1 files changed, 60 insertions, 0 deletions
diff --git a/widget/nsAppShellSingleton.h b/widget/nsAppShellSingleton.h
new file mode 100644
index 0000000000..cd554951c6
--- /dev/null
+++ b/widget/nsAppShellSingleton.h
@@ -0,0 +1,60 @@
+/* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; -*- */
+/* 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 nsAppShellSingleton_h__
+#define nsAppShellSingleton_h__
+
+/**
+ * This file is designed to be included into the file that provides the
+ * XPCOM module implementation for a particular widget toolkit.
+ *
+ * The following functions are defined:
+ *   nsAppShellInit
+ *   nsAppShellShutdown
+ *   nsAppShellConstructor
+ *
+ * The nsAppShellInit function is designed to be used as a module constructor.
+ * If you already have a module constructor, then call nsAppShellInit from your
+ * module constructor.
+ *
+ * The nsAppShellShutdown function is designed to be used as a module
+ * destructor.  If you already have a module destructor, then call
+ * nsAppShellShutdown from your module destructor.
+ *
+ * The nsAppShellConstructor function is designed to be used as a factory
+ * method for the nsAppShell class.
+ */
+
+#include "nsXULAppAPI.h"
+
+static nsIAppShell* sAppShell;
+
+static nsresult nsAppShellInit() {
+  NS_ASSERTION(!sAppShell, "already initialized");
+
+  sAppShell = new nsAppShell();
+  if (!sAppShell) return NS_ERROR_OUT_OF_MEMORY;
+  NS_ADDREF(sAppShell);
+
+  nsresult rv = static_cast<nsAppShell*>(sAppShell)->Init();
+  // If we somehow failed to initialize the appshell, it's extremely likely
+  // that we are sufficiently hosed that continuing on is just going to lead
+  // to bad things later.  By crashing early here, the crash report will
+  // potentially contain a little more insight into what's going wrong than
+  // if we waited for a crash further down the line.  See also bug 1545381.
+  MOZ_RELEASE_ASSERT(NS_SUCCEEDED(rv));
+
+  return NS_OK;
+}
+
+static void nsAppShellShutdown() { NS_RELEASE(sAppShell); }
+
+nsresult nsAppShellConstructor(const nsIID& iid, void** result) {
+  NS_ENSURE_TRUE(sAppShell, NS_ERROR_NOT_INITIALIZED);
+
+  return sAppShell->QueryInterface(iid, result);
+}
+
+#endif  // nsAppShellSingleton_h__