diff options
Diffstat (limited to 'csharp/src/ProtocolBuffers/FieldAccess/ReflectionUtil.cs')
| -rw-r--r-- | csharp/src/ProtocolBuffers/FieldAccess/ReflectionUtil.cs | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/csharp/src/ProtocolBuffers/FieldAccess/ReflectionUtil.cs b/csharp/src/ProtocolBuffers/FieldAccess/ReflectionUtil.cs new file mode 100644 index 00000000..798f0dd7 --- /dev/null +++ b/csharp/src/ProtocolBuffers/FieldAccess/ReflectionUtil.cs @@ -0,0 +1,189 @@ +// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc. All rights reserved.
+// http://github.com/jskeet/dotnet-protobufs/
+// Original C++/Java/Python code:
+// http://code.google.com/p/protobuf/
+//
+// 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.
+using System;
+using System.Reflection;
+
+namespace Google.ProtocolBuffers.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 execute the given method and then return
+ /// the result as an object.
+ /// </summary>
+ public static Func<T, object> CreateUpcastDelegate<T>(MethodInfo method)
+ {
+ // The tricky bit is invoking CreateCreateUpcastDelegateImpl with the right type parameters
+ MethodInfo openImpl = typeof(ReflectionUtil).GetMethod("CreateUpcastDelegateImpl");
+ MethodInfo closedImpl = openImpl.MakeGenericMethod(typeof(T), method.ReturnType);
+ return (Func<T, object>) closedImpl.Invoke(null, new object[] {method});
+ }
+
+ /// <summary>
+ /// Method used solely for implementing CreateUpcastDelegate. Public to avoid trust issues
+ /// in low-trust scenarios.
+ /// </summary>
+ public static Func<TSource, object> CreateUpcastDelegateImpl<TSource, TResult>(MethodInfo method)
+ {
+ // Convert the reflection call into an open delegate, i.e. instead of calling x.Method()
+ // we'll call getter(x).
+ Func<TSource, TResult> getter = ReflectionUtil.CreateDelegateFunc<TSource, TResult>(method);
+
+ // Implicit upcast to object (within the delegate)
+ return delegate(TSource source) { return getter(source); };
+ }
+
+ /// <summary>
+ /// Creates a delegate which will execute the given method after casting the parameter
+ /// down from object to the required parameter type.
+ /// </summary>
+ public static Action<T, object> CreateDowncastDelegate<T>(MethodInfo method)
+ {
+ MethodInfo openImpl = typeof(ReflectionUtil).GetMethod("CreateDowncastDelegateImpl");
+ MethodInfo closedImpl = openImpl.MakeGenericMethod(typeof(T), method.GetParameters()[0].ParameterType);
+ return (Action<T, object>) closedImpl.Invoke(null, new object[] {method});
+ }
+
+ public static Action<TSource, object> CreateDowncastDelegateImpl<TSource, TParam>(MethodInfo method)
+ {
+ // Convert the reflection call into an open delegate, i.e. instead of calling x.Method(y) we'll
+ // call Method(x, y)
+ Action<TSource, TParam> call = ReflectionUtil.CreateDelegateAction<TSource, TParam>(method);
+
+ return delegate(TSource source, object parameter) { call(source, (TParam) parameter); };
+ }
+
+ /// <summary>
+ /// Creates a delegate which will execute the given method after casting the parameter
+ /// down from object to the required parameter type.
+ /// </summary>
+ public static Action<T, object> CreateDowncastDelegateIgnoringReturn<T>(MethodInfo method)
+ {
+ MethodInfo openImpl = typeof(ReflectionUtil).GetMethod("CreateDowncastDelegateIgnoringReturnImpl");
+ MethodInfo closedImpl = openImpl.MakeGenericMethod(typeof(T), method.GetParameters()[0].ParameterType,
+ method.ReturnType);
+ return (Action<T, object>) closedImpl.Invoke(null, new object[] {method});
+ }
+
+ public static Action<TSource, object> CreateDowncastDelegateIgnoringReturnImpl<TSource, TParam, TReturn>(
+ MethodInfo method)
+ {
+ // Convert the reflection call into an open delegate, i.e. instead of calling x.Method(y) we'll
+ // call Method(x, y)
+ Func<TSource, TParam, TReturn> call = ReflectionUtil.CreateDelegateFunc<TSource, TParam, TReturn>(method);
+
+ return delegate(TSource source, object parameter) { call(source, (TParam) parameter); };
+ }
+
+ /// <summary>
+ /// Creates a delegate which will execute the given static method and cast the result up to IBuilder.
+ /// </summary>
+ public static Func<IBuilder> CreateStaticUpcastDelegate(MethodInfo method)
+ {
+ MethodInfo openImpl = typeof(ReflectionUtil).GetMethod("CreateStaticUpcastDelegateImpl");
+ MethodInfo closedImpl = openImpl.MakeGenericMethod(method.ReturnType);
+ return (Func<IBuilder>) closedImpl.Invoke(null, new object[] {method});
+ }
+
+ public static Func<IBuilder> CreateStaticUpcastDelegateImpl<T>(MethodInfo method)
+ {
+ Func<T> call = ReflectionUtil.CreateDelegateFunc<T>(method);
+ return delegate { return (IBuilder) call(); };
+ }
+
+
+ internal static Func<TResult> CreateDelegateFunc<TResult>(MethodInfo method)
+ {
+#if !CF20
+ object tdelegate = Delegate.CreateDelegate(typeof(Func<TResult>), null, method);
+ return (Func<TResult>)tdelegate;
+#else
+ return delegate() { return (TResult)method.Invoke(null, null); };
+#endif
+ }
+
+ internal static Func<T, TResult> CreateDelegateFunc<T, TResult>(MethodInfo method)
+ {
+#if !CF20
+ object tdelegate = Delegate.CreateDelegate(typeof(Func<T, TResult>), null, method);
+ return (Func<T, TResult>)tdelegate;
+#else
+ if (method.IsStatic)
+ {
+ return delegate(T arg1) { return (TResult) method.Invoke(null, new object[] {arg1}); };
+ }
+ return delegate(T arg1) { return (TResult)method.Invoke(arg1, null); };
+#endif
+ }
+
+ internal static Func<T1, T2, TResult> CreateDelegateFunc<T1, T2, TResult>(MethodInfo method)
+ {
+#if !CF20
+ object tdelegate = Delegate.CreateDelegate(typeof(Func<T1, T2, TResult>), null, method);
+ return (Func<T1, T2, TResult>)tdelegate;
+#else
+ if (method.IsStatic)
+ {
+ return delegate(T1 arg1, T2 arg2) { return (TResult) method.Invoke(null, new object[] {arg1, arg2}); };
+ }
+ return delegate(T1 arg1, T2 arg2) { return (TResult)method.Invoke(arg1, new object[] { arg2 }); };
+#endif
+ }
+
+ internal static Action<T1, T2> CreateDelegateAction<T1, T2>(MethodInfo method)
+ {
+#if !CF20
+ object tdelegate = Delegate.CreateDelegate(typeof(Action<T1, T2>), null, method);
+ return (Action<T1, T2>)tdelegate;
+#else
+ if (method.IsStatic)
+ {
+ return delegate(T1 arg1, T2 arg2) { method.Invoke(null, new object[] {arg1, arg2}); };
+ }
+ return delegate(T1 arg1, T2 arg2) { method.Invoke(arg1, new object[] { arg2 }); };
+#endif
+ }
+ }
+}
\ No newline at end of file |