using System;
using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.Threading;
using System.Xml.Serialization;
using NewLife.Log;
#nullable enable
namespace NewLife
{
/// <summary>具有是否已释放和释放后事件的接口</summary>
public interface IDisposable2 : IDisposable
{
/// <summary>是否已经释放</summary>
[XmlIgnore]
Boolean Disposed { get; }
/// <summary>被销毁时触发事件</summary>
event EventHandler OnDisposed;
}
/// <summary>具有销毁资源处理的抽象基类</summary>
/// <example>
/// <code>
/// /// <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)。
/// /// 因为该方法只会被调用一次,所以该参数的意义不太大。</param>
/// protected override void Dispose(bool disposing)
/// {
/// base.OnDispose(disposing);
///
/// if (disposing)
/// {
/// // 如果是构造函数进来,不执行这里的代码
/// }
/// }
/// </code>
/// </example>
public abstract class DisposeBase : IDisposable2
{
#region 释放资源
/// <summary>释放资源</summary>
public void Dispose()
{
Dispose(true);
// 告诉GC,不要调用析构函数
GC.SuppressFinalize(this);
}
[NonSerialized]
private Int32 _disposed = 0;
/// <summary>是否已经释放</summary>
[XmlIgnore]
public Boolean Disposed => _disposed > 0;
/// <summary>被销毁时触发事件</summary>
[field: NonSerialized]
public event EventHandler? OnDisposed;
/// <summary>释放资源,参数表示是否由Dispose调用。重载时先调用基类方法</summary>
/// <param name="disposing"></param>
protected virtual void Dispose(Boolean disposing)
{
if (Interlocked.CompareExchange(ref _disposed, 1, 0) != 0) return;
if (disposing)
{
// 释放托管资源
//OnDispose(disposing);
// 告诉GC,不要调用析构函数
GC.SuppressFinalize(this);
}
// 释放非托管资源
OnDisposed?.Invoke(this, EventArgs.Empty);
}
/// <summary>释放资源,参数表示是否由Dispose调用。该方法保证OnDispose只被调用一次!</summary>
/// <param name="disposing"></param>
[Obsolete("=>Dispose")]
protected virtual void OnDispose(Boolean disposing) { }
/// <summary>析构函数</summary>
/// <remarks>
/// 如果忘记调用Dispose,这里会释放非托管资源
/// 如果曾经调用过Dispose,因为GC.SuppressFinalize(this),不会再调用该析构函数
/// </remarks>
~DisposeBase() { Dispose(false); }
#endregion
}
/// <summary>销毁助手。扩展方法专用</summary>
[EditorBrowsable(EditorBrowsableState.Advanced)]
public static class DisposeHelper
{
/// <summary>尝试销毁对象,如果有<see cref="IDisposable"/>则调用</summary>
/// <param name="obj"></param>
/// <returns></returns>
public static Object? TryDispose(this Object? obj)
{
if (obj == null) return obj;
// 列表元素销毁
if (obj is IEnumerable ems)
{
// 对于枚举成员,先考虑添加到列表,再逐个销毁,避免销毁过程中集合改变
if (!(obj is IList list))
{
list = new List<Object>();
foreach (var item in ems)
{
if (item is IDisposable) list.Add(item);
}
}
foreach (var item in list)
{
if (item is IDisposable disp)
{
try
{
//(item as IDisposable).TryDispose();
// 只需要释放一层,不需要递归
// 因为一般每一个对象负责自己内部成员的释放
disp.Dispose();
}
catch { }
}
}
}
// 对象销毁
if (obj is IDisposable disp2)
{
try
{
disp2.Dispose();
}
catch { }
}
return obj;
}
}
}
#nullable restore
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