1 files changed, 63 insertions, 0 deletions
diff --git a/dom/storage/SessionStorageObserver.h b/dom/storage/SessionStorageObserver.h
new file mode 100644
index 0000000000..dee472cc9c
--- /dev/null
+++ b/dom/storage/SessionStorageObserver.h
@@ -0,0 +1,63 @@
+/* -*- 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_SessionStorageObserver_h
+#define mozilla_dom_SessionStorageObserver_h
+
+#include "nsISupportsImpl.h"
+
+namespace mozilla::dom {
+
+class SessionStorageObserverChild;
+
+/**
+ * Effectively just a refcounted life-cycle management wrapper around
+ * SessionStorageObserverChild which exists to receive chrome observer
+ * notifications from the main process.
+ *
+ * ## Lifecycle ##
+ * - Created by SessionStorageManager::SessionStorageManager.  Placed in the
+ *   gSessionStorageObserver variable for subsequent SessionStorageManager's via
+ *   SessionStorageObserver::Get lookup.
+ * - The SessionStorageObserverChild directly handles "Observe" messages,
+ *   shunting them directly to StorageObserver::Notify which distributes them to
+ *   individual observer sinks.
+ * - Destroyed when refcount goes to zero due to all owning
+ *   SessionStorageManager being destroyed.
+ */
+class SessionStorageObserver final {
+  friend class SessionStorageManager;
+
+  SessionStorageObserverChild* mActor;
+
+ public:
+  static SessionStorageObserver* Get();
+
+  NS_INLINE_DECL_REFCOUNTING(SessionStorageObserver)
+
+  void AssertIsOnOwningThread() const {
+    NS_ASSERT_OWNINGTHREAD(SessionStorageObserver);
+  }
+
+  void SetActor(SessionStorageObserverChild* aActor);
+
+  void ClearActor() {
+    AssertIsOnOwningThread();
+    MOZ_ASSERT(mActor);
+
+    mActor = nullptr;
+  }
+
+ private:
+  // Only created by SessionStorageManager.
+  SessionStorageObserver();
+
+  ~SessionStorageObserver();
+};
+
+}  // namespace mozilla::dom
+
+#endif  // mozilla_dom_SessionStorageObserver_h