moel@165: /*
moel@165:   
moel@165:   Version: MPL 1.1/GPL 2.0/LGPL 2.1
moel@165: 
moel@165:   The contents of this file are subject to the Mozilla Public License Version
moel@165:   1.1 (the "License"); you may not use this file except in compliance with
moel@165:   the License. You may obtain a copy of the License at
moel@165:  
moel@165:   http://www.mozilla.org/MPL/
moel@165: 
moel@165:   Software distributed under the License is distributed on an "AS IS" basis,
moel@165:   WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
moel@165:   for the specific language governing rights and limitations under the License.
moel@165: 
moel@165:   The Original Code is the Open Hardware Monitor code.
moel@165: 
moel@165:   The Initial Developer of the Original Code is 
moel@165:   Michael Möller <m.moeller@gmx.ch>.
moel@165:   Portions created by the Initial Developer are Copyright (C) 2009-2010
moel@165:   the Initial Developer. All Rights Reserved.
moel@165: 
moel@165:   Contributor(s):
moel@165: 
moel@165:   Alternatively, the contents of this file may be used under the terms of
moel@165:   either the GNU General Public License Version 2 or later (the "GPL"), or
moel@165:   the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
moel@165:   in which case the provisions of the GPL or the LGPL are applicable instead
moel@165:   of those above. If you wish to allow use of your version of this file only
moel@165:   under the terms of either the GPL or the LGPL, and not to allow others to
moel@165:   use your version of this file under the terms of the MPL, indicate your
moel@165:   decision by deleting the provisions above and replace them with the notice
moel@165:   and other provisions required by the GPL or the LGPL. If you do not delete
moel@165:   the provisions above, a recipient may use your version of this file under
moel@165:   the terms of any one of the MPL, the GPL or the LGPL.
moel@165:  
moel@165: */
moel@165: 
moel@165: using System;
moel@165: using System.Collections.Generic;
moel@165: using System.Reflection;
moel@165: using System.Reflection.Emit;
moel@165: using System.Runtime.InteropServices;
moel@165: 
moel@165: namespace OpenHardwareMonitor.Hardware {
moel@165: 
moel@165:   internal sealed class PInvokeDelegateFactory {
moel@165: 
moel@165:     private static AssemblyBuilder assemblyBuilder;
moel@165:     private static ModuleBuilder moduleBuilder;
moel@165: 
moel@165:     private static IDictionary<DllImportAttribute, Type> wrapperTypes =
moel@165:       new Dictionary<DllImportAttribute, Type>();
moel@165: 
moel@165:     static PInvokeDelegateFactory() {
moel@165: 
moel@165:       AssemblyName assemblyName = new AssemblyName();
moel@165:       assemblyName.Name = "PInvokeDelegateFactoryInternalAssembly";
moel@165: 
moel@165:       assemblyBuilder =
moel@165:         AppDomain.CurrentDomain.DefineDynamicAssembly(assemblyName,
moel@165:         AssemblyBuilderAccess.Run);
moel@165: 
moel@165:       moduleBuilder = assemblyBuilder.DefineDynamicModule(
moel@165:         "PInvokeDelegateFactoryInternalModule");
moel@165:     }
moel@165: 
moel@165:     private PInvokeDelegateFactory() { }
moel@165: 
moel@165:     public static void CreateDelegate<T>(DllImportAttribute dllImportAttribute,
moel@165:       out T newDelegate) where T : class 
moel@165:     {
moel@165:       Type wrapperType;
moel@165:       wrapperTypes.TryGetValue(dllImportAttribute, out wrapperType);
moel@165: 
moel@165:       if (wrapperType == null) {
moel@165:         wrapperType = CreateWrapperType(typeof(T), dllImportAttribute);
moel@165:         wrapperTypes.Add(dllImportAttribute, wrapperType);
moel@165:       }
moel@165: 
moel@165:       newDelegate = Delegate.CreateDelegate(typeof(T), wrapperType,
moel@165:         dllImportAttribute.EntryPoint) as T;
moel@165:     }
moel@165: 
moel@165: 
moel@165:     private static Type CreateWrapperType(Type delegateType,
moel@165:       DllImportAttribute dllImportAttribute) {
moel@165: 
moel@165:       TypeBuilder typeBuilder = moduleBuilder.DefineType(
moel@165:         "PInvokeDelegateFactoryInternalWrapperType" + wrapperTypes.Count);
moel@165: 
moel@165:       MethodInfo methodInfo = delegateType.GetMethod("Invoke");
moel@165: 
moel@165:       ParameterInfo[] parameterInfos = methodInfo.GetParameters();
moel@165:       int parameterCount = parameterInfos.GetLength(0);
moel@165: 
moel@165:       Type[] parameterTypes = new Type[parameterCount];
moel@165:       for (int i = 0; i < parameterCount; i++)
moel@165:         parameterTypes[i] = parameterInfos[i].ParameterType;
moel@165: 
moel@165:       MethodBuilder methodBuilder = typeBuilder.DefinePInvokeMethod(
moel@165:         dllImportAttribute.EntryPoint, dllImportAttribute.Value,
moel@165:         MethodAttributes.Public | MethodAttributes.Static |
moel@165:         MethodAttributes.PinvokeImpl, CallingConventions.Standard,
moel@165:         methodInfo.ReturnType, parameterTypes,
moel@165:         dllImportAttribute.CallingConvention,
moel@165:         dllImportAttribute.CharSet);
moel@165: 
moel@165:       foreach (ParameterInfo parameterInfo in parameterInfos)
moel@165:         methodBuilder.DefineParameter(parameterInfo.Position + 1,
moel@165:           parameterInfo.Attributes, parameterInfo.Name);
moel@165: 
moel@165:       if (dllImportAttribute.PreserveSig)
moel@165:         methodBuilder.SetImplementationFlags(MethodImplAttributes.PreserveSig);
moel@165: 
moel@165:       return typeBuilder.CreateType();
moel@165:     }
moel@165:   }
moel@165: }