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using System; |
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using System.Diagnostics; |
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using System.Linq.Expressions; |
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using System.Reflection; |
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using System.Reflection.Emit; |
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namespace PropertyAccessTest |
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{ |
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internal static class Program |
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{ |
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private static void Benchmark(object obj, PropertyInfo prop, Func<object, object> accessor, string name) |
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{ |
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var stopWatch = Stopwatch.StartNew(); |
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for (var i = 0; i < 10000000; i++) |
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{ |
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var result = accessor(obj); |
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} |
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stopWatch.Stop(); |
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Console.WriteLine($"{name}: {stopWatch.ElapsedMilliseconds}ms."); |
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} |
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private static Func<object, object> ByReflection(PropertyInfo prop) |
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=> o => prop.GetGetMethod().Invoke(o, new object[] { }); |
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private static Func<object, object> ByCompile(PropertyInfo prop) |
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{ |
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var param = Expression.Parameter(typeof(object)); |
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var exp = Expression.Lambda<Func<object, object>>( |
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Expression.Convert( |
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Expression.Property( |
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Expression.Convert(param, prop.DeclaringType), |
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prop |
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), |
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typeof(object) |
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), |
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param |
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); |
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return exp.Compile(); |
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} |
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private static Func<object, object> Converter<I, O>(Delegate func) |
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=> o => ((Func<I, O>)func)((I)o); |
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private static Func<object, object> ByCreateDelegate(PropertyInfo prop) |
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{ |
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var converter = typeof(Program) |
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.GetMethod(nameof(Converter), BindingFlags.Static | BindingFlags.NonPublic) |
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.MakeGenericMethod(prop.DeclaringType, prop.PropertyType) |
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.CreateDelegate<Func<Delegate, Func<object, object>>>(); |
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var accessor = prop |
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.GetGetMethod() |
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.CreateDelegate(typeof(Func<,>).MakeGenericType(prop.DeclaringType, prop.PropertyType)); |
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return converter(accessor); |
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} |
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private static Func<object, object> ByEmit(PropertyInfo prop) |
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{ |
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var method = new DynamicMethod("GetProperty", typeof(object), new[] { typeof(object) }); |
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var il = method.GetILGenerator(); |
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var get = prop.GetGetMethod(); |
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il.Emit(OpCodes.Ldarg_0); |
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il.Emit(get.IsVirtual ? OpCodes.Callvirt : OpCodes.Call, get); |
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il.Emit(OpCodes.Ret); |
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return method.CreateDelegate<Func<object, object>>(); |
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} |
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private record Testee(int Value); |
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internal static void Main(string[] args) |
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{ |
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var testee = new Testee(1); |
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var prop = typeof(Testee).GetProperty(nameof(Testee.Value)); |
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Benchmark(testee, prop, ByReflection(prop), "By Reflection"); |
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Benchmark(testee, prop, ByCompile(prop), "By Compile"); |
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Benchmark(testee, prop, ByCreateDelegate(prop), "By CreateDelegate"); |
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Benchmark(testee, prop, ByEmit(prop), "By Emit"); |
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} |
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} |
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} |
