diff -r 000000000000 -r 6474c204b198 xpcom/base/nsGZFileWriter.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/xpcom/base/nsGZFileWriter.h	Wed Dec 31 06:09:35 2014 +0100
@@ -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 nsGZFileWriter_h
+#define nsGZFileWriter_h
+
+#include "nsIGZFileWriter.h"
+#include "zlib.h"
+
+/**
+ * A simple class for writing .gz files.
+ */
+class nsGZFileWriter : public nsIGZFileWriter
+{
+public:
+  nsGZFileWriter();
+  virtual ~nsGZFileWriter();
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIGZFILEWRITER
+
+  /**
+   * nsIGZFileWriter exposes two non-virtual overloads of Write().  We
+   * duplicate them here so that you can call these overloads on a pointer to
+   * the concrete nsGZFileWriter class.
+   */
+  nsresult Write(const char* aStr)
+  {
+    return nsIGZFileWriter::Write(aStr);
+  }
+
+  nsresult Write(const char* aStr, uint32_t aLen)
+  {
+    return nsIGZFileWriter::Write(aStr, aLen);
+  }
+
+private:
+  bool mInitialized;
+  bool mFinished;
+  gzFile mGZFile;
+};
+
+#endif