// 1. 需要池化的类型实现IPoolItem接口
public class TestItem : IPoolItem
{
    public int Value { get; set; }

    // 当对象返回对象池化时通过该方法进行重置实例状态
    public bool TryReset()
    {
        return true;
    }
}

// 2. 在任何地方使用new关键字创建该类型的对象
public class Test
{
    public void M()
    {
        var random = new Random();
        var item = new TestItem();
        item.Value = random.Next();
        Console.WriteLine(item.Value);
    }
}

// 编译后代码
public class Test
{
    public void M()
    {
        TestItem item = null;
        try
        {
            var random = new Random();
            item = Pool<TestItem>.Get();
            item.Value = random.Next();
            Console.WriteLine(item.Value);
        }
        finally
        {
            if (item != null)
            {
                Pool<TestItem>.Return(item);
            }
        }
    }
}

[PoolingExclusive(Types = [typeof(TestItemBuilder)], Pattern = "execution(* TestItemManager.*(..))")]
public class TestItem : IPoolItem
{
    public bool TryReset() => true;
}

public class TestItemBuilder
{
    private readonly TestItem _item;

    private TestItemBuilder()
    {
        // 由于通过PoolingExclusive的Types属性排除了TestItemBuilder，所以这里不会替换为对象池操作
        _item = new TestItem();
    }

    public static TestItemBuilder Create() => new TestItemBuilder();

    public TestItemBuilder SetXxx()
    {
        // ...
        return this;
    }

    public TestItem Build()
    {
        return _item;
    }
}

public class TestItemManager
{
    private TestItem? _cacheItem;

    public void Execute()
    {
        // 由于通过PoolingExclusive的Pattern属性排除了TestItemManager下的所有方法，所以这里不会替换为对象池操作
        var item = _cacheItem ?? new TestItem();
        // ...
    }
}

public class TestItem1 : IPoolItem
{
    public bool TryReset() => true;
}
public class TestItem2 : IPoolItem
{
    public bool TryReset() => true;
}
public class TestItem3 : IPoolItem
{
    public bool TryReset() => true;
}

public class Test
{
    [NonPooled]
    public void M()
    {
        // 由于方法应用了NonPooledAttribute，以下三个new操作都不会替换为对象池操作
        var item1 = new TestItem1();
        var item2 = new TestItem2();
        var item3 = new TestItem3();
    }
}

public class Test
{
    [NonPooled(Types = [typeof(TestItem1)], Pattern = "*..TestItem3")]
    public void M()
    {
        // TestItem1通过Types不允许进行池化操作，TestItem3通过Pattern不允许进行池化操作，仅TestItem2可进行池化操作
        var item1 = new TestItem1();
        var item2 = new TestItem2();
        var item3 = new TestItem3();
    }
}

namespace A.B.C;

public class Item1
{
    public object? GetAndDelete() => null;
}

public class Item2
{
    public bool Clear() => true;
}

public class Item3 { }

public class Test
{
    public static void M1()
    {
        var item1 = new Item1();
        var item2 = new Item2();
        var item3 = new Item3();
        Console.WriteLine($"{item1}, {item2}, {item3}");
    }

    public static async ValueTask M2()
    {
        var item1 = new Item1();
        var item2 = new Item2();
        await Task.Yield();
        var item3 = new Item3();
        Console.WriteLine($"{item1}, {item2}, {item3}");
    }
}

public class Test
{
    public static void M1()
    {
        Item1 item1 = null;
        Item2 item2 = null;
        Item3 item3 = null;
        try
        {
            item1 = Pool<Item1>.Get();
            item2 = Pool<Item2>.Get();
            item3 = Pool<Item3>.Get();
            Console.WriteLine($"{item1}, {item2}, {item3}");
        }
        finally
        {
            if (item1 != null)
            {
                item1.GetAndDelete();
                Pool<Item1>.Return(item1);
            }
            if (item2 != null)
            {
                if (item2.Clear())
                {
                    Pool<Item2>.Return(item2);
                }
            }
            if (item3 != null)
            {
                Pool<Item3>.Return(item3);
            }
        }
    }

    public static async ValueTask M2()
    {
        Item1 item1 = null;
        try
        {
            item1 = Pool<Item1>.Get();
            var item2 = new Item2();
            await Task.Yield();
            var item3 = new Item3();
            Console.WriteLine($"{item1}, {item2}, {item3}");
        }
        finally
        {
            if (item1 != null)
            {
                item1.GetAndDelete();
                Pool<Item1>.Return(item1);
            }
        }
    }
}

// TestAttribute
public class TestAttribute : MoAttribute
{
    // 为了让GC效果更明显，每个TestAttribute都将持有长度为1024的字节数组
    private readonly byte[] _occupy = new byte[1024];
}

// BenchmarkTest
public class BenchmarkTest
{
    [Benchmark]
    [Test]
    public void M() { }

    [Benchmark]
    [Test]
    public void N() { }
}

// Program
var config = ManualConfig.Create(DefaultConfig.Instance)
    .AddDiagnoser(MemoryDiagnoser.Default);
var _ = BenchmarkRunner.Run<BenchmarkTest>(config);

// 通用对象池
public class MicrosoftPool : IPool
{
    private static readonly ConcurrentDictionary<Type, object> _Pools = [];

    public T Get<T>() where T : class, new()
    {
        return GetPool<T>().Get();
    }

    public void Return<T>(T value) where T : class, new()
    {
        GetPool<T>().Return(value);
    }

    private ObjectPool<T> GetPool<T>() where T : class, new()
    {
        return (ObjectPool<T>)_Pools.GetOrAdd(typeof(T), t =>
        {
            var provider = new DefaultObjectPoolProvider();
            var policy = new DefaultPooledObjectPolicy<T>();
            return provider.Create(policy);
        });
    }
}

// 特定池化类型对象池
public class SpecificalMicrosoftPool<T> : IPool<T> where T : class, new()
{
    private readonly ObjectPool<T> _pool;

    public SpecificalMicrosoftPool()
    {
        var provider = new DefaultObjectPoolProvider();
        var policy = new DefaultPooledObjectPolicy<T>();
        _pool = provider.Create(policy);
    }

    public T Get()
    {
        return _pool.Get();
    }

    public void Return(T value)
    {
        _pool.Return(value);
    }
}

// 替换操作最好在Main入口直接完成，一旦对象池被使用就不再运行进行替换操作

// 替换通用对象池实现
Pool.Set(new MicrosoftPool());
// 替换特定类型对象池
Pool<Xyz>.Set(new SpecificalMicrosoftPool<Xyz>());

// 定义单例对象池
public class SingletonPool<T> : IPool<T> where T : class, new()
{
    private readonly T _value = new();

    public T Get() => _value;

    public void Return(T value) { }
}

// 替换对象池实现
Pool<ConcurrentDictionary<Type, object>>.Set(new SingletonPool<ConcurrentDictionary<Type, object>>());

// 通过配置，将ConcurrentDictionary<Type, object>设置为池化类型
// <Item stateless="System.Collections.Concurrent.ConcurrentDictionary&lt;System.Type, object&gt;" />

// 定义信号量对象池
public class SemaphorePool<T> : IPool<T> where T : class, new()
{
    private readonly Semaphore _semaphore = new(3, 3);
    private readonly DefaultPool<T> _pool = new();

    public T Get()
    {
        if (!_semaphore.WaitOne(100)) return null;

        return _pool.Get();
    }

    public void Return(T value)
    {
        _pool.Return(value);
        _semaphore.Release();
    }
}

// 替换对象池实现
Pool<Connection>.Set(new SemaphorePool<Connection>());

// 通过配置，将Connection设置为池化类型
// <Item stateless="X.Y.Z.Connection" />

// 定义现成单例对象池
public class ThreadLocalPool<T> : IPool<T> where T : class, new()
{
    private readonly ThreadLocal<T> _random = new(() => new());

    public T Get() => _random.Value!;

    public void Return(T value) { }
}

// 替换对象池实现
Pool<Random>.Set(new ThreadLocalPool<Random>());

// 通过配置，将Connection设置为池化类型
// <Item stateless="System.Random" />

// 定义现属性注入对象池
public class ServiceSetupPool : IPool<Service1>
{
    public Service1 Get()
    {
        var service1 = new Service1();
        var service2 = PinnedScope.ScopedServices?.GetService<Service2>();
        service1.Service2 = service2;

        return service1;
    }

    public void Return(Service1 value) { }
}

// 定义池化类型
public class Service2 { }

[PoolingExclusive(Types = [typeof(ServiceSetupPool)])]
public class Service1 : IPoolItem
{
    public Service2? Service2 { get; set; }

    public bool TryReset() => true;
}

// 替换对象池实现
Pool<Service1>.Set(new ServiceSetupPool());