A singleton Unity3D MonoBehaviour

MonoSingleton.cs

using System;
using UnityEngine;

/// <summary>
/// Base class for <see cref="MonoBehaviour"/> of which there should be a single instance.
/// </summary>
/// <threadsafety>This class is <b>not</b> thread safe.</threadsafety>
public abstract class MonoSingleton<T> : MonoBehaviour where T : MonoSingleton<T>
{
    static volatile T instance;
    static GameObject owner;
    static bool quitting;

    /// <summary>
    /// Gets the single instance of this class.
    /// </summary>
    /// <remarks>
    /// Initializes the singleton, if necessary.
    /// </remarks>
    public static T Instance
    {
        get
        {
            Initialize();
            return instance;
        }
    }

    /// <summary>
    /// Initializes the singleton, creating an instance of it, if necessary.
    /// </summary>
    public static void Initialize()
    {
        if (instance == null && !quitting)
        {
            instance = FindObjectOfType<T>();
            if (instance == null)
            {
                owner = new GameObject { hideFlags = HideFlags.HideInHierarchy };
                instance = owner.AddComponent<T>();
                DontDestroyOnLoad(owner);
            }
        }
    }

    private void Awake()
    {
        if (instance == null) instance = this as T;
        if (instance != this) Debug.LogError("Multiple instances of singleton: " + typeof(T).Name);
    }

    /// <summary>
    /// Called when the <see cref="MonoBehaviour"/> will be destroyed.
    /// </summary>
    /// <remarks>
    /// This method should not be overriden by derived classes,
    /// they should implement <see cref="IDisposable"/> instead.
    /// </remarks>
    protected void OnDestroy()
    {
        var disposable = this as IDisposable;
        if (disposable != null) disposable.Dispose();
        if (instance == this) instance = null;
        if (gameObject == owner) Destroy(owner);
    }

    /// <summary>
    /// Sent to all game objects before the application is quit.
    /// </summary>
    /// <remarks>
    /// This method should not be overriden by derived classes.
    /// </remarks>
    protected void OnApplicationQuit()
    {
        quitting = true;
    }
}