UnityObjectId - wrapper to smooth over migration from int UnityEngine.Object.GetInstanceId() to the EntityId UnityEngine.Object.GetEntityId()

UnityObjectId.cs

//////////////////////////////////////////////////////////////////////////////
// This source file is part of the "Darbotron Common" UPM Package
//
// File content © 2026 Darbotron Ltd
//
// Licensed under the MIT license: https://opensource.org/license/mit
//////////////////////////////////////////////////////////////////////////////
//#define FORCE_USE_ENTITY_ID

using System;

namespace Darbotron.Common
{
#if UNITY_6000_3_OR_NEWER

	public struct UnityObjectId : IEquatable< UnityObjectId >, IComparable< UnityObjectId >
	{
		public static UnityObjectId GetUnityObjectId( UnityEngine.Object unityObj ) => new UnityObjectId{ m_entityId = unityObj.GetEntityId() };

		public static implicit operator UnityEngine.EntityId( UnityObjectId id ) => id.m_entityId;

		public UnityEngine.Object GetObject() => UnityEngine.Resources.EntityIdToObject( m_entityId );

		#if UNITY_EDITOR
			public UnityEngine.Object EditorGetObject() => UnityEditor.EditorUtility.EntityIdToObject( m_entityId );
		#else
			public UnityEngine.Object EditorGetObject() => throw new Exception( $"cannot be used in builds" );
		#endif


		public bool Equals( UnityObjectId other ) => ( m_entityId == other.m_entityId );

		public int CompareTo( UnityObjectId other ) => ( m_entityId - other.m_entityId );

		public override bool Equals( object obj )
		{
			return obj is UnityObjectId other && Equals( other );
		}

		public override int GetHashCode()
		{
			return m_entityId;
		}

		public static bool operator==( UnityObjectId left, UnityObjectId right ) => left.Equals( right );

		public static bool operator!=( UnityObjectId left, UnityObjectId right ) => ! left.Equals( right );

		private UnityEngine.EntityId m_entityId;

	}

#else // #if UNITY_6000_3_OR_NEWER ...

	public struct UnityObjectId : IEquatable< UnityObjectId >, IComparable< UnityObjectId >
	{
		public static UnityObjectId GetUnityObjectId( UnityEngine.Object unityObj ) => new UnityObjectId{ m_instanceId = unityObj.GetInstanceID() };

		public static implicit operator int( UnityObjectId id ) => id.m_instanceId;

		public UnityEngine.Object GetObject() => UnityEngine.Resources.InstanceIDToObject( m_instanceId );

		#if UNITY_EDITOR
			public UnityEngine.Object EditorGetObject() => UnityEditor.EditorUtility.InstanceIDToObject( m_instanceId );
		#else
			public UnityEngine.Object EditorGetObject() => throw new Exception( $"cannot be used in builds" );
		#endif

		public bool Equals( UnityObjectId other ) => ( m_instanceId == other.m_instanceId );

		public int CompareTo( UnityObjectId other ) => ( m_instanceId - other.m_instanceId );

		public override bool Equals( object obj )
		{
			return obj is UnityObjectId other && Equals( other );
		}

		public override int GetHashCode()
		{
			return m_instanceId;
		}

		public static bool operator==( UnityObjectId left, UnityObjectId right ) => left.Equals( right );

		public static bool operator!=( UnityObjectId left, UnityObjectId right ) => ! left.Equals( right );

		private int m_instanceId;
	}

#endif // #if UNITY_6000_3_OR_NEWER ... #else ...

	public static class UnityObjectIdExtensions
	{
		public static UnityObjectId GetUnityObjectId( this UnityEngine.Object unityObject ) => UnityObjectId.GetUnityObjectId( unityObject );
	}

} // namespace Darbotron.Common