Sic03/FrameworkLocal/RTCore/ThreadLock/ThreadLock.cs

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2022-07-26 09:41:07 +08:00
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Globalization;
using System.Linq;
using System.Text;
using System.Threading;
namespace MECF.Framework.RT.Core.ThreadLock
{
#region 线
/// <summary>
/// 线程的协调逻辑状态
/// </summary>
internal enum CoordinationStatus
{
/// <summary>
/// 所有项完成
/// </summary>
AllDone,
/// <summary>
/// 超时
/// </summary>
Timeout,
/// <summary>
/// 任务取消
/// </summary>
Cancel
}
/// <summary>
/// 一个线程协调逻辑类详细参考书籍《CLR Via C#》page:681
/// 这个类可惜没有报告进度的功能
/// </summary>
internal sealed class AsyncCoordinator
{
private int m_opCount = 1;
private int m_statusReported = 0;
private Action<CoordinationStatus> m_callback;
private System.Threading.Timer m_timer;
/// <summary>
/// 每次的操作任务开始前必须调用该方法
/// </summary>
/// <param name="opsToAdd"></param>
public void AboutToBegin(int opsToAdd = 1) => Interlocked.Add(ref m_opCount, opsToAdd);
/// <summary>
/// 在一次任务处理好操作之后,必须调用该方法
/// </summary>
public void JustEnded()
{
if (Interlocked.Decrement(ref m_opCount) == 0)
{
ReportStatus(CoordinationStatus.AllDone);
}
}
/// <summary>
/// 该方法必须在发起所有的操作之后调用
/// </summary>
/// <param name="callback">回调方法</param>
/// <param name="timeout">超时时间</param>
public void AllBegun(Action<CoordinationStatus> callback, int timeout = Timeout.Infinite)
{
m_callback = callback;
if (timeout != Timeout.Infinite)
{
m_timer = new System.Threading.Timer(TimeExpired, null, timeout, Timeout.Infinite);
}
JustEnded();//修正一开始设置的初始值
}
/// <summary>
/// 超时的方法
/// </summary>
/// <param name="o"></param>
private void TimeExpired(object o) => ReportStatus(CoordinationStatus.Timeout);
/// <summary>
/// 取消任务的执行
/// </summary>
public void Cancel() => ReportStatus(CoordinationStatus.Cancel);
/// <summary>
/// 生成一次报告
/// </summary>
/// <param name="status">报告的状态</param>
private void ReportStatus(CoordinationStatus status)
{
//只报告一次的限制
if (Interlocked.Exchange(ref m_statusReported, 1) == 0)
{
m_callback(status);
}
}
/// <summary>
/// 乐观的并发方法模型具体参照《CLR Via C#》page:686
/// </summary>
/// <param name="target">唯一的目标数据</param>
/// <param name="change">修改数据的算法</param>
/// <returns></returns>
public static int Maxinum(ref int target, Func<int, int> change)
{
int currentVal = target, startVal, desiredVal;
do
{
startVal = currentVal;//设置值
//以下为业务逻辑,允许实现非常复杂的设置
desiredVal = change(startVal);
currentVal = Interlocked.CompareExchange(ref target, desiredVal, startVal);
}
while (startVal != currentVal);//更改失败就强制更新
return desiredVal;
}
}
#endregion
#region
/// <summary>
/// 一个用于高性能,乐观并发模型控制操作的类,允许一个方法(隔离方法)的安全单次执行
/// </summary>
public sealed class HslAsyncCoordinator
{
/// <summary>
/// 实例化一个对象,需要传入隔离执行的方法
/// </summary>
/// <param name="operater">隔离执行的方法</param>
public HslAsyncCoordinator(Action operater)
{
action = operater;
}
/// <summary>
/// 操作状态0是未操作1是操作中
/// </summary>
private int OperaterStatus = 0;
/// <summary>
/// 需要操作的次数
/// </summary>
private long Target = 0;
/// <summary>
/// 启动线程池执行隔离方法
/// </summary>
public void StartOperaterInfomation()
{
Interlocked.Increment(ref Target);
if (Interlocked.CompareExchange(ref OperaterStatus, 1, 0) == 0)
{
//启动保存
ThreadPool.QueueUserWorkItem(new WaitCallback(ThreadPoolOperater), null);
}
}
private Action action = null;
private void ThreadPoolOperater(object obj)
{
long currentVal = Target, startVal;
long desiredVal = 0;
do
{
startVal = currentVal;//设置值
// 以下为业务逻辑,允许实现非常复杂的设置
action?.Invoke();
// 需要清零值的时候必须用下面的原子操作
currentVal = Interlocked.CompareExchange(ref Target, desiredVal, startVal);
}
while (startVal != currentVal);// 更改失败就强制更新
// 退出保存状态
Interlocked.Exchange(ref OperaterStatus, 0);
// 最终状态确认
if (Target != desiredVal) StartOperaterInfomation();
}
}
#endregion
#region
// 一个高性能的读写锁由《CLR Via C#》作者Jeffrey Richter提供
/// <summary>
/// 一个高性能的读写锁,支持写锁定,读灵活,读时写锁定,写时读锁定
/// </summary>
public sealed class HslReadWriteLock : IDisposable
{
#region Lock State Management
#if false
private struct BitField {
private int m_mask, m_1, m_startBit;
public BitField(int startBit, int numBits) {
m_startBit = startBit;
m_mask = unchecked((int)((1 << numBits) - 1) << startBit);
m_1 = unchecked((int)1 << startBit);
}
public void Increment(ref int value) { value += m_1; }
public void Decrement(ref int value) { value -= m_1; }
public void Decrement(ref int value, int amount) { value -= m_1 * amount; }
public int Get(int value) { return (value & m_mask) >> m_startBit; }
public int Set(int value, int fieldValue) { return (value & ~m_mask) | (fieldValue << m_startBit); }
}
private static BitField s_state = new BitField(0, 3);
private static BitField s_readersReading = new BitField(3, 9);
private static BitField s_readersWaiting = new BitField(12, 9);
private static BitField s_writersWaiting = new BitField(21, 9);
private static OneManyLockStates State(int value) { return (OneManyLockStates)s_state.Get(value); }
private static void State(ref int ls, OneManyLockStates newState) {
ls = s_state.Set(ls, (int)newState);
}
#endif
private enum OneManyLockStates
{
Free = 0x00000000,
OwnedByWriter = 0x00000001,
OwnedByReaders = 0x00000002,
OwnedByReadersAndWriterPending = 0x00000003,
ReservedForWriter = 0x00000004,
}
private const int c_lsStateStartBit = 0;
private const int c_lsReadersReadingStartBit = 3;
private const int c_lsReadersWaitingStartBit = 12;
private const int c_lsWritersWaitingStartBit = 21;
// Mask = unchecked((int) ((1 << numBits) - 1) << startBit);
private const int c_lsStateMask = unchecked((int)((1 << 3) - 1) << c_lsStateStartBit);
private const int c_lsReadersReadingMask = unchecked((int)((1 << 9) - 1) << c_lsReadersReadingStartBit);
private const int c_lsReadersWaitingMask = unchecked((int)((1 << 9) - 1) << c_lsReadersWaitingStartBit);
private const int c_lsWritersWaitingMask = unchecked((int)((1 << 9) - 1) << c_lsWritersWaitingStartBit);
private const int c_lsAnyWaitingMask = c_lsReadersWaitingMask | c_lsWritersWaitingMask;
// FirstBit = unchecked((int) 1 << startBit);
private const int c_ls1ReaderReading = unchecked((int)1 << c_lsReadersReadingStartBit);
private const int c_ls1ReaderWaiting = unchecked((int)1 << c_lsReadersWaitingStartBit);
private const int c_ls1WriterWaiting = unchecked((int)1 << c_lsWritersWaitingStartBit);
private static OneManyLockStates State(int ls) { return (OneManyLockStates)(ls & c_lsStateMask); }
private static void SetState(ref int ls, OneManyLockStates newState)
{
ls = (ls & ~c_lsStateMask) | ((int)newState);
}
private static int NumReadersReading(int ls) { return (ls & c_lsReadersReadingMask) >> c_lsReadersReadingStartBit; }
private static void AddReadersReading(ref int ls, int amount) { ls += (c_ls1ReaderReading * amount); }
private static int NumReadersWaiting(int ls) { return (ls & c_lsReadersWaitingMask) >> c_lsReadersWaitingStartBit; }
private static void AddReadersWaiting(ref int ls, int amount) { ls += (c_ls1ReaderWaiting * amount); }
private static int NumWritersWaiting(int ls) { return (ls & c_lsWritersWaitingMask) >> c_lsWritersWaitingStartBit; }
private static void AddWritersWaiting(ref int ls, int amount) { ls += (c_ls1WriterWaiting * amount); }
private static bool AnyWaiters( int ls ) { return (ls & c_lsAnyWaitingMask) != 0; }
private static string DebugState(int ls)
{
return string.Format(CultureInfo.InvariantCulture,
"State={0}, RR={1}, RW={2}, WW={3}", State(ls),
NumReadersReading(ls), NumReadersWaiting(ls), NumWritersWaiting(ls));
}
/// <summary>
/// 返回本对象的描述字符串
/// </summary>
/// <returns>对象的描述字符串</returns>
public override string ToString() { return DebugState(m_LockState); }
#endregion
#region State Fields
private int m_LockState = (int)OneManyLockStates.Free;
// Readers wait on this if a writer owns the lock
private Semaphore m_ReadersLock = new Semaphore(0, int.MaxValue);
// Writers wait on this if a reader owns the lock
private Semaphore m_WritersLock = new Semaphore(0, int.MaxValue);
#endregion
#region Construction
/// <summary>
/// 实例化一个读写锁的对象
/// </summary>
public HslReadWriteLock() : base() { }
#endregion
#region IDisposable Support
private bool disposedValue = false; // 要检测冗余调用
void Dispose(bool disposing)
{
if (!disposedValue)
{
if (disposing)
{
// TODO: 释放托管状态(托管对象)。
}
// TODO: 释放未托管的资源(未托管的对象)并在以下内容中替代终结器。
// TODO: 将大型字段设置为 null。
m_WritersLock.Close(); m_WritersLock = null;
m_ReadersLock.Close(); m_ReadersLock = null;
disposedValue = true;
}
}
// TODO: 仅当以上 Dispose(bool disposing) 拥有用于释放未托管资源的代码时才替代终结器。
// ~HslReadWriteLock() {
// // 请勿更改此代码。将清理代码放入以上 Dispose(bool disposing) 中。
// Dispose(false);
// }
// 添加此代码以正确实现可处置模式。
/// <summary>
/// 释放资源
/// </summary>
public void Dispose()
{
// 请勿更改此代码。将清理代码放入以上 Dispose(bool disposing) 中。
Dispose(true);
// TODO: 如果在以上内容中替代了终结器,则取消注释以下行。
// GC.SuppressFinalize(this);
}
#endregion
#region Writer members
private bool m_exclusive;
/// <summary>
/// 根据读写情况请求锁
/// </summary>
/// <param name="exclusive">True为写请求False为读请求</param>
public void Enter(bool exclusive)
{
if (exclusive)
{
while (WaitToWrite(ref m_LockState)) m_WritersLock.WaitOne();
}
else
{
while (WaitToRead(ref m_LockState)) m_ReadersLock.WaitOne();
}
m_exclusive = exclusive;
}
private static bool WaitToWrite(ref int target)
{
int start, current = target;
bool wait;
do
{
start = current;
int desired = start;
wait = false;
switch (State(desired))
{
case OneManyLockStates.Free: // If Free -> OBW, return
case OneManyLockStates.ReservedForWriter: // If RFW -> OBW, return
SetState(ref desired, OneManyLockStates.OwnedByWriter);
break;
case OneManyLockStates.OwnedByWriter: // If OBW -> WW++, wait & loop around
AddWritersWaiting(ref desired, 1);
wait = true;
break;
case OneManyLockStates.OwnedByReaders: // If OBR or OBRAWP -> OBRAWP, WW++, wait, loop around
case OneManyLockStates.OwnedByReadersAndWriterPending:
SetState(ref desired, OneManyLockStates.OwnedByReadersAndWriterPending);
AddWritersWaiting(ref desired, 1);
wait = true;
break;
default:
Debug.Assert(false, "Invalid Lock state");
break;
}
current = Interlocked.CompareExchange(ref target, desired, start);
} while (start != current);
return wait;
}
/// <summary>
/// 释放锁,将根据锁状态自动区分读写锁
/// </summary>
public void Leave()
{
int wakeup;
if (m_exclusive)
{
Debug.Assert((State(m_LockState) == OneManyLockStates.OwnedByWriter) && (NumReadersReading(m_LockState) == 0));
// Pre-condition: Lock's state must be OBW (not Free/OBR/OBRAWP/RFW)
// Post-condition: Lock's state must become Free or RFW (the lock is never passed)
// Phase 1: Release the lock
wakeup = DoneWriting(ref m_LockState);
}
else
{
var s = State(m_LockState);
Debug.Assert((State(m_LockState) == OneManyLockStates.OwnedByReaders) || (State(m_LockState) == OneManyLockStates.OwnedByReadersAndWriterPending));
// Pre-condition: Lock's state must be OBR/OBRAWP (not Free/OBW/RFW)
// Post-condition: Lock's state must become unchanged, Free or RFW (the lock is never passed)
// Phase 1: Release the lock
wakeup = DoneReading(ref m_LockState);
}
// Phase 2: Possibly wake waiters
if (wakeup == -1) m_WritersLock.Release();
else if (wakeup > 0) m_ReadersLock.Release(wakeup);
}
// Returns -1 to wake a writer, +# to wake # readers, or 0 to wake no one
private static int DoneWriting(ref int target)
{
int start, current = target;
int wakeup = 0;
do
{
int desired = (start = current);
// We do this test first because it is commonly true &
// we avoid the other tests improving performance
if (!AnyWaiters(desired))
{
SetState(ref desired, OneManyLockStates.Free);
wakeup = 0;
}
else if (NumWritersWaiting(desired) > 0)
{
SetState(ref desired, OneManyLockStates.ReservedForWriter);
AddWritersWaiting(ref desired, -1);
wakeup = -1;
}
else
{
wakeup = NumReadersWaiting(desired);
Debug.Assert(wakeup > 0);
SetState(ref desired, OneManyLockStates.OwnedByReaders);
AddReadersWaiting(ref desired, -wakeup);
// RW=0, RR=0 (incremented as readers enter)
}
current = Interlocked.CompareExchange(ref target, desired, start);
} while (start != current);
return wakeup;
}
#endregion
#region Reader members
private static bool WaitToRead(ref int target)
{
int start, current = target;
bool wait;
do
{
int desired = (start = current);
wait = false;
switch (State(desired))
{
case OneManyLockStates.Free: // If Free->OBR, RR=1, return
SetState(ref desired, OneManyLockStates.OwnedByReaders);
AddReadersReading(ref desired, 1);
break;
case OneManyLockStates.OwnedByReaders: // If OBR -> RR++, return
AddReadersReading(ref desired, 1);
break;
case OneManyLockStates.OwnedByWriter: // If OBW/OBRAWP/RFW -> RW++, wait, loop around
case OneManyLockStates.OwnedByReadersAndWriterPending:
case OneManyLockStates.ReservedForWriter:
AddReadersWaiting(ref desired, 1);
wait = true;
break;
default:
Debug.Assert(false, "Invalid Lock state");
break;
}
current = Interlocked.CompareExchange(ref target, desired, start);
} while (start != current);
return wait;
}
// Returns -1 to wake a writer, +# to wake # readers, or 0 to wake no one
private static int DoneReading(ref int target)
{
int start, current = target;
int wakeup;
do
{
int desired = (start = current);
AddReadersReading(ref desired, -1); // RR--
if (NumReadersReading(desired) > 0)
{
// RR>0, no state change & no threads to wake
wakeup = 0;
}
else if (!AnyWaiters(desired))
{
SetState(ref desired, OneManyLockStates.Free);
wakeup = 0;
}
else
{
Debug.Assert(NumWritersWaiting(desired) > 0);
SetState(ref desired, OneManyLockStates.ReservedForWriter);
AddWritersWaiting(ref desired, -1);
wakeup = -1; // Wake 1 writer
}
current = Interlocked.CompareExchange(ref target, desired, start);
} while (start != current);
return wakeup;
}
#endregion
}
#endregion
#region
/// <summary>
/// 一个简单的混合线程同步锁,采用了基元用户加基元内核同步构造实现
/// </summary>
/// <example>
/// 以下演示常用的锁的使用方式,还包含了如何优雅的处理异常锁
/// <code lang="cs" source="HslCommunication_Net45.Test\Documentation\Samples\Core\ThreadLock.cs" region="SimpleHybirdLockExample1" title="SimpleHybirdLock示例" />
/// </example>
public sealed class SimpleHybirdLock : IDisposable
{
#region IDisposable Support
private bool disposedValue = false; // 要检测冗余调用
void Dispose(bool disposing)
{
if (!disposedValue)
{
if (disposing)
{
// TODO: 释放托管状态(托管对象)。
}
// TODO: 释放未托管的资源(未托管的对象)并在以下内容中替代终结器。
// TODO: 将大型字段设置为 null。
m_waiterLock.Close();
disposedValue = true;
}
}
// TODO: 仅当以上 Dispose(bool disposing) 拥有用于释放未托管资源的代码时才替代终结器。
// ~SimpleHybirdLock() {
// // 请勿更改此代码。将清理代码放入以上 Dispose(bool disposing) 中。
// Dispose(false);
// }
// 添加此代码以正确实现可处置模式。
/// <summary>
/// 释放资源
/// </summary>
public void Dispose()
{
// 请勿更改此代码。将清理代码放入以上 Dispose(bool disposing) 中。
Dispose(true);
// TODO: 如果在以上内容中替代了终结器,则取消注释以下行。
// GC.SuppressFinalize(this);
}
#endregion
/// <summary>
/// 基元用户模式构造同步锁
/// </summary>
private int m_waiters = 0;
/// <summary>
/// 基元内核模式构造同步锁
/// </summary>
private AutoResetEvent m_waiterLock = new AutoResetEvent(false);
/// <summary>
/// 获取锁
/// </summary>
public void Enter()
{
if (Interlocked.Increment(ref m_waiters) == 1) return;//用户锁可以使用的时候,直接返回,第一次调用时发生
//当发生锁竞争时,使用内核同步构造锁
m_waiterLock.WaitOne();
}
/// <summary>
/// 离开锁
/// </summary>
public void Leave()
{
if (Interlocked.Decrement(ref m_waiters) == 0) return;//没有可用的锁的时候
m_waiterLock.Set();
}
/// <summary>
/// 获取当前锁是否在等待当中
/// </summary>
public bool IsWaitting => m_waiters != 0;
}
#endregion
#region 线
/*******************************************************************************
*
* 201776 08:30:56
*
*
*******************************************************************************/
/// <summary>
/// 一个用于多线程并发处理数据的模型类,适用于处理数据量非常庞大的情况
/// </summary>
/// <typeparam name="T">等待处理的数据类型</typeparam>
public sealed class SoftMultiTask<T>
{
/// <summary>
/// 实例化一个数据处理对象
/// </summary>
/// <param name="dataList">数据处理列表</param>
/// <param name="operater">数据操作方法,应该是相对耗时的任务</param>
/// <param name="threadCount">需要使用的线程数</param>
public SoftMultiTask(T[] dataList, Func<T, bool> operater, int threadCount = 10)
{
m_dataList = dataList ?? throw new ArgumentNullException("dataList");
m_operater = operater ?? throw new ArgumentNullException("operater");
if (threadCount < 1) throw new ArgumentException( "threadCount can not less than 1", "threadCount");
m_threadCount = threadCount;
//增加任务处理
Interlocked.Add(ref m_opCount, dataList.Length);
//增加线程处理
Interlocked.Add(ref m_opThreadCount, threadCount);
}
/// <summary>
/// 操作总数,判定操作是否完成
/// </summary>
private int m_opCount = 0;
/// <summary>
/// 判断是否所有的线程是否处理完成
/// </summary>
private int m_opThreadCount = 1;
/// <summary>
/// 准备启动的处理数据的线程数量
/// </summary>
private int m_threadCount = 10;
/// <summary>
/// 指示多线程处理是否在运行中,防止冗余调用
/// </summary>
private int m_runStatus = 0;
/// <summary>
/// 列表数据
/// </summary>
private T[] m_dataList = null;
/// <summary>
/// 需要操作的方法
/// </summary>
private Func<T, bool> m_operater = null;
/// <summary>
/// 一个双参数委托
/// </summary>
/// <param name="item"></param>
/// <param name="ex"></param>
public delegate void MultiInfo(T item, Exception ex);
/// <summary>
/// 用于报告进度的委托当finish等于count时任务完成
/// </summary>
/// <param name="finish">已完成操作数量</param>
/// <param name="count">总数量</param>
/// <param name="success">成功数量</param>
/// <param name="failed">失败数量</param>
public delegate void MultiInfoTwo(int finish, int count, int success, int failed);
/// <summary>
/// 异常发生时事件
/// </summary>
public event MultiInfo OnExceptionOccur;
/// <summary>
/// 报告处理进度时发生
/// </summary>
public event MultiInfoTwo OnReportProgress;
/// <summary>
/// 已处理完成数量,无论是否异常
/// </summary>
private int m_finishCount = 0;
/// <summary>
/// 处理完成并实现操作数量
/// </summary>
private int m_successCount = 0;
/// <summary>
/// 处理过程中异常数量
/// </summary>
private int m_failedCount = 0;
/// <summary>
/// 用于触发事件的混合线程锁
/// </summary>
private SimpleHybirdLock HybirdLock = new SimpleHybirdLock();
/// <summary>
/// 指示处理状态是否为暂停状态
/// </summary>
private bool m_isRunningStop = false;
/// <summary>
/// 指示系统是否需要强制退出
/// </summary>
private bool m_isQuit = false;
/// <summary>
/// 在发生错误的时候是否强制退出后续的操作
/// </summary>
private bool m_isQuitAfterException = false;
#region Start Stop Method
/// <summary>
/// 启动多线程进行数据处理
/// </summary>
public void StartOperater()
{
if (Interlocked.CompareExchange(ref m_runStatus, 0, 1) == 0)
{
for (int i = 0; i < m_threadCount; i++)
{
Thread thread = new Thread(new ThreadStart(ThreadBackground));
thread.IsBackground = true;
thread.Start();
}
JustEnded();
}
}
/// <summary>
/// 暂停当前的操作
/// </summary>
public void StopOperater()
{
if (m_runStatus == 1)
{
m_isRunningStop = true;
}
}
/// <summary>
/// 恢复暂停的操作
/// </summary>
public void ResumeOperater()
{
m_isRunningStop = false;
}
/// <summary>
/// 直接手动强制结束操作
/// </summary>
public void EndedOperater()
{
if (m_runStatus == 1)
{
m_isQuit = true;
}
}
/// <summary>
/// 在发生错误的时候是否强制退出后续的操作
/// </summary>
public bool IsQuitAfterException
{
get
{
return m_isQuitAfterException;
}
set
{
m_isQuitAfterException = value;
}
}
#endregion
private void ThreadBackground()
{
while (true)
{
// 检测是否处于暂停的状态
while (m_isRunningStop)
{
;
}
// 提取处理的任务
int index = Interlocked.Decrement(ref m_opCount);
if (index < 0)
{
// 任务完成
break;
}
else
{
T item = m_dataList[index];
bool result = false;
bool isException = false;
try
{
if (!m_isQuit) result = m_operater(item);
}
catch (Exception ex)
{
isException = true;
// 此处必须吞噬所有异常
OnExceptionOccur?.Invoke(item, ex);
// 是否需要退出处理
if (m_isQuitAfterException) EndedOperater();
}
finally
{
// 保证了报告进度时数据的正确性
HybirdLock.Enter();
if (result) m_successCount++;
if (isException) m_failedCount++;
m_finishCount++;
OnReportProgress?.Invoke(m_finishCount, m_dataList.Length, m_successCount, m_failedCount);
HybirdLock.Leave();
}
}
}
JustEnded();
}
private void JustEnded()
{
if (Interlocked.Decrement(ref m_opThreadCount) == 0)
{
// 数据初始化
m_finishCount = 0;
m_failedCount = 0;
m_successCount = 0;
Interlocked.Exchange(ref m_opCount, m_dataList.Length);
Interlocked.Exchange(ref m_opThreadCount, m_threadCount + 1);
// 状态复位
Interlocked.Exchange(ref m_runStatus, 0);
m_isRunningStop = false;
m_isQuit = false;
}
}
}
#endregion
#region
#if !NET35
/// <summary>
/// 一个双检锁的示例,适合一些占内存的静态数据对象,获取的时候才实例化真正的对象
/// </summary>
internal sealed class Singleton
{
private static object m_lock = new object();
private static Singleton SValue = null;
public Singleton()
{
}
public static Singleton GetSingleton()
{
if (SValue != null) return SValue;
Monitor.Enter(m_lock);
if (SValue == null)
{
Singleton temp = new Singleton();
Volatile.Write(ref SValue, temp);
//上述编译不通过,简单的使用下述过程
SValue = new Singleton();
}
Monitor.Exit(m_lock);
return SValue;
}
}
#endif
#endregion
#region
#if !NET35
/// <summary>
/// 一个高级的混合线程同步锁,采用了基元用户加基元内核同步构造实现,并包含了自旋和线程所有权
/// </summary>
internal sealed class AdvancedHybirdLock : IDisposable
{
#region IDisposable Support
private bool disposedValue = false; // 要检测冗余调用
void Dispose( bool disposing )
{
if (!disposedValue)
{
if (disposing)
{
// TODO: 释放托管状态(托管对象)。
}
// TODO: 释放未托管的资源(未托管的对象)并在以下内容中替代终结器。
// TODO: 将大型字段设置为 null。
m_waiterLock.Close( );
disposedValue = true;
}
}
// TODO: 仅当以上 Dispose(bool disposing) 拥有用于释放未托管资源的代码时才替代终结器。
// ~SimpleHybirdLock() {
// // 请勿更改此代码。将清理代码放入以上 Dispose(bool disposing) 中。
// Dispose(false);
// }
// 添加此代码以正确实现可处置模式。
/// <summary>
/// 释放资源
/// </summary>
public void Dispose( )
{
// 请勿更改此代码。将清理代码放入以上 Dispose(bool disposing) 中。
Dispose( true );
// TODO: 如果在以上内容中替代了终结器,则取消注释以下行。
// GC.SuppressFinalize(this);
}
#endregion
/// <summary>
/// 基元用户模式构造同步锁
/// </summary>
private int m_waiters = 0;
/// <summary>
/// 基元内核模式构造同步锁
/// </summary>
private AutoResetEvent m_waiterLock = new AutoResetEvent( false );
/// <summary>
/// 控制自旋的一个字段
/// </summary>
//private int m_spincount = 4000;
/// <summary>
/// 指出哪个线程拥有锁
/// </summary>
private int m_owningThreadId = 0;
/// <summary>
/// 指示锁拥有了多少次
/// </summary>
private int m_recursion = 0;
/// <summary>
/// 获取锁
/// </summary>
public void Enter( )
{
int threadId = Thread.CurrentThread.ManagedThreadId;
if (threadId == m_owningThreadId)
{
m_recursion++;
return;//如果调用线程已经拥有锁,就返回
}
//SpinWait spinwait
if (Interlocked.Increment( ref m_waiters ) == 1) return;//用户锁可以使用的时候,直接返回,第一次调用时发生
//当发生锁竞争时,使用内核同步构造锁
m_waiterLock.WaitOne( );
}
/// <summary>
/// 离开锁
/// </summary>
public void Leave( )
{
if (Interlocked.Decrement( ref m_waiters ) == 0) return;//没有可用的锁的时候
m_waiterLock.Set( );
}
}
#endif
#endregion
}