Sic04/SicRT/Equipments/Systems/DeviceLocker.cs

// /************************************************************************
// * @file     DeviceLocker.cs
// * @author   Su Liang
// * @date     2022/11/16
// *
// * @copyright &copy Sicentury Inc.
// *
// * @brief    设备资源锁定器。
// *
// * @details  当某个设备或其它资源不能被多个线程同时使用时，可使用此锁定器实现资源互斥操作。
// *
// *
// * *****************************************************************************/


using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using MECF.Framework.Common.Equipment;

namespace SicRT.Equipments.Systems
{
    public class DeviceLocker
    {
        private readonly  object _syncRoot = new object();
        private readonly SemaphoreSlim _semResource;

        #region Constructor

        public DeviceLocker(string deviceName, int maxResCount)
        {
            DeviceName = deviceName;
            _semResource = new SemaphoreSlim(maxResCount, maxResCount);
        }

        #endregion

        #region Properties
        
        /// <summary>
        /// 设备名称。
        /// </summary>
        public string DeviceName { get; }

        /// <summary>
        /// 返回占有该设备的对象名称.
        /// <para>关于可能使用到的占用者名称，请参考枚举类型<see cref="ModuleName"/>。</para>
        /// </summary>
        public List<string> Occupiers { get; private set; }

        #endregion

        #region MyRegion

        /// <summary>
        /// 锁定设备。
        /// </summary>
        /// <param name="occupier"></param>
        /// <param name="timeoutInMillisecond"></param>
        /// <param name="reason"></param>
        /// <returns></returns>
        public bool Lock(ModuleName occupier, out string reason, int timeoutInMillisecond = 100)
        {
            lock (_syncRoot)
            {
                var a = Occupiers.FirstOrDefault(x => x == occupier.ToString());
                if (a != null)
                {
                    reason = $"{DeviceName} had been lock by {occupier}";
                    return false;
                }

                if (_semResource.Wait(timeoutInMillisecond))
                {
                    Occupiers.Add(occupier.ToString());
                    reason = "";
                    return true;
                }
                else
                {
                    reason = $"Unable to lock {DeviceName}, no enough resources, locked by {string.Join(", ", Occupiers)}";
                    return false;
                }
            }
        }

        /// <summary>
        /// 释放设备。
        /// </summary>
        /// <param name="occupier"></param>
        /// <param name="reason"></param>
        /// <returns></returns>
        public bool Release(ModuleName occupier, out string reason)
        {
            lock (_syncRoot)
            {
                var a = Occupiers.FirstOrDefault(x => x == occupier.ToString());
                if (a == null)
                {
                    reason = $"{DeviceName} is never locked by {occupier}";
                    return false;
                }

                try
                {
                    _semResource.Release(1);
                    Occupiers.Remove(occupier.ToString());
                    reason = "";
                    return true;
                }
                catch (Exception ex)
                {
                    reason = $"Unable to lock {DeviceName} by {occupier}, {ex.Message}";
                    return false;
                }
                
            }
        }
        
        #endregion
    }
}