SafeHandleCache.cs

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using System;
using System.Runtime.InteropServices;
using System.Threading;
 
namespace Microsoft.Win32.SafeHandles;
 
internal static class SafeHandleCache<T> where T : SafeHandle
{
    private static T s_invalidHandle;
 
    internal static T GetInvalidHandle(Func<T> invalidHandleFactory)
    {
        T val = Volatile.Read(ref s_invalidHandle);
        if (val == null)
        {
            T val2 = invalidHandleFactory();
            val = Interlocked.CompareExchange(ref s_invalidHandle, val2, null);
            if (val == null)
            {
                GC.SuppressFinalize(val2);
                val = val2;
            }
            else
            {
                val2.Dispose();
            }
        }
        return val;
    }
 
    internal static bool IsCachedInvalidHandle(SafeHandle handle)
    {
        return handle == Volatile.Read(ref s_invalidHandle);
    }
}