364 lines
16 KiB
C#
364 lines
16 KiB
C#
#region Copyright notice and license
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// Protocol Buffers - Google's data interchange format
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// Copyright 2008 Google Inc. All rights reserved.
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// https://developers.google.com/protocol-buffers/
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived from
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// this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#endregion
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using LC.Google.Protobuf.Compatibility;
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using System;
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using System.Reflection;
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namespace LC.Google.Protobuf.Reflection
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{
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/// <summary>
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/// The methods in this class are somewhat evil, and should not be tampered with lightly.
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/// Basically they allow the creation of relatively weakly typed delegates from MethodInfos
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/// which are more strongly typed. They do this by creating an appropriate strongly typed
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/// delegate from the MethodInfo, and then calling that within an anonymous method.
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/// Mind-bending stuff (at least to your humble narrator) but the resulting delegates are
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/// very fast compared with calling Invoke later on.
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/// </summary>
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internal static class ReflectionUtil
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{
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static ReflectionUtil()
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{
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ForceInitialize<string>(); // Handles all reference types
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ForceInitialize<int>();
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ForceInitialize<long>();
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ForceInitialize<uint>();
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ForceInitialize<ulong>();
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ForceInitialize<float>();
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ForceInitialize<double>();
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ForceInitialize<bool>();
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ForceInitialize<int?>();
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ForceInitialize<long?>();
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ForceInitialize<uint?>();
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ForceInitialize<ulong?>();
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ForceInitialize<float?>();
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ForceInitialize<double?>();
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ForceInitialize<bool?>();
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ForceInitialize<SampleEnum>();
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SampleEnumMethod();
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}
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internal static void ForceInitialize<T>() => new ReflectionHelper<IMessage, T>();
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/// <summary>
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/// Empty Type[] used when calling GetProperty to force property instead of indexer fetching.
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/// </summary>
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internal static readonly Type[] EmptyTypes = new Type[0];
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/// <summary>
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/// Creates a delegate which will cast the argument to the type that declares the method,
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/// call the method on it, then convert the result to object.
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/// </summary>
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/// <param name="method">The method to create a delegate for, which must be declared in an IMessage
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/// implementation.</param>
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internal static Func<IMessage, object> CreateFuncIMessageObject(MethodInfo method) =>
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GetReflectionHelper(method.DeclaringType, method.ReturnType).CreateFuncIMessageObject(method);
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/// <summary>
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/// Creates a delegate which will cast the argument to the type that declares the method,
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/// call the method on it, then convert the result to the specified type. The method is expected
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/// to actually return an enum (because of where we're calling it - for oneof cases). Sometimes that
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/// means we need some extra work to perform conversions.
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/// </summary>
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/// <param name="method">The method to create a delegate for, which must be declared in an IMessage
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/// implementation.</param>
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internal static Func<IMessage, int> CreateFuncIMessageInt32(MethodInfo method) =>
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GetReflectionHelper(method.DeclaringType, method.ReturnType).CreateFuncIMessageInt32(method);
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/// <summary>
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/// Creates a delegate which will execute the given method after casting the first argument to
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/// the type that declares the method, and the second argument to the first parameter type of the method.
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/// </summary>
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/// <param name="method">The method to create a delegate for, which must be declared in an IMessage
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/// implementation.</param>
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internal static Action<IMessage, object> CreateActionIMessageObject(MethodInfo method) =>
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GetReflectionHelper(method.DeclaringType, method.GetParameters()[0].ParameterType).CreateActionIMessageObject(method);
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/// <summary>
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/// Creates a delegate which will execute the given method after casting the first argument to
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/// type that declares the method.
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/// </summary>
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/// <param name="method">The method to create a delegate for, which must be declared in an IMessage
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/// implementation.</param>
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internal static Action<IMessage> CreateActionIMessage(MethodInfo method) =>
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GetReflectionHelper(method.DeclaringType, typeof(object)).CreateActionIMessage(method);
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internal static Func<IMessage, bool> CreateFuncIMessageBool(MethodInfo method) =>
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GetReflectionHelper(method.DeclaringType, method.ReturnType).CreateFuncIMessageBool(method);
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internal static Func<IMessage, bool> CreateIsInitializedCaller(Type msg) =>
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((IExtensionSetReflector)Activator.CreateInstance(typeof(ExtensionSetReflector<>).MakeGenericType(msg))).CreateIsInitializedCaller();
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/// <summary>
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/// Creates a delegate which will execute the given method after casting the first argument to
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/// the type that declares the method, and the second argument to the first parameter type of the method.
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/// </summary>
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internal static IExtensionReflectionHelper CreateExtensionHelper(Extension extension) =>
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(IExtensionReflectionHelper)Activator.CreateInstance(typeof(ExtensionReflectionHelper<,>).MakeGenericType(extension.TargetType, extension.GetType().GenericTypeArguments[1]), extension);
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/// <summary>
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/// Creates a reflection helper for the given type arguments. Currently these are created on demand
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/// rather than cached; this will be "busy" when initially loading a message's descriptor, but after that
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/// they can be garbage collected. We could cache them by type if that proves to be important, but creating
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/// an object is pretty cheap.
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/// </summary>
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private static IReflectionHelper GetReflectionHelper(Type t1, Type t2) =>
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(IReflectionHelper) Activator.CreateInstance(typeof(ReflectionHelper<,>).MakeGenericType(t1, t2));
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// Non-generic interface allowing us to use an instance of ReflectionHelper<T1, T2> without statically
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// knowing the types involved.
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private interface IReflectionHelper
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{
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Func<IMessage, int> CreateFuncIMessageInt32(MethodInfo method);
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Action<IMessage> CreateActionIMessage(MethodInfo method);
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Func<IMessage, object> CreateFuncIMessageObject(MethodInfo method);
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Action<IMessage, object> CreateActionIMessageObject(MethodInfo method);
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Func<IMessage, bool> CreateFuncIMessageBool(MethodInfo method);
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}
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internal interface IExtensionReflectionHelper
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{
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object GetExtension(IMessage message);
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void SetExtension(IMessage message, object value);
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bool HasExtension(IMessage message);
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void ClearExtension(IMessage message);
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}
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private interface IExtensionSetReflector
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{
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Func<IMessage, bool> CreateIsInitializedCaller();
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}
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private class ReflectionHelper<T1, T2> : IReflectionHelper
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{
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public Func<IMessage, int> CreateFuncIMessageInt32(MethodInfo method)
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{
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// On pleasant runtimes, we can create a Func<int> from a method returning
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// an enum based on an int. That's the fast path.
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if (CanConvertEnumFuncToInt32Func)
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{
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var del = (Func<T1, int>) method.CreateDelegate(typeof(Func<T1, int>));
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return message => del((T1) message);
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}
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else
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{
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// On some runtimes (e.g. old Mono) the return type has to be exactly correct,
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// so we go via boxing. Reflection is already fairly inefficient, and this is
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// only used for one-of case checking, fortunately.
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var del = (Func<T1, T2>) method.CreateDelegate(typeof(Func<T1, T2>));
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return message => (int) (object) del((T1) message);
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}
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}
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public Action<IMessage> CreateActionIMessage(MethodInfo method)
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{
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var del = (Action<T1>) method.CreateDelegate(typeof(Action<T1>));
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return message => del((T1) message);
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}
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public Func<IMessage, object> CreateFuncIMessageObject(MethodInfo method)
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{
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var del = (Func<T1, T2>) method.CreateDelegate(typeof(Func<T1, T2>));
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return message => del((T1) message);
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}
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public Action<IMessage, object> CreateActionIMessageObject(MethodInfo method)
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{
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var del = (Action<T1, T2>) method.CreateDelegate(typeof(Action<T1, T2>));
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return (message, arg) => del((T1) message, (T2) arg);
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}
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public Func<IMessage, bool> CreateFuncIMessageBool(MethodInfo method)
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{
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var del = (Func<T1, bool>)method.CreateDelegate(typeof(Func<T1, bool>));
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return message => del((T1)message);
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}
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}
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private class ExtensionReflectionHelper<T1, T3> : IExtensionReflectionHelper
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where T1 : IExtendableMessage<T1>
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{
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private readonly Extension extension;
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public ExtensionReflectionHelper(Extension extension)
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{
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this.extension = extension;
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}
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public object GetExtension(IMessage message)
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{
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if (!(message is T1))
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{
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throw new InvalidCastException("Cannot access extension on message that isn't IExtensionMessage");
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}
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T1 extensionMessage = (T1)message;
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if (extension is Extension<T1, T3>)
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{
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return extensionMessage.GetExtension(extension as Extension<T1, T3>);
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}
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else if (extension is RepeatedExtension<T1, T3>)
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{
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return extensionMessage.GetOrInitializeExtension(extension as RepeatedExtension<T1, T3>);
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}
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else
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{
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throw new InvalidCastException("The provided extension is not a valid extension identifier type");
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}
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}
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public bool HasExtension(IMessage message)
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{
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if (!(message is T1))
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{
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throw new InvalidCastException("Cannot access extension on message that isn't IExtensionMessage");
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}
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T1 extensionMessage = (T1)message;
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if (extension is Extension<T1, T3>)
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{
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return extensionMessage.HasExtension(extension as Extension<T1, T3>);
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}
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else if (extension is RepeatedExtension<T1, T3>)
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{
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throw new InvalidOperationException("HasValue is not implemented for repeated extensions");
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}
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else
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{
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throw new InvalidCastException("The provided extension is not a valid extension identifier type");
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}
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}
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public void SetExtension(IMessage message, object value)
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{
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if (!(message is T1))
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{
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throw new InvalidCastException("Cannot access extension on message that isn't IExtensionMessage");
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}
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T1 extensionMessage = (T1)message;
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if (extension is Extension<T1, T3>)
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{
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extensionMessage.SetExtension(extension as Extension<T1, T3>, (T3)value);
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}
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else if (extension is RepeatedExtension<T1, T3>)
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{
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throw new InvalidOperationException("SetValue is not implemented for repeated extensions");
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}
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else
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{
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throw new InvalidCastException("The provided extension is not a valid extension identifier type");
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}
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}
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public void ClearExtension(IMessage message)
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{
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if (!(message is T1))
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{
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throw new InvalidCastException("Cannot access extension on message that isn't IExtensionMessage");
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}
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T1 extensionMessage = (T1)message;
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if (extension is Extension<T1, T3>)
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{
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extensionMessage.ClearExtension(extension as Extension<T1, T3>);
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}
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else if (extension is RepeatedExtension<T1, T3>)
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{
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extensionMessage.GetExtension(extension as RepeatedExtension<T1, T3>).Clear();
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}
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else
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{
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throw new InvalidCastException("The provided extension is not a valid extension identifier type");
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}
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}
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}
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private class ExtensionSetReflector<T1> : IExtensionSetReflector where T1 : IExtendableMessage<T1>
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{
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public Func<IMessage, bool> CreateIsInitializedCaller()
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{
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var prop = typeof(T1).GetTypeInfo().GetDeclaredProperty("_Extensions");
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#if NET35
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var getFunc = (Func<T1, ExtensionSet<T1>>)prop.GetGetMethod(true).CreateDelegate(typeof(Func<T1, ExtensionSet<T1>>));
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#else
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var getFunc = (Func<T1, ExtensionSet<T1>>)prop.GetMethod.CreateDelegate(typeof(Func<T1, ExtensionSet<T1>>));
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#endif
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var initializedFunc = (Func<ExtensionSet<T1>, bool>)
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typeof(ExtensionSet<T1>)
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.GetTypeInfo()
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.GetDeclaredMethod("IsInitialized")
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.CreateDelegate(typeof(Func<ExtensionSet<T1>, bool>));
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return (m) => {
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var set = getFunc((T1)m);
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return set == null || initializedFunc(set);
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};
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}
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}
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// Runtime compatibility checking code - see ReflectionHelper<T1, T2>.CreateFuncIMessageInt32 for
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// details about why we're doing this.
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// Deliberately not inside the generic type. We only want to check this once.
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private static bool CanConvertEnumFuncToInt32Func { get; } = CheckCanConvertEnumFuncToInt32Func();
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private static bool CheckCanConvertEnumFuncToInt32Func()
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{
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try
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{
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// Try to do the conversion using reflection, so we can see whether it's supported.
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MethodInfo method = typeof(ReflectionUtil).GetMethod(nameof(SampleEnumMethod));
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// If this passes, we're in a reasonable runtime.
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method.CreateDelegate(typeof(Func<int>));
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return true;
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}
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catch (ArgumentException)
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{
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return false;
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}
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}
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public enum SampleEnum
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{
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X
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}
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// Public to make the reflection simpler.
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public static SampleEnum SampleEnumMethod() => SampleEnum.X;
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}
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}
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