PoolKit.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Reflection;
using UnityEngine;

namespace QFramework
{
    #region API
    /// <summary>
    /// Unity 游戏框架搭建 (十九) 简易对象池：http://qframework.io/post/24/ 的例子
    /// </summary>
    /// <typeparam name="T"></typeparam>
    public class SimpleObjectPool<T> : Pool<T>
    {
        readonly Action<T> mResetMethod;

        public SimpleObjectPool(Func<T> factoryMethod, Action<T> resetMethod = null,int initCount = 0)
        {
            mFactory = new CustomObjectFactory<T>(factoryMethod);
            mResetMethod = resetMethod;

            for (int i = 0; i < initCount; i++)
            {
                mCacheStack.Push(mFactory.Create());
            }
        }

        public override bool Recycle(T obj)
        {
            if (mResetMethod != null)
            {
                mResetMethod.Invoke(obj);
            }
            
            mCacheStack.Push(obj);
            return true;
        }
    }
    
/// <summary>
    /// Object pool.
    /// </summary>
    public class SafeObjectPool<T> : Pool<T>, ISingleton where T : IPoolable, new()
    {
        #region Singleton
        void ISingleton.OnSingletonInit() {}

        protected SafeObjectPool()
        {
            mFactory = new DefaultObjectFactory<T>();
        }

        public static SafeObjectPool<T> Instance
        {
            get { return SingletonProperty<SafeObjectPool<T>>.Instance; }
        }

        public void Dispose()
        {
            SingletonProperty<SafeObjectPool<T>>.Dispose();
        }
        #endregion

        /// <summary>
        /// Init the specified maxCount and initCount.
        /// </summary>
        /// <param name="maxCount">Max Cache count.</param>
        /// <param name="initCount">Init Cache count.</param>
        public void Init(int maxCount, int initCount)
        {
            MaxCacheCount = maxCount;
            
            if (maxCount > 0)
            {
                initCount = Math.Min(maxCount, initCount);
            }

            if (CurCount < initCount)
            {
                for (var i = CurCount; i < initCount; ++i)
                {
                    Recycle(new T());
                }
            }
        }

        /// <summary>
        /// Gets or sets the max cache count.
        /// </summary>
        /// <value>The max cache count.</value>
        public int MaxCacheCount
        {
            get { return mMaxCount; }
            set
            {
                mMaxCount = value;

                if (mCacheStack != null)
                {
                    if (mMaxCount > 0)
                    {
                        if (mMaxCount < mCacheStack.Count)
                        {
                            int removeCount = mCacheStack.Count - mMaxCount;
                            while (removeCount > 0)
                            {
                                mCacheStack.Pop();
                                --removeCount;
                            }
                        }
                    }
                }
            }
        }

        /// <summary>
        /// Allocate T instance.
        /// </summary>
        public override T Allocate()
        {
            var result = base.Allocate();
            result.IsRecycled = false;
            return result;
        }

        /// <summary>
        /// Recycle the T instance
        /// </summary>
        /// <param name="t">T.</param>
        public override bool Recycle(T t)
        {
            if (t == null || t.IsRecycled)
            {
                return false;
            }

            if (mMaxCount > 0)
            {
                if (mCacheStack.Count >= mMaxCount)
                {
                    t.OnRecycled();
                    return false;
                }
            }

            t.IsRecycled = true;
            t.OnRecycled();
            mCacheStack.Push(t);

            return true;
        }
    }

/// <summary>
	/// Object pool 4 class who no public constructor
	/// such as SingletonClass.QEventSystem
	/// </summary>
	public class NonPublicObjectPool<T> :Pool<T>,ISingleton where T : class,IPoolable
	{
		#region Singleton
		public void OnSingletonInit(){}
		
		public static NonPublicObjectPool<T> Instance
		{
			get { return SingletonProperty<NonPublicObjectPool<T>>.Instance; }
		}

		protected NonPublicObjectPool()
		{
			mFactory = new NonPublicObjectFactory<T>();
		}
		
		public void Dispose()
		{
			SingletonProperty<NonPublicObjectPool<T>>.Dispose();
		}
		#endregion

		/// <summary>
		/// Init the specified maxCount and initCount.
		/// </summary>
		/// <param name="maxCount">Max Cache count.</param>
		/// <param name="initCount">Init Cache count.</param>
		public void Init(int maxCount, int initCount)
		{
			if (maxCount > 0)
			{
				initCount = Math.Min(maxCount, initCount);
			}

			if (CurCount >= initCount) return;
			
			for (var i = CurCount; i < initCount; ++i)
			{
				Recycle(mFactory.Create());
			}
		}

		/// <summary>
		/// Gets or sets the max cache count.
		/// </summary>
		/// <value>The max cache count.</value>
		public int MaxCacheCount
		{
			get { return mMaxCount; }
			set
			{
				mMaxCount = value;

				if (mCacheStack == null) return;
				if (mMaxCount <= 0) return;
				if (mMaxCount >= mCacheStack.Count) return;
				var removeCount = mMaxCount - mCacheStack.Count;
				while (removeCount > 0)
				{
					mCacheStack.Pop();
					--removeCount;
				}
			}
		}

		/// <summary>
		/// Allocate T instance.
		/// </summary>
		public override T Allocate()
		{
			var result = base.Allocate();
			result.IsRecycled = false;
			return result;
		}

		/// <summary>
		/// Recycle the T instance
		/// </summary>
		/// <param name="t">T.</param>
		public override bool Recycle(T t)
		{
			if (t == null || t.IsRecycled)
			{
				return false;
			}

			if (mMaxCount > 0)
			{
				if (mCacheStack.Count >= mMaxCount)
				{
					t.OnRecycled();
					return false;
				}
			}

			t.IsRecycled = true;
			t.OnRecycled();
			mCacheStack.Push(t);

			return true;
		}
	}

public abstract class AbstractPool<T> where T : AbstractPool<T>, new()
{
	private static Stack<T> mPool = new Stack<T>(10);

	protected bool mInPool = false;

	public static T Allocate()
	{
		var node = mPool.Count == 0 ? new T() : mPool.Pop();
		node.mInPool = false;
		return node;
	}

	public void Recycle2Cache()
	{
		OnRecycle();
		mInPool = true;
		mPool.Push(this as T);
	}

	protected abstract void OnRecycle();
}
    #endregion

    #region interfaces
    /// <summary>
    /// 对象池接口
    /// </summary>
    /// <typeparam name="T"></typeparam>
    public interface IPool<T>
    {
	    /// <summary>
	    /// 分配对象
	    /// </summary>
	    /// <returns></returns>
	    T Allocate();

	    /// <summary>
	    /// 回收对象
	    /// </summary>
	    /// <param name="obj"></param>
	    /// <returns></returns>
	    bool Recycle(T obj);
    }
    
    /// <summary>
    /// I pool able.
    /// </summary>
    public interface IPoolable
    {
	    void OnRecycled();
	    bool IsRecycled { get; set; }
    }
    
    /// <summary>
    /// I cache type.
    /// </summary>
    public interface IPoolType
    {
	    void Recycle2Cache();
    }
    
    /// <summary>
    /// 对象池
    /// </summary>
    /// <typeparam name="T"></typeparam>
    public abstract class Pool<T> : IPool<T>
    {
	    #region ICountObserverable
	    /// <summary>
	    /// Gets the current count.
	    /// </summary>
	    /// <value>The current count.</value>
	    public int CurCount
	    {
		    get { return mCacheStack.Count; }
	    }
	    #endregion
        
	    protected IObjectFactory<T> mFactory;

	    /// <summary>
	    /// 存储相关数据的栈
	    /// </summary>
	    protected readonly Stack<T> mCacheStack = new Stack<T>();

	    /// <summary>
	    /// default is 5
	    /// </summary>
	    protected int mMaxCount = 12;

	    public virtual T Allocate()
	    {
		    return mCacheStack.Count == 0
			    ? mFactory.Create()
			    : mCacheStack.Pop();
	    }

	    public abstract bool Recycle(T obj);
    }
    

    #endregion

    #region DataStructurePool
    /// <summary>
    /// 字典对象池：用于存储相关对象
    /// </summary>
    /// <typeparam name="TKey"></typeparam>
    /// <typeparam name="TValue"></typeparam>
    public class DictionaryPool<TKey, TValue>
    {
	    /// <summary>
	    /// 栈对象：存储多个字典
	    /// </summary>
	    static Stack<Dictionary<TKey, TValue>> mListStack = new Stack<Dictionary<TKey, TValue>>(8);

	    /// <summary>
	    /// 出栈：从栈中获取某个字典数据
	    /// </summary>
	    /// <returns></returns>
	    public static Dictionary<TKey, TValue> Get()
	    {
		    if (mListStack.Count == 0)
		    {
			    return new Dictionary<TKey, TValue>(8);
		    }

		    return mListStack.Pop();
	    }

	    /// <summary>
	    /// 入栈：将字典数据存储到栈中 
	    /// </summary>
	    /// <param name="toRelease"></param>
	    public static void Release(Dictionary<TKey, TValue> toRelease)
	    {
		    toRelease.Clear();
		    mListStack.Push(toRelease);
	    }
    }
    
    /// <summary>
    /// 对象池字典 拓展方法类
    /// </summary>
    public static class DictionaryPoolExtensions
    {
	    /// <summary>
	    /// 对字典拓展 自身入栈 的方法
	    /// </summary>
	    /// <typeparam name="TKey"></typeparam>
	    /// <typeparam name="TValue"></typeparam>
	    /// <param name="toRelease"></param>
	    public static void Release2Pool<TKey,TValue>(this Dictionary<TKey, TValue> toRelease)
	    {
		    DictionaryPool<TKey,TValue>.Release(toRelease);
	    }
    }
    /// <summary>
    /// 链表对象池：存储相关对象
    /// </summary>
    /// <typeparam name="T"></typeparam>
    public static class ListPool<T>
    {
	    /// <summary>
	    /// 栈对象：存储多个List
	    /// </summary>
	    static Stack<List<T>> mListStack = new Stack<List<T>>(8);

	    /// <summary>
	    /// 出栈：获取某个List对象
	    /// </summary>
	    /// <returns></returns>
	    public static List<T> Get()
	    {
		    if (mListStack.Count == 0)
		    {
			    return new List<T>(8);
		    }

		    return mListStack.Pop();
	    }

	    /// <summary>
	    /// 入栈：将List对象添加到栈中
	    /// </summary>
	    /// <param name="toRelease"></param>
	    public static void Release(List<T> toRelease)
	    {
		    toRelease.Clear();
		    mListStack.Push(toRelease);
	    }
    }

    /// <summary>
    /// 链表对象池 拓展方法类
    /// </summary>
    public static class ListPoolExtensions
    {
	    /// <summary>
	    /// 给List拓展 自身入栈 的方法
	    /// </summary>
	    /// <typeparam name="T"></typeparam>
	    /// <param name="toRelease"></param>
	    public static void Release2Pool<T>(this List<T> toRelease)
	    {
		    ListPool<T>.Release(toRelease);
	    }
    }

    #endregion

    #region Factories
    
     /// <summary>
    /// 对象工厂
    /// </summary>
    public class ObjectFactory
    {
        /// <summary>
        /// 动态创建类的实例：创建有参的构造函数
        /// </summary>
        /// <param name="type"></param>
        /// <param name="constructorArgs"></param>
        /// <returns></returns>
        public static object Create(Type type, params object[] constructorArgs)
        {
            return Activator.CreateInstance(type, constructorArgs);
        }

        /// <summary>
        /// 动态创建类的实例：泛型扩展
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="constructorArgs"></param>
        /// <returns></returns>
        public static T Create<T>(params object[] constructorArgs)
        {
            return (T) Create(typeof(T), constructorArgs);
        }

        /// <summary>
        /// 动态创建类的实例：创建无参/私有的构造函数
        /// </summary>
        /// <param name="type"></param>
        /// <returns></returns>
        public static object CreateNonPublicConstructorObject(Type type)
        {
            // 获取私有构造函数
            var constructorInfos = type.GetConstructors(BindingFlags.Instance | BindingFlags.NonPublic);

            // 获取无参构造函数
            var ctor = Array.Find(constructorInfos, c => c.GetParameters().Length == 0);

            if (ctor == null)
            {
                throw new Exception("Non-Public Constructor() not found! in " + type);
            }

            return ctor.Invoke(null);
        }

        /// <summary>
        /// 动态创建类的实例：创建无参/私有的构造函数  泛型扩展
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <returns></returns>
        public static T CreateNonPublicConstructorObject<T>()
        {
            return (T) CreateNonPublicConstructorObject(typeof(T));
        }

        /// <summary>
        /// 创建带有初始化回调的 对象
        /// </summary>
        /// <param name="type"></param>
        /// <param name="onObjectCreate"></param>
        /// <param name="constructorArgs"></param>
        /// <returns></returns>
        public static object CreateWithInitialAction(Type type, Action<object> onObjectCreate,
            params object[] constructorArgs)
        {
            var obj = Create(type, constructorArgs);
            onObjectCreate(obj);
            return obj;
        }

        /// <summary>
        /// 创建带有初始化回调的 对象：泛型扩展
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="onObjectCreate"></param>
        /// <param name="constructorArgs"></param>
        /// <returns></returns>
        public static T CreateWithInitialAction<T>(Action<T> onObjectCreate,
            params object[] constructorArgs)
        {
            var obj = Create<T>(constructorArgs);
            onObjectCreate(obj);
            return obj;
        }
    }
     
    /// <summary>
    /// 自定义对象工厂：相关对象是 自己定义 
    /// </summary>
    /// <typeparam name="T"></typeparam>
    public class CustomObjectFactory<T> : IObjectFactory<T>
    {
	    public CustomObjectFactory(Func<T> factoryMethod)
	    {
		    mFactoryMethod = factoryMethod;
	    }

	    protected Func<T> mFactoryMethod;

	    public T Create()
	    {
		    return mFactoryMethod();
	    }
    }
    
    /// <summary>
    /// 默认对象工厂：相关对象是通过New 出来的
    /// </summary>
    /// <typeparam name="T"></typeparam>
    public class DefaultObjectFactory<T> : IObjectFactory<T> where T : new()
    {
	    public T Create()
	    {
		    return new T();
	    }
    }
    
    /// <summary>
    /// 对象工厂接口
    /// </summary>
    /// <typeparam name="T"></typeparam>
    public interface IObjectFactory<T>
    {
	    /// <summary>
	    /// 创建对象
	    /// </summary>
	    /// <returns></returns>
	    T Create();
    }
    
    /// <summary>
    /// 没有公共构造函数的对象工厂：相关对象只能通过反射获得
    /// </summary>
    /// <typeparam name="T"></typeparam>
    public class NonPublicObjectFactory<T> : IObjectFactory<T> where T : class
    {
	    public T Create()
	    {
		    var ctors = typeof(T).GetConstructors(BindingFlags.Instance | BindingFlags.NonPublic);
		    var ctor = Array.Find(ctors, c => c.GetParameters().Length == 0);

		    if (ctor == null)
		    {
			    throw new Exception("Non-Public Constructor() not found! in " + typeof(T) + "\n 在没有找到非 public 的构造方法");
		    }

		    return ctor.Invoke(null) as T;
	    }
    }
    #endregion


    #region SingletonKit For Pool
     /// <summary>
    /// 单例接口
    /// </summary>
    internal interface ISingleton
    {
        /// <summary>
        /// 单例初始化(继承当前接口的类都需要实现该方法)
        /// </summary>
        void OnSingletonInit();
    }

    /// <summary>
    /// 普通类的单例
    /// </summary>
    /// <typeparam name="T"></typeparam>
    internal abstract class Singleton<T> : ISingleton where T : Singleton<T>
    {
        /// <summary>
        /// 静态实例
        /// </summary>
        protected static T mInstance;

        /// <summary>
        /// 标签锁：确保当一个线程位于代码的临界区时，另一个线程不进入临界区。
        /// 如果其他线程试图进入锁定的代码，则它将一直等待（即被阻止），直到该对象被释放
        /// </summary>
        static object mLock = new object();

        /// <summary>
        /// 静态属性
        /// </summary>
        public static T Instance
        {
            get
            {
                lock (mLock)
                {
                    if (mInstance == null)
                    {
                        mInstance = SingletonCreator.CreateSingleton<T>();
                    }
                }

                return mInstance;
            }
        }

        /// <summary>
        /// 资源释放
        /// </summary>
        public virtual void Dispose()
        {
            mInstance = null;
        }

        /// <summary>
        /// 单例初始化方法
        /// </summary>
        public virtual void OnSingletonInit()
        {
        }
    }

    /// <summary>
    /// 属性单例类
    /// </summary>
    /// <typeparam name="T"></typeparam>
    internal static class SingletonProperty<T> where T : class, ISingleton
    {
        /// <summary>
        /// 静态实例
        /// </summary>
        private static T mInstance;

        /// <summary>
        /// 标签锁
        /// </summary>
        private static readonly object mLock = new object();

        /// <summary>
        /// 静态属性
        /// </summary>
        public static T Instance
        {
            get
            {
                lock (mLock)
                {
                    if (mInstance == null)
                    {
                        mInstance = SingletonCreator.CreateSingleton<T>();
                    }
                }

                return mInstance;
            }
        }

        /// <summary>
        /// 资源释放
        /// </summary>
        public static void Dispose()
        {
            mInstance = null;
        }
    }

    /// <summary>
    /// 普通单例创建类
    /// </summary>
    internal static class SingletonCreator
    {
        static T CreateNonPublicConstructorObject<T>() where T : class
        {
            var type = typeof(T);
            // 获取私有构造函数
            var constructorInfos = type.GetConstructors(BindingFlags.Instance | BindingFlags.NonPublic);

            // 获取无参构造函数
            var ctor = Array.Find(constructorInfos, c => c.GetParameters().Length == 0);

            if (ctor == null)
            {
                throw new Exception("Non-Public Constructor() not found! in " + type);
            }

            return ctor.Invoke(null) as T;
        }

        public static T CreateSingleton<T>() where T : class, ISingleton
        {
            var type = typeof(T);
            var monoBehaviourType = typeof(MonoBehaviour);

            if (monoBehaviourType.IsAssignableFrom(type))
            {
                return CreateMonoSingleton<T>();
            }
            else
            {
                var instance = CreateNonPublicConstructorObject<T>();
                instance.OnSingletonInit();
                return instance;
            }
        }


        /// <summary>
        /// 单元测试模式 标签
        /// </summary>
        public static bool IsUnitTestMode { get; set; }

        /// <summary>
        /// 查找Obj（一个嵌套查找Obj的过程）
        /// </summary>
        /// <param name="root">父节点</param>
        /// <param name="subPath">拆分后的路径节点</param>
        /// <param name="index">下标</param>
        /// <param name="build">true</param>
        /// <param name="dontDestroy">不要销毁 标签</param>
        /// <returns></returns>
        private static GameObject FindGameObject(GameObject root, string[] subPath, int index, bool build,
            bool dontDestroy)
        {
            GameObject client = null;

            if (root == null)
            {
                client = GameObject.Find(subPath[index]);
            }
            else
            {
                var child = root.transform.Find(subPath[index]);
                if (child != null)
                {
                    client = child.gameObject;
                }
            }

            if (client == null)
            {
                if (build)
                {
                    client = new GameObject(subPath[index]);
                    if (root != null)
                    {
                        client.transform.SetParent(root.transform);
                    }

                    if (dontDestroy && index == 0 && !IsUnitTestMode)
                    {
                        GameObject.DontDestroyOnLoad(client);
                    }
                }
            }

            if (client == null)
            {
                return null;
            }

            return ++index == subPath.Length ? client : FindGameObject(client, subPath, index, build, dontDestroy);
        }

        /// <summary>
        /// 泛型方法：创建MonoBehaviour单例
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <returns></returns>
        public static T CreateMonoSingleton<T>() where T : class, ISingleton
        {
            T instance = null;
            var type = typeof(T);

            //判断T实例存在的条件是否满足
            if (!IsUnitTestMode && !Application.isPlaying)
                return instance;

            //判断当前场景中是否存在T实例
            instance = UnityEngine.Object.FindObjectOfType(type) as T;
            if (instance != null)
            {
                instance.OnSingletonInit();
                return instance;
            }

            //MemberInfo：获取有关成员属性的信息并提供对成员元数据的访问
            MemberInfo info = typeof(T);
            //获取T类型 自定义属性，并找到相关路径属性，利用该属性创建T实例
            var attributes = info.GetCustomAttributes(true);
            foreach (var atribute in attributes)
            {
                var defineAttri = atribute as MonoSingletonPath;
                if (defineAttri == null)
                {
                    continue;
                }

                instance = CreateComponentOnGameObject<T>(defineAttri.PathInHierarchy, true);
                break;
            }

            //如果还是无法找到instance  则主动去创建同名Obj 并挂载相关脚本 组件
            if (instance == null)
            {
                var obj = new GameObject(typeof(T).Name);
                if (!IsUnitTestMode)
                    UnityEngine.Object.DontDestroyOnLoad(obj);
                instance = obj.AddComponent(typeof(T)) as T;
            }

            instance.OnSingletonInit();
            return instance;
        }

        /// <summary>
        /// 在GameObject上创建T组件（脚本）
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="path">路径（应该就是Hierarchy下的树结构路径）</param>
        /// <param name="dontDestroy">不要销毁 标签</param>
        /// <returns></returns>
        private static T CreateComponentOnGameObject<T>(string path, bool dontDestroy) where T : class
        {
            var obj = FindGameObject(path, true, dontDestroy);
            if (obj == null)
            {
                obj = new GameObject("Singleton of " + typeof(T).Name);
                if (dontDestroy && !IsUnitTestMode)
                {
                    UnityEngine.Object.DontDestroyOnLoad(obj);
                }
            }

            return obj.AddComponent(typeof(T)) as T;
        }

        /// <summary>
        /// 查找Obj（对于路径 进行拆分）
        /// </summary>
        /// <param name="path">路径</param>
        /// <param name="build">true</param>
        /// <param name="dontDestroy">不要销毁 标签</param>
        /// <returns></returns>
        private static GameObject FindGameObject(string path, bool build, bool dontDestroy)
        {
            if (string.IsNullOrEmpty(path))
            {
                return null;
            }

            var subPath = path.Split('/');
            if (subPath == null || subPath.Length == 0)
            {
                return null;
            }

            return FindGameObject(null, subPath, 0, build, dontDestroy);
        }
    }

    /// <summary>
    /// 静态类：MonoBehaviour类的单例
    /// 泛型类：Where约束表示T类型必须继承MonoSingleton<T>
    /// </summary>
    /// <typeparam name="T"></typeparam>
    internal abstract class MonoSingleton<T> : MonoBehaviour, ISingleton where T : MonoSingleton<T>
    {
        /// <summary>
        /// 静态实例
        /// </summary>
        protected static T mInstance;

        /// <summary>
        /// 静态属性：封装相关实例对象
        /// </summary>
        public static T Instance
        {
            get
            {
                if (mInstance == null && !mOnApplicationQuit)
                {
                    mInstance = SingletonCreator.CreateMonoSingleton<T>();
                }

                return mInstance;
            }
        }

        /// <summary>
        /// 实现接口的单例初始化
        /// </summary>
        public virtual void OnSingletonInit()
        {
        }

        /// <summary>
        /// 资源释放
        /// </summary>
        public virtual void Dispose()
        {
            if (SingletonCreator.IsUnitTestMode)
            {
                var curTrans = transform;
                do
                {
                    var parent = curTrans.parent;
                    DestroyImmediate(curTrans.gameObject);
                    curTrans = parent;
                } while (curTrans != null);

                mInstance = null;
            }
            else
            {
                Destroy(gameObject);
            }
        }

        /// <summary>
        /// 当前应用程序是否结束 标签
        /// </summary>
        protected static bool mOnApplicationQuit = false;

        /// <summary>
        /// 应用程序退出：释放当前对象并销毁相关GameObject
        /// </summary>
        protected virtual void OnApplicationQuit()
        {
            mOnApplicationQuit = true;
            if (mInstance == null) return;
            Destroy(mInstance.gameObject);
            mInstance = null;
        }

        /// <summary>
        /// 释放当前对象
        /// </summary>
        protected virtual void OnDestroy()
        {
            mInstance = null;
        }

        /// <summary>
        /// 判断当前应用程序是否退出
        /// </summary>
        public static bool IsApplicationQuit
        {
            get { return mOnApplicationQuit; }
        }
    }

    /// <summary>
    /// MonoSingleton路径
    /// </summary>
    [AttributeUsage(AttributeTargets.Class)] //这个特性只能标记在Class上
    internal class MonoSingletonPath : Attribute
    {
        private string mPathInHierarchy;

        public MonoSingletonPath(string pathInHierarchy)
        {
            mPathInHierarchy = pathInHierarchy;
        }

        public string PathInHierarchy
        {
            get { return mPathInHierarchy; }
        }
    }

    /// <summary>
    /// 继承Mono的属性单例？
    /// </summary>
    /// <typeparam name="T"></typeparam>
    internal static class MonoSingletonProperty<T> where T : MonoBehaviour, ISingleton
    {
        private static T mInstance;

        public static T Instance
        {
            get
            {
                if (null == mInstance)
                {
                    mInstance = SingletonCreator.CreateMonoSingleton<T>();
                }

                return mInstance;
            }
        }

        public static void Dispose()
        {
            if (SingletonCreator.IsUnitTestMode)
            {
                UnityEngine.Object.DestroyImmediate(mInstance.gameObject);
            }
            else
            {
                UnityEngine.Object.Destroy(mInstance.gameObject);
            }

            mInstance = null;
        }
    }

    /// <summary>
    /// 如果跳转到新的场景里已经有了实例，则不创建新的单例（或者创建新的单例后会销毁掉新的单例）
    /// </summary>
    /// <typeparam name="T"></typeparam>
    internal abstract class PersistentMonoSingleton<T> : MonoBehaviour where T : Component
    {
        protected static T mInstance;
        protected bool mEnabled;

        /// <summary>
        /// Singleton design pattern
        /// </summary>
        /// <value>The instance.</value>
        public static T Instance
        {
            get
            {
                if (mInstance == null)
                {
                    mInstance = FindObjectOfType<T>();
                    if (mInstance == null)
                    {
                        var obj = new GameObject();
                        mInstance = obj.AddComponent<T>();
                    }
                }

                return mInstance;
            }
        }

        /// <summary>
        /// On awake, we check if there's already a copy of the object in the scene. If there's one, we destroy it.
        /// </summary>
        protected virtual void Awake()
        {
            if (!Application.isPlaying)
            {
                return;
            }

            if (mInstance == null)
            {
                //If I am the first instance, make me the Singleton
                mInstance = this as T;
                DontDestroyOnLoad(transform.gameObject);
                mEnabled = true;
            }
            else
            {
                //If a Singleton already exists and you find
                //another reference in scene, destroy it!
                if (this != mInstance)
                {
                    Destroy(this.gameObject);
                }
            }
        }
    }

    /// <summary>
    /// 如果跳转到新的场景里已经有了实例，则删除已有示例，再创建新的实例
    /// </summary>
    /// <typeparam name="T"></typeparam>
    internal class ReplaceableMonoSingleton<T> : MonoBehaviour where T : Component
    {
        protected static T mInstance;
        public float InitializationTime;

        /// <summary>
        /// Singleton design pattern
        /// </summary>
        /// <value>The instance.</value>
        public static T Instance
        {
            get
            {
                if (mInstance == null)
                {
                    mInstance = FindObjectOfType<T>();
                    if (mInstance == null)
                    {
                        GameObject obj = new GameObject();
                        obj.hideFlags = HideFlags.HideAndDontSave;
                        mInstance = obj.AddComponent<T>();
                    }
                }

                return mInstance;
            }
        }

        /// <summary>
        /// On awake, we check if there's already a copy of the object in the scene. If there's one, we destroy it.
        /// </summary>
        protected virtual void Awake()
        {
            if (!Application.isPlaying)
            {
                return;
            }

            InitializationTime = Time.time;

            DontDestroyOnLoad(this.gameObject);
            // we check for existing objects of the same type
            T[] check = FindObjectsOfType<T>();
            foreach (T searched in check)
            {
                if (searched != this)
                {
                    // if we find another object of the same type (not this), and if it's older than our current object, we destroy it.
                    if (searched.GetComponent<ReplaceableMonoSingleton<T>>().InitializationTime < InitializationTime)
                    {
                        Destroy(searched.gameObject);
                    }
                }
            }

            if (mInstance == null)
            {
                mInstance = this as T;
            }
        }
    }

    

    #endregion
}