1 files changed, 35 insertions, 0 deletions
diff --git a/xpcom/base/MacStringHelpers.mm b/xpcom/base/MacStringHelpers.mm
new file mode 100644
index 0000000000..cf0b03665d
--- /dev/null
+++ b/xpcom/base/MacStringHelpers.mm
@@ -0,0 +1,35 @@
+/* -*- 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/. */
+
+#include "MacStringHelpers.h"
+#include "nsObjCExceptions.h"
+
+#include "mozilla/IntegerTypeTraits.h"
+#include <limits>
+
+namespace mozilla {
+
+nsresult CopyCocoaStringToXPCOMString(NSString* aFrom, nsAString& aTo) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NSUInteger len = [aFrom length];
+  if (len > std::numeric_limits<nsAString::size_type>::max()) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  if (!aTo.SetLength(len, mozilla::fallible)) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  [aFrom getCharacters:reinterpret_cast<unichar*>(aTo.BeginWriting())
+                 range:NSMakeRange(0, len)];
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+}  // namespace mozilla