Haxe friendly root api (#1292)

* Root api

* Null checking

* Some tests

---------

Co-authored-by: Aidan Lee <[email protected]>

Author: Aidan63

include/cpp/marshal/Definitions.inc

@@ -213,6 +213,21 @@ namespace cpp
             T& operator[] (int64_t index) const;
         };
 
+        class RootHandle
+        {
+            ::hx::Object** object;
+
+            RootHandle(hx::Object** obj);
+
+        public:
+            static RootHandle create(Dynamic obj);
+            static RootHandle fromVoidPointer(::cpp::Pointer<void> ptr);
+
+            ::cpp::Pointer<void> toVoidPointer();
+            Dynamic getObject();
+            void close();
+        };
+
         struct Marshal final
         {
 #ifdef HXCPP_BIG_ENDIAN

include/cpp/marshal/RootHandle.hpp

@@ -0,0 +1,46 @@
+#pragma once
+
+#include "Definitions.inc"
+
+inline cpp::marshal::RootHandle::RootHandle(::hx::Object** obj) : object(obj) {}
+
+inline cpp::marshal::RootHandle cpp::marshal::RootHandle::create(::Dynamic obj)
+{
+	if (null() == obj)
+	{
+		hx::NullReference("Dynamic", false);
+	}
+
+	auto root = new hx::Object* { obj.mPtr };
+
+	hx::GCAddRoot(root);
+
+	return RootHandle(root);
+}
+
+inline cpp::marshal::RootHandle cpp::marshal::RootHandle::fromVoidPointer(cpp::Pointer<void> ptr)
+{
+	if (nullptr == ptr.ptr)
+	{
+		hx::NullReference("Dynamic", false);
+	}
+
+	return RootHandle(static_cast<hx::Object**>(ptr.ptr));
+}
+
+inline void cpp::marshal::RootHandle::close()
+{
+	hx::GCRemoveRoot(object);
+
+	delete object;
+}
+
+inline ::Dynamic cpp::marshal::RootHandle::getObject()
+{
+	return ::Dynamic{ *object };
+}
+
+inline cpp::Pointer<void> cpp::marshal::RootHandle::toVoidPointer()
+{
+	return object;
+}

include/hxcpp.h

@@ -358,6 +358,7 @@ typedef PropertyAccessMode PropertyAccess;
 #include <cpp/marshal/PointerReference.hpp>
 #include <cpp/marshal/View.hpp>
 #include <cpp/marshal/Marshal.hpp>
+#include <cpp/marshal/RootHandle.hpp>
 #include <cpp/encoding/Ascii.hpp>
 #include <cpp/encoding/Utf8.hpp>
 #include <cpp/encoding/Utf16.hpp>

test/native/Native.hx

@@ -47,6 +47,8 @@ class Native
             new tests.marshalling.view.TestMarshal(),
             new tests.marshalling.view.TestViewExtensions(),
 
+            new tests.marshalling.root.TestRoot(),
+
             new tests.encoding.TestAscii(),
             new tests.encoding.TestUtf8(),
             new tests.encoding.TestUtf16(),

test/native/tests/marshalling/root/TestRoot.hx

@@ -0,0 +1,34 @@
+package tests.marshalling.root;
+
+import cpp.marshal.RootHandle;
+import utest.Assert;
+import utest.Test;
+
+class TestRoot extends Test {
+	function test_null_object() {
+		Assert.raises(() -> RootHandle.create(null));
+	}
+
+	function test_null_void_pointer() {
+		Assert.raises(() -> RootHandle.fromVoidPointer(null));
+	}
+
+	function test_get_object() {
+		final obj    = "Hello, World!";
+		final handle = RootHandle.create(obj);
+
+		Assert.equals(obj, handle.getObject());
+
+		handle.close();
+	}
+
+	function test_void_pointer_roundtrip() {
+		final obj    = "Hello, World!";
+		final ptr    = RootHandle.create(obj).toVoidPointer();
+		final handle = RootHandle.fromVoidPointer(ptr);
+
+		Assert.equals(obj, handle.getObject());
+
+		handle.close();
+	}
+}