63 lines
2.5 KiB
C#
63 lines
2.5 KiB
C#
// Copyright (c) Ben A Adams. All rights reserved.
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// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
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using System.Collections.Generic;
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using System.Reflection;
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using System.Threading;
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namespace System.Diagnostics.Internal
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{
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/// <summary>
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/// A helper class that contains utilities methods for dealing with reflection.
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/// </summary>
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public static class ReflectionHelper
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{
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private static PropertyInfo? tranformerNamesLazyPropertyInfo;
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/// <summary>
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/// Returns true if the <paramref name="type"/> is a value tuple type.
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/// </summary>
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public static bool IsValueTuple(this Type type)
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{
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return type.Namespace == "System" && type.Name.Contains("ValueTuple`");
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}
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/// <summary>
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/// Returns true if the given <paramref name="attribute"/> is of type <code>TupleElementNameAttribute</code>.
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/// </summary>
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/// <remarks>
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/// To avoid compile-time depencency hell with System.ValueTuple, this method uses reflection and not checks statically that
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/// the given <paramref name="attribute"/> is <code>TupleElementNameAttribute</code>.
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/// </remarks>
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public static bool IsTupleElementNameAttribue(this Attribute attribute)
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{
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var attributeType = attribute.GetType();
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return attributeType.Namespace == "System.Runtime.CompilerServices" &&
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attributeType.Name == "TupleElementNamesAttribute";
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}
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/// <summary>
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/// Returns 'TransformNames' property value from a given <paramref name="attribute"/>.
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/// </summary>
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/// <remarks>
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/// To avoid compile-time depencency hell with System.ValueTuple, this method uses reflection
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/// instead of casting the attribute to a specific type.
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/// </remarks>
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public static IList<string>? GetTransformerNames(this Attribute attribute)
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{
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Debug.Assert(attribute.IsTupleElementNameAttribue());
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var propertyInfo = GetTransformNamesPropertyInfo(attribute.GetType());
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return propertyInfo?.GetValue(attribute) as IList<string>;
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}
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private static PropertyInfo? GetTransformNamesPropertyInfo(Type attributeType)
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{
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#pragma warning disable 8634
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return LazyInitializer.EnsureInitialized(ref tranformerNamesLazyPropertyInfo,
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#pragma warning restore 8634
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() => attributeType.GetProperty("TransformNames", BindingFlags.Instance | BindingFlags.Public));
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}
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}
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}
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