Separate the DOM and layout into separate crates.

1 files changed, 68 insertions, 0 deletions

diff --git a/src/components/script/dom/bindings/codegen/Nullable.h b/src/components/script/dom/bindings/codegen/Nullable.h
new file mode 100644
index 00000000000..8b2cc08642b
--- /dev/null
+++ b/src/components/script/dom/bindings/codegen/Nullable.h
@@ -0,0 +1,68 @@
+/* -*- 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/. */
+
+#ifndef mozilla_dom_Nullable_h
+#define mozilla_dom_Nullable_h
+
+#include "mozilla/Assertions.h"
+
+namespace mozilla {
+namespace dom {
+
+// Support for nullable types
+template <typename T>
+struct Nullable
+{
+private:
+  T mValue;
+  bool mIsNull;
+
+public:
+  Nullable()
+    : mIsNull(true)
+  {}
+
+  Nullable(T aValue)
+    : mValue(aValue)
+    , mIsNull(false)
+  {}
+
+  void SetValue(T aValue) {
+    mValue = aValue;
+    mIsNull = false;
+  }
+
+  // For cases when |T| is some type with nontrivial copy behavior, we may want
+  // to get a reference to our internal copy of T and work with it directly
+  // instead of relying on the copying version of SetValue().
+  T& SetValue() {
+    mIsNull = false;
+    return mValue;
+  }
+
+  void SetNull() {
+    mIsNull = true;
+  }
+
+  const T& Value() const {
+    MOZ_ASSERT(!mIsNull);
+    return mValue;
+  }
+
+  T& Value() {
+    MOZ_ASSERT(!mIsNull);
+    return mValue;
+  }
+
+  bool IsNull() const {
+    return mIsNull;
+  }
+};
+
+} // namespace dom
+} // namespace mozilla
+
+#endif /* mozilla_dom_Nullable_h */