netcore/System.Private.CoreLib/shared/System/Diagnostics/Tracing/TraceLogging/SimpleEventTypes.cs

   1 // Licensed to the .NET Foundation under one or more agreements.
   2 // The .NET Foundation licenses this file to you under the MIT license.
   3 // See the LICENSE file in the project root for more information.
   4
   5 using System;
   6 using System.Diagnostics;
   7 using Interlocked = System.Threading.Interlocked;
   8
   9 #if ES_BUILD_STANDALONE
  10 namespace Microsoft.Diagnostics.Tracing
  11 #else
  12 namespace System.Diagnostics.Tracing
  13 #endif
  14 {
  15     /// <summary>
  16     /// TraceLogging: Contains the metadata needed to emit an event, optimized
  17     /// for events with one top-level compile-time-typed payload object.
  18     /// </summary>
  19     /// <typeparam name="T">
  20     /// Type of the top-level payload object. Should be EmptyStruct if the
  21     /// event has no payload.
  22     /// </typeparam>
  23     internal static class SimpleEventTypes<T>
  24     {
  25         private static TraceLoggingEventTypes? instance;
  26
  27         public static TraceLoggingEventTypes Instance => instance ?? InitInstance();
  28
  29         private static TraceLoggingEventTypes InitInstance()
  30         {
  31             var info = TraceLoggingTypeInfo.GetInstance(typeof(T), null);
  32             var newInstance = new TraceLoggingEventTypes(info.Name, info.Tags, new TraceLoggingTypeInfo[] { info });
  33             Interlocked.CompareExchange(ref instance, newInstance, null);
  34             Debug.Assert(instance != null);
  35             return instance;
  36         }
  37     }
  38 }