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authorGravatar Jon Skeet <jonskeet@google.com>2015-07-17 08:26:04 +0100
committerGravatar Jon Skeet <jonskeet@google.com>2015-07-17 08:26:04 +0100
commit59eeebee870332ea2b9085688ba524c69311f662 (patch)
tree4300e8aeaff6a3b706c398496a692f5ed25f43b7 /csharp/src/Google.Protobuf/Reflection/ReflectionUtil.cs
parent0f442a7533b1d06ce0092b28f10af481b99e1369 (diff)
First pass at the big rename from ProtocolBuffers to Google.Protobuf.
We'll see what I've missed when CI fails...
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+#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.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<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 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<object, T> CreateFuncObjectT<T>(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(T));
+ return Expression.Lambda<Func<object, 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<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();
+ }
+ }
+} \ No newline at end of file