86 lines
3.0 KiB
C#
86 lines
3.0 KiB
C#
// This file is part of YamlDotNet - A .NET library for YAML.
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// Copyright (c) Antoine Aubry and contributors
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy of
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// this software and associated documentation files (the "Software"), to deal in
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// the Software without restriction, including without limitation the rights to
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// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
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// of the Software, and to permit persons to whom the Software is furnished to do
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// so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in all
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// copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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// SOFTWARE.
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#if !NET20
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using System;
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using System.Diagnostics.CodeAnalysis;
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using System.Linq.Expressions;
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using System.Reflection;
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namespace YamlDotNet.Helpers
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{
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public static class ExpressionExtensions
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{
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/// <summary>
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/// Returns the <see cref="PropertyInfo" /> that describes the property that
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/// is being returned in an expression in the form:
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/// <code>
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/// x => x.SomeProperty
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/// </code>
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/// </summary>
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public static PropertyInfo AsProperty(this LambdaExpression propertyAccessor)
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{
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var property = TryGetMemberExpression<PropertyInfo>(propertyAccessor);
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if (property == null)
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{
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throw new ArgumentException("Expected a lambda expression in the form: x => x.SomeProperty", nameof(propertyAccessor));
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}
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return property;
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}
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[return: MaybeNull]
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private static TMemberInfo TryGetMemberExpression<TMemberInfo>(LambdaExpression lambdaExpression)
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where TMemberInfo : MemberInfo
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{
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if (lambdaExpression.Parameters.Count != 1)
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{
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return null;
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}
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var body = lambdaExpression.Body;
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if (body is UnaryExpression castExpression)
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{
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if (castExpression.NodeType != ExpressionType.Convert)
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{
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return null;
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}
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body = castExpression.Operand;
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}
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if (body is MemberExpression memberExpression)
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{
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if (memberExpression.Expression != lambdaExpression.Parameters[0])
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{
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return null;
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}
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return memberExpression.Member as TMemberInfo;
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}
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return null;
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}
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}
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}
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#endif
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