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Diffstat (limited to 'csharp/src/Google.Protobuf/Reflection/ReflectionUtil.cs')
| -rw-r--r-- | csharp/src/Google.Protobuf/Reflection/ReflectionUtil.cs | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/csharp/src/Google.Protobuf/Reflection/ReflectionUtil.cs b/csharp/src/Google.Protobuf/Reflection/ReflectionUtil.cs new file mode 100644 index 00000000..df820ca3 --- /dev/null +++ b/csharp/src/Google.Protobuf/Reflection/ReflectionUtil.cs @@ -0,0 +1,107 @@ +#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.Collections.Generic; +using System.Linq.Expressions; +using System.Reflection; + +namespace Google.Protobuf.Reflection +{ + /// <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<IMessage, object> CreateFuncIMessageObject(MethodInfo method) + { + ParameterExpression parameter = Expression.Parameter(typeof(IMessage), "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<IMessage, object>>(upcast, parameter).Compile(); + } + + /// <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 the specified type. + /// </summary> + internal static Func<IMessage, T> CreateFuncIMessageT<T>(MethodInfo method) + { + ParameterExpression parameter = Expression.Parameter(typeof(IMessage), "p"); + Expression downcast = Expression.Convert(parameter, method.DeclaringType); + Expression call = Expression.Call(downcast, method); + Expression upcast = Expression.Convert(call, typeof(T)); + return Expression.Lambda<Func<IMessage, T>>(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<IMessage, object> CreateActionIMessageObject(MethodInfo method) + { + ParameterExpression targetParameter = Expression.Parameter(typeof(IMessage), "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<IMessage, 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<IMessage> CreateActionIMessage(MethodInfo method) + { + ParameterExpression targetParameter = Expression.Parameter(typeof(IMessage), "target"); + Expression castTarget = Expression.Convert(targetParameter, method.DeclaringType); + Expression call = Expression.Call(castTarget, method); + return Expression.Lambda<Action<IMessage>>(call, targetParameter).Compile(); + } + } +}
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