1 files changed, 59 insertions, 0 deletions
diff --git a/components/script/dom/bindings/codegen/ErrorResult.h b/components/script/dom/bindings/codegen/ErrorResult.h
new file mode 100644
index 00000000000..bbd9404a865
--- /dev/null
+++ b/components/script/dom/bindings/codegen/ErrorResult.h
@@ -0,0 +1,59 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-*/
+/* vim: set ts=2 sw=2 et tw=79: */
+/* 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/. */
+
+/**
+ * A struct for tracking exceptions that need to be thrown to JS.
+ */
+
+#ifndef mozilla_ErrorResult_h
+#define mozilla_ErrorResult_h
+
+#include "nscore.h"
+#include "mozilla/Assertions.h"
+
+namespace mozilla {
+
+class ErrorResult {
+public:
+  ErrorResult() {
+    mResult = NS_OK;
+  }
+
+  void Throw(nsresult rv) {
+    MOZ_ASSERT(NS_FAILED(rv), "Please don't try throwing success");
+    mResult = rv;
+  }
+
+  // In the future, we can add overloads of Throw that take more
+  // interesting things, like strings or DOM exception types or
+  // something if desired.
+
+  // Backwards-compat to make conversion simpler.  We don't call
+  // Throw() here because people can easily pass success codes to
+  // this.
+  void operator=(nsresult rv) {
+    mResult = rv;
+  }
+
+  bool Failed() const {
+    return NS_FAILED(mResult);
+  }
+
+  nsresult ErrorCode() const {
+    return mResult;
+  }
+
+private:
+  nsresult mResult;
+
+  // Not to be implemented, to make sure people always pass this by
+  // reference, not by value.
+  ErrorResult(const ErrorResult&) MOZ_DELETE;
+};
+
+} // namespace mozilla
+
+#endif /* mozilla_ErrorResult_h */