1 files changed, 49 insertions, 0 deletions
diff --git a/xpcom/glue/nsWeakReference.h b/xpcom/glue/nsWeakReference.h
new file mode 100644
index 0000000000..fc875ba968
--- /dev/null
+++ b/xpcom/glue/nsWeakReference.h
@@ -0,0 +1,49 @@
+/* -*- 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 nsWeakReference_h__
+#define nsWeakReference_h__
+
+// nsWeakReference.h
+
+// See mfbt/WeakPtr.h for a more typesafe C++ implementation of weak references
+
+#include "nsIWeakReferenceUtils.h"
+
+class nsWeakReference;
+
+class nsSupportsWeakReference : public nsISupportsWeakReference
+{
+public:
+  nsSupportsWeakReference() : mProxy(0) {}
+
+  NS_DECL_NSISUPPORTSWEAKREFERENCE
+
+protected:
+  inline ~nsSupportsWeakReference();
+
+private:
+  friend class nsWeakReference;
+
+  // Called (only) by an |nsWeakReference| from _its_ dtor.
+  // The thread safety check is made by the caller.
+  void NoticeProxyDestruction() { mProxy = nullptr; }
+
+  nsWeakReference* MOZ_NON_OWNING_REF mProxy;
+
+protected:
+
+  void ClearWeakReferences();
+  bool HasWeakReferences() const { return !!mProxy; }
+};
+
+inline
+nsSupportsWeakReference::~nsSupportsWeakReference()
+{
+  ClearWeakReferences();
+}
+
+#endif