Interlocked.CompareExchange() 后的讀取值

Question

假設我有一些基類

public abstract class ReflectionSupport
{
    private const int UnresolvedFieldsFlag = -1;
    private const int TrueFieldsFlag = 1;
    private const int FalseFieldsFlag = 0;

    // flag holder
    private int _flagHasFields = UnresolvedFieldsFlag;

    // variant 1 
    protected bool HasFields
    {
       get
       {
          Interlocked.CompareExchange(ref _flagHasFields, ResolveHasFieldsFlag(), UnresolvedFieldsFlag);
          return (TrueFieldsFlag == Volatile.Read(ref _flagHasFields));
       }
    }

    // variant 2
    protected bool HasFields
    {
         get
         {
             Interlocked.CompareExchange(ref _flagHasFields, ResolveHasFieldsFlag(), UnresolvedFieldsFlag);
             return (TrueFieldsFlag == _flagHasFields);
         }
    }

    private int ResolveHasFieldsFlag()
    { 
         // here reflection is used 
         // to analyze current instance 
         // and returns TRUE-flag if instance 
         // contains field
    }
}

我的問題 - 在Interlocked.CompareExchange()之后我應該使用什么變體HasFields屬性。 存儲在字段中的標志值是聯鎖操作后的最新值還是我將不得不使用易失性讀取？

Answer 1

根據您的評論信息，您可以通過以下方式使用Lazy

public abstract class ReflectionSupport
{
    private readonly Lazy<bool> _hasFields;
    protected bool HasFields => _hasFields.Value;

    protected ReflectionSupport()
    {
        _hasFields = new Lazy<bool>(HasFieldsFlag);
    }

    private bool HasFieldsFlag()
    { 
        // just return true if instance 
        // contains field
    }
}

如您所見，不再需要UnresolvedFieldsFlag ，因此可以使用bool代替