASSERT(mBrowsingContext, "Don't set WindowProxyHolder to null.");
+    return *this;
+  }
+
+  BrowsingContext* get() const {
+    MOZ_ASSERT(mBrowsingContext, "WindowProxyHolder hasn't been initialized.");
+    return mBrowsingContext;
+  }
+
+ private:
+  friend void ImplCycleCollectionUnlink(WindowProxyHolder& aProxy);
+
+  RefPtr<BrowsingContext> mBrowsingContext;
+};
+
+inline void ImplCycleCollectionTraverse(
+    nsCycleCollectionTraversalCallback& aCallback, WindowProxyHolder& aProxy,
+    const char* aName, uint32_t aFlags = 0) {
+  CycleCollectionNoteChild(aCallback, aProxy.get(), "mBrowsingContext", aFlags);
+}
+
+inline void ImplCycleCollectionUnlink(WindowProxyHolder& aProxy) {
+  aProxy.mBrowsingContext = nullptr;
+}
+
+extern bool GetRemoteOuterWindowProxy(JSContext* aCx, BrowsingContext* aContext,
+                                      JS::Handle<JSObject*> aTransplantTo,
+                                      JS::MutableHandle<JSObject*> aValue);
+
+}  // namespace mozilla::dom
+
+#endif /* mozilla_dom_WindowProxyHolder_h__ */