urho3d.UrhoSharp/Bindings/Portable/Runtime/ReferenceHolder.cs

using System;

namespace Urho
{
	internal class ReferenceHolder<T> where T : class
	{
		public T StrongRef { get; private set; }
		public WeakReference<T> WeakRef { get; private set; }

		public ReferenceHolder(T obj, bool weak)
		{
			if (weak)
				WeakRef = new WeakReference<T>(obj);
			else
				StrongRef = obj;
		}

		public T Reference
		{
			get
			{
				if (StrongRef != null)
					return StrongRef;

				T wr;
				WeakRef.TryGetTarget(out wr);
				return wr;
			}
		}

		/// <summary>
		/// Change Weak to Strong 
		/// </summary>
		public bool MakeStrong()
		{
			if (StrongRef != null)
				return true;
			T strong = null;
			WeakRef?.TryGetTarget(out strong);

			StrongRef = strong;
			WeakRef = null;
			return StrongRef != null;
		}

		/// <summary>
		/// Change Strong to Weak
		/// </summary>
		public bool MakeWeak()
		{
			if (StrongRef != null)
			{
				WeakRef = new WeakReference<T>(StrongRef);
				StrongRef = null;
				return true;
			}
			return false;
		}
	}
}