1 files changed, 46 insertions, 0 deletions
diff --git a/dom/base/nsCCUncollectableMarker.h b/dom/base/nsCCUncollectableMarker.h
new file mode 100644
index 0000000000..2948cc0589
--- /dev/null
+++ b/dom/base/nsCCUncollectableMarker.h
@@ -0,0 +1,46 @@
+/* -*- 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 nsCCUncollectableMarker_h_
+#define nsCCUncollectableMarker_h_
+
+#include "js/TracingAPI.h"
+#include "mozilla/Attributes.h"
+#include "nsIObserver.h"
+
+class nsCCUncollectableMarker final : public nsIObserver {
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIOBSERVER
+
+  /**
+   * Inits a global nsCCUncollectableMarker. Should only be called once.
+   */
+  static nsresult Init();
+
+  /**
+   * Checks if we're collecting during a given generation
+   */
+  static bool InGeneration(uint32_t aGeneration) {
+    return aGeneration && aGeneration == sGeneration;
+  }
+
+  template <class CCCallback>
+  static bool InGeneration(CCCallback& aCb, uint32_t aGeneration) {
+    return InGeneration(aGeneration) && !aCb.WantAllTraces();
+  }
+
+  static uint32_t sGeneration;
+
+ private:
+  nsCCUncollectableMarker() = default;
+  ~nsCCUncollectableMarker() = default;
+};
+
+namespace mozilla::dom {
+void TraceBlackJS(JSTracer* aTrc);
+}  // namespace mozilla::dom
+
+#endif