1 files changed, 56 insertions, 0 deletions
diff --git a/layout/build/nsLayoutStatics.h b/layout/build/nsLayoutStatics.h
new file mode 100644
index 0000000000..984f7c984e
--- /dev/null
+++ b/layout/build/nsLayoutStatics.h
@@ -0,0 +1,56 @@
+/* -*- 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 nsLayoutStatics_h__
+#define nsLayoutStatics_h__
+
+#include "nscore.h"
+#include "MainThreadUtils.h"
+#include "nsISupportsImpl.h"
+#include "nsDebug.h"
+
+// This isn't really a class, it's a namespace for static methods.
+// Documents and other objects can hold a reference to the layout static
+// objects so that they last past the xpcom-shutdown notification.
+
+class nsLayoutStatics {
+ public:
+  // Called by the layout module constructor. This call performs an AddRef()
+  // internally.
+  static nsresult Initialize();
+
+  static void AddRef() {
+    NS_ASSERTION(NS_IsMainThread(),
+                 "nsLayoutStatics reference counting must be on main thread");
+
+    NS_ASSERTION(sLayoutStaticRefcnt,
+                 "nsLayoutStatics already dropped to zero!");
+
+    ++sLayoutStaticRefcnt;
+    NS_LOG_ADDREF(&sLayoutStaticRefcnt, sLayoutStaticRefcnt, "nsLayoutStatics",
+                  1);
+  }
+  static void Release() {
+    NS_ASSERTION(NS_IsMainThread(),
+                 "nsLayoutStatics reference counting must be on main thread");
+
+    --sLayoutStaticRefcnt;
+    NS_LOG_RELEASE(&sLayoutStaticRefcnt, sLayoutStaticRefcnt,
+                   "nsLayoutStatics");
+
+    if (!sLayoutStaticRefcnt) Shutdown();
+  }
+
+ private:
+  // not to be called!
+  nsLayoutStatics();
+
+  static void Shutdown();
+
+  static nsrefcnt sLayoutStaticRefcnt;
+};
+
+#endif  // nsLayoutStatics_h__