diff -r 000000000000 -r 6474c204b198 toolkit/components/url-classifier/nsCheckSummedOutputStream.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/components/url-classifier/nsCheckSummedOutputStream.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,53 @@
+//* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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 nsCheckSummedOutputStream_h__
+#define nsCheckSummedOutputStream_h__
+
+#include "nsILocalFile.h"
+#include "nsIFile.h"
+#include "nsIOutputStream.h"
+#include "nsICryptoHash.h"
+#include "nsNetCID.h"
+#include "nsString.h"
+#include "../../../netwerk/base/src/nsFileStreams.h"
+#include "nsToolkitCompsCID.h"
+
+class nsCheckSummedOutputStream : public nsSafeFileOutputStream
+{
+public:
+  NS_DECL_ISUPPORTS_INHERITED
+
+  // Size of MD5 hash in bytes
+  static const uint32_t CHECKSUM_SIZE = 16;
+
+  nsCheckSummedOutputStream() {}
+  virtual ~nsCheckSummedOutputStream() { nsSafeFileOutputStream::Close(); }
+
+  NS_IMETHOD Finish();
+  NS_IMETHOD Write(const char *buf, uint32_t count, uint32_t *result);
+  NS_IMETHOD Init(nsIFile* file, int32_t ioFlags, int32_t perm, int32_t behaviorFlags);
+
+protected:
+  nsCOMPtr<nsICryptoHash> mHash;
+  nsAutoCString mCheckSum;
+};
+
+// returns a file output stream which can be QI'ed to nsIFileOutputStream.
+inline nsresult
+NS_NewCheckSummedOutputStream(nsIOutputStream **result,
+                              nsIFile         *file,
+                              int32_t         ioFlags       = -1,
+                              int32_t         perm          = -1,
+                              int32_t         behaviorFlags =  0)
+{
+    nsCOMPtr<nsIFileOutputStream> out = new nsCheckSummedOutputStream();
+    nsresult rv = out->Init(file, ioFlags, perm, behaviorFlags);
+    if (NS_SUCCEEDED(rv))
+      NS_ADDREF(*result = out);  // cannot use nsCOMPtr::swap
+    return rv;
+}
+
+#endif