[Player] Add AI Pathfinding on a 2D grid to the player character

Assets/External/AstarPathfindingProject/PackageTools/VersionedMonoBehaviour.cs

@@ -0,0 +1,53 @@
+using UnityEngine;
+
+namespace Pathfinding {
+	/// <summary>Exposes internal methods from <see cref="Pathfinding.VersionedMonoBehaviour"/></summary>
+	public interface IVersionedMonoBehaviourInternal {
+		void UpgradeFromUnityThread();
+	}
+
+	/// <summary>Base class for all components in the package</summary>
+	public abstract class VersionedMonoBehaviour : MonoBehaviour, ISerializationCallbackReceiver, IVersionedMonoBehaviourInternal {
+		/// <summary>Version of the serialized data. Used for script upgrades.</summary>
+		[SerializeField]
+		[HideInInspector]
+		int version = 0;
+
+		protected virtual void Awake () {
+			// Make sure the version field is up to date for components created during runtime.
+			// Reset is not called when in play mode.
+			// If the data had to be upgraded then OnAfterDeserialize would have been called earlier.
+			if (Application.isPlaying) version = OnUpgradeSerializedData(int.MaxValue, true);
+		}
+
+		/// <summary>Handle serialization backwards compatibility</summary>
+		protected virtual void Reset () {
+			// Set initial version when adding the component for the first time
+			version = OnUpgradeSerializedData(int.MaxValue, true);
+		}
+
+		/// <summary>Handle serialization backwards compatibility</summary>
+		void ISerializationCallbackReceiver.OnBeforeSerialize () {
+		}
+
+		/// <summary>Handle serialization backwards compatibility</summary>
+		void ISerializationCallbackReceiver.OnAfterDeserialize () {
+			var r = OnUpgradeSerializedData(version, false);
+
+			// Negative values (-1) indicate that the version number should not be updated
+			if (r >= 0) version = r;
+		}
+
+		/// <summary>Handle serialization backwards compatibility</summary>
+		protected virtual int OnUpgradeSerializedData (int version, bool unityThread) {
+			return 1;
+		}
+
+		void IVersionedMonoBehaviourInternal.UpgradeFromUnityThread () {
+			var r = OnUpgradeSerializedData(version, true);
+
+			if (r < 0) throw new System.Exception();
+			version = r;
+		}
+	}
+}