Add LayoutManager/BoxLayout APIs

atom/common/api/constructor.h

@@ -0,0 +1,33 @@
+// Copyright (c) 2018 GitHub, Inc.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+#ifndef ATOM_COMMON_API_CONSTRUCTOR_H_
+#define ATOM_COMMON_API_CONSTRUCTOR_H_
+
+#include "native_mate/constructor.h"
+
+namespace mate {
+
+// Create a FunctionTemplate that can be "new"ed in JavaScript.
+// It is user's responsibility to ensure this function is called for one type
+// only ONCE in the program's whole lifetime, otherwise we would have memory
+// leak.
+template <typename T, typename Sig>
+v8::Local<v8::Function> CreateConstructor(v8::Isolate* isolate,
+                                          const base::Callback<Sig>& func) {
+#ifndef NDEBUG
+  static bool called = false;
+  CHECK(!called) << "CreateConstructor can only be called for one type once";
+  called = true;
+#endif
+  v8::Local<v8::FunctionTemplate> templ = CreateFunctionTemplate(
+      isolate, base::Bind(&mate::internal::InvokeNew<Sig>, func));
+  templ->InstanceTemplate()->SetInternalFieldCount(1);
+  T::BuildPrototype(isolate, templ);
+  return templ->GetFunction();
+}
+
+}  // namespace mate
+
+#endif  // ATOM_COMMON_API_CONSTRUCTOR_H_