/// <summary>子类重载实现资源释放逻辑时必须首先调用基类方法</summary>
/// <param name="disposing">从Dispose调用（释放所有资源）还是析构函数调用（释放非托管资源）</param>
protected override void OnDispose(bool disposing)
{
base.OnDispose(disposing);
Clear();
Top = null;
}
void PushNode(SingleListNode <T> node)
{
// 断开关系链，避免内存泄漏
node.Item = default(T);
//// 如果自由节点太多，就不要了
//if (FreeCount > MaxFreeCount) return;
SingleListNode <T> newTop = node;
SingleListNode <T> oldTop;
//SpinWait sw = null;
while (true)
{
// 记住当前
oldTop = FreeTop;
// 设置新对象的下一个节点为当前栈顶
newTop.Next = oldTop;
if (Interlocked.CompareExchange <SingleListNode <T> >(ref FreeTop, newTop, oldTop) == oldTop)
{
break;
}
Thread.SpinWait(1);
//if (sw == null) sw = new SpinWait();
//sw.SpinOnce();
}
Interlocked.Increment(ref FreeCount);
}
/// <summary>在单向链表中查找指定项</summary>
/// <param name="item"></param>
/// <returns></returns>
public Boolean Contain(T item)
{
for (SingleListNode <T> node = this; node != null; node = node.Next)
{
if (Object.Equals(node.Item, item))
{
return(true);
}
}
return(false);
}
/// <summary>清空</summary>
public void Clear()
{
var top = Top;
_Count = 0;
Top = null;
for (var node = top; node != null;)
{
top = node;
node = node.Next;
// 断开关系链，避免内存泄漏
top.Next = null;
top.Item = default(T);
}
}
/// <summary>在单向链表中移除指定项</summary>
/// <param name="item">指定项</param>
/// <returns></returns>
public Boolean Remove(T item)
{
// 当前项
if (Object.Equals(Item, item))
{
return(true);
}
// 下一项
for (SingleListNode <T> node = this; node.Next != null; node = node.Next)
{
if (Object.Equals(node.Next.Item, item))
{
node.Next = node.Next.Next;
return(true);
}
}
return(false);
}
/// <summary>向栈压入一个对象</summary>
/// <remarks>重点解决多线程环境下资源争夺以及使用lock造成性能损失的问题</remarks>
/// <param name="item"></param>
public void Push(T item)
{
Debug.Assert(item != null);
//SingleListNode<T> newTop = PopNode(item);
SingleListNode <T> newTop = UseNodePool ? PopNode(item) : new SingleListNode <T>(item);
SingleListNode <T> oldTop;
//SpinWait sw = null;
while (true)
{
// 记住当前栈顶
oldTop = Top;
// 设置新对象的下一个节点为当前栈顶
newTop.Next = oldTop;
// 比较并交换
// 如果当前栈顶第一个参数的Top等于第三个参数，表明没有被别的线程修改，保存第二参数到第一参数中
// 否则，不相等表明当前栈顶已经被修改过，操作失败，执行循环
if (Interlocked.CompareExchange <SingleListNode <T> >(ref Top, newTop, oldTop) == oldTop)
{
break;
}
Thread.SpinWait(1);
//if (sw == null) sw = new SpinWait();
//sw.SpinOnce();
}
Interlocked.Increment(ref _Count);
// 数量较多时，自动采用节点池
if (!UseNodePool && _Count > 100)
{
UseNodePool = true;
}
}
/// <summary>使用一个对象和下一个节点初始化一个节点</summary>
/// <param name="item"></param>
/// <param name="next"></param>
public SingleListNode(T item, SingleListNode <T> next)
{
Item = item;
Next = next;
}
