using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;

namespace Island.StandardLib.Utils
{
    /// <summary>
    /// 一组不精确的非原子锁
    /// </summary>
    /// <typeparam name="LockIdType">锁定项标识，需要实现 <see cref="object.GetHashCode()"/></typeparam>
    public class LockerList<LockIdType>
    {
        readonly ConcurrentDictionary<LockIdType, bool> mapLck;
        readonly object globalLck;

        public LockerList()
        {
            mapLck = new ConcurrentDictionary<LockIdType, bool>();
            globalLck = new object();
        }

        /// <summary>
        /// 加读锁
        /// </summary>
        /// <param name="lckId">标识</param>
        public void Lock(LockIdType lckId)
        {
            if (mapLck.TryGetValue(lckId, out bool __lck))
            {
                do Thread.Sleep(1);
                while (__lck);
                lock (globalLck) mapLck[lckId] = true;
            }
            else
            {
                lock (globalLck) mapLck.TryAdd(lckId, true);
            }
        }

        /// <summary>
        /// 解锁
        /// </summary>
        /// <param name="lckId">标识</param>
        public void Unlock(LockIdType lckId)
        {
            lock (globalLck) mapLck[lckId] = false;
        }
    }
}