Refactor managed array unboxing to handle case of C# array passes as object

#1415

Source/Engine/Engine/NativeInterop.Unmanaged.cs

@@ -559,6 +559,19 @@ namespace FlaxEngine.Interop
             return managedArray.Pointer;
         }
 
+        [UnmanagedCallersOnly]
+        internal static IntPtr GetArray(ManagedHandle handle)
+        {
+            if (!handle.IsAllocated)
+                return IntPtr.Zero;
+            object value = handle.Target;
+            if (value is ManagedArray)
+                return (IntPtr)handle;
+            if (value is Array)
+                return Invoker.MarshalReturnValueGeneric(value.GetType(), value);
+            return IntPtr.Zero;
+        }
+
         [UnmanagedCallersOnly]
         internal static int GetArrayLength(ManagedHandle arrayHandle)
         {

Source/Engine/Scripting/ManagedCLR/MCore.h

@@ -85,6 +85,7 @@ public:
         static MClass* GetClass(MClass* elementKlass);
         static int32 GetLength(const MArray* obj);
         static void* GetAddress(const MArray* obj);
+        static MArray* Unbox(MObject* obj);
 
         template<typename T>
         FORCE_INLINE static T* GetAddress(const MArray* obj)

Source/Engine/Scripting/ManagedCLR/MUtils.h

@@ -363,11 +363,12 @@ struct MConverter<Array<T>>
 
     void Unbox(Array<T>& result, MObject* data)
     {
-        const int32 length = data ? MCore::Array::GetLength((MArray*)data) : 0;
+        MArray* array = MCore::Array::Unbox(data);
+        const int32 length = array ? MCore::Array::GetLength(array) : 0;
         result.Resize(length);
         MConverter<T> converter;
         Span<T> resultSpan(result.Get(), length);
-        converter.ToNativeArray(resultSpan, (MArray*)data);
+        converter.ToNativeArray(resultSpan, array);
     }
 };
 

Source/Engine/Scripting/Runtime/DotNet.cpp

@@ -408,6 +408,12 @@ void* MCore::Array::GetAddress(const MArray* obj)
     return CallStaticMethod<void*, void*>(GetArrayPointerPtr, (void*)obj);
 }
 
+MArray* MCore::Array::Unbox(MObject* obj)
+{
+    static void* GetArrayPtr = GetStaticMethodPointer(TEXT("GetArray"));
+    return (MArray*)CallStaticMethod<void*, void*>(GetArrayPtr, (void*)obj);
+}
+
 MGCHandle MCore::GCHandle::New(MObject* obj, bool pinned)
 {
     ASSERT(obj);

Source/Engine/Scripting/Runtime/Mono.cpp

@@ -804,6 +804,11 @@ void* MCore::Array::GetAddress(const MArray* obj)
     return mono_array_addr_with_size((MonoArray*)obj, 0, 0);
 }
 
+MArray* MCore::Array::Unbox(MObject* obj)
+{
+    return (MArray*)obj;
+}
+
 MGCHandle MCore::GCHandle::New(MObject* obj, bool pinned)
 {
     return mono_gchandle_new(obj, pinned);

Source/Engine/Scripting/Runtime/None.cpp

@@ -141,6 +141,11 @@ void* MCore::Array::GetAddress(const MArray* obj)
     return nullptr;
 }
 
+MArray* MCore::Array::Unbox(MObject* obj)
+{
+    return nullptr;
+}
+
 MGCHandle MCore::GCHandle::New(MObject* obj, bool pinned)
 {
     return (MGCHandle)(uintptr)obj;