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author | Jan Tattermusch <jtattermusch@users.noreply.github.com> | 2018-03-27 13:31:29 +0200 |
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committer | GitHub <noreply@github.com> | 2018-03-27 13:31:29 +0200 |
commit | 2537bea6b855d195f046f2ad0d9659ff63b6c1cc (patch) | |
tree | c97657feb98f5567c1c2e518c7bb5f79f60067a6 | |
parent | 63bba9bba10eec02201f7bfa309da4f7089554ec (diff) | |
parent | 9c05c353414cc4439085151362756536511c2f0d (diff) | |
download | protobuf-2537bea6b855d195f046f2ad0d9659ff63b6c1cc.tar.gz protobuf-2537bea6b855d195f046f2ad0d9659ff63b6c1cc.tar.bz2 protobuf-2537bea6b855d195f046f2ad0d9659ff63b6c1cc.zip |
Merge pull request #3794 from jskeet/reflection
Change C# reflection to avoid using expression trees
-rw-r--r-- | Makefile.am | 1 | ||||
-rw-r--r-- | csharp/src/Google.Protobuf/Compatibility/MethodInfoExtensions.cs | 47 | ||||
-rw-r--r-- | csharp/src/Google.Protobuf/Reflection/OneofAccessor.cs | 2 | ||||
-rw-r--r-- | csharp/src/Google.Protobuf/Reflection/ReflectionUtil.cs | 156 |
4 files changed, 166 insertions, 40 deletions
diff --git a/Makefile.am b/Makefile.am index 8e85484b..41b68b2b 100644 --- a/Makefile.am +++ b/Makefile.am @@ -133,6 +133,7 @@ csharp_EXTRA_DIST= \ csharp/src/Google.Protobuf/Collections/ProtobufEqualityComparers.cs \ csharp/src/Google.Protobuf/Collections/ReadOnlyDictionary.cs \ csharp/src/Google.Protobuf/Collections/RepeatedField.cs \ + csharp/src/Google.Protobuf/Compatibility/MethodInfoExtensions.cs \ csharp/src/Google.Protobuf/Compatibility/PropertyInfoExtensions.cs \ csharp/src/Google.Protobuf/Compatibility/StreamExtensions.cs \ csharp/src/Google.Protobuf/Compatibility/TypeExtensions.cs \ diff --git a/csharp/src/Google.Protobuf/Compatibility/MethodInfoExtensions.cs b/csharp/src/Google.Protobuf/Compatibility/MethodInfoExtensions.cs new file mode 100644 index 00000000..7b946cb6 --- /dev/null +++ b/csharp/src/Google.Protobuf/Compatibility/MethodInfoExtensions.cs @@ -0,0 +1,47 @@ +#region Copyright notice and license +// Protocol Buffers - Google's data interchange format +// Copyright 2017 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 + +#if NET35 +using System; +using System.Reflection; + +namespace Google.Protobuf.Compatibility +{ + // .NET Core (at least netstandard1.0) doesn't have Delegate.CreateDelegate, and .NET 3.5 doesn't have + // MethodInfo.CreateDelegate. Proxy from one to the other on .NET 3.5... + internal static class MethodInfoExtensions + { + internal static Delegate CreateDelegate(this MethodInfo method, Type type) => + Delegate.CreateDelegate(type, method); + } +} +#endif diff --git a/csharp/src/Google.Protobuf/Reflection/OneofAccessor.cs b/csharp/src/Google.Protobuf/Reflection/OneofAccessor.cs index 8714ab18..97596218 100644 --- a/csharp/src/Google.Protobuf/Reflection/OneofAccessor.cs +++ b/csharp/src/Google.Protobuf/Reflection/OneofAccessor.cs @@ -52,7 +52,7 @@ namespace Google.Protobuf.Reflection throw new ArgumentException("Cannot read from property"); } this.descriptor = descriptor; - caseDelegate = ReflectionUtil.CreateFuncIMessageT<int>(caseProperty.GetGetMethod()); + caseDelegate = ReflectionUtil.CreateFuncIMessageInt32(caseProperty.GetGetMethod()); this.descriptor = descriptor; clearDelegate = ReflectionUtil.CreateActionIMessage(clearMethod); diff --git a/csharp/src/Google.Protobuf/Reflection/ReflectionUtil.cs b/csharp/src/Google.Protobuf/Reflection/ReflectionUtil.cs index df820ca3..1afaa90c 100644 --- a/csharp/src/Google.Protobuf/Reflection/ReflectionUtil.cs +++ b/csharp/src/Google.Protobuf/Reflection/ReflectionUtil.cs @@ -30,11 +30,14 @@ // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. #endregion +using Google.Protobuf.Compatibility; using System; -using System.Collections.Generic; -using System.Linq.Expressions; using System.Reflection; +#if NET35 +using Google.Protobuf.Compatibility; +#endif + namespace Google.Protobuf.Reflection { /// <summary> @@ -53,55 +56,130 @@ namespace Google.Protobuf.Reflection internal static readonly Type[] EmptyTypes = new Type[0]; /// <summary> - /// Creates a delegate which will cast the argument to the appropriate method target type, + /// Creates a delegate which will cast the argument to the type that declares the method, /// 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(); - } + /// <param name="method">The method to create a delegate for, which must be declared in an IMessage + /// implementation.</param> + internal static Func<IMessage, object> CreateFuncIMessageObject(MethodInfo method) => + GetReflectionHelper(method.DeclaringType, method.ReturnType).CreateFuncIMessageObject(method); /// <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. + /// Creates a delegate which will cast the argument to the type that declares the method, + /// call the method on it, then convert the result to the specified type. The method is expected + /// to actually return an enum (because of where we're calling it - for oneof cases). Sometimes that + /// means we need some extra work to perform conversions. /// </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(); - } + /// <param name="method">The method to create a delegate for, which must be declared in an IMessage + /// implementation.</param> + internal static Func<IMessage, int> CreateFuncIMessageInt32(MethodInfo method) => + GetReflectionHelper(method.DeclaringType, method.ReturnType).CreateFuncIMessageInt32(method); /// <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. + /// the type that declares 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(); - } + /// <param name="method">The method to create a delegate for, which must be declared in an IMessage + /// implementation.</param> + internal static Action<IMessage, object> CreateActionIMessageObject(MethodInfo method) => + GetReflectionHelper(method.DeclaringType, method.GetParameters()[0].ParameterType).CreateActionIMessageObject(method); /// <summary> /// Creates a delegate which will execute the given method after casting the first argument to - /// the target type of the method. + /// type that declares the method. /// </summary> - internal static Action<IMessage> CreateActionIMessage(MethodInfo method) + /// <param name="method">The method to create a delegate for, which must be declared in an IMessage + /// implementation.</param> + internal static Action<IMessage> CreateActionIMessage(MethodInfo method) => + GetReflectionHelper(method.DeclaringType, typeof(object)).CreateActionIMessage(method); + + /// <summary> + /// Creates a reflection helper for the given type arguments. Currently these are created on demand + /// rather than cached; this will be "busy" when initially loading a message's descriptor, but after that + /// they can be garbage collected. We could cache them by type if that proves to be important, but creating + /// an object is pretty cheap. + /// </summary> + private static IReflectionHelper GetReflectionHelper(Type t1, Type t2) => + (IReflectionHelper) Activator.CreateInstance(typeof(ReflectionHelper<,>).MakeGenericType(t1, t2)); + + // Non-generic interface allowing us to use an instance of ReflectionHelper<T1, T2> without statically + // knowing the types involved. + private interface IReflectionHelper + { + Func<IMessage, int> CreateFuncIMessageInt32(MethodInfo method); + Action<IMessage> CreateActionIMessage(MethodInfo method); + Func<IMessage, object> CreateFuncIMessageObject(MethodInfo method); + Action<IMessage, object> CreateActionIMessageObject(MethodInfo method); + } + + private class ReflectionHelper<T1, T2> : IReflectionHelper { - 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(); - } + + public Func<IMessage, int> CreateFuncIMessageInt32(MethodInfo method) + { + // On pleasant runtimes, we can create a Func<int> from a method returning + // an enum based on an int. That's the fast path. + if (CanConvertEnumFuncToInt32Func) + { + var del = (Func<T1, int>) method.CreateDelegate(typeof(Func<T1, int>)); + return message => del((T1) message); + } + else + { + // On some runtimes (e.g. old Mono) the return type has to be exactly correct, + // so we go via boxing. Reflection is already fairly inefficient, and this is + // only used for one-of case checking, fortunately. + var del = (Func<T1, T2>) method.CreateDelegate(typeof(Func<T1, T2>)); + return message => (int) (object) del((T1) message); + } + } + + public Action<IMessage> CreateActionIMessage(MethodInfo method) + { + var del = (Action<T1>) method.CreateDelegate(typeof(Action<T1>)); + return message => del((T1) message); + } + + public Func<IMessage, object> CreateFuncIMessageObject(MethodInfo method) + { + var del = (Func<T1, T2>) method.CreateDelegate(typeof(Func<T1, T2>)); + return message => del((T1) message); + } + + public Action<IMessage, object> CreateActionIMessageObject(MethodInfo method) + { + var del = (Action<T1, T2>) method.CreateDelegate(typeof(Action<T1, T2>)); + return (message, arg) => del((T1) message, (T2) arg); + } + } + + // Runtime compatibility checking code - see ReflectionHelper<T1, T2>.CreateFuncIMessageInt32 for + // details about why we're doing this. + + // Deliberately not inside the generic type. We only want to check this once. + private static bool CanConvertEnumFuncToInt32Func { get; } = CheckCanConvertEnumFuncToInt32Func(); + + private static bool CheckCanConvertEnumFuncToInt32Func() + { + try + { + MethodInfo method = typeof(ReflectionUtil).GetMethod(nameof(SampleEnumMethod)); + // If this passes, we're in a reasonable runtime. + method.CreateDelegate(typeof(Func<int>)); + return true; + } + catch (ArgumentException) + { + return false; + } + } + + public enum SampleEnum + { + X + } + + // Public to make the reflection simpler. + public static SampleEnum SampleEnumMethod() => SampleEnum.X; } -}
\ No newline at end of file +} |