#region Copyright notice and license | |
// Protocol Buffers - Google's data interchange format | |
// Copyright 2008 Google Inc. All rights reserved. | |
// https://developers.google.com/protocol-buffers/ | |
// | |
// Redistribution and use in source and binary forms, with or without | |
// modification, are permitted provided that the following conditions are | |
// met: | |
// | |
// * Redistributions of source code must retain the above copyright | |
// notice, this list of conditions and the following disclaimer. | |
// * Redistributions in binary form must reproduce the above | |
// copyright notice, this list of conditions and the following disclaimer | |
// in the documentation and/or other materials provided with the | |
// distribution. | |
// * Neither the name of Google Inc. nor the names of its | |
// contributors may be used to endorse or promote products derived from | |
// this software without specific prior written permission. | |
// | |
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR | |
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT | |
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT | |
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
#endregion | |
using System; | |
using System.Linq.Expressions; | |
using System.Reflection; | |
namespace Google.Protobuf.FieldAccess | |
{ | |
/// <summary> | |
/// The methods in this class are somewhat evil, and should not be tampered with lightly. | |
/// Basically they allow the creation of relatively weakly typed delegates from MethodInfos | |
/// which are more strongly typed. They do this by creating an appropriate strongly typed | |
/// delegate from the MethodInfo, and then calling that within an anonymous method. | |
/// Mind-bending stuff (at least to your humble narrator) but the resulting delegates are | |
/// very fast compared with calling Invoke later on. | |
/// </summary> | |
internal static class ReflectionUtil | |
{ | |
/// <summary> | |
/// Empty Type[] used when calling GetProperty to force property instead of indexer fetching. | |
/// </summary> | |
internal static readonly Type[] EmptyTypes = new Type[0]; | |
/// <summary> | |
/// Creates a delegate which will cast the argument to the appropriate method target type, | |
/// call the method on it, then convert the result to object. | |
/// </summary> | |
internal static Func<object, object> CreateFuncObjectObject(MethodInfo method) | |
{ | |
ParameterExpression parameter = Expression.Parameter(typeof(object), "p"); | |
Expression downcast = Expression.Convert(parameter, method.DeclaringType); | |
Expression call = Expression.Call(downcast, method); | |
Expression upcast = Expression.Convert(call, typeof(object)); | |
return Expression.Lambda<Func<object, object>>(upcast, parameter).Compile(); | |
} | |
/// <summary> | |
/// Creates a delegate which will execute the given method after casting the first argument to | |
/// the target type of the method, and the second argument to the first parameter type of the method. | |
/// </summary> | |
internal static Action<object, object> CreateActionObjectObject(MethodInfo method) | |
{ | |
ParameterExpression targetParameter = Expression.Parameter(typeof(object), "target"); | |
ParameterExpression argParameter = Expression.Parameter(typeof(object), "arg"); | |
Expression castTarget = Expression.Convert(targetParameter, method.DeclaringType); | |
Expression castArgument = Expression.Convert(argParameter, method.GetParameters()[0].ParameterType); | |
Expression call = Expression.Call(castTarget, method, castArgument); | |
return Expression.Lambda<Action<object, object>>(call, targetParameter, argParameter).Compile(); | |
} | |
/// <summary> | |
/// Creates a delegate which will execute the given method after casting the first argument to | |
/// the target type of the method. | |
/// </summary> | |
internal static Action<object> CreateActionObject(MethodInfo method) | |
{ | |
ParameterExpression targetParameter = Expression.Parameter(typeof(object), "target"); | |
Expression castTarget = Expression.Convert(targetParameter, method.DeclaringType); | |
Expression call = Expression.Call(castTarget, method); | |
return Expression.Lambda<Action<object>>(call, targetParameter).Compile(); | |
} | |
} | |
} |