// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
 
#nullable disable
 
using System;
using System.Collections.Generic;
using Microsoft.CodeAnalysis.PooledObjects;
 
namespace Microsoft.CodeAnalysis.ExternalAccess.Pythia.Api
{
    internal static class PythiaObjectPool
    {
        [Obsolete("Use specific GetInstance overloads")]
        public static IDisposable GetInstance<T>(out T instance) where T : class, new()
        {
            var disposer = Default<T>().GetPooledObject<T>();
            instance = disposer.Object;
            return disposer;
        }
 
        public static IDisposable GetInstance<T>(out Stack<T> instance)
        {
            var disposer = Default<Stack<T>>().GetPooledObject();
            instance = disposer.Object;
            return disposer;
        }
 
        public static IDisposable GetInstance<T>(out HashSet<T> instance)
        {
            var disposer = Default<HashSet<T>>().GetPooledObject();
            instance = disposer.Object;
            return disposer;
        }
 
        private static ObjectPool<T> Default<T>() where T : class, new()
            => DefaultNormalPool<T>.Instance;
 
        private static class DefaultNormalPool<T> where T : class, new()
        {
            public static readonly ObjectPool<T> Instance = new(() => new T(), 20);
        }
    }
}